Small footprint 2nd battery?

[woytovich]

I'm thinking about adding a second battery to my 60 and I'd like to save some space under the hood. I plan on mounting it in the standard second battery location next to the radiator on the left side. (I have a few "extras" in there already: an electrical junction box, ARB compressor, Warn solenoid box... and I want to mount my ExtremeAire compressor as well so space is at a premium)

BUT don't want to go smaller if the gain is small (pun aware) and there is a significant penalty in functionality. I also want to use a standard off-the-shelf car battery rather than a more expensive specialty battery or LiFePo battery.

It'll be used mainly to increase capacity overall for winching & running the ExtremeAire electric compressor (usually with truck running). I will also have a small fridge/freezer hooked to this 2nd battery. (isolated for the short times I'm out on the trail and the truck is off. The fridge will likely be turned off when the truck will not be running for longer periods such as overnight or longer.)

So... has anyone given any thought to this compromise between size/footprint and capacity? I'm going to do my research but thought maybe someone else has some insight as well.

 

[Devils Paw 80]

Gotta sign up to follow this. Where will your radiator overflow bottle go?

 

[Prairie Swamp]

I haven't given it much thought but - there's no free lunch for a given chemistry. A smaller size means less peak amps and less amp-hour capacity. I guess if square area is a concern you could go taller if it fits. But I believe the rule of thumb in multiple battery systems is the batteries need to be as identical as they can be.

If you get into multiple battery sizes, types and even ages (4 yr old paired with brand new for example) you get into a kid of science experiment thing. It's probably been done by somebody with very simple wiring just not recommended.

What I have thought about is a second battery made up from 18650 cells ganged together. (Like Tesla's "Power Wall" or whatever they call it.) In theory you could have small 18650 based batteries squirreled away all over the vehicle. I have a LiFePo battery in my motorcycle and it saved 10 lbs over lead acid. But this then comes with the issues of having to have a carefully designed charging system and isolator. But I know this is outside your scope and just a pipe dream for me.

I'll be curious to see what you come up with.

 

[Willard]

Overflow could go on the passenger side, lots of people did this.

Winching, your winch should be on the main battery.
Second battery should be isolated from the main one and only in circuit to boost.
Any good fridge should be able to run for days on battery. Most have a low draw so that really is not an issue. You want something that is more of a deep cycle battery or the very least something that is designed for multiple charge discharge for the second battery. A race car type or marine battery is ideal. Race car type (like a Braille) or similar would work. Small like a motorcycle battery, but design to be beat on. Or go with a Marine battery.

What are you looking to do for an isolator? I have had great luck with the T-max dual battery system. Cheap and it works.
I ditched the crappy ford starter relay and build my own.
I believe I got this an FJCruiser forum but I cannot remember it was 2013. Nice thing about the design is you can have switched and always on circuits. So the fridge, accessory power for the rear were always on. Where the CB, Ham, accessories interior light, etc were on switched.

I will be building the exact same thing for my 60. It ran fine in my FJcruiser for 2 years and I pulled it out sold it an the new owner i believe is still using it.
The only thing I did different was wire this to my second battery and my battery isolator.

 

[Randy88FJ62]

Post #62 in this thread shows my engine bay with a full size battery in the second location and where I plumbed my overflow.

Show us your engine bay!

 

[woytovich]

Yes, the winch will stay on the main battery.

 

[MANUCHAO]

Winching, your winch should be on the main battery.

A group 31AGM as your main battery would be plenty for winching?

Second battery should be isolated from the main one and only in circuit to boost.
Any good fridge should be able to run for days on battery. Most have a low draw so that really is not an issue. You want something that is more of a deep cycle battery or the very least something that is designed for multiple charge discharge for the second battery.

^^^This... !!

Heat kills your cheap/expensive battery.....
Have you consider installing the battery elsewhere (not engine bay) ?

I have been running X2 brand batteries (northstar brand), and just replace them after 7 years of service.
These (still hold charge) dont seem to have the cranking power to turn the engine....
I dont winch much, but do car-camp lots, so a Group 31 is the Aux and a group 27 is the main.
Having a way to join the batteries (self boost) as stated by @Willard is a great options as well....

 

[woytovich]

As far as installing in the cargo area vs under hood:

1. I am trying to avoid running full battery cable sized cable back to the rear. Not as much for cost as it is for complexity and safety.
2. It is my internet experience that it is very common to install a 2nd battery under the hood. While it probably impacts a battery's life it can't be that they are particularly harmed by engine bay heat. Given that this is on the exhaust side I would be planning on a heat shield in any case.
3. I like the idea that all of the high draw equipment is close to the batteries if it all is under the hood.

 

[Willard]

As far as installing in the cargo area vs under hood:

1. I am trying to avoid running full battery cable sized cable back to the rear. Not as much for cost as it is for complexity and safety.
2. It is my internet experience that it is very common to install a 2nd battery under the hood. While it probably impacts a battery's life it can't be that they are particularly harmed by engine bay heat. Given that this is on the exhaust side I would be planning on a heat shield in any case.
3. I like the idea that all of the high draw equipment is close to the batteries if it all is under the hood.

