Fully charged lead acid battery specific gravity,best battery car vacuum cleaner india,used car batteries for sale in minneapolis area - How to DIY

16.06.2015
Lead acid batteries should be charged in three stages, which are [1] constant-current charge, [2] topping charge and [3] float charge.
The switch from Stage 1 to 2 occurs seamlessly and happens when the battery reaches the set voltage limit.
Once fully charged through saturation, the battery should not dwell at the topping voltage for more than 48 hours and must be reduced to the float voltage level. These described voltage settings apply to flooded cells and batteries with a pressure relief valve of about 34kPa (5psi). Aging batteries pose a challenge when setting the float charge voltage because each cell has its own unique condition. Measuring the open circuit voltage (OCV) while in storage provides a reliable indication as to the state-of-charge of the battery. Some buyers do not accept shipments of new batteries if the OCV at incoming inspection is below 2.10V per cell.
Watering is the single most important step in maintaining a flooded lead acid battery; a requirement that is all too often neglected.
The formation of gas bubbles in a flooded lead acid indicates that the battery is reaching full state-of-charge.
If your golf trolley is discharging your batteries when not being used, you must have a short circuit or partial short in the speed controller or wiring. I would like to ask you two questions regarding the process of charging sealed lead acid batteries, i would be so grateful for you for taking in consideration a simple answer as i am so far from the technology of batteries. 1)- I bought 2 new 6v 10Ah sealed lead acid batteries to use instead of the dead ones in my child’s ride-on, i also bought a simple wall charger which states that it charges at 1Ah, does this mean that to charge them for the 1st time i should leave them connected to the mains for 10 hours?
2)- I also have a 12v 1.5Ah charger, can i connect those 2 new 6v 10Ah batteries in series and charge them together and how much time would they take to be fully charged. More of a question:  Is it possible for a 6 volt charger to charge a automobile 12 volt lead acid battery to the point where it will have enough energy to start a car? Can i use Sealed maintenance free batteries instead of Electrolyte filled ( Distilled water recharge )lead acid batteries. For connecting the battery as a buffer I just nead to conect in parallel the battery with my device and the charger?
I have a two year old car battery which gives enough power to start my car when cold , but it refuses to crank the engine after the car runs for more than 10 kms. I tested this battery, It initially read 12.76V, and I had applied a top-up charge using a 600ma smart charger intended for smaller batteries. I connected a paralell series of 3x 15 ohm,  and 3x 22 Ohm, 10W resistors, with a 1 ohm 10W resister in series with the combination, to use as a current indicator.
As expected on connection, the voltage dropped very quickly, and the current was below what would be expected for the voltage. I believe this effect was due to thermal changes, and a delay in the chemical reactions in the battery, mentioned elsewhare in article on battery perfomance.
Most guides to rested open circuit voltage suggest that with an open circuit voltage of 12.26V, the battery is about 65% cahrged.
These statement would indicate that the battery is in good condition, and close to stated capicity. Is the rapid change in discharge curve normal, or does that indicate there could be a fault? This page is a good reference about lead acid Battery charging, but few points are incorrect, but not fatal mistake.
I set up a 50W network of resistors to create a loat to discharge them and graphed the in-circuit terminal voltage and current over a period of 25 hours.
The Terminal voltage initially dropped very quickly from it’s resting state, then took about 30 mins to stabilise.
The calculated AH removed from the battery and the open circuit voltage after the test both indicated about 40% drain re the stated 220AH capacity of the battery. How much charging current is required for charging above batteries in parallel connection condition. PS.This kind of discharging test is really not necessary and it is unwise because it will damage your battery. It is easy to charge with a higher voltage to a lower voltage, in your case, a 12V to a 6V.
The voltage of a lead acid battery when at rest (not supplying current or being charged) will vary according to how fully charged the battery is.
The graph shown to the right represents a typical 24 volt lead acid battery which has not been charged or had current drawn from it for a couple of hours. With further drawing of current, the rate of voltage drop slows down and will reach around 24.0 volts when the bettery is at half capacity.
As the battery approaches the fully discharged state, the voltage starts to fall more quickly again. It is important for a battery to never be fully discharged, so your inverter will normally disconnect the supply when the voltage is around 22 volts. An interesting point to note here is that when an inverter or other power load is drawing a high current from the battery, the voltage will drop.
The larger the battery, the smaller this voltage drop will be, and the greater the % of the charge will be useable when drawing high currents.
If a voltage is applied to the battery which is greater than the battery's voltage, a current will flow through the battery in the reverse direction to when it is supplying current, and the battery will charge. The rate of charge or current that will flow will depend on the difference between the battery voltage and the voltage that is applied to it (from solar panels etc). While it is beneficial to a battery's performance and life to be fully charged on regular occasions, however once a battery has been charged to it's full capacity, it is important not to continue charging as this will damage the battery. The Lead Acid battery is not 100% efficient at storing electricity - you will never get out as much as you put in when charging. The efficiency will depend on a number of factors including the rate of charging or discharging. However it has been found that if a battery is only partially charged, efficency may be reduced with each charge. Try our new Category View for Detailed topics segregated by their topic.Now it's even easier to find the information you need. You can also receive our Detailed Auto Topics, delivered to your computer, as soon as they are written.
Lead acid batteries have large capacities and are often available in many places around the world. Starter batteries are designed to deliver short, high-current bursts for starting the engine, and are designed to discharge only a very small part of their capacity. For solar charging applications, you instead want a deep cycle battery, similar to those used for marine vessels or golf carts – a typical car battery will not work. There are a few types of lead acid deep cycle batteries: flooded, sealed gelled, or sealed AGM.
