Converting Polaris Ranger - Question on controller & Voltage

[Lorax_UK]

I am mid way into converting a Polaris Ranger (400 Petrol) to EV.

The plan is/was to use a QS180 motor and Fardriver 96850 controller, which I have already purchased. I got these at a good price.

The problem is that I was hoping to use a 48V battery pack, which I've designed to be modular, so I can use it for a number of different applications. But I see in the controller spec, that it's rated for a nominal battery voltage of 60-96v.
The battery I've built is just over 300Ah, and so at 1C can discharge at 300 Amps. I guess this gives me about 15kW? The motor is rated at 8kW continuous, and 15kW peak, though probably not at an under-rated 48V.

So the ideas I'm considering, are:
1- Just try the controller with 48V and see what happens
2- Buy a similar controller that's rated to run with 48V
(presumably this means I'll not be getting max performance from the QS180 motor, but this probably isn't a huge deal for me)
3- Build a battery specifically for this application, using NMC prismatic cells, about 120Ah, 96V

Do you have any advice? Thanks in advance

 

[dominik h]

What about splitting your cells in two 48V 150Ah batteries, if this is possible. So you could use them i series for the polaris and in parallel for other things.

 

[Lorax_UK]

Thank you, that's certainly a valid idea.
I'm not sure I have the expertise needed to know whether it would work for me.
So far I've used JK BMS units with battery builds, which seem to do a good job of keeping cells balanced and protected. But I'm not sure if these would be happy running in series?
Also, I've been using 304Ah lifepo4 cells, which are quite content at a 1C discharge rate, giving 300 or so amps. But if I were using 150Ah cells, I think I'd need to switch to a different cell chemistry (NMC?) to get the discharge rate I'd ideally like.

I see you're using a Li-NMC battery. Was the discharge rate factor why you went this direction?

 

[dominik h]

If you have double the voltage you will have only half the current for your desired power level.
48x300=96x150

If you already have the 304Ah cells, I would start with them. Estimated power will be half of what others get with the QS180 and you will also get only 3/4 to half of their rpm.

8C continous (800A for my 21S100Ah battery) and the cells where for free.
That is why I have installed such a big and heavy battery. I also had to lenghten the wheelbase for my battery.
The scooter was originally equipped with 24 Lifepo4 60Ah cells. But the BMS was crap and the most of this scooters survived only one or two winters without driving and charging for 3-4 months.
If I would build again I would install two 12S2P VW MEB batteries. Having 75% more energy available with 10kg reduced weight.

 

[Lorax_UK]

Thanks for your help.
I see what you mean with the higher voltage battery needing fewer amps for any given power output.

Do you have any idea if the Fardriver controller I have (96850) will even run from a 48V battery?
I guess I just need to finishing building this battery and hook it up, see what happens.

 

[amberwolf]

If the controller has an LVC, you could see if it can change down as far as your pack will be when empty.

If not, it'll require a higher voltage battery, above the controller's LVC.

 

[Lorax_UK]

Cheers
I'll give it a try and see how I get on

 

[dominik h]

You can just try it with a normal DC power supply,.
You can also spin the motor with a power supply, as long as you do not turn on regen.