[patrol28]

Just wondering, is 8 b+s cable large enough to charge my aux battery which is in the back of the car so the cable run is about 4 or 5 metres long. The battery is a 120 amp hr agm and ill be using a smart start voltage sensing relay thingy (like a redarc)

 

[jimako]

Mate depends on what your running, with 8 b+s dont even think of giving yourself a jump start or running a winch.
Also the thinner the cable the greater the voltage drop and over 5 metres that would be a great loss.
Im about to setup my system with 2b+s

 

[patrol28]

will only be using it to charge the aux battery which will only be running a fridge. If I had a winch I would be running it off the main battery.

 

[drivesafe]

Hi patrol28, the 8B&S is a bit small but it will charge your auxiliary battery, but it will just take a lot longer if your auxiliary battery is in a low state of charge.

8B&S ( 7.9mm2 ) is fine for a second battery under the bonnet but with the much longer cable run, 10mm2 is the minimum recommended for a battery in the rear of a vehicle and if you going to haul a camper trailer or caravan, minimum size would be 6B&S ( 13.5mm2 )

 

[patrol28]

Ok thanks for that mate, I better run the larger cable then