I recently built a portable but powerful solar battery system to power some LED string lights, a stereo, and an evaporation cooler.
The final touch is to attach a cigarette lighter socket to the load terminal on the charge controller.
I used a similar system to build a solar powered cell phone charging station at the 2012 Dumbo Arts Festival. Can I use also by electrical devices without cigarette lighter connector with such a battery system? Hi Dave, You can use electronics that you would plug into your wall in your home (120Vac) with this setup, but you would need to use an inverter with your battery. Quite often when your battery stops charging you are left wondering why subsequent attempts at component replacement fail to cure the problem. Second, when talking about current, in the automotive field we more often mean conventional current which states that current flows from positive to negative. The charging system is made up of 3 components: (A) the battery, (C) alternator and (C') voltage regulator. The alternator charges the battery while the engine is running; without it, the battery would run down very quickly. How and when to charge the battery is determined by the voltage regulator which controls the current flow from the alternator to the battery.
Because the battery, alternator and VR are so closely coupled, figuring out which one is at fault can be difficult without following the proper diagnostic steps. In the wiring schematic you can see how the alternator is indirectly connected to the battery via the starter solenoid.
Because the battery is the easiest to test and the most essential, we'll figure out how to test it first.
The stock size battery for the bus is a Group 42 or Group 41 as rated by the Battery Council International (BCI). As you can see, of the two batteries the dimensions are very similar with the Group 41 being about 2" longer. Cranking Amps (CA) - How many amps that can be delivered in the same scenario but for 30s at 32F (zero C). Reserve Capacity (RC) - This is the time in minutes that the bus can be driven with the headlights on after the alternator fails. The rule of thumb with regard to battery selection is to favor CCA in cold climates and RC in warmer climates when comparison shopping.
As you can see the amount of running time you'll have at night will be slightly longer than the RC rating of you battery because the load is less than 25A specified by the standard. Beyond size, there are two basic types of batteries that are constructed differently: starter and deep cycle. Because we are so used to hearing about 12V automotive electrical systems, we tend to ignore the exact battery voltage.
When batteries go bad, the plates inside sulphate and interfere with the normal chemical reaction. It's also possible for vibration and deep discharging to cause the lead plates to shed their coating and eventually short out the cell. Low electrolyte levels and sulfation from deep discharging are reported to account for over 50% of battery failures yet they are easy to prevent. Once you turn on the engine and the alternator kicks in, the battery voltage will rise near 14V. Be sure to test the voltage at the battery posts and not at the clamps because there maybe corrosion that will affect the true reading. A seemingly good battery when tested for voltage can exhibit a large voltage drop under load. A battery like this will often spring back to a 12.xx voltage after you turn the lights off which demonstrates the importance of taking multiple voltage readings and watching the results while the lights are still on. It is much easier to notice these decremental voltage drops on a digital meter compared to an analog one. If you can't figure out why your battery is running down when your let you bus sit you may have a current drain issue. Anytime the current draw is greater than 35mA you should suspect an accessory or wiring problem. A lead acid battery is so named because it consists of lead plates and a sulfuric acid solution.
If you have a sealed battery it will often have an indicator on the top that indicates the battery state of charge along with a legend to read it. Many batteries are not sealed and you have to check on the electrolyte level by popping the sealing caps. The filler caps are designed to let hydrogen gasses escape and allow the acid mist to condense and drop back into the battery. The state of the electrolyte is measured using a hydrometer which measures the specific gravity of solution. Specific gravity (SG) is a term from chemistry that indicates the weight of a solution relative to water which is given the value of 1.000.
If the difference between the higher and lowest value from all six cells is greater than 0.050 you also have a bad battery. Be sure your battery is secured properly: vibration has been known to cause them to fail prematurely. If you've determined your battery is dead and is too weak to start the engine, you've got to charge it. Connect the -ve jumper cable from the good battery to the engine block or a good ground away from the dead battery to avoid sparks. Your VR won't be able to tell you've got a good or bad battery while connected to the other booster car. Remember to always disconnect the ground cable if you are going to charge the battery in the bus to avoid voltage spikes and limit the voltage that is seen by accessories because the chargers operate above 14V during some of their charging phases. While voltmeters and hydrometers are good diagnostic tools, once you determine that your battery is at least 75% charged, it's safe to load test without further charging.
If you still aren't sure if your battery is bad after testing and attempting to recharge, you can have it load tested at the local auto parts store. Most of these load testers are NOT compatible with the newer AGM style batteries like Optima. Midtronics is a company that makes a new kind of battery tester that is starting to appear at auto parts stores. As the battery terminals corrode, the electrical resistance that builds up is enough to impede both the charging and starting system. A majority of charing and starting difficulties can be traced to the wiring in the form of corrosion or damage to terminal or sometimes it's as simple as loose connection. When measuring resistance you want to first determine what reading you get by simply touching the probes together.
In addition to the braided cable connecting the battery negative to the body you must also check the transmission ground strap that connects the starter (via it's casing) to the body. Heavy corrosion can be neutralized and cleaned with a wire brush and a solution of baking soda and water.
When terminals are clean and dry, reattach the cables and coat the terminals with petroleum jelly or a special purpose battery terminal spray. Some people insist that you replace the entire cable but that depends on the condition of the cable and if they sell cables! In addition, you need to make sure you've got good continuity between between all the starter terminals because if you can't start you can't charge either. Lastly, the battery case itself should be clean because voltage can leak from the positive terminal to the battery body to ground through the dust and acid that collects on top. Before I explain how to test the voltage regulator and alternator I need to explain how both work. The alternator charges the battery by reversing the current flow through it and reversing the chemical reaction inside as a result.
