Dual Battery Setups! Let's see them! Multiple Batteries Thread!

How are you folks wiring your dual batteries in general? Are you primarily,
Using it as a dedicated "aux" circuit for powering specific accessories, like a dedicated 12v circuit to the bed?
OR
Wiring it in parallel with a start isolator to provide reserve capacity for the start battery?

 

ML-acr per instruction.

All my accessories are powered by a dedicated house battery.

 

Does that include hard mounted accessories like light bars, etc or just things like fridge, etc?

 

Everything not factory other than my winch is powered off the house battery.

 

Making some progress.. starting to hang and wire some chingaderas’s and gadgets..


safety wire on the fire extinguisher hose clamps…

 

Smart isolator. Everything but the winch off the aux battery. Solar charges both.

 

Looking to do a dual setup with a LiP04. Question about the redarc bcdc12xx line. Does it trickle charge your start battery after the house battery is fully charged?

 

I know the Alpha series trickle charge the starter battery once the auxiliary battery is full. They also have a recovery function that will send a charge for I believe around 15min to the starter battery in order to start the vehicle. I've had both the original BCDC 1225 and now a Alpha50. For the difference in price the added features were worth it to me.

 

Is the alpha 50 ip65 like the bcdc? I don’t think it’s worth it for me for the upgrade

 

I'd compare the two on the Redarc website. There's roughly a $134 difference between the classic and the Alpha, if the added features aren't for you then save the cash and go classic.

 

No, the BCDC does not have this function (I have the

$540 BCDC1240D REDARC 40A in-Vehicle DC to DC Charger with MPPT — Dual Input for Solar & Alternator Charging, Green Power Priority - 12 or 24V Battery Charger Suitable with AGM, Gel, Lithium LiFePO4 Batteries

BCDC1240D). The newer Alpha 50 has this. BCDC is older and probably better for under hood mounting, Alpha is newer and if I was starting from scratch probably the one I'd choose if you have the money to spare. Can't go wrong either way though, don't over-think it - both are good to go.

If you go the BCDC route and save the ~$150, I'd suggest picking up a jump start pack like the NOCO. Not only can you jump your truck (versus just trickle charging your own starter battery), but it's very portable and you can jump other vehicles without getting close enough to use jumper cables. More versatile, consider the application if you are offroad on a tight trail and your buddy's battery goes flat where the jump pack would be more useful. Just my 2 cents on pros/cons of each setup. Again, all just depends what your preferences are.

 

I ended up picking up a BCDC40 for a great deal used locally ($200). I do have a jump pack but the idea of trickle charging would be to keep the battery in good shape as the truck isnt a DD anymore. It is basically a dedicated wheeler/material hauler/ get to work in snow truck.

In reality I should just take it to work once a week to keep everything in good shape.

 

If anyone is looking to build a dual battery setup, I have a

$459 RedArc BCDC1225D REDARC 25A in-Vehicle DC to DC Charger with MPPT — Dual Input for Solar & Alternator Charging, Green Power Priority - 12 or 24V Battery Charger Suitable with AGM, Gel, Lithium LiFePO4 Batteries

RedArc BCDC1225D pre-wired with fuses from my old Off Grid Dual Battery setup for sale:

 

Is there any concern to leaving a dual battery setup always active even if nothing on the house battery side is being used for a few months? I have a 20a DC-DC and 100ah lithium in the truck now, but we usually have a couple months between trips when we use it, and I daily the truck.

I thought about adding disconnects so I can shut it all off when not needed, but in my head I don't see the need.

 

I wanted to separate stock from mods and assure that the starter battery always starts, even if I run down the house battery. I have an insulator 13.3V for the charging process. Thinking of getting an isolator switch to actively isolate the two batts if needed.

 

A little overwhelmed by all the info in this behemoth of a thread - Could someone point me in the right direction - Where should someone who's just confirmed a use-case for a dual battery setup begin?

I'm pretty close to scraping every page of the thread and feeding into an AI, but figured I'd start by asking.

 

What is the use-case? Where do you want to place the battery?

 

Basically a mobile office setup (Starlink + laptop + 2 USB-C portable monitors + router + fan + LED lights + charging phone and various other camping- and office-related gadgets). Conservative estimate of ~150-175 W. Typically work 8-10 hours/ day, so it needs to provide energy after the sun goes down. Planning on minimum of 240 W of rigid panel, and possibly a supplementary hood panel for trickle/ top-up while driving (if the budget allows).

I was considering engine bay, but after seeing how simple and clean @trezpass setup is, I'll likely do something similar, and build a box in the bed. I have an enclose camper shell.

 

I am in the process of collecting parts for my setup right now and its actually not that complicated figuring out what you need if you know your average electrical draw like you do.

If we use 150 watts at 10 hrs you will need 1500wh of battery assuming no solar input (cloudy/rainy days you will get next to no solar input). You then also need to think about your usage after work, lights, fridge, phone charging, fans and have enough battery to get you to the next morning. Then there is the issue of 2 days with not solar input but you get the point.

 

Does that account for charging the battery by driving the truck for a couple hours or so a day?