4Runner - Dual/Single battery

[Jeepncj7]

So I have been reading countless (probably 100's) of threads about dual battery vs single battery to power a fridge, and just can't decide. Wanted to see if anyone has any recommendations.

Background:

2007 4runner w/ 4.0 V6 completely stock.

Power needs:
44 - 50 Qt fridge + charge laptops/ phones etc for up to 3-4 day trips through the PNW (ie not a ton of sun). I don't plan staying stationary longer than 2 days most of the time.

Most likely picking up a Costway (Amazon) unit or a used ARB
/Dometic in same price point.


My needs I think should be met with a single group 31 deep cycle ( Thinking Northstar 31M) + 100watt solar on the roof. Then a backup jump pack.

But I also am thinking I do like the security of a dual system. If I went that route I was thinking about dual Duracell AGMs ( group 27 maybe?) And then just roll my own wiring setup incorporating a Blue Sea ACR. Eventually I would add solar as well, but not right away.

Piecing the dual system together, it's not that far off from a single Northstar 31m in terms of cost.

Any words of wisdom?

 

[Plasmajab]

Isolation switch for sure. You'd want the battery that the fridge's load to be isolated from the starting battery.

So you drive up to the site. Flip the switch to isolate the secondary battery from the vehicles main. Oops. 2 days passed and that battery is dead. No worries because the Primary battery can still start the rig. Start the rig, flip the switch and charge up the dead secondary battery.

 

[Plasmajab]

Another way Ive seen it done is that behind the fridge was a smaller 12v battery that the fridge ran from. When its charge was low, the owner would just start the rig, plug the battery into the cigarette lighter in the trunk and recharge it.

 

[Plasmajab]

Ha.. Another way I saw it done (yes another). My freinds silverado. It has twin batteries, but what he has is a switch that shuts off the secondary battery. In the field he runs everything on the primary battery. If he kills that one, no big deal. He flips the switch and can start the truck on the secondary battery. Like a built in booster pack.

 

[Rexplorer]

I think some timez its better to keep the batteries seperate for starting and use jumper cables. Less likely to blow fuses or relays. I have 2 batteries with 100amp fuses seperating them and a 600amp continuous rated solenoid. A start with the batteries connected would probably blow something.

 

[bundi3180]

Great Knowledge to pass on. Thank You

 

[Rexplorer]

Seems single is too sketchy, especially with a fridge. I'd bring a booster pack all the time, just in case. Then you might as well just wire a 2nd battery since you are basically carrying one anyway, just in booster form. Or run the fridge from the pack.

 

[v_man]

Having done a dual battery in my LX, it was probably overkill and possibly unnecessary for our power needs, but I'm still glad we have it. We camp (or try to) with very small kids and having car starting redundancy feels a little more safe and secure. If you have space for a second batt. in your vehicle, you have some extra cash lying around, and you want an engaging project, than a dual battery is a fun setup.

Last tip, the temp at which you set your fridge greatly affects power consumption. If you set your fridge temp super low, and camp in hot weather, you will quickly draw down a battery.

Here's a writeup I did on a dual:

https://www.overlandbound.com/forums/threads/dueling-batteries-a-dual-setup-on-my-07-lx.9245/

 

[Jeepncj7]

Thanks for all of the input! Lol now I'm thinking more about just doing a dual battery and not having the anxiety of working about it running too low.

As far as a dual setup, my plan is to use the blue sea ACR that has a delay to connect to allow for cranking of the starter before it connects. If I need to jump myself, I'll connect the batteries with jumper cables.

V_man - are you using a regular starting battery with a yellow top? Ideally I would like to do that, but I have heard you want to keep the duals the same (both AGM or FLA). Wasn't sure if you had an AGM starting battery as well.

 

[v_man]

V_man - are you using a regular starting battery with a yellow top? Ideally I would like to do that, but I have heard you want to keep the duals the same (both AGM or FLA). Wasn't sure if you had an AGM starting battery as well.

