Battery Charging and Battery Health

Question:

Hi Jeff. I had a 3000W Xantrex Inverter/charger installed by PYS last year. I just want to check that it is charging properly. I ran the house bank down to about 65% and then turned on the generator and the charger. The charging amps ramp up quickly to about 140A and then ramp down again to about 40A. It fluctuates between about 40 and 50A even though the battery bank still shows about 65%. The charging rate then drops to about 17A even though the charge is 83%. Does this seem correct for this charger? I would like to see it charges at a higher rate in order to run the generator less, if possible. Not sure if this is enough info for you to assess? I can get more info or can set up a visit to the boat. Let me know. Thanks.  - Colin

Answer:

Hi Colin, as we know charging and batteries are directly linked to one another. In other words, a battery charger, will reduce charging amperage to keep battery voltage from increasing too high. In order to isolate the problem we need to confirm the state of health of the batteries.   Here is a procedure for you to test the current capacity of your house battery bank: https://www.pysystems.ca/resources/ask-pys/geoff-measure-battery-capacity/  Let me know if you have any questions on this C20 test and please share the data with me so we can figure out the link between your battery bank and the charger.  - Jeff