GX470 dual battery install

[nakman]

Ok, about 18 months later and version 2.0 of the GX470 battery install is complete. Forgot that I had a thread on this, so I'll use this same one to wrap things up here. To update you on what has transpired, last March my Blue Sea switch got a little friendly with an AC line, so I had to relocate it higher up, which I didn't like. I was able to fix the truck easy enough, a little JB weld & duct tape and we're back in business. 100% operator error, but I like learning lessons. Battery system has been working fine, and full-time solar has been working also, feeding into battery 2 first, then jumping the two once it's topped off.

Fast forward to last August, I camped next to Matt & crew from Off Grid Engineering. Had seen their stuff enough times on the website, but seeing in person really made me want to just have it- I admit my setup was a little homebrew, and his stuff is super top shelf, granted they share a lot of the same components, but after hearing him explain it for 3 days on end I was sold. And somewhat serendipitously, Matt had a really pretty 4th gen 4Runner running a stock roof rack.. so you can see where this is going, and yeah one thing led to another and we worked out a little deal.

So while his rack was in process, and my battery system was being assembled, I stumbled upon a 3D printed bezel that allows for the Blue Sea switch and dual voltmeter in the stock location. Here's where I got the bezel: https://sbeprecision.com/product/gx470-mirror-switch-plate-plus-2-switch-openings/ and this is what it looks like:

 

[nakman]

The digital volt meter came from Australia, not sure if this link will last but here's the Ebay ad: https://www.ebay.com/itm/222372167933?ul_noapp=true this is what the volt meter looks like once installed:

 

[rover67]

does the voltmeter stay on full time?

 

[nakman]

What makes this upgrade really sweet though is Off Grid Engineering makes a plug & play wiring harness that connects the Blue Sea switch to the auxiliary switch.. which now that it's working I have full control from the comfort of the driver's seat. I also have real time voltage. And I don't have a big box or readout sticky taped to my dash or console anywhere, making this the best dual battery setup I've had to date (other contenders being the Hellroaring, IBS, and the above homebrew system). If the red switch were a little more Toyota-like, you'd think this was a factory option. Link to the system: https://www.offgrid4x4.com/collecti.../2003-2009-toyota-4runner-dual-battery-system


The aluminum battery trays, wire sheathing, and insanely anal ways that Matt terminates every single wire make this whole setup look like it's ready for an auto show display. He was kind enough to not criticize my hacks too much as we ripped out my old, and installed his new. He also power washed the engine bay... hey first time for everything!

Here's the after pic... all new mil spec terminals, even the factory connection on the main battery is upgraded. I've never had such a clean electrical setup in a rig...

 

[nakman]

does the voltmeter stay on full time?

for now, yes the voltmeter stays on all the time. My initial plan was to run a switch through the negative sides so that I could flip it off, but I have actually not been annoyed by it- when I had a similar setup in my 80 the volt meter was really high up and kinda bright, but this one is a little dimmer, and being down by my knee I can't even see it while driving. It's actually in a blind spot behind the steering wheel, so I have to either move my head down or move the steering wheel up to see it. Also kinda neat to be able to peek through the window to see how the battery is doing, is the fridge running it down or are we good, etc. I suspect it only draws a few milliamps (haven't measured) and I wouldn't even be able to calculate how long it would take it to run down 2 AGM's, with solar backup- not sure it's possible.

 

[Jacket]

Good stuff Tim. I have one of those Australian voltmeters sitting in my garage; it's been awaiting a dual battery install in our GX460. I'll probably steal some other ideas from here when the time comes.

 

[DaveInDenver]

@nakman, a data point or two. I have one of these little dial type voltmeters in the truck.

https://www.qsradio.com/shop-now.html#!/Play-Series™-Voltmeter/p/67959033/category=13310007

It's draw is 8mA.

The dual display version is 10mA and I'd expect the guts are probably similar across all of them.

The consumption is about 0.2A-days. It'll drain my PC1400 completely in about, oh, most of a year. That would be to 10V, e.g. the whole 60 A-hr. In practical terms it would take a few months to seriously drain a battery low enough not to theoretically start a truck. You're talking consuming 10% of a battery's capacity per month.

 

[nakman]

thanks Dave, I figured you'd have figured that out.. confirming my bliss that I am not going to worry about it.

 

[CO Hunter]

I found a post on Expo portal where a guy made an elevated tray tall enough to clear that a/c line and he was able to get a group 34 in there. I think that is the only way to get larger than a group 35 in there.

 

[Shark Bait]

thanks Dave, I figured you'd have figured that out.. confirming my bliss that I am not going to worry about it.

Guys, I'm getting ready to install one of these in my GX460. Any update on the draw? Any issues?

 

[nakman]

I am still going strong... though I have noticed if I don't drive the truck for a number of days the battery voltage is lower than I like to see, like 12.0-12.1 rather than 12.4. I don't put that on the little digital display though, I think it's more of an outcome of having AGM batteries and sub-optimized charging. Those like to be charged at around 14.5v and my alternator tops out at 14.1... if you're geeking out and watching Redarc videos you've noticed one of their hot points is that it'll raise the charge voltage for you to 14.5 for this reason. I'm going to hook a solar panel back up to gain a little more charging voltage while parked, see how that does.

 

[DaveInDenver]

It's worthwhile to check what the manufacturer suggests for the correct voltage. I run Odyssey batteries and their recommendation is 14.7V for absorption and 13.6V for float. In their tech literature they mention testing determined battery life doubled if you use 14.7V as a set point instead of 14.2V. AGMs are fickle.

