Dual battery setup (1 Viewer)

[Fj80oregon]

I am also going to add this here just to help people researching dual batteries, kits, etc. Sorry @Fj80oregon I am not trying to pick apart your install, but I have had numerous conversations with people about what type of auxiliary battery to buy, and I can use your picture as an example. I always recommend that people spec in a battery from a 91-92 as the terminals are mirrored from the DS of the later models. This keeps the positive terminal more inboard and further from the underside of the hood. It also makes the cabling a bit cleaner and will mimic more like what Toyota intended. If you were to use the same size battery that comes with the rig, the drivers side would fit a Group 24F and the passenger side tray would get a Group 24. Same batteries, just different post orientation.

In the example below, this is the same post orientation as the drivers side. Ideally, it would be opposite of what is shown here.

View attachment 2999469

Thanks for the help 2 years to late!!!!
All in fun don’t get mad!
Your kit is still working great even though I installed some stuff my way! It’s amazing I even accomplished this I can barely get my shoes on the right foot. The ACR unlatching still catches me off guard sometime with that loud CLICk!

 

[DivByZero]

Here's a pic of that switch installed on my rig:

 

[80seriesnut]

I am also going to add this here just to help people researching dual batteries, kits, etc. Sorry @Fj80oregon I am not trying to pick apart your install, but I have had numerous conversations with people about what type of auxiliary battery to buy, and I can use your picture as an example. I always recommend that people spec in a battery from a 91-92 as the terminals are mirrored from the DS of the later models. This keeps the positive terminal more inboard and further from the underside of the hood. It also makes the cabling a bit cleaner and will mimic more like what Toyota intended. If you were to use the same size battery that comes with the rig, the drivers side would fit a Group 24F and the passenger side tray would get a Group 24. Same batteries, just different post orientation.

In the example below, this is the same post orientation as the drivers side. Ideally, it would be opposite of what is shown here.

View attachment 2999469

Wow it's the little things that you don't think about. When I picked up my second battery I just told them I needed a replacement for my 96 which puts my positive next to the fender.

 

[NKP Garage]

In terms of a switch, here's a good option:

Push Switch BATTERY LINK T2B63SG fits LandCruiser 80s & 79s , Hilux, Prado 90s & 95s Horizontal with dual LED in green ON-OFF/MOMENTARY

12V 3A Laser etched ON-OFF / MOMENTARY OEM Replacement HORIZONTAL Push Switch with dual GREEN LED lights for TOYOTA LandCruiser 60 Series With twin headlights ONLYTOYOTA LandCruiser 75 Series (All Models)TOYOTA LandCruiser 80 Series 1990 ~ 1997TOYOTA LandCruiser 78 / 79 Series with Steel...

www.aironboard.com.au

View attachment 2999937
Comes in either vertical or horizontal orientation. I use it in my rig, with a RedArc battery isolator, which is really just a solenoid like @98 SNAKE EATER posted, but with a small microcontroller on the top to handle the connection/disconnection based on the switch and charge level. Also allows you to illuminate this switch to indicate in the cabin when the batteries are connected or not. I run this in my 80, and I'm very happy with it. I'll post a pic later.

I'm not really about the dual battery thing, but I'm diggin that switch.

 

[79F250]

In terms of a switch, here's a good option:

Push Switch BATTERY LINK T2B63SG fits LandCruiser 80s & 79s , Hilux, Prado 90s & 95s Horizontal with dual LED in green ON-OFF/MOMENTARY

12V 3A Laser etched ON-OFF / MOMENTARY OEM Replacement HORIZONTAL Push Switch with dual GREEN LED lights for TOYOTA LandCruiser 60 Series With twin headlights ONLYTOYOTA LandCruiser 75 Series (All Models)TOYOTA LandCruiser 80 Series 1990 ~ 1997TOYOTA LandCruiser 78 / 79 Series with Steel...

www.aironboard.com.au

View attachment 2999937
Comes in either vertical or horizontal orientation. I use it in my rig, with a RedArc battery isolator, which is really just a solenoid like @98 SNAKE EATER posted, but with a small microcontroller on the top to handle the connection/disconnection based on the switch and charge level. Also allows you to illuminate this switch to indicate in the cabin when the batteries are connected or not. I run this in my 80, and I'm very happy with it. I'll post a pic later.

