Is it time to buy new batteries?

robertrael · 02-03-2017, 09:21 AM

Sorry this is wordy, I thought too long on how to present all the details. MY TL;DR is at the bottom.

I ran my Golf Cart batteries (Energizer EGC2 T105) 6V each in series completely out of water (I think.) Each battery took a gallon of distilled water to fill. I'm sure this is covered somewhere here, but maybe someone can help me determine if I have ruined my batteries? The date code on one of the batteries says 1/11, so I may have lucked out (for the most part) and it might have been time to replace them soon anyhow.

I have a solar panel on the batteries constantly, but for about 1-2 weeks we got cloudy days and a lot of rain, something we're not used to here in San Diego.

I have charged the batteries to full capacity as reported by my Xantrex converter/inverter, yet with no inverter load the voltage reading seems to drop rather quick. No inverter load is confirmed by the reading on the output of the inverter as being zero.

I'll be honest, I never really paid attention to the voltage and voltage drop, but I know the inverter shuts down at somewhere around 11.? volts. When I first disconnect from shore power, I see 13.1 V from the batteries, and maybe 5-10 minutes later I see 12.6 and lower. At this point, the only things on the battery were the carbon monoxide detector, and the bat wing antenna. I can't think of anything else that was using the battery at that point.

TL;DR
Full charge on batteries, rapid voltage drop as reported by inverter with no inverter load, and minimal battery load. One of 2 batteries has a 1/11 sticker on it. I made the mistake of running the batteries dry.

Padgett · 02-03-2017, 11:29 AM

Think you need to check the acid level. There is a little glass tube with a rubber bulb on the end and a number of beads inside like an antifreeze tester that is at most FLAPS.

ps the drop from 13.1 to 12.6 is just the surface charge bleeding off. A fully charged lead-acid battery cell is 2.1v so 6 are 12.6v.

robertrael · 02-03-2017, 11:45 AM

Would this be a hydrometer? I am not familiar with FLAPS.

Lets say I determine low acid in the battery, then what would I do next?

Thank you for your response.

**Bill** · 02-03-2017, 12:23 PM

Quote:

Originally Posted by robertrael

I am not familiar with FLAPS.

New to me, too. But it probably means Friendly Local Auto Parts Store.

Bill

**Bill** · 02-03-2017, 12:31 PM

Batteries are filled with acid and water, mixed to a desired strength. My understanding is that the acid part of the mix does not go away, so you don't have to replenish it. The mix merely gets stronger as the water in the mix is driven off or evaporates. Although you can buy bags of acid at your FLAPS, most battery sites caution you - DO NOT ADD ACID TO A BATTERY.

The problem is that as the mix gets more strongly acidic, it eats at the lead plates, either coating them with insoluble crystals of lead sulfate, or causing them to shed flakes which settle to the bottom of the battery where they short out the plates. Neither effect is recoverable, and I think this is what you are seeing.

If you would like more info, go to sites like batterystuff.com or any of the battery makers' tech support/FAQ sections. Progressive Dynamics' FAQ site says

Quote:

Do I ever need to add acid to my battery?

Under normal operating conditions, you never need to add acid. Only distilled or deionized water should be added to achieve the recommended electrolyte levels.

and Batterystuff.com says

Quote:

"When Should I Add Extra Sulfuric Acid to my Battery?
When you see your battery acid level begin to drop, you may wonder when and if it is appropriate to add acid, or just water.

We recommend that unless a battery was tipped over and all the acid spilled out, that you add only distilled water. Think of it like this: If you were to fill a pot up with salt water, and put it on your stove to boil, what happens? All the water will boil off, and you will be left with only salt. To re-create the original salt water mixture, you simply add straight water, because all the original salt is still in the pan, waiting to be re-suspended in the water. Batteries are the same way. All the chemical needed to make sulfuric acid is still in the battery, it is just the water that is gone. If you add more acid, you will be changing the chemical makeup of the battery which can lead to an incorrect sulfuric content.

Bill

**B_and_D** · 02-03-2017, 07:57 PM

We had ours for about 11 years before they finally died. I'd fill them up with water and give them another try.

tentcamper · 02-03-2017, 08:45 PM

I would have the batteries tested to see their capacity.

My understanding is whatever part of the plates that was above the water/acid level, has lost or nearly lost its amp transferring capability for ever. There is some chemical reaction to the exposed part of the plates and it developed a coating on that part of the plate.

Padgett · 02-03-2017, 09:09 PM

Correct for FLAPS. Did not say to add acid, just to check the acidity.

Two of my battery chargers have desulphating modes.

robertrael · 02-06-2017, 03:33 PM

Thank you all for your responses. So the voltage drop to 12.6 might not be something to be worried about. I will have to try everything with a load. We've already filled the batteries with distilled water -- I checked them again before my original post and they are still full of water (or mixture hopefully).