A battery question

[Cuppa]

At half load that is still 225 amps and will quickly overheat and kill an alternator.

In my case the setup is that the winch is connected to the crank battery & I can turn a switch to parallel the 360Ah aux batteries to it when required. On the limited occasions where I have used my winch I have restricted use to short bursts. Engine set to fast idle. I think I did bother to parallel the batteries once, but mostly haven't. But I haven't needed to do any long winches like some of the hardcore 4wd'ers who seem to enjoy such things.

No Jon, sorry I don't have a link.

[Peter and Sandra]

The Cummins in the Oka has a 160 amp alternator that is rated to supply 100 amps at idle.
Just to see what would happen I activated the dirty big solenoid that can connect the truck battery to the 400ah lithium house battery which was at about 50% SOC. The alternator did indeed provide the 100 amps but very quickly dialled it back as the alternator temperature climbed, increasing engine revs caused it to climb back up due to increased airflow and me opening the engine hatch to point the infrared temp gauge at various places.
Nothing was particularly hot mostly at or slightly above engine coolant temp of 85 C.
The lithiums never even blinked just absorbed whatever was supplied.

[BruceS]

Peter was your alternator gear driven?
I think a lot of BIG trucks now days are gear driven rather than belt drive.