Tried to order this from Australian site, doesn't work for US addresses. Tried the US site, they don't carry this particular switch.

 

[DivByZero]

Tried to order this from Australian site, doesn't work for US addresses. Tried the US site, they don't carry this particular switch.

Welcome to the problem the rest of the world has when ordering from most US sellers.

When buying from the US, I've had to use shipping forwarding services in the past, to give a domestic US address that will then forward the package to Australia. I'm not familiar with services that work in reverse, but I imagine some probably exist. In this case though, you might have better luck going another route. This seller also sells direct on ebay.

https://www.ebay.com.au/itm/294961263924

Although their listing doesn't offer US shipping, if you contact them there, you might be able to work something out. Might be worth checking out their range too and getting a few others if you're so inclined. I also use three other named switches from them for extra lighting on my rig (led light bar, rear lights, off road lights).

 

[79F250]

Welcome to the problem the rest of the world has when ordering from most US sellers.

When buying from the US, I've had to use shipping forwarding services in the past, to give a domestic US address that will then forward the package to Australia. I'm not familiar with services that work in reverse, but I imagine some probably exist. In this case though, you might have better luck going another route. This seller also sells direct on ebay.

https://www.ebay.com.au/itm/294961263924

Although their listing doesn't offer US shipping, if you contact them there, you might be able to work something out. Might be worth checking out their range too and getting a few others if you're so inclined. I also use three other named switches from them for extra lighting on my rig (led light bar, rear lights, off road lights).

I just looked at the Ebay listing. Specifically says may not post to US. Oh well, I'll figure something else out.

 

[beatle_bayly]

I agree, having the +ve post outboard puts it dangerously close to the hood structure. However, there is one advantage to having identical batteries in both positions.

If your start battery completely fails (drops a cell, cracks the case etc), having an identical auxiliary battery means you can easily physically swap it into the start batt cradle and the cables will still reach the terminals. If you electrically pull that trashed battery into the start circuit (via jumper cables or using your VSR solenoid) you risk frying the remaining good battery.

On my RHD vehicle, the OE cables aren't long enough to fit a mirrored battery terminal arrangement.

When I had identical batteries I'd also swap the batts over at each oil change so they both get a workout in the start battery position. Seemed to prolong the life of both batteries.

I used a short length of radiator/heater hose, cut to fit over the terminals, as added insulation on any +ve/hot connections.

I am also going to add this here just to help people researching dual batteries, kits, etc. Sorry @Fj80oregon I am not trying to pick apart your install, but I have had numerous conversations with people about what type of auxiliary battery to buy, and I can use your picture as an example. I always recommend that people spec in a battery from a 91-92 as the terminals are mirrored from the DS of the later models. This keeps the positive terminal more inboard and further from the underside of the hood. It also makes the cabling a bit cleaner and will mimic more like what Toyota intended. If you were to use the same size battery that comes with the rig, the drivers side would fit a Group 24F and the passenger side tray would get a Group 24. Same batteries, just different post orientation.

In the example below, this is the same post orientation as the drivers side. Ideally, it would be opposite of what is shown here.

 

[jaymar]

Dunno much about electrical, so wanted to ask a few questions:

1) Has anyone routed the #2 battery cables along the firewall?

2) Is there any good reason (other than cost) NOT to do this?

My thinking is to avoid water- metal- adjacent bare wire and ripped-out terminals in the event of serious front end damage...

 

[cvenom96]

Mine is routed back along the firewall.