FWIW, I found a Ford diode that fits in the fuse box in place of the Alt-S fuse (the one marked "1.0"). This bumps my charging voltage to nearly 15V. That's actually higher than I want so I don't leave it in all the time. But I'll run it when I'm 'wheeling or if I haven't driven or charged the battery recently. My truck's charging system normally runs at around 14.4V max so it's bumping about 0.6V.

 

[Shark Bait]

I am still going strong... though I have noticed if I don't drive the truck for a number of days the battery voltage is lower than I like to see, like 12.0-12.1 rather than 12.4. I don't put that on the little digital display though, I think it's more of an outcome of having AGM batteries and sub-optimized charging. Those like to be charged at around 14.5v and my alternator tops out at 14.1... if you're geeking out and watching Redarc videos you've noticed one of their hot points is that it'll raise the charge voltage for you to 14.5 for this reason. I'm going to hook a solar panel back up to gain a little more charging voltage while parked, see how that does.

I got a solar panel, too, I need to hook up. Then I should be fine. If you've got any tips for that, please send them my way!

 

[AimCOTaco]

My 100 was always on the low side of charge voltage so I run a diode full time and my Optimas seem to be lasting a lot longer as a result. There is likely some variation from truck to truck like Dave mentions as his goes over 15 with a single diode, mine now runs right about 14.5 most of the time and I've never been over about 14.8 running the diode. Mine is a diode hacked into a piggyback fuse thing...

Maybe try one and see if you like it, cheap and easy.

 

[DaveInDenver]

My 100 was always on the low side of charge voltage so I run a diode full time and my Optimas seem to be lasting a lot longer as a result. There is likely some variation from truck to truck like Dave mentions as his goes over 15 with a single diode, mine now runs right about 14.5 most of the time and I've never been over about 14.8 running the diode. Mine is a diode hacked into a piggyback fuse thing...

Maybe try one and see if you like it, cheap and easy.

Slick, nice work. Doing something similar with a Schottky to hopefully find a nice mid-range voltage is a few lines down the do-to list.

 

[Shark Bait]

I did find this, and like the idea of installing the panel under the rack. https://forum.ih8mud.com/threads/re...iti-roof-rack-for-lc100.1093902/post-11971104

One thing I'm still looking for is where to connect the panel wires to charge the battery. Can I connect it to the fuse block I run from the house battery? I'm thinking I will route the wires down the PS into the rear cargo area since that is where the door hinge is. Then maybe I run it under the headliner over to the DS where I plan to put the fuse box and power outlets. There is a nice cubby hole there.

 

[DaveInDenver]

Do you intend to charge the house battery only from solar or do you want to be able to charge it from either the truck or solar? Do you want solar permanently connected? It gets a little more messy if you want the ability to run it in parallel with the truck charging system.

FWIW I run a pair of 50W panels made into a suitcase and just carry it and the charge controller in the truck and just set it out when I'm parked. The way my batteries are set up this means both my batteries get topping charges from the solar once the house is full. If the house side draws down the ML-ACR will isolate it from the starting side and leaves the solar on only the house battery.

 

[Shark Bait]

Do you intend to charge the house battery only from solar or do you want to be able to charge it from either the truck or solar? Do you want solar permanently connected? It gets a little more messy if you want the ability to run it in parallel with the truck charging system.

FWIW I run a pair of 50W panels made into a suitcase and just carry it and the charge controller in the truck and just set it out when I'm parked.

Not sure. Since I went to all the trouble of hooking up the ACR, I guess that's to charge from the truck, right? But it seems like a good idea to keep the house battery charged while I am parked. I got one of these. https://www.amazon.com/gp/product/B07Y5TKMZ4/ref=ppx_yo_dt_b_asin_title_o09_s00?ie=UTF8&psc=1 I was thinking I would just leave it hooked up all the time. My 460 sits a lot, especially now.

 

[DaveInDenver]

The ACR isn't a charger, it just gives you the option to combine and isolate batteries. You generally want to combine them during charging and isolate the house so that you don't risk being unable to start the truck. That's all it does, though. What I do is use the truck charging system to charge both when it's running through the normal factory system so it's biased for starter with the house hung on. When I stop I feed solar into the house side so the starter is just sitting there sipping. At night the house side continues to supply the fridge and eventually it'll disconnect from the starter, which is just fat, dumb and happy fully charged. In the morning the solar brings the house up and if it's a bright day by mid afternoon the house is charged enough that the ACR snaps back in and floats both for a couple of hours. Wash, rinse, repeat as long as you're parked. At home I feed shore power or a battery maintainer into the house side through the solar connection and both just sit there and condition as though it's perpetual sunlight.

 

[Shark Bait]

Here's my wiring job. I flipped the ACR so I wouldn't be crossing the positive wires over each other. I'm not real happy with the remote wires. Eventually, I will install the switch. It's kind of close quarters. Not a lot of room between the batteries and the fuse box. I had to trim the tab on the battery fuse holder on the house battery because it wouldn't fit. Plus, the hole was way too big, anyway. Not sure why I went with bolt holes instead of posts, but that is what I have. I could always get some all thread and put some sort of spacer in there and then use some nylock nuts like I've seen others do. Next, I'll run some 8GA back to a fuse block in the cargo area.