Heat shield is a good idea. I have yet to kill a 2nd battery under the hood yet and have run them in everything except my F150. Hell my F350 had two of them stock.
The nice think is you can run a heavier wire (not battery cable size) using the breakers and relays providing you are not drawing more than 40 amps at once. Otherwise get a heavier unit.
And run this to the back for some of the accessories. Air compressor etc, would benefit from the distance of being closer to the battery or aux fuse box.
Fridge and other lighter draw accessories are not an issue and could run to the back using a junction panel or breaking up the fuse box.

 

[woytovich]

@Willard, yes. I have an (old school at this point) isolator (for charging) and solenoid/relay (for joining) system that I bought years ago. I know it is not state of the art but it'll work fine for my wheeling rig (and I already own it). I'll run (relatively short) full gauge battery cable (that i already have for that system as well) so I can draw full amps to the starter and winch as needed.

Just want to find a smaller battery to help with fitting it all up.

 

[Willard]

Look at those racing batteries. Most are very small and work very well.
Alternatively you could look at a motorcycle battery. Small as hell and run alot of things off them. My KLR is very light on available amps, but I still run headlight, LED taillights, LED off road light, GPS, heated jacket and gloves when cold etc and it holds up well. Much more and the generator cannot handle it, Not an issue on the 60.
that battery is very small (fits under the seat)

Yuasa AGM High Performance Maintenance-Free Batteries YIX30L-BS
Braille Battery No-Weight Standard Batteries B14115
Odyssey Drycell Batteries PC680
As some examples (I did not research much)
To give you an idea on size

the Braille
Length (in):5.800 in.
Width (in):3.400 in.
Height (in):5.800 in.
Weight:11.500 lbs.

The odyssey is also right around that size and is a deep cycle.

 

[OSS]

If a Toyota HJ series battery tray is installed on the left side or any battery tray really, the battery tray will take up that whole spot. Might as well fill the tray with whatever can fit in there. My vote: group size 27 wet cell deep cycle.
Smaller batteries have less juice, so choose what's most important: size /amps/weight. After doing the dual battery thing for 30 years in my 60, (winch, fridge & lots of other stuff) I'm a firm believer of using identical mid grade batteries in the engine compartment and replacing both at the same time. I was using 2 deep cycle Die Hards group 27 size. Fit perfectly. Also they have accessory lugs on them which come in very handy.
There's definitely better and more expensive batteries out there, but convenience, availability and price are important too. The way I use the batteries (with solar panels too) they don't last long, so there's no point in buying top end expensive batteries.

I once used a smaller & heavier & more expensive group 31 Sears AGM along with a wet cell 27. It sure cranked the engine fast. Had them separated with a big manual boat switch. Nothing automatic. I had to abandon it after a year in MX to cut down on weight (my brakes had gone to hell) so I don't know how long it would have lasted.

Adding another 60 lb battery to the front of the truck definitely affects the ride. And in my case back then - the braking. I no longer keep 2 batteries in the truck except for long long camping trips. You're just dragging that weight around everywhere. Having two batteries wears out the alternator faster too (cuz it's charging two).

 

[Willard]

I agree with @OSS but sometimes you have to use what your have. Buying two batteries is great, but really the 2nd battery does not need to be anywhere the power of the first. The big thing is deep cycle as he mentioned and can it dun everything you want (amps)
My second battery is a DieHard Platinum 34 Marine battery that I have had for a while. Still works fine for everything.

 

[morganism]

Someone onsite has dual AGM motorcycle batts mounted in rear cargo panel setup, is sweet and out of sight.

 

[Randy88FJ62]

I'll second Willard's comment. I run a deep cycle as my second battery. I like the idea I can bring it back if it ever gets 100% discharged.

When I winch I connect the two batteries together to give max amps to the winch. As soon as I am done they get disconnected. My winch power cables go to a manual marine battery switch that can handle the high amperage draw and then it gets switched to off so the winch never has power in case I get in an accident.

I used a blue sea 7622 ACR and it has worked fine for me dual charging needs.

You can mount you large compressor under the passenger pan. Lots of space under the truck or mount it in the back behind the quarter panels? Lots of options.

 

[woytovich]

Don't want to mount the compressor under the truck: damage & dirt.
Don't want to mount batteries in the back to avoid long heavy cable runs.
Like the idea of a deep cycle but want to keep the size and price down if possible, I'll research.
I can build my own battery tray to suit.
I'll research the batteries @Willard mentioned too.
I might add the manual switch to the winch power cables - belt and suspenders!

 

[Randy88FJ62]

You can build an enclosure to keep weather off the compressor under the truck. This would allow a full size second battery and free up engine bay space. I don't know of anyone in my club running a full size compressor in their engine bay at the moment.

 

[woytovich]

I wheel enough in deep water and over some pretty serious rocks to not want to have to worry about the compressor under the truck.

 

[woytovich]

Compressor should fit where the front (headlight) washer bottle (empty spot in center of image) was with plenty of room for a standard size battery - although I still might look for a slightly smaller solution to make it easier to keep the intake hose in place.

 

[OSS]

The second battery is going to put the ninx on keeping the cool air intake hose where it is. It's in the way. I resorted to this routing, but then it takes up some of that precious space. Maybe a smaller battery (less wide) will allow the cool air duct to scooch by.