If you let your old beetle idle, the battery tends to run down more easily with a generator.
An alternator consist of a moving coil of wire called the rotor and a stationary coil of wire called the stator. DC current is supplied to the rotor by the voltage regulator and this generates a current in the stator. To make the alternator more efficient, three sets of wires make up the stator and because of the way they are wrapped, voltage is produced in 3 separate phases much like transmission in city power lines.
The shape of the rotor is a claw-pole design consisting of an magnetic iron shell that keeps the wiring inside from flying out (exploding) at high rpms. Just above the idle speed is the cut-in speed at which the alternator begins to deliver current for the first time. There is also a speed rating for the maximum current output, typically 6000 rpm (3000 engine rpm) and there is a maximum rpm at which the alternator can spin which is dictated by the roller bearings and carbon brushes inside as well as the fan because it take power to pull air through. Finally, the alternator can't run all day long at 100% duty cycle (80% is more reasonable) so you should factor your current load requirements with that in mind. The earliest voltage regulators installed on baywindows were mechanical relay based devices but they have been replaced by longer lasting more accurate solid state versions.
In the diagram the left image shows the basic wiring layout and the 3 diagrams on the right show how current flows in the 3 stages of operation.
The blue wire leads to the warning lamp in the instrument panel and the red wire at B+ leads to the battery (via the starter solenoid). In stage 2 (alternator on) the engine has started, the alternator spins up at 2x engine speed and near the alternator's zero-ampere speed (around 500 engine rpm), it begins to produce voltage at B+ through one set of diodes which is fed to the battery and also to D+ which is picked up at the voltage regulator. The voltage at D+ is fed to DF by the VR and the increasing magnetic field in the rotor induces an alternating current in the stator which is rectified into DC and fed to the battery via B+. In the 3rd stage (alternator idle) the output voltage has reached the 14V set point at which time the relay (coil) inside the regulator energizes and breaks the contact inside which connects D+ and DF and shunts DF to ground via D-. As the voltage drops at B+, the relay contacts re-open and the VR cycles to stage 2 and the process begins all over again. When the regulator fails, the battery is either a) in danger of being overcharged or b) fails to charge. If the lamp is not coming on when you turn the key to on you need to verify that the bulb is good. To test the regulator you need a voltmeter and a set of probes that can reach into the underside of the connector to touch the terminals. It takes very little time for the engine to spin the alternator fast enough to generate full output voltage.
If the VR seems to be charging the battery correctly then a full-field test of the alternator should be performed. Inside is a field coil (solenoid), a choke and a pair of contacts that resemble a set of Bosch ignition points.
If you have the later style VR with a real power transistor mounted on the bottom (solid state), then your readings will be very different so don't worry. On the bottom is a thermal resistor that drops in resistance as the intake temperature decreases. It's not possible to test the thermistor without switching the contacts inside because the current from your ohm meter takes the path of least resistance which is between D+ and DF. If the regulator checks out, then you need to perform a full-field test of the alternator to rule the VR out completely. Engine on - attraction means magnetic field is present so brushes and rotor are making good contact.
Be sure to test that the screwdriver has no residual magnetic pull before you test it against the alternator. A Bosch alternator has 9 diodes: 3 negative and 3 positive power diodes form the full-wave bridge rectifier that convert AC to DC. Disconnecting the battery while the alternator is running can fry the diodes inside so never do that even when the engine if turned off. If the alternator checks out electrically, you still need to inspect the parts so you don't get stuck on the road. If you have been researching solar system you would have come across two terms quite frequently.
One of the interesting things I learnt in the early days was a single battery cell (what I am describing below) has a nominal voltage of 2 volts. As the battery cell is discharged, electrons migrate from the positive post to the negative plate, which produces a conventional current flow from the positive to negative.


The final result of a fully discharged battery is lead sulfate deposits on both the positive and negative posts and the sulphuric acid diluted right down. I dont think you will be to surprised to hear the recharge process is exactly the opposite to the discharge process. Some interesting things do occur if you keep charging the battery cell past is fully charged state; basically the electric current starts the split the water into hydrogen and oxygen. Stand alone power systems require a special type of battery known as a deep cycle battery, these batteries are designed to be fully discharged many times.
A normal lead acid battery (like your car battery) will only allow you to take about 20% of its stored power, after that point it is permanently damaged; it doesnt take long before the battery is rendered useless. I have chosen to specifically pick out Flooded cell and Gel cell lead acids for discussion, because these are the batteries you will be buying. Gel cells are all the rage in standalone power systems these days, they are a lot more expensive but they do not require any maintenance, you dont need to add water to these batteries. There is another battery type that is also a VRLA battery, and it is not suitable for standalone power systems; the battery is called an Absorbed Glass Mat (AGM) battery.
Batteries capacity is measured in Ampere Hours (Ah), it is the discharge current (in Amperes) multiplied by how long (in hours) the battery can sustain that current. The tricky bit is that a batteries capacity (in Ah) changes based on the actual current being drawn from the battery.
So lets say you have a planning to put 6 x 2V, 1000Ah batteries in series to store your energy. This means your battery bank voltage will be 12 volts and you have nominally 1000Ah of available capacity.
The chart above shows the relationship between Depth of Discharge (DOD) and the cycle life of the battery. These valve regulated sealed lead acid (SLA) batteries are great in applications where current drain is high, such as Radio controlled Boats, spill-proof construction allows trouble-free, safe operation in any position.
