Power drop down with battery on fardriver

[padawann10]

Hi all,

I just installed fardriver controller nd72680 on my scooter.
My previous one stop working (on my original scooter).
I set up properly without issue.

I just have a problem. Power drop down considerably with battery drop down.
At 50% of battery capacity, I estimate the power raise down of about 50 to 60%.
3 speed selection is great working...

Do I miss a parameter ?
Thanks

 

[dominik h]

What value have you set at
Low vol protect
Low volrestore
Low vol way
Battsignal

 

[padawann10]

 

[padawann10]

I keep it by default.
Check on live my battery was way higher than 65V.
I try other settings for LowVolway, without good result.
I put in charge right now and hope to find back good power at full charge.

 

[dominik h]

The controller limits battery current during acceleration when the battery voltage drops below the low voltage restore value plus the value in low vol way.

On my scooter at freezing temperatures the power starts dropping under 60% soc.
Normally my controller draws 4C 400A from the battery during acceleration.

What rated voltage and amp hours has your battery and how much current are you drawing

 

[padawann10]

My battery has 80Ah. And current line is set at 300A.
And yes temperature was low today. Maybe was the reason. But I didn’t get such effect with my old controller.

 

[dominik h]

I have an 8C capable 100Ah battery and at 10 degrees Celcius , battery resistance is doubled compared to 25 degrees Celsius an the voltage sag raises from 5V to 10V at 400A

 

[padawann10]

Ok
So you have exactly same effect than me ? You have made some setup to reach a better limit ?

 

[dominik h]

No, the last years I had a temperature controlled battery heating and keept it at 15 degrees celcius.
This year I changed to a new JK-BMS with integrated heating control but there I can not heat the battery to my desired temperature without cutting regen.
Now i leave the setup exactly like this to not stress my battery to much. The scooter still drives 120kph only acceleration is a little slower, which is not the badest thing at low temperatures. Or do you know how the traction controll works or what is needed to get it to work.

 

[padawann10]

Ok.
On my side scooter was not able to reach 120kph as it can do normally. It was limited I will say to 95/100kph but was very slow to go to this speed. You're right maybe it’s better to save battery and not have high acceleration. Just to be very careful because it’s not possible to overtake a car !

 

[dominik h]

Have you set weakening field to reach 120kph.
Mine does 125kph without weakening field.
Before I had another motor installed with an ND72680 and there I also needed weakening field to reach 120kph. With activated weakening field the current draw was around 270A now with the new motor it is only 200A.
Bad thing I need more phase current to accelerate. Actual setting is 1400A. With that setting the controller reaches 400A battery current at 30kph.

A few pics from the first conversion steps of my scooter to see how big my 6 year old 8C 21S100Ah battery is. I even had to lenghten the wheelbase 3cm and the battery housing 7cm to fit this 70kg monster.
If I would build it again today, I could install in the same place a 150Ah 10C battery.

 

[padawann10]

Nice setup.

This morning with full battery all was OK. Let’s see in the next day with I hope better temperature.