Monday, February 20, 2012

BATTERY INVESTIGATION PART THREE: Overnight Charge & Battery Analyzer Test

So a few days later I came back on board to see what was going on with the problem battery in the 48 volt string. Here is a video of what happens when I plug in the Dual Pro Quad charger. It first goes through a quick self test then measures the battery voltage and checks the charge and then displays the results on an LED bar on front of the charger for each battery in the string:

I decided to leave the charger on overnight and see if that last battery bank would come up to a full charge. Below is a video of what I saw when I came back on board the next day:

Battery 1 (most negative battery in the string) definitely still has a problem. At the suggestion a fellow named Arby over on the electric boats group I bought a Centech battery-analyzer. It seemed like a good idea to buy one. This device measures the voltage, internal resistance of the battery and the capacity including the Cold Cranking Amps. I tested the suspect battery and the next one up in the string and also the highest (most positive) battery in the 48 volt string. Here are the results:

                                                VOLTS  mOHMS  CC AMPS
BATTERY 1 (SUSPECT)       13.03     2.34         1273
BATTERY 2                           13.62    2.42          1437
BATTERY 4*                         14.45    2.43          1724

* Reading taken soon after shutting down charger which may explain the higher numbers in volt & CCA readings. Also note I did not take any readings off of battery 3 for this test. 

The voltage of the suspect battery 1 is a little low but, not overly so. The internal resistance seems OK compared to the other two batteries in the string tested. The Cold Cranking Amps available is certainly lower but, it's not a completely dead battery. I've once again disconnected the Paktrakr as this problem did not show up until I added the optional data recording cable to it. I'm sure it added an additional load to the battery beyond the Paktrakr's 25 milliamps but, I doubt it was that great. Still I'm trying to eliminate what might have caused the sudden change in this battery. Next warm day I'll be doing a load test on the suspect battery.

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