Yes, a Bosch flooded starting batt and a Optima deep cycle batt. Not really sure what info is out there about having a flooded batt and an AGM in the same setup. I did read time and again that having two batteries of similar age was important, IE, you don't want to have a five year old batt and a brand new batt in the same setup. I've seen no ill effects in close to 2 years of my current setup...YMMV

 

[Matoolie]

6 years with Diehard Platinum group 31 AGM and normal flooded battery on current 2014 4runner. AGM is accessory/secondary battery and flooded is normal OEM loads. AGM is probably over 8 years old and flooded was replaced in last two years. No issues. However did recently add diode to alternator sensing circuit to bump the alternator charge from 13.9-13.5V to 14.5-14.0V. To get more charge on AGM.

 

[slomatt]

I wouldn't be too concerned with the fridge killing your battery since most 12v fridges have a low-voltage shut off. My Edgestar fridge has reached the voltage cut off many times and I've never had an issue with starting the truck.

That said, if you have other draws such as lights or charging a laptop they could overly drain your battery. The solar panel will obviously help re-charge the battery, and a portable LiPo jump starter could give inexpensive peace of mind. If you plan to heavily draw down your "house" battery often then dual batteries may make sense, but at the expense of significant complexity and cost.

A friend of mine runs a large "house" battery and a small motorcycle sized battery that he uses for emergency starting. Another has a single DieHard Platinum and a small LiPo jump starter. Both have fridges and other loads, and neither have had issues with their setups.

 

[Louisiana Overland]

I had the same questions for my build a few months back....

I have a 2017 4runner trd off road. I ran an always on arb wiring and threaded receptacle for the fridge. The fridge is a cfx50 dometic. It has been on 24-7 for about 5 months now. For power I skipped on dual batteries and instead run an odessey group 34. My research led me to believe that the charging capability of the stock altenator simply wouldnt be able to maintain a group 31 let alone two of them. The agm odessey needs to be charge at (optimally) 14.5 volts. I added a rectifyer from an austrailian company(hbk i think) to boost the charging voltage. Before the voltage boost i periodically used a smart charger to top the battery off. I no longer have to do that. I do have a pretty good drive to work, about 30 minutes each way but i also work shift work so there are times the truck will sit a couple days without being run at all. I carry a booster pack but have never needed it. The battery, jump pack, wiring kit, and recifyer all together cost under $600 and seems to be working well. I have added a couple 20000 mah batteries to my kit for charging phones and running lights etc for camping. I use the anker ones sold on amazon with lumanoodles and usb powered fans mostly.

Be careful of overkill!

 

[systemdelete]

I was very aware of my ARB 50qt's draw on my stock single battery, but I didn't have anything else tipping me past the point of requiring the weight of an entire second battery. I went with an 80w high efficiency solar panel with a very efficient MPPT charge controller. The setup weighs significantly less than a second battery, and extends my time I can be parked without having to run the vehicle. The panel generally bulk fills the battery and by the time I leave work my alt is just topping it off.

Solar Monitor by Erik, on Flickr

 

[Jeepncj7]

Hey thanks for these insights as well! Haha that's the dilemma I have. It really boils down to cost. I'm going solar regardless of the setup, so it's really what the cost to benefit will be. I like wiring projects so I'm fine either way. I'll let you know which route I go.

Side note, what solar charge controllers are you using?

 

[JamesB]

So I have been reading countless (probably 100's) of threads about dual battery vs single battery to power a fridge, and just can't decide. Wanted to see if anyone has any recommendations.

Background:

2007 4runner w/ 4.0 V6 completely stock.

Power needs:
44 - 50 Qt fridge + charge laptops/ phones etc for up to 3-4 day trips through the PNW (ie not a ton of sun). I don't plan staying stationary longer than 2 days most of the time.

Most likely picking up a Costway (Amazon) unit or a used ARB
/Dometic in same price point.


My needs I think should be met with a single group 31 deep cycle ( Thinking Northstar 31M) + 100watt solar on the roof. Then a backup jump pack.

But I also am thinking I do like the security of a dual system. If I went that route I was thinking about dual Duracell AGMs ( group 27 maybe?) And then just roll my own wiring setup incorporating a Blue Sea ACR. Eventually I would add solar as well, but not right away.

Piecing the dual system together, it's not that far off from a single Northstar 31m in terms of cost.

Any words of wisdom?

If you decide to run a dual setup, just install a battery isolator. You can pick one up at most auto parts stores, or an RV supply store. It will keep both batteries charged when your driving. Then it automatically isolates each battery when you turn the engine off. Allowing one battery to be used for the fridge, chargers and other accessories, then you will always have a fully charged starting battery.

