Is there really no definitive dual battery write up?

I keep coming back to this topic hoping I’m just missing something but I cannot find a guide for an under hood dual battery set up. I see stuff for using the bed but nothing but an occasional photo of someone putting one under the hood with no thorough, idiot proof(me), instructions. With all the awesome guides we have for this truck surely someone has figured this one out and writing it up on here right? Anyone point me in the right direction? Nothing on YouTube either. Thanks!

 

While looking for a thread for you, I came across your 2020 thread.
https://www.tacomaworld.com/threads/best-first-gen-dual-battery-design.681312

I haven't noticed a 1st gen install since that time period. It appears to be a tight fit under the hood for 1st gen models. Those that have it done appear to know what they are doing but didn't have the forethought to do a step by step writeup. But several have said they will answer specific questions.

I did my own on my 2nd gen and can help answer questions as well but you first must decide where to fit a battery tray and if anything needs to be relocated.

Firstly, do you need a 2nd battery? Can you get away with a battery pack, or securing a deep cycle in the bed and charging it at home as needed?

I installed a 2nd battery because I offroad solo and it brought peace of mine should my primary die. I had a battery pack but it started losing a charge. Instead of buying a new one, which were pricey at the time, I wired in a 2nd battery, a Deka AGM 34 bci. This battery is going on 8 years in March and still working well.

 

Thanks for the reply! Funny you found that old thread. I forgot I had made one. So I do a fair bit of solo off-roading as well. Mostly looking into it as a convenience more than anything. I have a couple portable power stations that I am using in its place but if I can put something under the hood and simplify some of the set up I would like to.

 

A 1st gen is not the ideal platform for a dual battery setup with both batts under the hood. That is prime real estate, made worse if you have ABS. Can it be done? Sure, and has been. But is is a struggle. Way, way easier (and more common) to put the house battery somewhere other than under hood.

 

I certainly understand that. I guess my issue is the only other place is the bed and with a short bed I feel like that bed is even more prime real estate. Also I’m really heavy in the back as is and want to shift what I can to the engine.
Some friends have done battery systems in the backs of their rigs but they all have SUVs and no kids. I use this truck to take my wife and three kiddos on some big trips.

 

Bunking this in hopes someone has figured this out. Really would like to get a second battery under my hood. I think I have prematurely killed my starter battery from depleting it too low too many times.

 

I think you already know what the options are. You can delete ABS and cruise control and put it there, or maybe a cold air intake could give you enough space where the airbox sits. CAIs I’ve seen still take up most that space anyway though.
I’m afraid there just isn’t any other easy open spots under the hood, and that’s not going to change today, tomorrow or next year.

If in the bed or cab are both non-starters,
It’s time to get creative. You can look around under the bed. There should be space down there, particularly if you move the spare tire somewhere else like on the bumper. I’ve seen compressors mounted under there before. Needs a good box to keep it clean and dry though.

 

There are plenty of write ups on dual battery installs, but there isn’t one “definitive” way that works for everyone. They all depend on your specific setup, what batteries, where you have space, etc. The couple people I have seen mount both batteries together under the hood have had to make compromises with the size of the battery due to the limited space, and almost always end up with cracks in the core support and inner fender because of the weight. I believe @austinmtb has his set up like that, he might be able to weigh in.
https://www.tacomaworld.com/threads/austins-supercharged-mid-travel-build.514868/#post-16242464

More common is to put the second battery on the passenger side under the hood, but it takes the space that might have ABS modules, or air compressor, or windshield washer reservoir relocate. So if you have any of those it’s a no-go. Looks like @CoWj fit his there with a compressor, the 2.7L intake may allow for that. The v6 intake would probably not.
https://www.tacomaworld.com/threads/burt-the-old-man-with-a-hint-of-roger-and-daryl.596178/page-18#post-30076847

Otherwise, putting the second battery (or both batteries in my case) in the bed is a great way to distribute weight, not cram everything into the engine bay, and avoid cracking the tissue paper inner fenders with 60+ lbs of battery hanging off them.
You could also do something really unique like this guy:
https://www.tacomaworld.com/threads/your-unique-mod-on-the-1st-gens.118241/page-104#post-26728759

I think the point here is you’re going to have to get creative and come up with a solve for your specific needs, wants, and constraints. There’s no good bolt on solution for this unfortunately.

 

These Trucks are super limited in space. As well as it does vary by the 3.4 vs 2.7, 95.5-97 to 98-00 and 01-04 models and options. Like @drr said I was able to fit a group 34/78 on its side behind my airbox on a custom tray that I made. It also holds my ARB compressor. But its nearly up against the airbox and wiper motor. Then you also have to consider where you will mount the Charger or relay, mines under my starter battery on a tray I took out of a 4Runner dual battery kit we use to make and cut and rewelded the controller mount. Thirdly, its a lot of weight on the front end of these trucks, and we have all seen how crappy the sheet metal that toyota used and how much it fatigues and cracks with Off Road use, with out without additional weight pulling it down. There is a reason we never produced a dual battery kit for the 1st gen trucks a Off Grid Engineering. Its too custom and too many variables. I wont say you shouldn't do it, cause having dual batteries is rad and can save you in certain situations. But if you are just trying to run a fridge and camp lights Solar is a much cheaper and easier option to go for.

 

Dual batteries would be great. I'm not putting it under the hood. The metal cracks way too easy. A frame mount to help support it might work.

 

Whats wrong with the bed? 0GA cable is not that expensive..

 

Mostly just space. I use the truck for extended back country trips. At times taking my kids. We have a massive fridge plus the miscellaneous stuff. Makes space back there a premium.

 

I did have a dual battery setup under the hood but it led to a lot of cracking of the core support. I ended up putting a 200ah battery in my bed that can plug into an anderson connector to charge. It's basically a removable dual battery system that gets removed when I'm not on a camping trip.