Dual Battery setup (1 Viewer)

[isidhuji]

A quick update. The battery trays ordered look too big and even cutting them will probably not fit the said Group 24 batteries. I checked various things with the battery removed and it does look like any thing bigger than the PC1200 on @r2m build will most probably not fit. The max space available is around 14 L x 10L x 9 H which needs to fit the batteries and tray etc. Ultimately it does look like the Dual battery kit is not a bad idea conisdering how much custom work will need to be done and the component and labor costs. I think for now, I am going to upgrade to a 27 group battery (larger and higher capacity for winch if needed) as the starter and look into mounting the home battery in a different location. Maybe the Li battery in the back behind the plastic with an inverter and dc to dc charger. Just contemplating.

 

[giovanni]

A quick update. The battery trays ordered look too big and even cutting them will probably not fit the said Group 24 batteries. I checked various things with the battery removed and it does look like any thing bigger than the PC1200 on @r2m build will most probably not fit. The max space available is around 14 L x 10L x 9 H which needs to fit the batteries and tray etc. Ultimately it does look like the Dual battery kit is not a bad idea conisdering how much custom work will need to be done and the component and labor costs. I think for now, I am going to upgrade to a 27 group battery (larger and higher capacity for winch if needed) as the starter and look into mounting the home battery in a different location. Maybe the Li battery in the back behind the plastic with an inverter and dc to dc charger. Just contemplating.

I went a separate Li battery in the back with a DC-DC charger and am very happy with it. In an emergency situation, I can reverse the DC-DC charger and use the Li to charge the starter battery, so it is very flexible setup and works well.

Note that I elected to make a completely separate 12V circuit for the aux loads powered by the Li battery. It has a separate 12V bus bar and ground bus bar to avoid any circulating current losses.

Pictures of my solution: Builds - Giovanni’s 2016 460 build - https://forum.ih8mud.com/threads/giovannis-2016-460-build.1210780/page-7

 

[ducktapeguy]

I went a separate Li battery in the back with a DC-DC charger and am very happy with it. In an emergency situation, I can reverse the DC-DC charger and use the Li to charge the starter battery, so it is very flexible setup and works well.

Note that I elected to make a completely separate 12V circuit for the aux loads powered by the Li battery. It has a separate 12V bus bar and ground bus bar to avoid any circulating current losses.

Pictures of my solution: Builds - Giovanni’s 2016 460 build - https://forum.ih8mud.com/threads/giovannis-2016-460-build.1210780/page-7

My setup is almost identical. Li-FeP04 battery in the rear charged with a dual input controller from the start battery. The primary use for my battery is for the fridge and compressor, so having it in the back made the most sense rather than trying to shoehorn it under the hood. I don't like messing with factory wiring, so all aux loads are powered through a separate fuse/relay box.

I don't have the ability to reverse charge to jumpstart the car, but my controller automatically tops off the starting battery so the risk of having a dead battery is minimal. I also carry a lithium jump pack just in case, but that's usually used to jump other peoples vehicles more than my own.

 

[r2m]

Love my li jump pack! Probably never use jumper cables again.

 

[isidhuji]

Very nice. Looks like we have some folk running Li batteries. Did any one do a AGM 27F as the starter battery? My main concern is the air compressor (which is used with some regularity) and the winch (which is yet to be needed) will hurt the battery life. I will probably buy a li jump pack or figure a way to do it from the house battery.

I do keep the engine running when using the compressor or winch.

 

[giovanni]

I have an AGM as the starter battery - it's a 34R. I think if you always run those things with the engine running, the alternator can keep up with the demand and not significantly over discharge the battery.

 

[ducktapeguy]

Love my li jump pack! Probably never use jumper cables again.

They are a huge improvement over the older jump packs, but even the Lithium ones aren't perfect. I just had 2 more of them die on me recently, there's a shelf life to them no matter how much you use them. What I've started using a lot more is a capacitor jump starter, I think they work better in most situations.

Very nice. Looks like we have some folk running Li batteries. Did any one do a AGM 27F as the starter battery? My main concern is the air compressor (which is used with some regularity) and the winch (which is yet to be needed) will hurt the battery life. I will probably buy a li jump pack or figure a way to do it from the house battery.

I do keep the engine running when using the compressor or winch.

I'm still running lead acid, because I'm not sure if the alternator in the GX is capable of charging AGM correctly. Plus with the aux battery, I didn't see much of an advantage in switching the starting battery to something different. The alternator should have no problem keeping up with an air compressor, and the winch motor will probably need a break before you drain the battery with the engine running. The winch shouldn't be hooked up to a LiFeP04 battery because it's not meant to handle that kind of current draw. Better to keep it connected to the start battery.

 

[giovanni]

They are a huge improvement over the older jump packs, but even the Lithium ones aren't perfect. I just had 2 more of them die on me recently, there's a shelf life to them no matter how much you use them. What I've started using a lot more is a capacitor jump starter, I think they work better in most situations.




