[bobbyboblington]

The spend for the electric motor project so far:-

£500 for the motor
£300 for the Motor controller PCB
£100 for resolver to encoder converter PCB

£?00000 Batteries we are talking thousands right!

Here is the van in question link to build Build thread, quite a lot of work has gone into it already hand modified the electric elevating roof
and there was a lot of welding work on the floor, there is a lot of space for batteries under the floor so considering cutting away recesses to house them
and re welding and strengthening

http://www.vwt4forum.co.uk/showthread.php?t=241503&page=3

Firstly happy new year. I am in the process of converting my Mrs’ Nissan Figaro to electric, in the U.K. as well. My knowledge of power electronics is very limited so this is a steep learning curve but I do know a bit about batteries. You’re right to be looking at 18650 cells. Almost every EV on the road uses battery packs comprised of 18650 cells. They have 4 times the energy density of conventional cells and they’re capable of deep cycling. If treated properly most cells will retain a capacity of 80% after 3000 cycles. A Tesla Model S P100D has about 10,000 of these cells. My project will need between 3-6000 depending on range/drivetrain. Buying pre-built battery packs is horrifically expensive, building them yourself can be very cheap. If that’s something you’re interested in doing let me know and i’ll Send you some info.

I’m also looking to use the Remy HVH250 cartridge motor. I would love to know how you’ve gotten on with the motor controller kit. I tried the link but couldn’t find it. Any advice would be greatly appreciated.

 

[bobbyboblington]

I stand corrected, 18650 cells are used in Tesla’s but they are moving to a 17670 format. I would still like to hear how you’ve gotten on with the motor controller?

 

[bobbyboblington]

The cell actually used in the Model 3 is the 2170 format cylindrical - 21 mm x 70 mm - made by Panasonic at the "Gigafactory".

2170 sorry, is it correct they are rated at 5000mAh? Point taken about the pouch cells. I haven’t seen a DIY pouch battery made from scratch and as this is a DIY EV forum, the suggestion was to make one from 18650s which is far more common.

 

[bobbyboblington]

Sure, that makes sense if completely from-scratch pack construction is required. On the other hand, welding fine leads to every one of those cylindrical cells is a real pain for DIY manual construction... which is one reason that people were using prismatic cells (with a small number of connections, using screw terminals) and now avoid building packs from individual cells at all, instead assembling OEM modules (consisting internally of of pouch cells) to suit their needs. Even when people use 18650 cells, most of those cells going into recent projects are within complete Tesla modules, not as individual cells; some people do modify the Tesla modules (to change them from 6sNp to 12s(N/2)p), but even then they don't touch the individual cell connections.

Since sdb's intent is to convert a camper or van, it should not be necessary to custom-build a pack to suit some oddly shaped cavity; reconfiguring the modules of a production EV pack (whether those modules contain pouch cells or cylindrical cells) seems like the most practical approach.

Absolutely makes sense if you are going for the simplest/most compatible solution, however sdb’s just purchased the £500 remy cartridge motor and building a custom housing and cooling unit, along with a DIY motor controller. Either he’s going for an incredibly bespoke EV build or he’s looking to save money. If it’s the latter you can’t get a much cheaper LiIon sollution than recycling used 18650 cells, albeit very time consuming and requiring a lot of scrutiny. Tab welding is not difficult with the right equipment, and as you say if it is the former it does give some modularity to your battery pack design, but if you could get your hands on reasonably priced battery packs that would be the best option.