Dual battery for winch/other accessories

[amurp14]

Recently bought a 2016 Ram 2500 Laramie PW with an aftermarket winch. I've used the winch once, and after I was done using it, I couldn't retract the cable and my truck went into "power save mode". On the way home my truck died at a red light. Got it jump-started, started driving again, and it wouldn't stay running for more than 5 minutes, plus some warning lights (abs, traction control, trailer brake, etc.).

My best guess is the winch killed the battery, so I'm considering a dual-battery setup. I would like to use the auxiliary battery to only run the winch and some extra lights, and the primary battery to run all of the OEM components. Ideally, I would like the aux. setup to be completely separate from OEM system aside from the alternator charging the aux. battery.

Is this the best way to set this up? Or should I hook up the batteries in series/parallel?

Also, can my alternator handle charging both batteries?

Can I get a smaller aux. battery, or should they be the same size?

I have a background as a mechanic, but I've never done any major electrical modifications like this before, so any info is appreciated. Thanks!

 

[Travelin Ram]

Does that year model have the computer control charging, with a current sensor on the negative battery post?

That would affect whether you can easily parallel battery 2.

If you want to do an isolated battery 2, use a DC to DC charger for battery 2 and keep it completely isolated.

 

[Travelin Ram]

There are advantages either way.

Parallel will have the advantage in a long winch; more capacity. But more opportunity to compromise starting battery in extreme use.

Isolated has the advantage of better protection of truck electronics from low voltage. Disadvantage of less capacity to winch for sustained pulls. DC charger will limit recharging rate; however this also reduces opportunity for alternator overheating.

I’d personally isolate.

 

[zrock]

your battery had to be crap to begin with, i have winched lots and long pulls with a good single battery and never had it let me down..

 

[18CrewDually]

Your alternator should of recovered the battery on the drive home instead of dying at the traffic light. I'd first look into the health of the battery and alternator and consider replacing with a high amperage alternator and higher capacity battery.

 

[amurp14]

You are right, the alternator should've charged the battery. The only things aftermarket on the truck are the winch and a couple of lights. Sounds like I don't really need a second battery if my primary battery and alternator are doing their jobs. I'll look into that first.

 

[bcbouy]

i leave the truck running when i'm winching.dual alternators so i won't have battery issues.winching will kill a battery quick if you're doing it on just battery.

 

[zrock]

if the truck is running and your doing short pulls and letting the winch cool like instructions say the alternator should keep the battery charged enough to continue.. I have done long pulls and get in a hurry and just keep the winch pulling hard never had a issue with the battery or alt letting me down.. At some point i do stop and let things recover a bit.

 

[DILLIGAF]

Its cheaper to get 1 really good battery.

I used an H8 Odyssey and I put a 220amp Alt from a 6.4

Never had issues after that even when im winching at -40.

 

[danielmid]

Its cheaper to get 1 really good battery.

I used an H8 Odyssey and I put a 6.4 220amp Alt from a 6.4

Never had issues after that even when im winching at -40.

Was that a direct swap alternator?

 

[DILLIGAF]

Was that a direct swap alternator?

Yes Sir ! I had to trim a bit of plastic of the connector to clear my 6.4 intake. But it bolts right up .