A regulated current raises the terminal voltage until the upper charge voltage limit is reached, at which point the current drops due to saturation.
The constant-current charge applies the bulk of the charge and takes up roughly half of the required charge time; the topping charge continues at a lower charge current and provides saturation, and the float charge compensates for the loss caused by self-discharge. The topping charge is essential for the well-being of the battery and can be compared to a little rest after a good meal.
A warmer ambient requires a slightly lower voltage threshold and a colder temperature prefers a higher setting. This is especially critical for sealed systems because they are less tolerant to overcharge than the flooded type.
Cylindrical sealed lead acid, such as the Hawker Cyclon cell, requires higher voltage settings and the limits should be set to manufacturer’s specifications. Connected in a string, all cells receive the same charge current and controlling individual cell voltages as each reaches full capacity is almost impossible. A voltage peak constitutes an overcharge, causing hydrogen evolution, while the valley induces a brief discharge that creates a starved state resulting in electrolyte depletion. The results are inconclusive and manufacturers as well as service technicians are divided on the benefit.
Another method is the hysteresis charge that disconnects the float current when the battery goes to standby mode. A low voltage suggests a partial charge due to long storage or a high self-discharge caused by a micro-short. Battery University monitors the comments and understands the importance of expressing perspectives and opinions in a shared forum. If they discharge too quick during use only, it sounds like they are too small a capacity for the job. If the current I am taking is constant is imposible to do this, because my charger will never be able to charge the battery? Can I use one charger of 1000 mAh output to charge all 3 batteries in parallel and then keep them on a maintenance charge till neded?  Or will I need to charge them one at a time. I am not sure what is really you question is, but you can’t change a 12v using 24v power supply. I set out to test them to determine if they are working correctly for a 2 year old battery. It dropped slowly over the next 16 hours (to about 12V, then fell much more quickly over 8 hours to about 11V.
The easiest circuit requires just 1 electronic component which is a 7807 regulator (7 volt regulator). Since you have a 500mA charging current, you can’t continually use more than 500ma for 13 hours.
To simplify what I have said above, the answer to your question is yes, but if you continually use more power than you have provided from the charger, then the battery will eventually drained. Particularly How much they are applying the Excess percentage to the Practical Applications. Is it Possible to find out the Value of S.G with Voltage before Charging what will be the Values if them corresponding to our Charging Current with duration. As current is drawn off and the level of charge is reduced, the voltage will fall quite quickly at first (again it would be necessary to stop drawing current for a couple of hours to be able to measure the true voltage of the battery). This may mean that the battery needs to be somewhere over 50% charged to avoid the inverter cutting out due to low voltage.
Solar panels intended for a 24 volt system are likely to be capable of producing over 30 volts. With the battery at half charge or less, the charge efficiency may be over 90%, dropping to nearer 60% when the battery is above 80% charged. If this situation persists (the batteries never reaching full charge), the life of the battery may be reduced. A daily cycle of using most the capacity would corrode a car battery very quickly, the plates and the chemistry are designed to stay nearly 100% fully charged most of the time. Deep cycle batteries are designed with larger plates and different chemistry to avoid the corrosive effect of frequently using the full capacity.
It is important to maintain a full charge when ever possible, because it will extend its life and maintain a higher efficiency. The Trojan 22-AGM batteries are similar in size to the Xantrex PowerPack, but it does not have all of the extra features listed above. This allows you to draw a load directly from the solar panels when there is enough sunlight or from the battery when there is no solar production. In this project we used two of the Voltaic 16.8 Watt, 18 Volt solar panels, which were embedded into a dodecahedron shaped sculpture. In addition to making cool things with solar, he does consulting on alternative energy and is pursuing his Master’s Degree in Manufacturing Engineering at NYU Poly. I've provided a set of detailed steps to follow to help you determine which parts have failed. First, VW wiring systems are negative ground which means that the negative post of the battery is connected to the vehicle body. In reality, electrons (which are the charge carriers) flow from negative to positive but the conventional system is illustrated in more texts (a hold over from the early days of science). The battery is the heart of the system that produces voltage and provides storage for electrical current. Although the alternator is a source of current, you might think that once you start the engine you could disconnect the battery but the system is not designed to operate that way.
The alternator tries to power the electrical system and charge the battery at the same time but because the alternator's output is somewhat dependent on the engine rpm, when loads are high the battery can instantly supply more current when necessary. You can also see how the ignition switch is battery powered and activates the warning lamp which serves a dual purpose: it completes a circuit that also energizes the alternator via the voltage regulator even before the engine has been started. These are European style batteries: they look the same but the terminals are reversed compared to an "American" battery.
Always apply the minimum BCI group ratings in your selection process before you elect to choose another battery group that fits the battery clamp so you don't end up picking an underpowered battery.
A deep cycle battery can be discharged almost completely and recharged over and over but only with moderately low current draw. They are not designed to recharge a dead battery so you must test the battery before you attempt to diagnose the rest of the charging system. This is because the bond between the sulphate and the plate requires more electricity to break than can be generated thru normal charging.
Since the battery electrical chemistry is based on surface area, it becomes weaker in the same way that a low electrolyte level cause the battery to underperform (low voltage and low current capacity). Before taking any readings, with the engine off, turn on the headlights for 15 minutes to remove any surface charge from the battery then turn the lights off and take your measurements. The higher voltage is necessary to charge the battery (push the electrons against the battery voltage).