I'm still running lead acid, because I'm not sure if the alternator in the GX is capable of charging AGM correctly. Plus with the aux battery, I didn't see much of an advantage in switching the starting battery to something different. The alternator should have no problem keeping up with an air compressor, and the winch motor will probably need a break before you drain the battery with the engine running. The winch shouldn't be hooked up to a LiFeP04 battery because it's not meant to handle that kind of current draw. Better to keep it connected to the start battery.

With the GM diode mod, the Lexus will charge the AGM perfectly.

Alternator Voltage Booster for AGM Battery - ClubLexus - Lexus Forum Discussion

GX - 2nd Gen (2010-2023) - Alternator Voltage Booster for AGM Battery - Was browsing through the What did you to do your GX stickied thread and saw this post (https://www.clublexus.com/forums/gx-2nd-gen-2010-present/850986-what-did-you-do-to-your-thread-20.html#post10830474) by MarkVII. I...

www.clublexus.com

 

[r2m]

What I've started using a lot more is a capacitor jump starter, I think they work better in most situations.

Any product you recommend for a capacitor jumper?

 

[ducktapeguy]

Any product you recommend for a capacitor jumper?

I've only used this one

Jackco RZ-550 Rezervo Super-Capacitor Batteryless Jump Starter

Jackco RZ-550 Rezervo Super-Capacitor Batteryless Jump Starter. Battery Charging Equipment. In Stock. FREE SHIPPING on orders over $25! Call or Click Today! 1-855-550-2626.

tiresupplynetwork.com

so I can't really comment on any others, but a lot of them look to come from the same factory

DSR108 Schumacher 12 Volt 450 Amp Ultra-Capacitor Battery-less Jump Starter

DSR108 Schumacher 12 Volt 450 Amp Ultra-Capacitor Battery-less Jump Starter

www.centurytool.net

I was fortunate to get this as a sample test unit, and have been using it for about a year or two so far. For my purposes (i.e. a lot of project cars that need jumpstarts frequently) I like it better than the Lithium starters. These cap ones can be charged from a good battery in about a minute then used immediately, so it works almost like remote jumper cables. I've gone through three lithium jump packs already, their lifespan seems to be about a couple of years, shorter if you jumpstart a lot. This is because every time you use it for a jumpstart, you're killing the lithium batteries with essentially a dead short. The capacitor ones have a much longer advertised lifespan, I don't remember the exact number but long enough that I would never need to buy another one in my lifetime.

It is used differently than a normal jump pack. These are used when the battery is low, but not completely dead. It absorbs the remaining energy to charge the capacitor, then releases the energy in a burst to start the vehicle. However, since it's a capacitor and not a battery, it doesn't store the energy for very long, so it can't be used as a power supply or anything like that, and if your battery is completely dead you're out of luck. But with dual batteries, the chances of killing your starting battery is already much lower, and the probability of both batteries being dead is almost non-existent.

 

[BigSwede]

You are probably well down the road to dual batteries, but after looking at the whole dual battery question a while back for a previous rig, ultimately I backed away and went with the OBB (one big battery) plan, with jump pack backup. I also did this for the GX with an Odyssey PS 27F. I run a CPAP and a fridge overnight with no discernable impact on engine cranking performance the next day. I have run this setup for years and never needed the jump starter, and so I feel that a dual battery system is an unnecessary complication for my needs. And if you augment with solar recharge, even more so.

 

[ericm979]

Is the GX460 battery tray strong enough for a heavier battery? Some say the Tacoma's is not:

The NorthStar AGM Battery + Voltage Booster Upgrade

WTF happened there? Cables rubbed thru and shorted?? Regarding the voltage booster I found a diode from a GM at O’Reilly for about $4 that fits into...

www.tacomaworld.com

 

[isidhuji]

Is the GX460 battery tray strong enough for a heavier battery? Some say the Tacoma's is not:

The NorthStar AGM Battery + Voltage Booster Upgrade

WTF happened there? Cables rubbed thru and shorted?? Regarding the voltage booster I found a diode from a GM at O’Reilly for about $4 that fits into...

www.tacomaworld.com

The tray is not really supporting the weight. Actually with the current small battery size I think you can just toss it out as it does literally nothing. It is placed on top of a metal bracked made to support the battery on the fender. The battery brackets are also not part of the tray. They are directly attached to the fender as well. It however is for a 27F sized battery and will probably help reduce any lateral movement if the correct sized battery is installed. I will share some pics once I get the new battery installed.
I dont anticipate any issues with the larger sized one.

 

[r2m]

The tray is not really supporting the weight. Actually with the current small battery size I think you can just toss it out as it does literally nothing. It is placed on top of a metal bracked made to support the battery on the fender. The battery brackets are also not part of the tray. They are directly attached to the fender as well. It however is for a 27F sized battery and will probably help reduce any lateral movement if the correct sized battery is installed. I will share some pics once I get the new battery installed.
I dont anticipate any issues with the larger sized one.

