Battery chargers not charging at full power

[Snowandsail]

Hello all who may understand electrical systems better than I do.

I have two Cristec Ypower 12V/60Amp chargers on a 2020 lagoon 46. When I used to have low batteries I would start the generator and the chargers would put 120 amps into the batteries. Now in the same scenario they only put out 50 amps max. Can anyone tell me why this may be?

[Sailmonkey]

Most likely your batteries are done and their internal resistance is too high to accept more current.

[Stu Jackson]

Or your batteries are fine and are nearer to full than when you last needed to charge them.


Not really enough info in the OP to tell.

[PaulCrawhorn]

Chargeres (sources in general) do not "push" current, they just "offer" up to a certain maximum.

It is up to the batteries (loads in general) to PULL the amps desired / needed.

Lead chemistries' resistance determines the bank's CAR charge acceptance rate, AGM's much higher C-rate than flooded fir example

and this varies by wear level as well during a charge cycle proportional to SoC level.

If you want to test a charge siurce's maximum current rate, you need a large enough bank that is well depleted, say 40-60% at most.

But wire gauge, state of connections etc also can create bottlenecks...

[smac999]

Maybe only one charger works. Try one at a time. See if they both put out 50a. Or only 1. Ideally Each should be on its own ac breaker.

[sailcrazy]

Following. Our 3battery 50-amp charger has some years on it, but recently the output has been (intermittently) been very--unusual. sometimes, when I switch on the genset and batt charger, I see a near-full 50 amps going to each on our 3 house bank batteries. Other times I'll see 20-25 amps going to each initially and then after some time (30-45 minutes) the charge jumps up to 45+ amps.....and then eventually (another 30min-1 hr) come down to 15-20amps. Our LA batts are 5 years old, but show no other signs of old age.

[iGrf]

It could be a loose connection somewhere between the charger and the battery.
Check if all the nuts are still tight and feel if nothing along the line gets warm or hot !