A battery with a higher level of surface charge would show a much lower final value after the headlights had put the battery under load so you can see why testing the initial voltage isn't sufficient. The factory clock and draws only a few mA and if you have a stereo it might draw some current to keep it settings. The best way to attempt to isolate the issue is to pull fuses one and a time and watch your ammeter to see where the largest drop in current occurs.
Some sealed batteries will let you open them but only attempt this if there are caps on top.
More often that not the electrolyte level is too low from the heat having evaporated the water inside the battery.
Keep the area around these caps clean and do not allow any contaminants to fall into the battery. You may be able to fill, recharge and return the battery to normal but you will find that it slowly discharges and strands you within 2-3 months. You insert the hydrometer into the cell, squeeze the bulb to suck up the electrolyte and take the reading at the eye level of the fluid. The ones with colored balls or a floating strip are hard to read the exact specific gravity. It is because a) the acid solution already had some water content and b) those number are based on a standard temperature which is much lower than the ambient temperature that you are taking your measurements at.
Sometimes a cell fails completely and naturally results in a substantial total voltage drop (either 0V or any reading below 11V) so again it's time to replace that battery.
Once you disconnect, run your engine at speed for 30 minutes or so and will you be able to determine if your battery is charging properly by turning it off and attempting to restart. These are great for keeping shelf batteries charged because they slowly drain down on their own.
If you wait 5 minutes after the test the battery should regain it's 50% charge voltage level. They will often use a carbon pile based load tester that simulates a large current like a starter would draw.
AGM stands for Absorbed Glass Matte and the electrolyte is suspended in a gel so the battery doesn't leak. It's made by Johnson Controls (one the largest battery manufacturers) and is the closest yet to a leakproof design.
A small 0.1 ohm resistance at the battery terminals can reduce the starter's output by 92% because of the enormous current drawn. Either way, you are bound to experience this on a 25-30 year old vehicle like a baywindow bus.
Start by measuring the resistance between the terminal and the battery posts and then each end of the cable. Turn on the headlights when testing the voltage because a load on the battery will make voltage drops easier to witness. Wires and internal components that are part of your meter have resistance that you have to account for in your measurements. A large enough voltage drop there will also cause starting difficulties (more about this below).
Lead based terminals should be avoided because they don't hold their shape and corrode badly. A simple terminal replacement like this can bring your electrical system back to life and prevent the unnecessary purchase of a new starter or alternator. This means that unlike DC generators it produces AC and turns it into DC instead of producing DC directly.
A slip ring on the rotor is in continuous contact with a pair of brushes as it spins which connect the rotor to the voltage regulator. There is a zero-ampere speed at which the alternator reaches its rated voltage before it can generate any current. The exact speed depends on the battery voltage, voltage from the alternator warning light (pre-excitation power), the rate of change of rotational-speed and the magnetic remanence of the rotor's magnets. On average this limit is 20,000 rpm (10,000 engine rpm): much higher than any stock VW engine can reach and any that do are drag racers who have no need for an alternator (substitute a dry cell battery or magneto powered ignition system). Both styles are configured to produce 14V from the alternator and no more, hence their namesake. Yellow arrows indicate small current flow while orange arrows indicate a larger current flow. Using the legend in the wiring diagram section of Bentley's electrical chapter, you can learn to read the VR internal wiring schematic: inside is a relay controlling two contacts and a few resistors.
The first stage (key on) initiates when the ignition key is turned to the on position but before the engine is started (alternator off). The voltage at D+ follows B+ but varies slightly because D+ receives its signal from the stator through a separate set of diodes. It's also interesting to note that the zero-ampere speed is largely determined by the power rating of the warning lamp.
The output voltage varies according to the input voltage (fed back into the rotor by the VR) and the engine rpm. While the majority of current flows to ground, a small current is fed through the rotor so the alternator isn't completely turned off. At low rpms the field voltage can be set high to help the alternator keep the battery charged because it's less efficient at low rpms.
When the battery voltage is low (high current drain) the rotor voltage is increased to increase the output. When the voltage level is too high most batteries will give off gas as the sulphuric acid and water in the electrolyte decomposes into hydrogen and oxygen. To change the bulb you don't need to remove the instrument cluster but I would advise you to disconnect the battery before you accidentally short out the instrument panel and smoke the instrument wiring harness or start a fire. Undo the right-side mounting screw and the let the VR rotate 90 CW so you can more easily access the underside of the connector. If you try to measure the AC voltage at DF with the engine running you should see only a few mV. If you have to rev the engine to get the warning light to go out you will probably confirm an alternator problem by measuring a battery level voltage at D+ with the key on and the engine off. The purpose is the alter the charging set point because batteries can be charged to higher voltages in the cold. This involves, disconnecting the plug from the VR and connecting the battery positive via patch cable (preferably at the B+ terminal on the alternator) to the DF (green wire) terminal of the plug.
You need to disconnect the harness plug from the alternator to test the resistance of each wire.
I recommend using the same colors and be sure not to get the colors mixed up when you reattach the terminals to the plugs or you'll smoke the alternator. If there is little or no pull on the screwdriver, unplug the VR and short the red and green wires together. The alternator should produce 90% of its rated output during the test to be considered good.
When you drive the alternator with full input voltage at DF you risk damage to it unless the test is brief.
You should not do this in order to test the alternator by seeing if the car still runs or by checking the voltage at the battery. Often the bearings are so old that the grease inside has dried up, become contaminated or no longer contacts the bearings. With the engine running your cannot hear the noise from worn brushes although you can hear it when you spin the rotor by hand as well as see it on an oscilloscope.