Agreed, I have TWO (2) very heavy Odyssey P1200 batteries mounted in the stock location. I've been on many washboard roads, bounced the heck out of my rig for the last 4 or 5 years and never had an issue. Did have an issue with the bracket the shop that fabricated it. It came loose and I had to re fasten it.
So, in short, you can stick the biggest batter you want in there and be okay. You'll just need to figure out how to strap it down.

 

[r2m]

You are probably well down the road to dual batteries, but after looking at the whole dual battery question a while back for a previous rig, ultimately I backed away and went with the OBB (one big battery) plan, with jump pack backup. I also did this for the GX with an Odyssey PS 27F. I run a CPAP and a fridge overnight with no discernable impact on engine cranking performance the next day. I have run this setup for years and never needed the jump starter, and so I feel that a dual battery system is an unnecessary complication for my needs. And if you augment with solar recharge, even more so.

You make a great point, but pretty much any stock battery can handle a CPAP, fridge, phone charging and other small electrical draws overnight. People usually freak out about how much juice a fridge draws, but don't ever think that at night, the coolest time of a 24 hour period, a refrigerator my only come on once, if at all in the middle of the night, depending upon how cold it is outside. A fridge ONLY uses electricity when the temperature gets warm enough to trip the motor on. And when the motor does run, it's only just enough to get the internal temperature down to whatever you have it set at. So a fridge will usually only be on maybe a few minutes at a time. I've run my fridge along with charging phones, etc. off my second battery for several days before having to start my rig to recharge that battery.
If you start your vehicle every morning or next day after a night of it working the battery, I believe you'd be fine even with a stock battery.
I'd still keep some form of battery pack jumper just in case...

 

[ducktapeguy]

I think it depends on the situation. Dual batteries are not a necessity, but if you do have a lot of auxiliary loads it is very convenient.

I ran a single large SLA battery for maybe 4-5 years to power my fridge, and technically it works, kinda. I could run my fridge and start my car. But looking at the specs, my 80ah starting battery is really only 40 usable ah, and even at that level I was still killing batteries. It's easy to burn through that much power in a day or two with a fridge in a hot environment. I have a watt-hour meter connected to the battery to monitor how much energy the fridge is consuming, this past weekend with 2 fridges connected to my battery, over a 1 1/2 day period I used over 1000Wh, so on average about 500Wh or 40Ah per fridge.

Even with moderate use, I was replacing my battery every 18 months to 2 years, and thought that's just the price to pay for using a fridge. During that time, the capacity of the battery would slowly degrade, until it really wasn't useful as a power source. It also required a lot effort to maintain because I'd have to constantly charge my battery with an external charger because normal driving wasn't enough to keep the battery topped off.

I now have a 100ah LiFeP04 that I picked up on sale for about $400. When you look at the numbers, a full 100ah capacity, half the weight, 10X the lifespan, it's a pretty easy decision. Even if I had paid full price, I think I would've come out ahead financially if I'd gone that route from the very beginning. It was a bit of a pain to setup in the beginning, but it's a one time hassle then you never have to worry about it again, as opposed to the constant maintenance and worrying from a single battery.

The way I have mine setup now, the battery isn't really installed, just strapped down in the back. This was supposed to be a temporary setup until I could figure out a more permanent solution, but I think I like it better this way. Having the battery be semi-portable has a lot of advantages. I think the abundance of the lithium power stations has basically eliminated the need for a permanently installed dual battery system.

 

[r2m]

I now have a 100ah LiFeP04 that I picked up on sale for about $400. When you look at the numbers, a full 100ah capacity, half the weight, 10X the lifespan, it's a pretty easy decision.

Is this your battery? Amazon product ASIN B084DB36KW

 

[OCGX]

I also run a 100AH LiFePO4 (chins) battery. Runs my Iceco 24/7, it runs my diesel heater or heated blankets, my weboost, and recharges my gear.
I had an ecoflow which performed just as well, I just didn't have a permanent charging setup for that. My wife gave me a DC/DC charger for my birthday, so that was a catalysts for my dual battery setup. But if I setup my Ecoflow to recharge while driving, that would have been a good setup as well.

 

[isidhuji]

Quick update on my project. I decided to go with a larger battery 27f X2 power AGM for now. I plan to buy a battery box which can be connected using a dc-dc charger in the back. The 27f fit perfectly with no issues. It is the largest size you can put and the gx looks to be designed with that size in mind (The space under the hood and the tray size all point to a 27f battery).

 

[McDuff123]

Quick update on my project. I decided to go with a larger battery 27f X2 power AGM for now. I plan to buy a battery box which can be connected using a dc-dc charger in the back. The 27f fit perfectly with no issues. It is the largest size you can put and the gx looks to be designed with that size in mind (The space under the hood and the tray size all point to a 27f battery).

Congrats…same battery I have in my GX…its a powerhouse.
One suggestion…research “AGM diodes”…your battery will be happiest and live longest if your alternator can provide a higher voltage charge than it currently does.
I bought mine from HBK electronics, in Australia, but there are others available.
These diodes tell the alternator to put a higher voltage charge into your battery, which is what AGM‘s want.
Super easy install…literally pull a fuse, replace with the new fuse.