Battery was replaced approx 1 year ago. This new battery wouldn’t stay charged. Machine used every other week or so here and there. The none 1yr old battery fails. Replace with new battery and all good for a couple of months but now battery drained too low to take a charge. Master disconnect switch was left on, but when turn it off there is no sign of any power when turn key so assume disconnect is doing its job. Anyone have any suggestions or tricks to try. Both replacement batteries are CAT. Could I have gotten 2 bad CAT batteries back to back?
With that infrequent of a usage would a battery tender be the answer.?
I could definitely try one, but we’ve got lots of equipment with batteries much older that crank right up when sitting much longer. I’ve owned this particular machine for 6 yrs(2018 model) and it’s never acted like this. For a new battery to be as dead as this one after sitting about a week, I just feel it’s got something draining it. No aftermarket or accessories ever installed on it.
All I can suggest as a starting point is to open the master switch and use a clamp-on ammeter over the main positive battery cable to test for current draw. There shouldn't be any, but you never know. Probably best to check even if only to rule it out.