BATTERY INVESTIGATION PART 8: LOAD TESTING

After charging up the battery bank and then disconnecting the batteries I let them rest over night. I came back on board the next day and measured each battery's voltage and did two tests on each battery  using the Centech Battery Analyzer  and a 100 Amp Battery Load Tester.

Here's a quick video showing how to use the Centech Analyzer:




Here is the data I got from the Centech battery analyzer testing

                                      VOLTS   mOHM  CCA     BAT CAPACITY

BATTERY 1                   12.94      2.39      1235          100%

BATTERY 2                   12.45      2.33      1265          100%

BATTERY 3                   12.92      2.35      1241          100%

BATTERY 4 (suspect)   12.92      2.48      1179          100%

All batteries have passed the test from the analyzer. Though battery 4 (the lowest battery in the string) is certainly has a slightly diminished CCA (Cold Cranking Amps) reading compared to some of the others. But, it still passed the tests. The parasitic load from the Paktrakr that was on this battery for four years seems to have weakened it a little. It also has a slightly higher milliohm resistance reading compared to the other batteries not much more though. This might be due to some sulfation internal to the battery because of the parasitic load.

I followed the Centech battery analyzer test with the  100 Amp Battery Load Tester. All batteries passed that load test too:

Obviously, I will be keeping an eye on battery four which when I started this investigation would not even complete a charge on two separate battery chargers. After those results some might have just thrown the battery away and replaced it. But, as you can see it did manage to redeem it's self over time once the parasitic drain was removed. Why all of a sudden did I have this problem after four years? The only thing different this year is that I did not have my 48 volt Air X wind turbine also providing additional charging over the winter layup. This made the solar panels the only charging source and it may have not been enough considering the constant parascitic load on the fourth battery. I also added an additional device to monitor the charging of the battery bank. This additional load may have been enough to add additional sulfation to the suspect battery. So the lesson learned for this electric sailor is to keep parasitic loads off any one battery in the string. Another good thing from this investigation is I now have data to see how each individual battery the 48 volt propulsion bank ages from here on.

BATTERY INVESTIGATION PART 7: Much better balance

Well, it's been another two weeks since I was on board looking at the issue with the last battery in the string. When I last was on the boat I had charged up the bank fully and removed the Paktraker battery monitor which had been taking it's power from the suspect low battery. So for two weeks only the solar panels had been keeping the bank topped up and there were no parasitic loads off of any individual battery. When I powered up the Dual Pro PS4 battery charger this is what happened:



As you can see within a few seconds all four batteries immediately jumped up into the 90 to 100% range. This seems to indicate that all the batteries are pretty close in balance to one another.  It certainly is much improved situation  from the last time I fired up the charger which you can see here:



This time after an hour of charging all the batteries were fully charged within seconds of each other. The bank has come along way since I first discovered that the low battery in the bank was not able to accept a full charge.   I'm glad I took the time to investigate the reason for that battery's failure to charge fully. It seems to be related to the Paktraker's parasitic load off the suspect battery. Since I removed it from the battery there has been much improvement. The suspect battery has gradually over several weeks has come to be comparable charge wise to the other batteries in the bank. Now it is on par with the other three batteries in terms of charging.  The only thing left to do is to do one final charge and let the bank rest and then load test each battery.  I'll be doing that very shortly.

PREVIOUS BATTERY INVESTIGATION POST

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