Possible diluted battery electrolyte?

[8-point]

The other day I had to add a good bit more water as I normally would to my 3 year old US Batteries to get about ½” above the plates. This time I must confess I waited longer than I should, as some levels were pretty low to the point of barely above some of the plates. Since then, they are not holding the same 18 hour after-charge voltage they did before at about .6v less. I do know wet cell batteries are somewhat forgiving to a degree. Do you think I’m experiencing “excessive watering of a battery can result in additional dilution of the electrolyte, resulting in reduced battery performance”? Will they recover any at this point in their life?

[ThreeCW]

Originally Posted by 8-point

Do you think I’m experiencing “excessive watering of a battery can result in additional dilution of the electrolyte, resulting in reduced battery performance”? Will they recover any at this point in their life?

My 3 year old Trojans typically show a stabilized fully charged voltage of 52.0 volts at 24 hours after charging. I also note that after a water fill, my stabilized after charge voltage declines (most likely due to dilution of the electrolyte) by about 0.2 volts to 51.8 volts. The amount of decline seems to be proportional to how much water I add to the pack ... the more water, the more decline in stabilized voltage.

On the other hand, I have also noticed that my stabilized fully charged voltage will slowly increase over time as the electrolyte level in the pack reduces due to water usage (and I assume a stronger electrolyte concentration). If my stabilized after charge voltage gets above 52.2 volts, I know it is time to check my electrolyte level ... so my volt meter becomes a built in electrolyte gauge as well.

I do not notice a change in battery performance with the change in electrolyte concentration ... but I my discharges are normally fairly low ... only 10 to 20% discharge (to a 80 or 90% state of charge).

If your batteries behave as mine do, as water gets used and your electrolyte level deceases, I expect your stabilized after charge voltage will also increase.

[8-point]

Thank you for your reply and input, ThreeCW. That’s good info, now I feel like they should rebound.

[rib33024]

Charge them until the charger turns off. Wait about a half hour and start the charge again and let it finish

[ThreeCW]

8-point,

I found my charging sheet today and wanted to let you know my actual voltages. I typically see a fully charged static pack voltage of 52.0 volts at 24 hours after charging.

Before my last water addition, I had recorded a fully charged static pack voltage of 52.48 volts at 48 hours after charging. Note that this is 0.48 volts higher than what I would consider a normal fully charged pack voltage. I believe this higher voltage is due to a concentration of acid in the electrolyte due to water loss when charging.

I then filled my 8 x 6 volt batteries using 3.1 L (3.3 US quarts) of osmosis water.

I used my cart for a total of 3 hours over a number of days (gravel roads, rough pastures ... lots of mixing going on with the battery electrolyte) and charged the batteries 5 times in this period.

After the 5th charge, I recorded a fully charged pack voltage of 51.62 volts at 48 hours after charging. Note that this is a 0.38 volts lower than what I would consider a normal fully charged pack voltage (due to dilution of the acid in the electrolyte with the water addition).

So my voltage difference from before water to after water was actually 0.86 volts!

I am thinking that your results at a 0.6 volts reduction are pretty similar to mine ... which I also conclude is a normal reaction when watering batteries.

[Bama Brad]

I've noticed the same thing, lower voltage for a while after adding water. It does gradually climb back to normal after 5 or so charges.

[Mikefili]

Originally Posted by ThreeCW

My 3 year old Trojans typically show a stabilized fully charged voltage of 52.0 volts at 24 hours after charging. I also note that after a water fill, my stabilized after charge voltage declines (most likely due to dilution of the electrolyte) by about 0.2 volts to 51.8 volts. The amount of decline seems to be proportional to how much water I add to the pack ... the more water, the more decline in stabilized voltage.

On the other hand, I have also noticed that my stabilized fully charged voltage will slowly increase over time as the electrolyte level in the pack reduces due to water usage (and I assume a stronger electrolyte concentration). If my stabilized after charge voltage gets above 52.2 volts, I know it is time to check my electrolyte level ... so my volt meter becomes a built in electrolyte gauge as well.

I do not notice a change in battery performance with the change in electrolyte concentration ... but I my discharges are normally fairly low ... only 10 to 20% discharge (to a 80 or 90% state of charge).

If your batteries behave as mine do, as water gets used and your electrolyte level deceases, I expect your stabilized after charge voltage will also increase.

Yes I have seen the exact same thing on both of my 48v Trojans, the closer the electrolyte is to the top of the plates the higher my fully charged resting voltage is, if I fill to the bottom of the fill tubes I have somewhat lower full charge voltage. I have often wondered what the outcome would be if someone topped off the water level with electrolyte instead of distilled water…….

[8-point]

Ok so just a little update, my batteries have improved like you wouldn’t believe. Holding well over 100% for the longest they ever have. So. I figured I’d reward them along with the trays with a good baking soda/water bath. Thanks for the previous replies.