Testing 6 year old batteries

Voodoo · March 23, 2015

My 4 GC (6 volt) wet cell batteries showed a little sign of aging this past summer. Served me very adequately but seemed to go down a little sooner than times past. They are supported by 300 amps of solar and have not been abused. They all test a little into the green with a hydrometer when charged. They are 6 years old. I will be camping in a lot of low sun areas this summer (Mt Baker and Olympic NF) and hate using the generator.

Is there a way to test them other than taking them each for a load test? Cumbersome to do with their placement in the RV. Thanks, bill

Pat & Pete · March 23, 2015

Maybe bring your rig to an auto parts store and have them all tested there ?

Borrow a load tester ?

Yarome · March 23, 2015

I'm assuming they are wet cells... How long has it been since you changed out the water and equalized them? One little trick to revitalize aging cells is to add a little epsom salt. I wouldn't do more than 10:1, but you can go as high as 4:1. If those are like the costco/sam's club GC's though you've done pretty good at 6 years with pressed mesh plates over solid. A $1 of salt might get you another 2-4 years of solid performance though.

Jimalberta · March 23, 2015

Changed out the water?? Have never heard of this.

Voodoo · March 24, 2015

Thanks. Wet, like the post says. Have never changed water nor had it recommended. Add water regularly. Progressive Dynamics converter with charge wizard and a smart charger in solar from AMSolar. Not going to nurse a dying battery along so will not try first aid since I can just replace them if that is imminent anyway. Just trying to confirm my suspicion that it is time - or not. Wondered if there was a test I had overlooked. The work of hauling them out and putting the new ones in is as daunting as the cost.

skp51443 · March 24, 2015

A good temperature compensated hydrometer should be your first step, get the corrected reading for each cell and verify that all are nearly equal. If they are off then run an equalize cycle or two and check them again. If they don't read good on the hydrometer at that point it is time for new batteries.

If the specific gravity is good then a load test is in order, take it into a shop or pick up an inexpensive load tester and do it yourself.

If the batteries have never boiled over or been spilled your acid levels should be good. If you have never added anything but distilled water it should not be contaminated so changing it shouldn't make any difference. If there was a problem then maybe you could recover something by taking them to a shop and having them serviced but at current labor charges replacements might be a better deal.

I don't believe in adding anything to a battery until the battery is close enough to dead that it can do no real harm. If you are at that point and want to try something give it a try.

At six years old I'd personally test and if they are weak plan on a new set once I hit a state with low sales taxes. I really like Trojans, others have other top end brands that they really like but when it comes to dollars per watt over the life of the battery Sam's Club really seems like a good option.

Kirk W · March 24, 2015

I'm assuming they are wet cells... How long has it been since you changed out the water and equalized them? One little trick to revitalize aging cells is to add a little epsom salt. I wouldn't do more than 10:1, but you can go as high as 4:1. If those are like the costco/sam's club GC's though you've done pretty good at 6 years with pressed mesh plates over solid. A $1 of salt might get you another 2-4 years of solid performance though.

I'm interested in this also. I have heard stories of revitalizing wet cell batteries but most people that I have talked with who tried it have always told me that it doesn't work. Rather than hijacking this thread, how about starting one to tell us more about this subject and your experience with it?

Yarome · March 25, 2015

I'm interested in this also. I have heard stories of revitalizing wet cell batteries but most people that I have talked with who tried it have always told me that it doesn't work. Rather than hijacking this thread, how about starting one to tell us more about this subject and your experience with it?

Most folks that try the epsom salt solution generally wait too long to do so. The key is to catch them on the decline.. not trying to raise the dead once they have given up the ghost. It really does work with batteries that still have a half life.

The comment about changing the water is more about flushing impurities than it is about the actual properties of the water. Some might content that "refreshing" the H content can be beneficial, but from my limited experience, I really can't attest to that. I'm more of the school.. "when they done they done" and just replace the battery bank.