BATTERY INVESTIGATION PART 2: MORE BATTERY TROUBLE SHOOTING OF A 48 VOLT STRING

I used a warm weather window to go back on board and see if I could figure out why the most negative battery in the 48 volt EP string was not charging like the other three. When I left it's voltage had not risen past 12.9 volts. So when I got back on board I plugged in the Dual Pro charger and lo and behold the indicator light went almost immediately up to 90% and the voltage was reading 13.5 volts.

This was a good sign because when I left it a few days ago only two of the red Leds were lit showing it 30% charged. As you can see in the photo above the other three batteries in the string are near 100% charged. Don't know what changed in the two days since I was last on board (Though I did unpower the Paktrakr Battery monitor which does take it's power from the lowest battery before I left last time.) but, things were moving in a positive direction. I thought now that the battery bank was up near  90% charged as shown on the Dual Pro display. It would be just a little while before it was charged up near the other three. So I took a nap.
When I got up about an hour later things were still showing 90% but, then a while later the LED display showed the charge only at 70%. Now things were going in a negative direction and the puzzle continues. It was getting late and colder so I hooked up the Paktrakr battery monitor again and left the boat while I pondered what was going on:

1) I still may have a connection issue with the battery bank though I did clean the battery connections on the last visit. I'll clean them again on my next visit.

2) I'm wondering if the load of the Paktrakr is the cause of the problem. The load from the basic Paktrkr is 10 ma. Though I just recently added the ESR-1 data cable which has some data storage capabilities in it. Though I find it hard to believe the current draw could be that great to cause the battery to start to fail. But, it is the only new item added into the mix.

Soon as the temperatures warm up again I'll head back to do some more investigation. Something about hanging around a couple of hundred pounds of lead on a chilly day makes it not the most warming experience.

LINKS

BATTERY INVESTIGATION PART 1
BATTERY INVESTIGATION PART 3