How to make a cheap isolated dual-battery setup for $50

[luthj]

Pick a wire/cable that is rated for outdoor use in a wet location. Support larger wires no more than 12-18 inches with chafe protected supports. In areas that might chafe adding sleeving is good. The key to good protection is supporting the wire so that it won't move.

 

[dwh]

I usually just use bits of heater hose wrapped around and zip-tied in dodgy looking locations.

 

[continuecrushing]

well I'm now in the middle of my dual battery install. Things are going well...for now lol.

 

[evldave]

Wow I can't believe this thread continues to be active. Glad it is still working for folks. If I get some time I'll go review/update the links in the original post. Anything obvious that might help new readers I should add to the first post?

 

[salstoy]

Wow I can't believe this thread continues to be active. Glad it is still working for folks. If I get some time I'll go review/update the links in the original post. Anything obvious that might help new readers I should add to the first post?

I’d like an update regarding any hurdles to date that you may have encountered. Also, what extra accessories are you running in your vehicle and has this set up worked well for it

 

[DaveInDenver]

I usually just use bits of heater hose wrapped around and zip-tied in dodgy looking locations.

I've also used old garden hose and bicycle inner tubes in the same way.

 

[continuecrushing]

Renogy has a new DC to DC charger unit on amazon for $129 if anyone is on the fence about solenoids and such. Has 3 stage charge and can handle flooded, agm, gel, and lithium. Output is 20 or 40 amps ($199) depending on model, but 20a is nice for those who don't wanna install huge wire (of course bigger is always better).

Renogy 20A DC to DC Battery Charger for Flooded, Gel, AGM, and Lithium Batteries Using Multi-stage Charging on Amazon

 

[Presto88]

OK. Without going through the past 70 pages (because I know it's been mentioned!), exactly how big of a wire would I have to use for this 20A charger?

 

[john61ct]

what is the round-trip distance?

 

[dreadlocks]

OK. Without going through the past 70 pages (because I know it's been mentioned!), exactly how big of a wire would I have to use for this 20A charger?

Circuit Wizard - Blue Sea Systems

circuitwizard.bluesea.com

Length of Conductor is both positive and negative wiring combined.

 

[continuecrushing]

OK. Without going through the past 70 pages (because I know it's been mentioned!), exactly how big of a wire would I have to use for this 20A charger?

Like other said, depends on distance. Short stuff you could do 10 awg, but I’d go larger if possible, even on short runs.

 

[Presto88]

Wow. Thanks for the quick replies! This is really a great forum.

 

[carbon60]

Length of Conductor is both positive and negative wiring combined.

Yes.

I've always assumed that the frame is a zero resistance conductor when I use it for the negative return. What do others say?

 

[dreadlocks]

yeah thats fine, however if your going to pull some serious amps through the chassis you should have redundant grounding paths for battery/engine (alt).. I once had engine ground strap fail and the path to ground for the starter was a throttle cable, bet yeh can guess how that turned out.

 

[john61ct]

I've always assumed that the frame is a zero resistance conductor when I use it for the negative return. What do others say?

I only recommend using chassis return for cheap, unimportant and low current devices.

Don't do it much at all myself.