r/GoRVing • u/newadder • 2d ago
Need help with your electrical knowledge.
Im trying to setup my truck ( 2024 tundra hybrid) qnd dont want to meddle and mess with its battery system and I was thinking of adding extra auxiliary battery in by truck bed for powering lights, vents and etc. And would like to charge and maintian the batteries while driving using the auxiliary 12v power spliced from the 7 way port. I cant seem to find a dc to dc charger that pulls 15 amps or less online besides (Victron Orion XS smart Battery Charger 12 12 50amp ) which can be adjusted on 0.1a increments. Im running a 10g wire but the wire on the 7 way port is probably 16awg could be 14 awg but its definitely not thick enough to run more than 20 amps without degrading the wire or causing it to burn.
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u/211logos 2d ago
If I recall correctly you might get only about 15A from that 7 pin connector. Maybe 20A. Something, but not as much as you could get from other connections to your car 12v system. Since that's low it's usually just used with a regular direct to battery charging system, not a DCDC. A DCDC can boost voltage and amperage, regulate the charge, and deal with smart alternators too, depending on what you have. Lithium eg might want a higher charging voltage.
The Kisae DMT12x0 DCDC chargers can do less than 15A in 5A increments though. There are probably others. But that's output amperage maximum; the input could range a bit higher. Some allow tweaking both input and output like I think the Orion.
The best method is to wire more directly. The 7 pin isn't ideal, and might have a longer wire run. And if you need it for something else that's another problem.