A 12 volt battery is actually made up of 6 individual cells tied together in series to create the 12volts. The electron migration occurs as a result of the Lead oxide, sulphuric acid, and lead reacting together.
The lead sulfate is removed from the positive and negative post and lead oxide is re deposited back onto the positive post, as well as the sulphuric acid intensifying.
The process of continually charging past the point of full charge is called gassing (because hydrogen and oxygen gas is created).
When a retailer tells you the battery is a 250Ah battery they are normally quoting the C10 rating of the battery. You can see that if I take 100% of the energy out of the battery I will only be able to do it 1500.
It technically holds 12kWh of energy, but to make sure we get a long life out of the batteries we can only really access about 3.6kWh of that energy on any give day. If continually deprived, the battery will eventually lose the ability to accept a full charge and the performance will decrease due to sulfation.
A battery with high leakage may never attain this low saturation current, and a plateau timer takes over to end the charge. Chargers exposed to temperature fluctuations include temperature sensors to adjust the charge voltage for optimum charge efficiency.
Charging beyond the specified limits turns redundant energy into heat and the battery begins to gas.
Failing to apply the recommended voltage will cause a gradual decrease in capacity due to sulfation. If sulfation could be measured and the right amount of pulsing applied, then the remedy could be beneficial; however giving a cure without knowing the underlying side effects can be harmful to the battery. Using OCV to estimate state-of-charge works best when the battery has rested for a few hours, because a charge or discharge agitates the battery and distorts the voltage.
Battery users have found that a pack arriving at a lower than specified voltage has a higher failure rate than those with higher voltages. A naked plate will sustain irreversible damage through oxidation, leading to reduced capacity and lower performance.
Do not fill to the correct level before charging as this could cause an overflow during charging. However, all communication must be done with the use of appropriate language and the avoidance of spam and discrimination. We recommend posting your question in the comment sections for the Battery University Group (BUG) to share. How there are calculating the Capacity (Ah) in Theoretical Manner and how they are applying the Practical Ah to the battery.
Diagnosing repeat battery failure is easier with an understanding of how they operate.A battery is usually considered dead when it fails to crank a vehicle. I recommend using sealed AGM lead acid batteries wherever possible and will describe in this post the trade-offs of using different battery types with portable solar panels.


Always use a charge controller with solar panels, so they don’t over charge the battery or apply the wrong voltage. The Xantrex PowerPack comes with a built-in AC inverter, surge protector, low voltage disconnect (LVD), and can be wheeled around. The cell phones all charged from the DC side of the battery with cigarette lighter chargers. This may seem natural but positive ground systems exists (like vintage British made Jaguars) which can be confusing to people who have worked on the opposite system.
You should not run the engine without the battery connected especially if you have FI or sensitive electronics that always expect 12-14V. It's the electrical "shock absorber" in the system which is essential a huge capacitor (measured in F not uF!). Generally battery tests are simple but determining whether the alternator or VR is at fault can be complicated unless you understand how they work. What's important to note from the beginning is that there are a lot of electrical contacts involved.
When handling batteries, use all precautions because the contents are a highly corrosive potentially explosive poison. For Europe, positive is on the right and negative on the left with the terminals facing towards you.
While driving, a 3A load is below the typical current draw which is why batteries run down so easily. As you can see the group 42 is going to last about an hour if your alternator fails at night where as the slightly large group 41 will last 50% longer. The last entry in the table is the most interesting as it shows the alternator powering all of the electrical loads (minus the lights) while charging the battery at the same time. Each cell, contains positive lead plates that are coated with lead and negative plates that are coated with lead dioxide. Simply leaving a battery on the shelf for a month will cause a light level of sulfation that can be reversed by recharging. The voltage should hold fairly steady on a good battery while the lights are on but would 0.01V drop every 1-2s on a weak battery.
These accessories are called parasitic loads and they will eventually drain your battery down to the point that it cannot start your engine. From there you can examine the wiring diagram for that part of the wiring harness to try and pinpoint the problem. If you get this solution on your clothing it will eat through it so always be careful around an open battery. Because the battery has large plates inside any portion of the plates not covered by electrolyte, will not participate in the electrical reaction.
As the battery discharges, the sulphate ions in the solution combine with the lead plates and the solution becomes weaker. Luckily this variation is small enough that you can largely ignore it unless you are performing your tests at temperature extremes. If you don't understand the manufacturer's spec on your battery you may damage it by supplying too much current. The power to the headlights is also reduced by 32% which reduces the visual intensity by more than 50%. Any other electrical connection in the undercarriage that is protected by a boot is usually in great shape after 25-30 years.
Fully testing the alternator requires an understanding of how it operates and when it generates voltage and current. This is unlike the mechanical switching that occurs in the commutator of a generator which is limiting.
Current flows through the windings of the rotor and the exact amount flowing determines how much current is induced in the stator following the laws of electromagnetism.
If you've started your engine and "heard" the alternator slow down the engine at the beginning of fast idle warm-up this is the cut-in speed heard in action. This inverse relationship between the voltage regulator and the alternator is all that's required to keep the battery charged and the electrical system powered most of the time. The mechanical versions are the easiest to understand so I'll skip the details of the microcontroller and NPN power transistor wiring in the solid state version. Power from the ignition switch flows through the warning lamp and through the rotor field winding in order to excite the alternator. The diodes inside the alternator protect it from the battery at all times during these switching operations.
All this happens instantaneously as the solid state VR monitors the battery and alternator as the electrical load and rpms change.
What is often misunderstood is the back of the instrument cluster is not made from a single piece of metal.
