Battery Reconditioning

I am wanting to find out if the H2SO4 in a charged lead acid battery is more corrosive (higher pH) than the H2SO4 in a discharged one. Does the pH change at all?
Thanks,
Neb

As the battery is discharged both hydronium and sulfate ions are removed from solution, leaving the liquid more dilute. So the discharged battery has a higher (less acid) pH. (Higher pH does not correspond to "more corrosive". Higher pH means more basic, less acidic. The more acidic the lower the pH.)

Although a discharged battery is less corrosive than a charged one, it is by no means innocuous — it still needs to be treated with respect.

In a Diesel engine LPG is added to boost proformance. Could Hydrogen go the same, without expensive equipment? A Hybrid with lead acid batteries would produce more Hydrogen, maybe enough to make a difference.

There is not enough hydrogen coming out (and the pressure is low) so it would not serve that purpose.

Im working on a project and I have a volt meter hooked up to the circuit to tell me the voltage of the pack. I need to know at what voltage can i safely bring my lead acid battery pack down to without causing damage to the cells. Thank you.

it depends on the lead acid cell construction. There are deep discharge types, such as are used in marine batteries, that can be totally discharged without damage. Automobile types, however, cannot take more than about a half discharge without damage.

It also depends on the load current, which will change the voltmeter reading, specially as you get closer to discharge. It also depends on the temperature.

IF you have deep discharge types, and measure the voltage with no current flowing, and the temperature is close to 20ºC, then for a 12 volt battery, full charge is 12.7 volts, full discharge is 11.7 volts, half discharge is 12.5 volts. Multiply by 3 for a 36 volt battery.

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how many times can you charge a lithium battery and how many times can you charge a lead acid battery?

Typical rechargeable LiPo batteries today have about 1,000 charge cycles. However there are research prototypes that can demonstrate deep discharge cycle batteries that have 10,000 cycles. It is all a matter of how much you want to pay for the batteries. The other alternative is to have proper management of the discharge cycles, i.e. never let it go into deep discharge, thus allowing for greater than 100,000 miles of usage. This is the case with Prius batteries.

I am building a electric car and would like to have nimh batteries but cant afford them. If i buy lead acid batteries and as i get the money replace the batteries one by one with nimh batteries. This for a while would mean having a mix of lead acid and nimh batteries. Is this possible? Will it work? please no critizism of this is a stupid ? or about the electric carr concept.

no it won’t work very well. Lead-Acid and Nimh have different Capacity, Amp-hour, and self-discharge ratings…not to mention different charging requirements. Battery packs need to be consistent to be used effectively…that means same chemistry, voltage, and AH ratings on each individual battery. What you’ll end up with is poor run-time and certain types discharge faster, incomplete recharging, and reduced battery life as the stronger ones work harder to make up for the weaker ones.