Can only charge battery to about 60% max!?

[Starr Niu]

I can only charge battery to about 60% max!?
No matter if it’s chared via motor or directly on the battery.

Simply it stops charging (green on charger) and it never reaches more than 60-65%. Tried many times and always the same.

Any clues?

[pihl]

Hello Starr Niu,

I had the very same problem. After some time, I took to the dealer/service and it turn out that the battery was severely out of balance. They stated that 6 out of (I think) 16 cells in series were dead and the battery needs either replacement of dead cells or a brand new (€600 – €1200, depending on the option).

The funny thing was, that the battery didn’t seem unhealthy (if you ignore the fact it didn’t charge). Mine charged to only 47%, but the indicated state of charge actually gave me 25 km of range with full power. Usually when the battery is bad as they said, power wouldn’t be available as soon as you turn full throttle and range (state of charge) would just go away quickly. At least that is my experience with batteries (I did some fair amount of DIY FPV drone building and electronics engineering).

After that, I gave my battery a gentle treatment, drove it in Mode 2 whenever possible and charged it as soon as I got the chance. My theory was, when battery already out of balance, violently discharging it with full power would lead to even more disbalance and the BMS (battery management system) apparently isn’t able to keep it in check (bad algorithm or something). Gentle driving would drain the battery more evenly.

Soon (after 2 – 3 weeks) after daily driving 5-10km, day by day, battery started to charge to higher percentage and eventually charged to 100% and had it’s full range.

Conclusion is that battery just doesn’t like to sit during the winter. I kept mine indoor (room temperature) and charged it from time to time and this happened. Although this is unacceptable design, it is what it is. Seems like the BMS drains the battery when in idle and just isn’t able to keep it well balanced. We just need to take care of it and get the most out of it.

One of the options could be ordering and replacing the BMS with some of the aftermarket ones (200€). Those have Bluetooth connectivity and actually give you insight in battery health on your phone.

I hope this helps and works for you as well.
My NIU is 2016 N1S.

Pihl

[Starr Niu]

Thank you pihl. Well explained.

Very likely I have the same issue and it’s been active for a couple of months now.

Usually it stops charging somewhere around 80% then I give it a short ride, charge it again I can get to 90%, etc.. up to like 95%.

So something is definitely out of balance.

I was thinking of “investing” into a new BMS to see if that would help and later potentially replace the bad cells.

Anyone with experience doing this before?

[Author]

Posts