My Unimogs normally use two 12 volt truck batteries in series. They weigh a ton and not suited very well for off road, as they can leak electrolyte which rots out the battery trays. I think its a Nato requirement as civilian versions use 12 volt systems. Both of mine are parked all winter and used sporadically in late spring summer and fall. One of mine came with Optima AGM batteries and they have lasted several years with no issues. It has a battery cut off switch that cuts off all power. The other one came with a couple of marginal truck batteries that needed replacement. I decided to bite the bullet and put in two Optima batteries. They were great for two years but this spring one was low and the other lower, this truck also has a battery cut off but there are a few circuits that I think bypass it. I gave it a charge and things were fine for my spring wood hauling. I was busy with other things this summer so didnt use this truck for about 2 months. When I turned it over this fall, no start. I checked the volts and one battery was 7 volts and the other 4. Not good. I hooked up my high tech Century (lincoln electric) charger and it gave me an error code "bad battery". I have another Schumacher charger and that also did not seem to want to charge the battery but didnt turn off.
I have a portable solar trailer with two large 48 volt forklift batteries on it. It is hooked to my house so the only time the batteries have to do any work is on the rare occasions that the power goes out. They are probably $4K each so definitely want to keep them alive as long as possible. I have read that one of the keys to long battery life in "float" service is using something called a desulfator. It zaps the battery occasionally with an AC pulse that breaks down sulfation that can form on the battery cells. I have one on each of my big batteries that run continuously. I had not tried one on regular car batteries as I assumed that when they will not take a charge and tester says its bad, its time for new one. The warranty was up a few months ago on the Optimas so I decided to try to save them. The rigs on my 48 volt batteries are battery powered so no good but over the years these brand battery maintainers seem to get a good reputation Amazon product ASIN B00Q3CM2QY . I had read and I think the instructions said it may take awhile. I hooked up one and overnight it came up from 7 volts to 11.5 volts. I left it going for a couple of days and it came up 12.4 volts. I hooked up the other one and it came up from 4 volts to 12.3. A friend of mine offered to do some testing so we hooked up a dump load ( a long piece of steel fence wire) and it pulled 20 amps for about 20 minutes with no voltage drop once the load was off, That looked positive and then one of his friends stopped by and offered up battery load tester that a mechanic had given him. This one pulled an 80 amp load and the meter showed both to be good batterys.
The Unimogs just got parked for the winter using one set of batteries being swapped around so I havent tried starting either one with the salvaged batteries but at this point I am sold. New batteries would be about $450 for the pair, so the $60 spent looks to be worth it. My friend the electrical genius said this it typical, in order to break up the sulfation the charger has to charge against a high resistance and most chargers just assume its a shorted cell. This rig just trickle charges while pulsing it with AC to break up the resistance until it will take a normal charge. No guarantees, sometime a battery is just shot but worked for me.
I have a portable solar trailer with two large 48 volt forklift batteries on it. It is hooked to my house so the only time the batteries have to do any work is on the rare occasions that the power goes out. They are probably $4K each so definitely want to keep them alive as long as possible. I have read that one of the keys to long battery life in "float" service is using something called a desulfator. It zaps the battery occasionally with an AC pulse that breaks down sulfation that can form on the battery cells. I have one on each of my big batteries that run continuously. I had not tried one on regular car batteries as I assumed that when they will not take a charge and tester says its bad, its time for new one. The warranty was up a few months ago on the Optimas so I decided to try to save them. The rigs on my 48 volt batteries are battery powered so no good but over the years these brand battery maintainers seem to get a good reputation Amazon product ASIN B00Q3CM2QY . I had read and I think the instructions said it may take awhile. I hooked up one and overnight it came up from 7 volts to 11.5 volts. I left it going for a couple of days and it came up 12.4 volts. I hooked up the other one and it came up from 4 volts to 12.3. A friend of mine offered to do some testing so we hooked up a dump load ( a long piece of steel fence wire) and it pulled 20 amps for about 20 minutes with no voltage drop once the load was off, That looked positive and then one of his friends stopped by and offered up battery load tester that a mechanic had given him. This one pulled an 80 amp load and the meter showed both to be good batterys.
The Unimogs just got parked for the winter using one set of batteries being swapped around so I havent tried starting either one with the salvaged batteries but at this point I am sold. New batteries would be about $450 for the pair, so the $60 spent looks to be worth it. My friend the electrical genius said this it typical, in order to break up the sulfation the charger has to charge against a high resistance and most chargers just assume its a shorted cell. This rig just trickle charges while pulsing it with AC to break up the resistance until it will take a normal charge. No guarantees, sometime a battery is just shot but worked for me.
