VX1 Li Ion 18650 conversion

Now that is going to be a lot of work but you just the man to do it, please keep us posted with photos of your assembly. I sent you a PM about the item's and hope you have good fortune with your build.

Really interesting. How much are the 1050 cells?

Later on I will add the nickel strips and busbars and probably shrink-wrap each module.

Hi Paul,
I don't know if you've already seen the following video but you might find it very interesting if you haven't:

Apparently, it is done differently on the Tesla battery packs, instead of using high current nickel links on each of the modules, they are simply joined to a common high current bus bar using small fusible wires that only need to carry the current from each individual cell in each module.
This allows the wire to fuse if a fault develops on an individual cell so that it is automatically disconnected from the circuit instead of drawing excessive current, generating unwanted heat and discharging the other good cells in the module.

If you used 10A fuse-wire to connect each of the cells in your 24 cell modules to a common bus bar you would still be able to draw up to 240A from your pack without worrying about the fuse-wires blowing. The motor controller only has a 200 Amp fuse, which should be the weakest link.

You might want to consider implementing something similar while building your pack modules.

35 in series seems a bit low (147V max) compared to the typical 18 leaf modules (36 Cells in series). Is this because of space limitations?

Alan

Now i need to find some fuse wire and start soldering instead of welding :-)

Methinks the fuse wire should be spot-welded to the cell terminals, not soldered?

REALLY NICE.

I think there are many people really interested in what you are doing - I for one certainly am - please keep up the pictures + I'm very interested to know exactly how you are going to weld the wire/straps to each battery pole... because that is what can take all the time...

Good luck and please keep the information flowing.

Jonathan

I had not seen that model of charger before...I have only used the Elcon/TC chargers...which incidentally I see are also for sale on the Thunderstruck page...again please keep showing the progress....Tesla like battery conversion looks very interesting...

FYI - there are many DIY spot welders - the majority made from transformers and various parts from old micro wave ovens - look on youtube - quite a number of them appear to function very well...

In the mean time i'm working on installing a bigger charger and programing a controller to drive the charger and the dashboard.

This is going to be one nice job, you have good hands and a sharp brain to do this. keep us posted although, I have my leaf conversion I still like to see other battery set-up's.

Hi Prensel,
This build looks similar to the Vectrix I built in 2013. It was built with the Panasonic CGR18650CG batteries as used in the Tesla Roadster.
http://www.evalbum.com/preview.php?vid=4802

In total 130Volt and 85,5Ah pack which would mean about 150km of distance.

I'm also curious about the voltage. My Li-ion conversion has 42 cells (CHL LiFePo), 3.65V each, all connected in series for a total voltage of about 153V (50AH). The original NiMH pack had similar voltage.
Will the lower voltage lower the "horsepower" of the bike?

Love the capacity - 85AH!

Hi oobflyer,
The 130 volts mentioned is the nominal voltage of the battery pack. This is different to the voltage of a fully charged battery pack.
The original NiMH batteries nominal voltage was 102 cells x 1.2 volts = 122.4 volts. When fully charged this battery reaches 102 x 1.49 volts = 152 volts.
Your LiFePO4 battery nominal voltage is 42 cells x 3.2 volts = 134.4 volts. This battery can safely charge to 42 x 3.65 volts = 153.3 volts.
The batteries that Prensel is using are NMC batteries commonly used in Ebike battery packs.
LiNiMnCo batteries are nominal 3.7 volts per cell. 35 x 3.7 volts = 129.5 volts. When fully charged this battery reaches 35 x 4.20 volts = 147 volts.
The regenerative braking on the Vectrix will reduce progressively at voltages over 146 volts. The 35s setup matches the voltage range of regen braking, nominal voltage and motor controller low voltage battery protection correctly.
From my experience the 85.5 Ah battery pack will give a range of 210 - 220 km at a constant 60 Km/Hr.

With the availability now of customized motor controller software from www.vectrixsupport.com, I think opting for higher pack max. voltage is advantageous, while low voltage protection in use is still possible. The bike just feels more powerful when fully charged vs. when half-charged. Might be my imagination, but I think mine's zippier at 146V than at 130V... Plus the battery is charged to lower levels than max, which is supposed to be good for it.

Without mods, the factory MC software on mine noticeably starts to auto-protect from low voltage at something around 118V and stops the bike around 115V if I remember right. I think power begins to be limited even a couple of volts earlier. I forgot which version MC software I'm running, but I'm pretty sure it's a late revision Li one. That's a safe level for the 18 cell Nissan Leaf conversion that I have. Regen is weak after my "full" charge at 146V, but by 144V or so (which comes pretty soon as the discharge curve is steep there) regen seems back to normal.

I agree that the best setup when using Leaf battery blocks is 18 blocks. This is a 36s setup. Works well in the Vectrix VX1.

I was actually suggesting that 19 would be better :) I went with 18, because at the time I was not sure if the MC software would be modifiable or not and I wanted to have some low voltage protection from the OEM controller software. I think, if the MC low voltage limit can be raised, then 19 modules would be better - charged to a little lower SoC than the 18 would be (but perhaps a bit higher voltage), so the top voltage will still be something like 146-150V but that would be a lower SoC than 150V is on the 18 module setup. So the battery would be less stressed when charging, and will be in the more linear section of the discharge curve so the voltage will stay high longer than with 18 modules...

Probably splitting hairs anyway. I'm very happy with the 18 module setup. If I had 5-10mph higher top speed it would be perfect. With a max of 68mph I'm relegated to the right two lanes (that's the slow lanes for those of us who drive on the proper side of the road ;) ) when traffic is light, and I think the bike could probably safely handle bursts of higher top speed on flats and downhill without overstressing the electronics.

I agree that the best setup when using Leaf battery blocks is 18 blocks. This is a 36s setup. Works well in the Vectrix VX1.

I have used an insulator between the rows. I cut them from sheets of plastic to separate the rows.

Very nice work,keep us posted since we all are interested in your build.

EDIT: after I wrote the below, I see you seem to have something between cells in a block - can't see well from the photos...

I'd be a bit worried about something like this happening between cells in a group. Especially, the ones near the bottom, where the rest of the cells push on them from above.

Also, I suppose, heat-up may not be a huge issue in the Vectrix where currents are not huge vs. these cell capacities. Still, the cells touching each other and being shrink-wrapped and triple-insulated will keep them from dissipating heat. You save space by not having a plastic separator honeycomb-like structure where each cell is locked, but will it work safely without it?

Then I realized i had made a BIG mistake.
I had totaly forgotten to pack each cell in shrink tube and additionally added protection on the top ends.
How i found out ?

Well look at this as two adjacent blocks had apparently damaged the cell plastic and touched each other and big sparks flew around.

So at this time i'm taking all blocks out of the chassis and will cover them with shrink foil and separate all 4 rows of cells with additional polystyrol separator plates.

Kocho, every cell block has ALL cells facing the same way, they are all in parallel, so their cases are already all connected via the minus bus bars ;-)