Battery Vehicle Society

Glad to hear that, Tim, as I'll admit to being just a bit concerned about some of your massive investment in cells being lost, after my recent discovery. I think you had the advantage of having evidence that the cells were tested, so presumably charged, before they were shipped. I've no evidence that this was the case for mine.

At just over a year old, all you'll have lost is a small bit of age-related capacity. No one seems to be able to pin this down for LiFePO4, but I'd guess at a loss rate of around 5% per year would be about right. Certainly, my experience with the electric bike pack seems to show that any capacity loss with age is quite modest for this chemistry, much less than for other lithium cell types it seems.

Jeremy

Not made much progress in the last 12 months. I'm inviting folk around this weekend to help enthuse me. viewtopic.php?f=18&t=2625

I have all the major bits now, I think. I chose the Guantuo BMS system that Russ Sciville has in his Elise, and have reduced the size of the pack by 25%. Only 600Ah at 162v now...

How are you going to interact that with the controller Tim ??

ChrisB

A bit of help from Evan Tuer, but mostly have them running separately and just connect the big battery leads up to the controller in the normal way. We shall see what happens...

I intent to disconnect the regen input from the brake pedal, so I only have over-run regen to deal with. Don't want to kill my cells with a big voltage spike downhill on a full pack.

Evan has modified the on-board charger in his 106 to do constant voltage charging rather than the constant current the NiCads need (did I get that the right way around?). I had planned to use my HiPower balancing charger, but Evan's solution is much neater. Or maybe both, and charge at 25 Amps. Then it will only take 2 days to charge...

I will need Evan's help to re-scale the energy meter from 100Ah to 600Ah, if the software goes that high. Evan has modified his own for the 180Ah his 106 now has. If it won't, I still have capacity indication on the BMS, but again Evan's solution is neater.

Ah I see

Look forward to further progression

ChrisB

Today was good fun!

I arrived in the middle of the afternoon to find the pack being brought into the garage. Tim was tapping the terminal holes, Jon was winding in some M10 set screws and Ian was bringing in cells and stacking them into rows.

I took over the tapping and we eventually got all the cells fitted with threaded posts.

Ian and I were quiet happily fitting the link plates while Tim became more and more nervous, not helped by our banter.
With a bit of reorganisation we ended up with three rows of 33 cells and two rows of 27 cells. The cells were linked in groups of three for each row and not linked to the adjacent row. We decided this would maintain a level of safety.


We decided to set up the links between the rows with a fusable link and so extra busbars were added and a 5 amp fuse wire used to join them.



So we finally managed to get a complete pack and the voltage measured in at 168v open circuit.

We were keen to test the pack to see it doing something. We managed to get an inspection lamp to light up and....

Well, I'll let the video tell the tale.




So to celebrate we ate some EV toast!

Night Train wrote:Today was good fun!
So to celebrate we ate some EV toast!

Excellent dummy load just add a kettle and you are laughing!

Nice to see some progress. Keep at it Tim.

We, well Ian, did keep asking about the kettle but Tim didn't want to damage it as it is one that has LED lights in it to light up the water.

Nice to hear you are making progress.
Well done and keep up the good work.

Wow thats some pack

Nice work there folks, looking good, where on earth is it all going to go though and do you know how much it weighs now Tim has put the pack on a diet since its first incarnation ??

One word of warning using AC mains equipment for load testing is the switches arnt rated for DC, as I found out in my Feista I installed a 110v socket for boiling a 110v AC kettle, not a problem you'd think.........well it managed 3 boils before the contacts welded themselves together bought another one and that did exactly the same, then realised the problem

ChrisB