wet-cell battery gravity test

Hi Don,

"~" meant approximate, so I don't remember exactly what it read. Could have been well over 13 volts, but the question in my post was whether that Sears manager was BS'in me.

Thanks for your feedback. Mike

battery

gravity

13.2

idea to

more

Mike posted:

Yeh, I've actually heard of that procedure. It's more or less "blasting" the battery with a load to dislodge the crystals....

Thanks! Mike

will

it

look

on

I

thus

Hi

My recollection of the battery section that I once took and my work as a industrial controls mechanic, is that as a battery discharges its internal resistance increases. As the internal resistance increases the voltage will drop across a constant load.

Further, allowing a battery to sit with the acid in it and not charged is one of the worst things that can happen to a battery aside from freezing.

When a battery has been sitting for extended periods, the material on the plates turns into more or less insoluble lead sulfate crystals. This reduces the surface area in the active battery approximating a permanent discharged condition.

There is a process that allows such batteries to sometimes be saved, but it has some dangers and you are well advised to get in the net and take a look at some of the interesting information that battery manufactures post.

Al.

eventually

battery

gravity

The manager was not entirely wrong. Specific gravity tells you if the battery is charged and what percent of charge it is at. But the battery can have a high internal resistance as another poster said. What the guy at the store probably was talking about was a "load test". It is commonly done in the battery service shops. They put a load of so many amps and measure how much the voltage drops and how quickly. That is the real test to see if the battery is any good.

By the way, when charging it needs to be charged at around 14 volts to

14.6 volts. 13 volts will never charge it up fully. 13.6 volts is a good "float" voltage to maintain a battery at for long periods.

Desulphating a battery to recover it requires a charge voltage of around 16 volts or so. The temperature must be monitored closely. Sometimes it helps but if the battery has been sitting for a long period with no charge it is probably history.

If a battery is discharged to "flat" you must get it charged up as soon as possible. Letting it sit for more than a day in the discharged condition will pretty much ruin it.

Regards Gary

I performed a load test on the battery myself with a load tester, but I can't remember the exact results.

Thanks for your words of wisdom. Mike

have

Sears

on

failed. I

gravity

thus

When a

about

periodically.