Cloudy battery acid.

the sulphuric acid reacts with the lead in the plates with the result that the acid breaks down and tends to go water and the lead becomes lead sulphate
when a battery is dead flat, the plates are all lead sulphate and the density of the acid is approaching that of water
that can be tested with a hydrometer
When a charge is applied to the battery terminals , the process is reversed and the lead sulphate returns as lead and the water ( low ph acid) returns to sulphuric acid

11v is too low, should be over 13v, check the battery for low water if it's not a sealed one, refill if necessary to bottom of the fill ring, then charge battery. If you have a battery hydrometer tester, all the cells should then test about the same, if not and one or more cells show weak, the battery is shot. If you have no equipment, most chain auto parts stores will test it for you free, if you jump start it, and can get it there, they will also check the charging system, (alternator, belts, etc.)

For a battery to be good and operational, you need 3 things: Voltage, Cold Cranking Amps, and good cells.
A fully charged battery will have at least 2.1 Volts per cell. So, a 12V battery should read 12.6V to be fully charged. Before you can proceed any farther, the battery will need to be charged fully.

A "load test" will need to be performed to determine if the battery has enough energy to start your vehicle. Cold cranking amps (CCA) is the amount of energy the battery supplies at 32 degrees. This test can be performed with a hand held load tester that can be purchased at a parts store, or performed by a technician at a shop. Batteries lose their ability to supply CCA's when they begin to age or the lead material on the "plates" begins to sluff off.

If you are able to remove the battery caps, a specific gravity test can be accomplished with a hydrometer. This is a glass tube with a bulb on top for suctioning acid into the tube, which in turn will float the hydrometer. Fully charged batteries will float at 1.265 specific gravity. Each cell needs to lift the float at least at 1.265. If one or more of the cells fails to lift the float at all, it can be determined that that cell is dead.

If any of the above tests fail, the battery is considered defective.

To clean a battery, a mixture of water and baking soda can be used. Also, remove the cables from the terminal posts and clean with a wire brush. Remove all crusty buildup. Posts should be shiney as well as the inside the battery cables.

The lights are not really an indication of the battery condition. They require about 5% of the power it needs to turn the starter. Check if the dash lights dim or go out when you try start. The only other ways of testing a battery is with a load tester or a hydrometer which tests the SG of the acid and give an indication of the state of charge of the battery. Try charge the battery or you can attempt a jump start from another vehicle about the same age as yours.

Hello,

The first and most likely indication of a low battery would be a hard starting problem caused by slow cranking. If the battery seems weak or fails to crank your engine normally, it may be low. To find out, you need to check the battery's "state of charge."
A battery is nothing more than a chemical storage device for holding electrons until they're needed to crank the engine or run the lights or other electrical accessories on your vehicle. Checking the battery's state of charge will tell you how much juice the battery has available for such purposes.
If your battery is low, it needs to be recharged, not only to restore full power, but also to prevent possible damage to the battery. Ordinary automotive lead-acid storage batteries must be kept at or near full charge to keep the cell plates from becoming "sulfated" (a condition that occurs if the battery is run down and left in a discharged condition for more than a few days). As sulfate builds up, it reduces the battery's ability to hold a charge and supply voltage. Eventually the battery becomes useless and must be replaced.

The charge level depends on the concentration of acid inside the battery. The stronger the concentration of acid in the water, the higher the specific gravity of the solution, and the higher the state of charge.
On batteries with removable caps, state of charge can be checked with a "hydrometer." Some hydrometers have a calibrated float to measure the specific gravity of the acid solution while others simply have a number of colored balls. On the kind with a calibrated float, a hydrometer reading of 1.265 (corrected for temperature) indicates a fully charged battery, 1.230 indicates a 75% charge, 1.200 indicates a 50% charge, 1.170 indicates a 25% charge, and 1.140 or less indicates a discharged battery. On the kind that use floating balls, the number of balls that float tells you the approximate level of charge. All balls floating would indicate a fully charged battery, no balls floating would indicate a dead or fully discharged battery.
Some sealed-top batteries have a built-in hydrometer to indicate charge. The charge indicator only reads one cell, but usually shows the average charge for all battery cells. A green dot means the battery is 75% or more charged and is okay for use or further testing. No dot (a dark indicator) means the battery is low and should be recharged before it is returned to service or tested further. A clear or yellow indicator means the level of electrolyte inside has dropped too low, and the battery should be replaced.

