Hey guys I have a issue that I can’t seem to figure out. One of my batteries died on me and I went to replace it and everything seemed ok. Two days passed and I went to use it again and the other battery dies on me so I replaced it. Three days later the new battery I replaced the first time died on me and wouldn’t take a charge at all and had completely gone to the bad. This has happened to me two other times where I’ve purchased more batteries and they keep alternating each battery doing the same thing going completely dead where I can’t recharge or do anything to them. Please help me with ways to figure this out. Thanks!
If you have more than 1 battery always replace them all at the same time. Dont buy auto parts store batteries for heavy equipment either
I buy Napa and Advance Auto (Carquest) batteries all the time. Never an issue. The 31 and 30H batteries from each are made by East Penn (Deka), the same supplier that Caterpillar sources most batteries from. Back to the issue at hand..... That machine is 24V, so the two batteries in series are essentially one 12 cell, 24V, battery (6 cells in each battery), but still, as far as the alternator can see, it's just one big 24V battery. First, the only connections at the batteries should be the big battery cables, (+) to battery one, (-) battery one to (+) battery two, battery two (-) to the master switch. I've seen many times where an installer will "steal" 12V from the cable connection between the two batteries. This is a no-no. This will result in 6 cells out of the 12 cells being undercharged, resulting in one dead 12V battery. If you need 12V for an accessory, you need a voltage converter. How did you determine that just one battery had failed, each time?
How did you test them?
My excavator doesn’t have a master switch and I disconnected both batteries and tested them both with a load tester. I used my excavator for 3 years before I had any problems with the batteries. I hooked the new battery the same way they were hooked up before.
Again, you're changing only half of a 24Volt battery assembly. And, by George, there is definitely a master battery disconnect switch.
Sometimes, you get lucky installing one new battery in a combo. It usually comes back to bite you. Especially, a customer machine. I’ve had success installing a used gp31 battery in a stack of parallel gp31’s. So the measured capacitance, CCA rating, make somewhat match. A capacitance style tester helps with that.
Yes, ALWAYS replace both at the same time if they are in series. As a battery ages it's internal resistance increases. If only ONE battery is replaced the old battery will not get fully charged and the new battery will get over charged. If there is a significant difference in the batteries the new one will quickly die. Ohms law, in this case I= E/R. Parallel connected batteries can be individually replaced as each battery will only take as much of the available charge as it's resistance allows.
I never realized it before, but this matches my anecdotal experience.