Dual Battery systems - choosing between 3

rlynch356

Defyota
I am putting in a dual battery system into the D90, mostly to support the fridge but i am considering 3 different systems.
I need something that is A) reliable and B) allows a self jump capability since i go places that a far from help and driving a defender the last thing i need is an unreliable self jump system. (Its a defender, so insert you own joke at home here, and don’t share)
I can fit 2 G34’s in the truck in the battery compartment and will stick to that.
I am also adding solar for when I’m stopped but space is limited.

I use a trailer with integrated solar and a G31 put want a back up for that as well.
I also have a Li jump start box, but that’s failed me a time or 2. Do its time for a dual battery system.

1) National Luna - Pros: proven system, Cons: seen some weird stuff with them too
2) IBS with the extra bridging relay to allow self start
3) Bluesea - 7622

I’m the type to cry once and just buy the best that is currently available.

Which one does the expo collective favor in terms of long term reliability?

I was leaning to the IBS system....

Thanks


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WOODY2

Adventurer
Having used a NL for several years I migrated to a CTEK 250s and couldn't be happier. It solves boosts the voltage to the house battery and negates the need for a solar controller and is very compact. Oh yeah 1/2 price.
 

john61ct

Adventurer
The design scenario is unclear. Is the fridge in the TV or trailer? Are there significant other House loads in the other location?

Conventional design is a dedicated Starter batt, but that duty cycle is minimal so maybe worth rejecting, or getting creative with that.

Then a much larger, true deep-cycling House bank for the fridge.

2x G34 is marginal for running a fridge in the heat more than a day or two, unless lots of solar input and / or hours of driving every day or two.

Maybe two House banks, if one is also needed for the other location.

Further discussion pending clarification of the above.
 

rlynch356

Defyota
Glad you asked, the fridge is a pretty small domotec 25, the loads are really on the truck battery.. winching etc.. the trailer is usually detached and can run on its own with the solar..

i am space limited so what i can fit is 2xg34’s in the truck.. i can’t yet move a battery to the load space (i have a seat there, and tools and a fridge not to mention the d90 is pretty small)

The ctek is interesting but does not give me self jump capabilities which is what i was after.. as well well as reliability.

I do a lot of “leading” on the trails we do.. and winching other people out .. stuff happens and next thing you know you battery is dead.. hence the combining requirement





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Last edited:

john61ct

Adventurer
Missed this, check for others.
The design scenario is unclear. Is the fridge in the TV or trailer?
Winch is not normally a House load, get your alt rpm up while in use, is that not enough to prevent power being drawn from the battery?
 

Rando

Explorer
Any of the Blue Sea ACRs will serve you well, and seem to be built to higher marine standards than the 'off road' type systems (NL etc). They also have the convenience of being 'drop in', no need to run wires for a control box to the cab, unless you want to.

I also am not sure I understand the concern over "self jumping". If this is something that you are doing often enough that pulling out your jumper cables is a hardship, then there is something very wrong in your system that needs to be addressed first. You are also rapidly killing your (likely expensive) starter battery if you are running it flat on a regular basis.
 

DaveInDenver

Luddite
I have the Blue Sea ML-ACR and it's worked fine for me. Dual sensing, so if either side is of sufficient voltage the relay will close. So you can put alternator on main side, solar on aux side. Once the side with the charger is raised high enough the other side pulls in. With solar that usually means it takes a while (or may never) if the house battery is deeply discharged.

I bought it originally due to the 500 amp rating and the option to self jump and use both batteries for winching but that's something I've never actually done. So I would definitely lower it on the priority list. Since I still carry jumper cables for using with other vehicles the point is moot and as long as you have a back-up option that's within reach of those (e.g. both batteries are in the engine bay) there's no need for the ACR to be sized for it.

FWIW, I run a pair of small batteries, group 25/35 Odyssey PC1400 in particular. A single one will run an Engel MT45 for about a day or two at most. I bring along a group 27 just for it if I expect to remain stationary longer than just overnight.
 
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Scoutn79

Adventurer
I used an IBS relay with 200A constant and 500A intermittent and switched it with a N/O oil pressure switch at 10 psi.
While this isn't perfect or near as fancy as the Redarc and other types or DC/DC chargers it works for me and has for several years now.
The IBS uses a ground to operate so a single momentary switch run to ground will allow for self jump.
Basically when the engine is off and the oil psi drops below 10 the switch disconnects, then once started and the oil psi goes over 10 it reconnects.
It takes up virtually no room, is very simple, easily bypassed if fails, offers self jump and is inexpensive.

Darrell
 
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Scoutn79

Adventurer
Missed this, check for others.


Winch is not normally a House load, get your alt rpm up while in use, is that not enough to prevent power being drawn from the battery?
I run my winch from the house battery (which is a start battery not deep cycle) if I drown the engine or roll it and need to operate the winch without the engine running I can still start it when I need to. Under normal conditons the engine will be running and the batteries tied to gether plus the alt providing power so all is good.
IMO the start battery should be responsible for nothing other than starting the engine.

Darrell
 

zoblo

Observer
Check out hellroaring at http://www.hellroaring.com/. I have been using one of their isolators for 7 years and no problems. Pretty simple and mindless operation. They also make battery combiners like when using a second battery for winching that may work for what you are trying to do.
 

rlynch356

Defyota
thanks for the links -
The reason for self jump capability is want the redundancy when i am in a remote place w/o the trailer (it is dropped as a base camp normally). I of course have jumpers but not always another truck with me.
The fridge will be tied into the house battery along with some other odds and ins (USB chargers mostly) along with a solar controller and a small 50w panel (normally not used, but JIC)

I have flattened the main battery before when i had another person running the winch and they did not start the truck, i was kinda busy so didn’t notice (we were doing a pretty difficult extraction at the time). That time it was no problems, just jumped it off another truck and was good to go..

Starter battery will run the Truck, Winch, and lights as its primary load

When i upgrade the winch to a Red Winch i may need to run the batteries in parallel for the winch (dual motor), I’ll be upgrading the alternator again as well. Batteries will be G34 Odyssey or northstar.
The Bluesea ACR looks like the simplest and most reliable solution (lots of good reviews not only in the off road community but in boating as well) and has a switch to combine.

Thanks




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spressomon

Expedition Leader

Rando

Explorer
thanks for the links -
The reason for self jump capability is want the redundancy when i am in a remote place w/o the trailer (it is dropped as a base camp normally). I of course have jumpers but not always another truck with me.
The fridge will be tied into the house battery along with some other odds and ins (USB chargers mostly) along with a solar controller and a small 50w panel (normally not used, but JIC)

I have flattened the main battery before when i had another person running the winch and they did not start the truck, i was kinda busy so didn’t notice (we were doing a pretty difficult extraction at the time). That time it was no problems, just jumped it off another truck and was good to go..

Starter battery will run the Truck, Winch, and lights as its primary load

When i upgrade the winch to a Red Winch i may need to run the batteries in parallel for the winch (dual motor), I’ll be upgrading the alternator again as well. Batteries will be G34 Odyssey or northstar.
The Bluesea ACR looks like the simplest and most reliable solution (lots of good reviews not only in the off road community but in boating as well) and has a switch to combine.

Thanks




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My point was that you can jump yourself with the jumper cables (ie connect them between main and aux batteries), this is not something that needs to be built into the dual battery system.
 

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