A reading of 1-2V reading at both D+ and DF after the engine starts indicates a diode problem in the alternator.
When the ignition is on, battery voltage at D+ comes from the ignition switch and flows through the points to the rotor. Similarly when they get too hot, the set point is lowered in order to keep them from boiling over. Now turn on the key and this will provide the rotor with a direct 12V field which should increase the magnetic pull.
In the photo you can see the technician at the rebuild shop just uses a large electric motor to spin up the alternator. The last 3 are the ones that control D+ on the voltage regulator but most auto part stores have no inclination of testing them: they apply a voltage to DF, spin it up, the alternator puts out 90-100% rated amps at B+ and they say it's good but that test doesn't prove the alternator is working correctly!
If the test is skipped, you may simply get back home with your alternator, reinstall it, replace the regulator on the advice of the auto parts store and still have charging problems.
The battery also acts like a huge capacitor that smoothes out the power delivery from the alternator.
In there is excessive endplay it means that the rotor is not press fit to the bearing anymore or the drive end bearing retaining cap has come loose and the bearing is no longer press fit to the drive end plate (housing). Bearing grease can dry out long before the expected life of the bearing is reached, so you may have worn bearings after 100k miles if your alternator sat unused for many years. When the springs are fully extended (about 4-6mm of wear) they no longer make good contact with the slip-rings. You can turn the slip rings if they are not too worn but the mileage of the alternator will depend on how much copper is left. Both types of batteries are of the Lead Acid variety, we will talk about each of them in more detail later.
The negative plate is Lead with no coating (technically the terminals are not pure lead, they are always alloyed with something to improve their electrical and mechanical properties). The battery has a filler cap that allows you to add distilled water to the cells as the acid levels get low.
Deep Discharge Recovery Special separators, advanced plate composistion, and a carefully balanced electrolyte system have greatly improved the ability to recover from excessively deep discharge. A float current that is too high for the faded cell might sulfate the strong neighbor due to undercharge. Although in-house service can often bring such batteries to full performance, the time and equipment required adds to operational costs. Old batteries loose capacity but yours should be in good condition being only one year old. Little current will take forever to fully charge it up, so you can safely charge it using 10A. This is more efficient than using the AC inverter because we are simply stepping down the voltage from 12Vdc to 5Vdc. When you are trying to start the engine, the battery powers the starter and ignition system. When the alternator is spinning at high rpm it is easily producing enough electricity to meet all of the current requirements.
If you purchase another group battery for your bus, the cables might not reach if you flip it around so the terminals face the body, especially on a 73-79 bus. Whenever the battery reads 11.99V or lower it is basically a "dead" battery that has lost almost all of its charge. When the battery is connected to a load that causes current to flow, the hydrogen and sulphate ions in the electrolyte combine with the plates to form lead sulphate which form as crystals. The longer the battery size that more layers of crystals build up and eventually the battery dies. After 15min if the battery voltage is in the 9.xx range and still dropping you can be sure that it is time to replace the battery because it cannot deliver power for electrical loads anymore.
Connect your ammeter between the battery negative cable and post to test for excessive loads. It's very important to keep the hydrometer clean otherwise you will contaminate the electrolyte and the mineral deposits will interfere with battery cell operation. When you finally turn off the engine, you should check the voltages and SG again to confirm if the battery has been partially restored to health. If you use the motorcycle units to charge a car battery they will taken a long time but still work effectively (good to know if you have both types of vehicles because the average auto charger will over-charge a motorcycle battery). This tester measures the conductance of the battery instead of simulating a real load like the carbon pile testers. They cost more than a normal battery but they also last longer because they don't lose water long before you've noticed with a regular battery.
They don't corrode and provide a soldered moisture proof connection from the cable to the terminals.
The constant contact is possible because the solid state power diodes in the rectifier circuit of the alternator provide the current polarity switching function. The frequency of the AC is derived from the speed of the rotor which is governed by the engine speed. Precisely metering the output current is the job of the voltage regulator which monitors the battery voltage to determine its load and state of charge. I came up which the second figure because the alternator pulley on the bus is half the size of the engine fan pulley and so the alternator spins at twice the engine speed.
It's hoped that a) any sudden changes are absorbed by the battery b) a 10V "dead" battery won't be present to force the alternator to run 100% duty cycle trying to charge it. You don't not want any sparks to occur when this is happening which is why the jump starting tips recommend that you connect the negative jumper cable to a good engine ground away from the battery negative post. You will see ~5V on a fully charged battery and up to 12V as the SOC of the battery decreases.
You'll find that the mechanical voltage regulators have trouble keeping the voltage right at 14V when the system is under load. It should read about 2.3 ohms at 68F and decrease with temperature (a quick blast of cold spray will confirm).
This should only be done for an instant because the voltage coming out of the alternator will be unregulated but it will determine if the VR needs to be replaced or if the alternator is at fault. Corrosion is usually heavier on the alternator side but you should also examine the voltage regulator plug including the wiring that leads to the indicator light on the dash. They all seem to have this kind of home made setup and usually have some hard to read oscilloscope.
Too much gassing is bad, however gassing of batteries does have some benefits which we will talk about later. Cell-balancing devices are available compensate for the differences in voltages caused by cell imbalance. As stated above, a fully charged 6 cell battery shows about 12.65 Volts when fully charged whether it is a small car battery or a massive forklift truck battery. A dead battery in cold will work after it warm up, so be sure to know that Voltage reading is not accurate in winter time.
Other task include, subsidizing the alternator at low engine speed, preserving memory for the onboard computers and keeping system voltage closely regulated. Flooded batteries have the advantage of being significantly less expensive, but they require adequate ventilation, maintenance, and also have the potential liability of tipping or spilling.
