Gen2 PHEV Kit with 32 nissan leaf battery cells, BMS2 or BMS+ opinions

Hi all,

I have recently purchased a nissan leaf battery pack from a salvage yard, and decided to upgrade my phev kit that was 76 off 33ah type 26650 cells. The kit is / was working well before, the leaf pack came along at a very reasonalbe price so decided to do the upgrade, and re use the original lifepo4 cells in a home energy recovery project for me and my brother, more on that later.

ok, so, I installed 32 nissan leaf cells into the car as the pic will show, still leaving me 16 cells left over.

Now, after one full charge / discharge cycle covered, batteried performed well, but something snt right with the kit in general.
Before the battery swap, the PIS kit i have would sometimes drop out, without warning, this was especially troublesome in out of gas mode, as i had no notice the kit had recided to sop working, the prius battery woiuld go very quickly to blue bars, then again quickly to purple needing a fast stop, recycle and engine warm up to recover the prius battery voltage before the PIS kit could be re started.

I have checked all the wiring, it all looks ok, but these episodes are getting more frequent.
One thing that is true with the PIS kit that i hve whitnessed as a user is that is has a narrow voltage operating window, and too much sag will send the voltage low which in turn switches the kit off, meaning mote cells in series have to be added to get any meaningfull range within the voltage window of the batteries.

So, with this in mind, and having a very good battery installed, i was thnking of taking the plunge and build a hybrid interface pcb designed by Norm, all the info is on here, i think its in my capabilities to take on the task.

Any help with the setting up of the BMS2 after its build would be very helpful, or please share your settings on your set up with the dip switches, and what you have set your voltage window to would be a great help.

With 32 leaf cells in series charged to 8.1v per cells gives 259v high voltge, too high in my opinion, but needed with the pis kit as the kit knocks off at about 230V is what i have whitnessed.

with the BMS2 i could maybe drop to 30 cells with a max voltage of 243V.

Please fell free to add your settings, opinions, it would be greatly appreciated.

Thanks, Anthony.

 

Update for you.

Checked wiring again, and found that the cat5 cable going into the rear pcb connection although was in all the way and could here the click on the connection during the push in phase, the connection wasn't being made properly.
Fortunately, the "bad" connection on the cable end was on a short extension cable, changed that cable, and the kit is now working as normal, haven't suffered any drop outs for the last few days and have gone through numerous full charge / discharge cycles.
Hopefully this has solved the drop out issues.
I'll report back if the problem re occurs.

Anthony.

 

Hi planitaire,

My charge profile is charge to 4.05v and discharge to 3.6v.

In the short time the cells have been is and used, they don't bounce as much as lifepo4, like, after the charge cut off, the settle very near to the charger trip set point, my older lifepo4 would shut off at 3.5v and settle at around 3.33v, I'm not seeing this with these leaf cells,

Similarly, when at the lower limit, with the lifepo4 I would dip below my 2.8v Lower limit under load, and the cells would bounce back to around 3.15, close to empty,

With the leaf cells they tend to stay quite stable at the voltage being displayed, if that makes any sense at all.

As for charge max when cold, I'm not sure on that level to be honest, I figured, if these cells can power an 80 kW leaf motor with regen, then it should have no trouble at all powering my gen2 Prius motor which is about 65% lower in power, so I think they should be ok in whatever I put them through, hopefully anyway.

I would say with the charge settings I am using I'm probable using around 70% of the cells capacity, maybe alittle less.
I'll run in this state for a while whilst I get used to using the cells and seeing their characteristics under various driving and environmental conditions.

Cheers for the input, best regards, Anthony.

 

yes did that and ir run very well to be honest.

Sorry for the very late reply.

 

Hi buddy,

Ive still got the prius, but removed the kit. Only removed as ive got a fill EV now, a nissan e-NV200.

Ive also still got the kit here, all complete, and the batteries, have part reconfigured the batteries to make a home energy store to work with our solar panels, but that project is still work in progress.

Where you located, im in south wales, a town called Aberdare.