ive seen a couple of options for underslung battery trays for VW vans but i don't see much out there for others.
Ive an NV400 with a deep area between the monocoque chassis rails and I've got 2 x 110ah leisure batteries that take up alot of space inside - and it came to mind last night when i was lining them up I've a lot to gain by getting them outside.
Really don't want to do a sunk floor mainly as my floors finished inside.
Has anyone seen a box that could be mounted to the chassis rail or the floor pan but can hinge or drop down to allow access to the batteries from under the van - or do i even need to enclose them - is there any harm to just making shelves on either side and clamping the bare battery to them - like they do on certain trucks in warmer climes.
Batteries are maintained by fixed install solar year round I'm not super concerned about the cold but would probably insulate them manually for events like the puffer.
Thoughts - or reasons why this is a bad idea , Usually there is a reason why you cant buy these things - small vans excepted because they are too small people will put up with bad ideas to create space.
I'd imagine a couple of three problems; damage from debris on the road, the environment (cold, salt, wet, exhaust heat) and theft
A bit of careful design would overcome the first two and the stealth nature of the storage would help with the second. I don't know what an insurer would think
Cable management would need attention to avoid excessive flexing over a longer cable and passing through steel panels, etc.
EV batteries (and petrol tanks) are fitted underneath where the consequences of a damaged cell(s) include fire
You definitely can't get them hidden under seat or back of a cupboard?
Not your van - but page 79 of
You could also consider switching to a LiFePo4 battery, that'd reduce the space your batteries took up considerably (you probably only need half the Ah).
i have a blank canvas atm in the back save for 2 seats. - i have an LPG tank on one side ( that i cant change for an underslung) - it runs the heater mounted vertically on the wall over the wheel well - all hidden by the kitchen cupboards then behind the rear seats but before the wheel well i have the fridge. and i could stick the batterys in a box under the fridge as my second choice - as i wanted to keep the top of the folded seat and the fridge level for longer objects - and the Shore power box and solar inverter were the perfect height to hide down there and ensure the heights were level . the batteries are about 75mm taller
never considered theft - figured that if anyone's far enough under my van to see that i have batteries then we already have issues - if im making it my self i planned to have a Steel shelf for them to be on slung between the chassis rail - so really the batteries shouldnt be any more exposed than the OEM one in the passengers step.
changing to life4po isnt an option.
Cable routing shouldnt be an issue - my split charge is already 4m long the battery leads wont be any longer.
The T5 campervan we owned for years had 2 x batteries in an underslung cage. No issues whatsoever. That was a conversion done in 2010 and still in use in 2026 (sold the van to a work colleague). Conversion company have been using underslung batteries for 20+ years, around 50-60 vans a year:
JERBACAMPERVANS.CO.UK 
DIYVAN.COM
These guys seem to have designs to do what im looking for stateside.
Thats got shed engineering written all over it to make it suit my battery sizes - frankly probably wont be much cheaper that buying it but at least itll fit both my van and my batteries.
Will get my tape out tonight.
50kg does seem alot of weight to suspend mind you might need a few bolts
Have you checked whether there is space for another battery under the bonnet?
We had a Bongo for a short period which had space for 2 batteries (apparently in cold winters in Japan this can be common) and when I had a T4 I bought a steel plate that enabled a leisure battery to slot in next to the starter battery.
Otherwise under one of the front seats is common.
You could bolt short battery cables permanently to the terminals and terminate them with anderson plugs. This way you don’t need to access the terminals or have long battery cables to connect them up. Also means you can isolate them easily in a rush rather than hunting for tools.
I don’t think I’d insulate them, unless you had a heater inside the insulation they will still end up at ambient temperature after a while, plus during heavy use/charging they won’t be able to dissipate excess heat. No one insulates batteries under the bonnet.
No space for batteries under the bonnet. They live under the passengers step in a cubby. There's room for a second starter batt but my leisure batteries are about 30% larger and so don't fit . For same reason they don't fit under the passengers seat base and it's not a mirror image on the driver's side. I checked. 🙁
Measured up last night and while I do have the depth required - it's only if I include the exhaust box - which as a lowest point I'd rather have that than a couple of leisure batteries. My monocoques only actually 140mm deep. Batteries are 175 without anything bolted to the terminals so it's a non starter currently -although not entirely off the cards if I relocate the spare wheel to the roof - which I'll need to do for the water tank anyway.
In my connect I discovered there was some extra space under a fake floor space behind the front seats - it seems to be for when sold as a dual cab so passengers have footwell space. I fitted an 100ah lifepo4 and diesel heater down there, you could easily fit another
Got similar?