On sealed-top batteries that do not have a built-in charge indicator, the state of charge can be determined by checking the battery's base or open circuit voltage with a digital voltmeter or multimeter. This is done by touching the meter leads to the positive and negative battery terminals while the ignition key is off.
A reading of 12.66 volts indicates a fully charged battery; 12.45 volts is 75% charged, 12.24 volts is 50% charged, and 12.06 volts is 25% charged.

In recharging the battery do not attempt to recharge a battery with low (or frozen) electrolyte! Doing so risks blowing up the battery if the hydrogen gas inside is ignited by a spark.
Your charging system should be capable of recharging the battery if it is not fully discharged. Thirty minutes or so of normal driving should be enough.
If your battery is completely dead or extremely low, it should be recharged with a fast or slow charger. This will reduce the risk of overtaxing and damaging your vehicle's charging system. One or both battery cables should be disconnected from the battery prior to charging it with a charger. This will eliminate any risk of damage to your vehicle's electrical system or its onboard electronics.

Take care and good luck

NB: Your alternator might not also be charging the battery while the car is on, so try to check the alternator.

Alternators are pretty rugged, but can succumb to excessive heat and overwork. They can also be damaged by sudden voltage overloads (as when someone attempts to jump start a dead battery and crosses up the jumper connections or if someone disconnects a battery cable from the battery while the engine is running).
Sometimes alternators can partially fail. In the back of every alternator is a "diode trio" that converts the alternators AC (alternating current) output to DC (direct current). If one or more of these diodes fail, the alternator's amperage output will be reduced. It may continue to produce some current, but not enough to keep the battery fully charged -- especially at idle or low speed.
Most service facilities have test equipment that can identify these kind of problems. So if you suspect a weak alternator, you should have it tested to see if it needs replacing.
Most service facilities do not repair or rebuild alternators because it's too time consuming and requires special parts. Most will replace your old unit with a new or remanufactured unit. Your old alternator is usually traded in or exchanged for a credit (so it can be remanufactured and sold to someone else).

Sounds like your alternator isn't charging your battery.

This is a high charging on the battery, as it is overcharged . this can be failure of the alternator rectifier or the regulator.
so use a voltmeter and confirm the voltage range to rectify the fault.
A high charging of this nature can damage the battery in the long run.

Most time's you can not revive them. But the best way to check if it can is. Remove all the caps and put in on a charger. With the charger turned on check if the acid in any of the cell's bubble's. If any of them does then it has a faulty cell and cannot be revived. If it just got run down completely and let sit for a while without charge this causes the acid to return to distilled water. To bring it back to acid it must be put on a very slow charge for 24 hours. You will need a special charger for this because most small charger's won't go low enough they will charge up the battery to fast and the distilled water wont hold the charge. I bought a slow charger it was for a motorbike battery it was'nt expensive but it burned out charging the first battery. Charger was only a bit cheaper than a battery so ever since when I have a problem I just buy a new one. Sorry this not what you wanted to hear and is only my experience and oppinion. Cheers

Hi, seems that your alternator diodes are faulty.
You can check this by disconnecting the radio & switching off all interior lights etc.
Then remove one battery lead.
Then get an amp meter and connect it between the battery & the removed lead.
If you get a reading the alternator is drawing current , hence faulty diodes.
The alternator will still charge the battery when the engine is going but then discharges when stopped.
Also check your batteries with a hydrometer by checking the battery acid in each cell as you could have a dodgey cell in them.

Hi angelakelly

Bad battery
The best way to check a battery is to put it on charge (10-15 amps overnight) and then check it with a hydrometer.

The hydrometer measures the specific gravity of the Battery which is an indication of the amount of acid in the liquid.

Batteries are a limited life item. If the hydrometer reading is low (after an overnight charge) this means the battery needs to be replaced.You can get a hydrometer at any walmart or auto parts store, They are only about $5.

Good luck Loringh PS Please leavr a rating if appropriate