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Battery / Generator / mouse

Yahoo Message Number: 63386
Hi all,

Both my Chassis and House batteries(PowerVolt. lead acid 8D's) are about 18 months old. I decided to service my Onan 12.5 generator which needed a fan belt replaced, oil and filter changed, fuel filter, air filter and some of the exterior panels were starting to rust around the edges so I decided to strip and repaint it while I had it out. So I decided to pull both the chassis and all four house batts out since I had to disconnect the generator from the batteries and repaint the battery trays while I was at it. So I took the batteries out and checked the voltages on each battery while disconnected. Both chassis batteries checked 12.6v, the two lower house batteries checked 12.5volts while the two in the upper house tray were checking 10.6 volts about a day after I took it out.
So I put two ounces of cadmium sulfate in each cell and fully charged both of these batteries on a separate charger and equalized them. Two days later I checked and the voltage is 8.5v on both batteries. What would cause both the batteries to fail identically in the same tray? There was no corrosion on the main terminals on any of the house connections.
I know it's a no-no to replace just two out of the four batteries, but I hate to have to buy four more batts when there only 18 months old. Any Ideas? Now the reason for the long description of what I doing. I had to take the generator apart to strip and repaint it. In order to remove the front panel you have to remove the air resonator from the inside wall of it. In the process of removing it I went ahead and removed the air filter canister. In the hose, between the resonator and canister, I found a petrified mouse blocking about 80% of the intake air. Hard as a rock. I had to break it in half with a screwdriver to get him out. There is no screen on the hole in the bottom of the generator from keeping a mouse or other varmint from getting into the air resonator, thus being able to be sucked into the inlet of the air filter canister. You couldn't even see it if you don't completely take off your filter canister.
Kevin Burns

00 affinity #5865

Re: Battery / Generator / mouse

Reply #1 –
Yahoo Message Number: 63393

Hi Kevin:

I had never heard of adding cadmium sulfate before your post. A quick search shows there are commerical products with various names that contain that and other chemical salts with the promise of desulfation of the battery plates and extension of battery life. There are also warnings on various websites that while this might give a poorly maintained or failing battery a few extra months it isn't a good idea for otherwise healthy well cared for batteries. One guy called it "ninja desulfation" because it is very agressive chemical action. That isn't usually a good thing.
If that is true, and given the timing of the failures, the cadmium sulfate is at least a suspect. One thought - the way most lead-acid cell batteris fail is the sulfation flakes fall off the plates onto the bottom of the cell. When the flakes get high enough to contact the plates the cell shorts and the battery fails. As your voltage has dropped that usually means one or more cells have failed.
If you replace only two of 4 batteries they will hold unequal charges, the older batteries will not be able to hold as much as the new ones. The weakest battery(ies) will then draw on the stronger units and eventually drain them all down. This will kill the old and new batteries requiring you buy 4 more. Buy 4 now and not 6 over a short time frame. You need to have them all as close to identical as possible. Replacing all at the same time is the best way to ensure success.

Bob (rthandren@...)
'05 Inspire 51178

Re: Battery / Generator / mouse

Reply #2 –
Yahoo Message Number: 63395
Hi Bob,

Thanks for the reply. I added the cadmium sulfate after the battery showed signs it wouldn't hold a charge as the voltages were dropping. But why do you think that both batteries in the same tray failed and not the other two? I had a motorcycle battery that was unable to hold a charge. It wouldn't start the bike after a 30 min. ride. I added cadmium sulfate and it's worked for almost three years now and is still in the bike. So from my experience it doesn't scare me to use it in any lead acid battery. I'm considering adding a aftermarket desulfinator to the MH but first I need to stop all the parasitic loads so I can truly disconnect my batteries. I don't think it should be nessacery to leave it plugged into shore power all the time.
Thanks again,
Kevin

00 Affinity 5865

Re: Battery / Generator / mouse

Reply #3 –
Yahoo Message Number: 63396
Kevin,

Those 18 month old batteries should still be in warranty. Some mfg have no charge replacement on short time periods of service . Might be worth checking.
AL

00 affinity
 

Re: Battery / Generator / mouse

Reply #4 –
Yahoo Message Number: 63397

Kevin:

If you figure out a way to predict which battery will fail when and why you could become a rich man. ;-)

Bob (rthandren@...)
'05 Inspire 51178