Battery Vehicle Society

I didn't really trust what HiPower told me, which is why my cells are all vertical, but here goes:

They said that any orientation except completely upside down (with terminals and vent on the bottom) was fine. They also said that you could clamp the cells if you want them to stay pretty, but that swelling has no effect on cell life or performance (!).

My pack is sufficiently big that I never draw more than C/3 (180 Amps total, as I run 3 cells in parallel), so I think I can get away with my cells being mounted closely together but not physically clamped.

I am not sure which came first ( chicken or egg) but what I have ended up with is 2 dead cells that are swollen to hell. It makes sense to me that high current would make for high temperature and I assume swelling like I have would surely need high temperature. I think I have read that cells swell when they are over discharged?

Rory

Most I have come across are caused by over discharge. Got plenty of them actually. None due to over charge. Even a 1w bleed resistor will cause extreme bloating if its left to take the cell right down. This is why bottom balancing is so important. If you get a pack being taken down, the whole pack will go down the voltage will be very low and hopefully cause the system to shut down, if one cell is low the rest can still be delivering power causing that low cell to get even lower and even go negative. Its then dead. Sight bloating isnt a problem, but can crush the cell beside it, cauing the plates to short. SO dont assume if you have a shorted burnt cell that it had a fault, it could have been crushed. The force is tremendous. On splitting a duff pack I had one cell that had around 15mm swell each side once unrestrained. I always use a 5 tonne ratchet strap to compress the pack before releasing the steel straps, and then gently release the ratchet strap. The force is huge and you can get badly hurt. I then use the ratchet strap to compress the pack to refit the steel straps.
On thunderskys with a slight swell, I will release the pressure. Just to save neighbours.
I always use restraints, o one off packs 6mm alloy plates with 6mm stud works nicely. It also means you can better mount a pack, and if they are restrained, then the copper joiners dont come loose as the cells dont move around.
Grumpy-b

It's all coming together now. The heater is in, wired up and working (at long last).
My Type 2 lead works (Tested today, see photo).
I plan to get a bigger axle from http://www.imaxle.co.uk/ in Melton Mowbray, which should fix the saggy back end.
A faster charger would be nice, but the 2kW charger continues to work.

The camera tracking vehicles I work on use the heavier torsion bars from the heavier load version, and also a set of airbags to lift the rear end. Works a treat.
Glad to see alls working ok.

Grumpy-b

SELLING UP

I got the axle from IM axles last December, and it has made the van much nicer to drive. However, I am now looking to sell the vehicle if I can find the right buyer.

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Thats a shame, but I suppose life moves on, at least you know you've done it

ChrisB

Well, the great re-wire has begun, from 3 parallel down to 2 parallel. This means I have for sale 51 x 200Ah cells at £175 each. The van is also still for sale, now with a range of 200 miles theoretical, 160 probable real-world miles, offers around £19,500. I am hoping performance will be improved with less weight to carry.