Inverter/charger variable charging rate

I have a Heart 25 inverter/charger. I have noticed that more often then not, my charging rate will fluctuate rapidly by up to 20 amps. About 20% of the time it's spot on. No problem when charging from the Alts. This happens whether I'm on shore power or the genset. I assume it's not a gauge problem as my separate AC amp gauge will fluctuate as well. Any thoughts as to what might be the problem?

Thanks, Tator

Not sure if you have a problem. As the battery charges, you should read max amps and the voltage should increase. The voltage generally peaks at 14.1 and then you see the amps tapering off.

Hi Tator,

What do you mean by "spot on"? What is that referenced against?

When it is fluctuating, is it trending in a direction for a bit and then reversing trend? Or random? What is the load doing at the time?

If you have varying loads while charging this could be a cause of varying amounts of current going into the batteries. If the charger is truly varying 20 amps with no external reasons then something in the system, (charger, batteries, cabling) is acting up. If it were my boat the first thing to determine is if there is an external load switching on and off. Perhaps an ACR that's acting up? Perhaps other loads.


Ken

Sorry that I wasn't clearer. For example in bulk charge, while viewing my Link 1000, I might see the reading of DC amps into the bank go randomly 125, 121,108,114, 106 all within a couple of seconds. The genset AC amps are varying as well as the genset changes it's speed to match the demand ( remember that it does this on shorepower as well). When it appears to be charging correctly, the DC amps read a steady 125 varying only if another DC load is added and then holding steady at that amperage until the load changes.

Tator said:

Sorry that I wasn't clearer. For example in bulk charge, while viewing my Link 1000, I might see the reading of DC amps into the bank go randomly 125, 121,108,114, 106 all within a couple of seconds. The genset AC amps are varying as well as the genset changes it's speed to match the demand ( remember that it does this on shorepower as well). When it appears to be charging correctly, the DC amps read a steady 125 varying only if another DC load is added and then holding steady at that amperage until the load changes.

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I think that the fluctuations are normal.

My Victron inverter/charger modulates output constantly.

Ok as other posters have stated the battery charger of the inverter may be responding to other AC loads. Most inverters will load shed to a pre set amp load. So if you set the amp load at 30A AC and other devices are utilizing 15A AC or so the inverter will adjust the battery charging current to maintain it's AC draw below the 30A AC level. It really is a feature. IF this is happening when there are no other significant AC loads then it's probably either poor instrumentation (i.e. your not actually reading the DC current going to the battery correctly) or there is a bad connection in the charging circuit.

RB Cooper