Looking for house battery placement input

[UncleTodo]

So I have a conversion van that I've gutted to convert. The house battery I'd planned on mounting in the alcove above the front seats as it's a nice out of the way spot.
Then I got to thinking it may get too hot up there in the summer so I was thinking about mounting them in the back behind the rear wheel well. In colder weather however I was thinking they would probably stay warmer in the alcove.
I did end up getting a prismatic cell array and cells would be mounted flat side by side if in the alcove.
Weight up above I'm not worried about, the alcove bottom is the vans roof and it would be nicely stowed out of the way up there.
So which spot would you say is better for the batteries and performance?
Thanks!
~T

 

[Luthj]

Heat is the enemy of LFP batteries long term. Do you plan on deep winter usage? If so you want them in a heated space if possible. In very cold weather any uninsulated compartment, or even an insulated one without airflow, will get below freezing.

Another option is a thermostatic heating pad on the pack, and then insulated it very well.

 

[UncleTodo]

I'm planning on travelling around a bit trying to travel with the weather, southerly in the winter and northerly in the summer in hopes of avoiding lengthy extreme heat or cold.
So I wouldn't expect below 32 nights frequently, but in warmer weather in the alcove in direct sunlight I'd imagine may get warm up there.
I came across heat shielding for batteries under hood, would something like that help and maybe some Reflecktix on the underside of the high top?
I could always hook up 120MM fans to help circulate air up in the alcove.

 

[Luthj]

Heat shielding won't help in a hot compartment like that. But if you aren't in extreme temperatures it probably won't matter where you put the pack.

Time and material used for insulating the inside of a full-time vehicle is rarely wasted.

 

[UncleTodo]

Okey doke, I'll go with the alcove then and put a couple circulating fans in and monitor temps in the summer/warmer weather.
I'd looked into thermal environments etc but didn't find anything to help this decision.
Thanks!

 

[Luthj]

The only real concern with an LFP pack is that you need to keep it above freezing in order to charge. If you rarely see any temps near freezing, its a non issue.

Extended periods above 90F can shorten the pack life via degradation, but given the lifespan of these packs, its only noticeable in really hot conditions, where the pack is above that temperature half the day or more.

 

[HRTKD]

My choice of battery location was based on proximity to the load sources (the main distribution panel in my RV), weight support, available space and finally the ability to work in that available space.

My 4s battery weighs about 45 lbs and I have two of them. I installed extra weight bearing surfaces to ensure that the 90 lbs of battery didn't cause any problems. The unused space was about 5' from where the loads all tie into, so that was a win. I didn't need to run heavy cable a long distance.

 

[UncleTodo]

Yes, but I believe it will still discharge down to 0ish or so.
That's where I think up top will help in the winter, even it dips to freezing or below at night being under the high top should warm up fairly quickly once the sun is up.

I'm converting my conversion van, so where ever I end up mounting the battery, that would also be where the other bits & components are mounted.
In the conversion van, it has a fiberglass high top, they cut out the metal roof over the rear section leaving over the front seats intact. This is where it would be mounted. Not the easiest access, but I'm envisioning building it all onto a slide out shelf for full access.
There is a whole cut out in the metal roof between the front seats I'll use for quick access to fuses etc.
Being a Chevy Astro van, space is rather limited so I think this would be good space utilization.

 

[HRTKD]

Consider using a CAD program to map out the available space and then fit the components into that virtual space. That's what I did. The first compartment I considered ended up being too small.

When fitting components into a virtual space, it's hard to take into account the wiring. Big cables can be bent/curved only so much.

 

[UncleTodo]

Thanks, that's a good idea. I'd actually just dabbled with a FreeCAD last year, time to do some more!

Along with fitting, being able to slide out/remove the works I'd have to have some easy disconnect points or something like this:
2 AWG 175 Amp

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