There is of course a finite limit to the trigger circuits fan-out
capability but I have no idea what it is. I have had this concern myself
when adding a second battery. A simple way to avoid increasing the
current drain on the trigger circuit is to not use the trigger circuit
for the added relay. Just connect a wire from the high current output of
the stock relay to the trigger circuit input on the second relay. This
small added load to the stock relay would be very minor and this method
helps isolate the stock wiring from the high current auxiliary battery
wiring.

Mark Drillock

harald_nancy wrote:

> I am mostly concerned about the relay trigger
> circuit. I would not want to overload it, with
> a too heavy "industrial" type of relay.
> Personally, I would rather that the breaker
> shuts off once in awhile than risk overloading
> the trigger wires with too big a relay.
> And as you once said, a deep
> cycle should not be charged too fast anyway.
> My main concern is not to damage anything that is stock,
> in this case, the wiring harness with the trigger wires.