 

[DivByZero]

I also routed along the back firewall. It felt cleaner. If the connection is fused at both ends right near the batteries (which it should be), then the risk from a front end collision isn't much different either way, but I opted for the rear run. I don't like the idea of having to lean over such a high amp link each time I service the vehicle, or having that many amps running over the top of the radiator. The cost difference is significant though, both because of the extra length, and the need to use a thicker wire to compensate for the extra length. The Toyota factory second battery cable is routed along the front. I still prefer the firewall route though. From memory, I used 2 B&S wire (32mm2 area), which I crimped myself with quality copper terminals from an electrical supplier (think it was RS electronics down here). It's not that big a job actually, but you want to have your route fully planned and measured before you start cutting cable.

 

[jaymar]

Mine is routed back along the firewall.

Got pix?

 

[jaymar]

I also routed along the back firewall. It felt cleaner. If the connection is fused at both ends right near the batteries (which it should be), then the risk from a front end collision isn't much different either way, but I opted for the rear run. I don't like the idea of having to lean over such a high amp link each time I service the vehicle, or having that many amps running over the top of the radiator. The cost difference is significant though, both because of the extra length, and the need to use a thicker wire to compensate for the extra length. The Toyota factory second battery cable is routed along the front. I still prefer the firewall route though. From memory, I used 2 B&S wire (32mm2 area), which I crimped myself with quality copper terminals from an electrical supplier (think it was RS electronics down here). It's not that big a job actually, but you want to have your route fully planned and measured before you start cutting cable.

Happen to have any photos?

 

[80seriesnut]

I have a question about connecting the pigtail that comes out of the blue sea ACR. I read somewhere on here that you dont want to connect the brown isolation #1 wire to start. Is this correct?

 

[DivByZero]

Happen to have any photos?

I do, but it ain't pretty!

I didn't take pics inside the fuse holders, but they're just like this:

It's all just crimped ring connectors onto screw terminals end to end. I used an adhesive backed heat shrink around the terminal ends.

 

[beatle_bayly]

Another 'trick' is to take your accessory power off the +ve aux battery output on the battery isolator/VSR/Manager rather than off the +ve of the auxiliary battery. That way you can remove the aux battery more easily and not have a bunch of wires flopping about (you only need to remove the main battery cables, and isolate the +ve). Plus, depending how your isolator operates, your accessories will still get power once the isolator switches over, even though you don't have the aux battery installed (obviously only with the engine running).

 

[80seriesnut]

Another 'trick' is to take your accessory power off the +ve aux battery output on the battery isolator/VSR/Manager rather than off the +ve of the auxiliary battery. That way you can remove the aux battery more easily and not have a bunch of wires flopping about (you only need to remove the main battery cables, and isolate the +ve). Plus, depending how your isolator operates, your accessories will still get power once the isolator switches over, even though you don't have the aux battery installed (obviously only with the engine running).

You totally lost me here.

 

[beatle_bayly]

Sorry,

My Redarc Voltage Sensitive Relay (VSR) is mounted near the MAIN battery. Then a heavy wire connects from the output of the VSR and runs across the front to the +ve post of the AUX battery. Same way most of us do it.

I had always struggled to find battery terminal connectors with enough posts to attach all my accessory wires, and it always looked like a rat's nest.

Looking at my AUX batt now you only see an earth and +ve lead connected. Everything else I've tapped off the OUTPUT terminal of my VSR (to a heavy bus bar and additional fuse block adjacent the MAIN).

To pull the AUX batt:
1. disconnect the two battery terminals, and importantly
2. disconnect the AUX batt feed at the VSR (so there is no risk of shorting at the disconnected AUX batt +ve lead),
3. remove clamp and lift it out of the cradle.

The accessory bus bar and fuse block will still receive power once the once the VSR senses the main battery is up to voltage, closes, and allows power to the VSR aux batt output terminal.

If it's still fuzzy, I'll attempt to draw a picture.

 

[cvenom96]

Requested pics. You can't see most of it along the firewall since it's tucked in w/ the main harness back there.

 

[80seriesnut]

You have this wire backwards.

View attachment 2999460

Why is this wire backwards? The wiring diagram on blue seas website says the house battery should be hooked to the A(left) side of the ACR.