 

[Snupee]

Even running dual batteries if your planning on it keeping you fridge running for a couple days, you'll be lucky if it lasts a day and you would need to recharge it by running your rig. I just run a single AGM battery and have a 200W panel and MPPT charge controller. I can stay pretty much anywhere for multiple days (even in low light cloudy conditions) and my battery stays at 13V+ all day. I do carry a good booster pack just in case but rarely have ever needed it. I personally would prefer generating power while I'm parked knowing my battery will always stay charged. My 2 cents anyway.

 

[Stickman]

So I have been reading countless (probably 100's) of threads about dual battery vs single battery to power a fridge, and just can't decide. Wanted to see if anyone has any recommendations.

Background:

2007 4runner w/ 4.0 V6 completely stock.

Power needs:
44 - 50 Qt fridge + charge laptops/ phones etc for up to 3-4 day trips through the PNW (ie not a ton of sun). I don't plan staying stationary longer than 2 days most of the time.

Most likely picking up a Costway (Amazon) unit or a used ARB
/Dometic in same price point.


My needs I think should be met with a single group 31 deep cycle ( Thinking Northstar 31M) + 100watt solar on the roof. Then a backup jump pack.

But I also am thinking I do like the security of a dual system. If I went that route I was thinking about dual Duracell AGMs ( group 27 maybe?) And then just roll my own wiring setup incorporating a Blue Sea ACR. Eventually I would add solar as well, but not right away.

Piecing the dual system together, it's not that far off from a single Northstar 31m in terms of cost.

Any words of wisdom?

Genesis Off Road Dual battery set up. Running a snomaster 42s. Works great installs quickly.

 

[Joel S]

I had the same questions for my build a few months back....

I have a 2017 4runner trd off road. I ran an always on arb wiring and threaded receptacle for the fridge. The fridge is a cfx50 dometic. It has been on 24-7 for about 5 months now. For power I skipped on dual batteries and instead run an odessey group 34. My research led me to believe that the charging capability of the stock altenator simply wouldnt be able to maintain a group 31 let alone two of them. The agm odessey needs to be charge at (optimally) 14.5 volts. I added a rectifyer from an austrailian company(hbk i think) to boost the charging voltage. Before the voltage boost i periodically used a smart charger to top the battery off. I no longer have to do that. I do have a pretty good drive to work, about 30 minutes each way but i also work shift work so there are times the truck will sit a couple days without being run at all. I carry a booster pack but have never needed it. The battery, jump pack, wiring kit, and recifyer all together cost under $600 and seems to be working well. I have added a couple 20000 mah batteries to my kit for charging phones and running lights etc for camping. I use the anker ones sold on amazon with lumanoodles and usb powered fans mostly.

Be careful of overkill!

Do you plan to put a solar panel on top? I’m the same boat, have a 2018 T4R5 TRDOR, and am looking to add a second battery this spring.

Also I’m looking to add this.

So maybe I can charge the second? Hopefully it’ll be an easy setup

 

[Dana L]

I just installed the Genesis Off Road Dual Battery equipment in my 2014 4Runner Trail Edition. I bought two Group 24 Odyssey batteries. Follow the instructions, and installation is fairly easy. I don't have to figure out complicated wiring and charging systems if I bought piece parts, and hope they work. The complete setup is not cheap. I installed it for peace of mind when I'm miles from anywhere in the Nevada, Arizona or Southern Utah desert. I've had many occasions where I go in my garage to start one of my cars, and dead battery. No warning, just dead. I've been driving for 50+ years so dead batteries are nothing new, especially in the Nevada heat. What would I do miles from nowhere with a dead battery! Usually I off-road in groups, but sometimes not. A dead battery is one of the single points of failure on any rig that can stop you. That single point of failure is now solved. Two spare tires also solves another single point of failure. I just installed the Wilco Off Road Hitch Spare Tire Carrier with dual Rotopax gas packs. More peace of mind traveling over sharp rocks. I know people who have experienced two flat tires. Hopefully with my Nitto Ridge Grappler 10-ply tires I won't have any flat tires. Changing a tire on a steep mountain grade could be tricky. I don't want to find out. One other single point of failure is the serpentine belt. A spare can be carried but I've been trying to figure out if I could change the belt in the middle of nowhere. Has anyone tried?