Also, by avoiding the use of the AC inverter, we don’t need to convert the DC to AC and back to DC again.
It also energizes the alternator which begins to produce its own current when the alternator nears the engine's idle speed. Note that the 68-72 models have the battery cables reversed (ground strap is behind the taillight) so you could use a US battery.
Because it's not deigned to deliver high current loads for short periods of time to run the starter. As the electrolyte becomes devoid of ions, it becomes weaker and the ability to pass current lessens. If you overfill them, they make leak on you if the battery boils over from being overcharged.
The conductance (inverse of resistance) changes as the surface condition of the plates inside change.
They can also deliver a huge amount of starting current compared to a normal battery because they have a very low internal resistance of 3 milliohms. The large terminal where the battery (black) and alternator (grey) cables meet is terminal 30. Six volt electrical systems were even worse: the headlight output would increase as you revved the engine because the generator was so poor and providing current to keep the battery charged at idle. This also means that no output current passes through the brushes to wear them out prematurely.
Next in the series of important events during alternator spin up is the idling speed: typically at 1500 rpm (750 engine rpm) the alternator must be able to satisfy the needs for long term consumers (basic electrical demands) without running down the battery. These are two reasons that solid state regulators are so much better: the better ones are microcontroller based and understand a lot more about the state of the electrical system than a simple relay.
You'll see a tab on that insulated section to provide 12V just for those lights instead of the usual ground.
When the engine is off it will also depend on the battery voltage (SOC + electrical load) and the reading will be less than 1V. To remove the cap, simply cut the tape in the middle all the way around with a utility knife and carefully wiggle the top off. When the alternator starts producing the 14V set point voltage, the coil energizes, breaks the contacts and the field current goes almost to zero. Use a pick and bend the tabs inside from the front to remove the uninsulated terminals from the rear. Watering systems eliminate low electrolyte levels by automatically adding the right amount of water.
Lead acid batteries must always be stored in a fully charged state and be periodically recharged even when not in use. It is best if u built ur own charger, or you really want to get a more expensive smart charger.
When the battery is recharged (current reversed) the lead sulphate returns to solution leaving lead behind on one plate and lead dioxide on the other. All batteries have some internal resistance inside and the microprocessor inside the tester put the battery through a series of tests before rendering a decision.
You just have to make sure you invest in one from Bosch (0 192 062 007) pictured right and not a piece of junk from Autozone.
As a side note, even though the alternator output is rectified from AC to DC, some of the AC leaks through the diodes and appears as a DC ripple. If your engine is fuel injected I recommend that you take the alternator to an alternator repair shop for a full field bench test instead (tests are usually free). Badly corroded terminals can be replaced easily because this harness tends to have a lot of slack in it. The lead acid battery operates by a chemical reaction between the sulfuric acid in the electrolyte, and the metal plates.A fully charged battery has positive plates, made of lead peroxide. Do not connect your ammeter if you are not 100% sure that the current draw is less than the current rating of your ammeter if you are not using a current clamp and instead measuring it directly. Because its results are table lookup based, if it asks for the CCA of the battery and you can't find it on the battery label you won't be able to test it and depend on the results. The latter contains an underpowered switching transistor and only about $1 worth of electronic parts inside. As the battery discharges, oxygen (O2) molecules in the lead peroxide, are displaced by the sulfur (SO4) from the sulfuric acid. Sulfur converts the plates to lead sulfate (PbSO4) and the oxygen combines with the acid to form water (H20).
When this occurs the battery is discharged and no longer produces the needed electricity.Recharging the battery immediately after discharge reverses the process. Allowing a battery to remain discharged, even for a short period will shorten the life considerably.
Sulfates on the lead plates become extremely difficult to remove if allowed to remain in place. If not removed, they insulate the lead from the acid and the battery loses capacity.A similar situation occurs if the electrolyte becomes low.
Most often this is the result of overcharging, as with a bad alternator or exposure to extreme heat.Temperature has a dramatic affect on a battery. Higher temperatures will increase output, but also shorten battery life.Colder temperatures slow the chemical reaction and reduce battery output. A battery reduced to 80 percent capacity by summer heat, may fall below 50 percent on the first cold day.
Even a battery with 100 percent capacity at 80 degrees, will only produce around 65 percent of its capacity at 32 degrees Fahrenheit. Hot weather does the damage and cold weather reveals it.Parasitic draw robs life from a batteryParasitic draw is current that continues to flow, even when the vehicle is switched off. Everyone is familiar with the result of leaving headlights on or leaving lights on inside the vehicle. If one or more computers remain on, due to a malfunction, the current draw can easily increase ten fold. If the discharge is not too severe, the alternator may restore much of the power when the vehicle is driven.
This is also extremely hard on the charging system and shortens alternator life.Parasitic draws of this nature may give no outward signs other than repeat battery failure. After each circuit is disabled the process must start again, waiting for everything to power down, before another reading can be taken. With the huge number of possibilities, the process may take several hours.A much more difficult problem is an intermittent draw. Testing for such a draw is impossible, unless it is occurring at the time the vehicle is tested.Professionals use judgement, experience and a great knowledge of the system to locate parasitic draws. It can be one of the most difficult task in auto repair.Batteries that last considerably less than three years indicate a problem.



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Comments Fully charged lead acid battery specific gravity

  1. LADY
    Back up for single second due to sort by high voltage but recommended.
  2. BIG_BOSS
    The other rate to charge as well as to maintain your home.