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

I just installed thier kit. So far so good but I've only have had it for a few weeks. My scanguage says the alternator is keeping up but I still plan on getting a device to adjust the voltage output.

 

It’s a ~$225 Littelfuse version of the Blue Sea ML-ACR isolator, and then $474 worth of cable, bracket, and bussbars. It’s clean and relatively painless for install but you could do the same for quite a bit less. The “boost mode” they advertise is just the manual combine function of the battery isolator.

 

understood, i do like the idea of having that particular part of the dual battery setup already done and nice & neat

any issues with the stock alternator keeping things topped off? @Hilborn

 

Not yet. I am monitoring it.

 

@tacomavan I am noticing the alternator is having fun trying to charge 2 AGM batteries. It's reading 13.8 with fresh batteries. I'd like to see it at 14.1. I will be looking at something to increasing it's output.

 

Question for you guys since I don't know much about the lithium batteries. I currently have 2 yellow tops with the stater battery isolated by a MLACR with a solar panel hooked up to the accessories battery. Can I switch my acc battery to lithium and still charge both that and the yellow top straight from the alternator? Or will I have to completely change up my wiring and install a controller to properly charge the lithium battery?

 

do you have the tow package w/ the larger alternator (130 AMP?)?

 

Yes.

 

after reading more (with still even more to go!) leaning towards the off grid engineering dual batt system w/ the

$465 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

BCDC1225D & passenger side mount. Separating out that weight to avoid damage to the driver side front and being able to keep my current starter battery and only buy a single group 35 AGM is also appealing.

i've been reading some of @bagleboy 's posts and i like his philosophy in regards to having multiple smaller panels spread throughout the truck. So i'm thinking of a Blue Sea 6-circuit in the rear passenger-side cubbie (i have an ARB twin in the driver side). If anyone could critique the following that'd be great:

Group 35 AGM (Off grid engineering w/ BCDC1225D) House Batt -> 4 awg wire -> Blue Sea 285 Series Surface Mount 80A (285080F) within 12" of House Batt -> 4 awg wire to rear passenger cubbie (probably 20-24' run?) -> blue sea 6-circuit part #5025

then from there camper lights (Hardkorr) and fridge (probably on the smaller side), then eventually some solar tying into the redarc w/ the MPPT.

 

4 gauge wire seems a might overkill. The Blue Seas fuse panels have a 100 amp total power limit, I believe. And, it does not sound like you are running any appliances that will draw massive power (the ARB compressor being the exception).

I think 8 or even 10 gauge wire will suffice for your application.

 

would also mean downsizing the breaker to fit the smaller wire size? 40 amp for 8 or 30 amp for 10?

https://www.thehulltruth.com/attachment.php?attachmentid=642947&stc=1&d=1461122558

 

I ran #10 from a 40A fuse to the panel and ground buss in the center console(only 10’) and a dedicated fuse/wire to the compressor, and another dedicated fuse/wire to the bed panel. Size the wire to the load and length, longer runs you’ll want to bump the wire size to avoid excessive losses but overkill adds weight as well as unnecessary cost. If all you’re running off the house battery is a fridge and some lights then #8 or #10 is plenty. High draw items like a compressor should be run from the starter battery with the motor running since draws that high cause excessive battery drain. For that reason it’s good to put the compress up front unless you have a specific need or desire for it to be in the back(air hose is cheaper than copper wire).

 

Yes, to be safe.

The main reason you use a breaker/fuse on a power line is to trip if the line shorts to ground - such as when the vehicle is in an accident.

Granted, if the fuse/breaker keeps tripping during use, then your current draw is greater than the system you have designed/built, and you will want to reevaluate your design.

As I said, it doesn't sound like you will be running a large load - the compressor is the exception. Plan for the compressor draw, add a little capacity, and you should be fine.

I run my compressor off my second battery. While it does draw the battery down during use, it does not kill the battery airing up 4 tires. And, if I keep the engine runnning, the DC/DC charger replenishes the charge.

 

the compressor I'll be keeping it as-is & attached to the starter battery and only run it while the vehicle is running. The house battery will likely only have a fridge and camper lights (X5 hardkoor - 1 on each door, 2 up top) although i want to leave room for a small fan or recharging phone overnight, etc.

if a standard fridge pulls 9A & X5 hardkorr's pull 1.2A/ea, it doesnt seem like a group 35 would support that w/ 60 AH at 50% Depth of discharge, so 30 AH? figure lights only run 3 hours max, but the fridge would be pulling 9A from the time i got to camp and turned off the vehicle until the next morning departing.

 

100AH deep cycle seems pretty common. I don’t think it’s 9A continuous but I could be wrong.

 

those are primarily LiPo4's though right? I'd like to keep the battery under the hood if possible, and from what i've read you're not supposed to put a LiPo4 in the engine bay due to heat tolerancess

 

Amazon description on the ARB 50 qt "0.85 amps/hour average power consumption tested at 37.4˚F cabinet temp. 78.8˚F - 87.8˚F ambient temperature range. Test duration of 66 hours and supply voltage of 12V DC. " No idea how accurate that is, but that would make a group 35 under the hood very doable for my needs. Fridge would be pulling around 15 amps total if i turned the truck off from 4 and didnt start it again till 9 next day. would leave another 15 or so for lights + some charging which is plenty

 

Ran a 2/0 line from the bed dual battery setup to the engine bay stud mount. The way it was previously wired was fine but I’m changing it up a bit and the existing 2awg wasn’t cutting it for the length of run and starting.

 

i made a box to house the battery, charger, etc at the front of my driver side full length drawer system. First time working on something of this scale w/ 12V, this is what i have so far. Running into a bit of a snag as to how to arrange the positive bus bar. The pencil in the below wiring schematic is where i'm not quite sure. I also want to add a master switch in there, does this look correct? If members want to give some feedback that would be much appreciated!

Along with the 40A fused red 6 awg welding wire cable from the starter battery, i was going to run a black 6 awg welding wire cable to the ground point on the frame near the starter battery to the negative bus bar in the box, then ground everything in the box to the bus bar...any issues with that regarding length of run or is there a better way to ground to chasis?

all my wires will be coming in through the same hole on the left side, then through a hole on the front of the driver rear wheel well on down to the frame. I'll also be doing a run to a fuse panel behind the driver's side taillight, and from there circuits up into the super pacific



NOT COMPLETE, WORK IN PROGRESS:

 

To address the wire size question, here is what I typically go off of:


I do have a few questions on your choice of fuses/breakers.

For your master switch, just make sure it can handle the total current you plan on running through it. As for the fuse before it, same deal.

If you plan on running either fuse panels at max capacity at any point in time, those circuit breakers won’t pop because of the 40A fuse you have at the master switch. I would personally lower those breakers to something like 30A. That being said, if you run both panels at max capacity (assuming 30A) then the fuse would pop. Or you could up the fuse before the main switch.

If you plan on using the breakers as switches for the fuse panels, that’s fine. Otherwise I don’t think you really need them.

I may be wrong on some things, so just keep that in mind when other people post up too.