60 Amp alternator charging question

[luken7]

Good day, I have a B361 with the Yanmar 3GM30 engine, with the 60amp alternator. Quick electrical question. I have 2x 6volt Energizer golf cart batteries with 225 amp hours and two x Trojan T-145 6 volt batteries with 260Ah, total of 485Ah.

When on the hook for a couple of days and need to run the engine to recharge, do I calculate that the batteries will absorb 60 amps from the alternator per hour? Example, if I've consumed 240Ah over a day or two, I would need to run the engine for four hours to replenish 240Ah?

Is it that simple to calculate?

 

[Philip_Oceanis 361]

Good day, I have a B361 with the Yanmar 3GM30 engine, with the 60amp alternator. Quick electrical question. I have 2x 6volt Energizer golf cart batteries with 225 amp hours and two x Trojan T-145 6 volt batteries with 260Ah, total of 485Ah.

When on the hook for a couple of days and need to run the engine to recharge, do I calculate that the batteries will absorb 60 amps from the alternator per hour? Example, if I've consumed 240Ah over a day or two, I would need to run the engine for four hours to replenish 240Ah?

Is it that simple to calculate?

I am not expert on this but the answer is no. The altenator will give high charge when the batteries are relatively empty but the fuller they get the less charge will give. It may take 4 hours to charge them to say 80-90% but will take much longer afterwards to fully charge them using the engine.

485amps in total!! Oh my God, what sort of equipment do you have on board? I only have 200amp for the services and a 70amp to start the engine.

 

[Rick I]

Without a smart regulator (which the standard alternator does not have) it will take you all day to charge up your batteries. The standard alternator with the internal regulator will shut down to a very small charge rate fairly quickly.