Battery capacity+ powerbox

Hi i have a question. We have had our Twizy for a week and what fun ( i will try to post some photos)
We fitted a powerbox straight away. The Twizy had 1500 miles on it and the powerbox showes 100% battery.
I have put about 150 miles on it this week. When i am not using it i charge it in the garage. I have noticed the SOC is going down after every charge. i am now down to 97.8%
Is this normal?

Front view with my mother in law in. She is short just see the top of her head


SOC is State of Charge. Does change dramatically while driving and charging :wink:
SOH is State of Health. Should only go down very slowly over many cycles :slight_smile:

98% SoC after starting up a fully charged Twizy is a BMS quirk that was alway present.
Batteries cool of after charging.
Also the BMS so enables the charger to start again and check the voltage if a charge is necessary.
(Useful after some time not using the twizy)

So don´t worry.

I noticed that actually the charger turns off at 98% if you reconnect a couple of times it will go too 100%.

in early charger models they do this.

Calibrating the SoC solely by voltage is a tricky thing.
The BMS counts the power drained from the battery and tries to make sense of the voltage and milage you get.

Ever notice that the miles you still get around 50% seem to stagnate.
The BMS is trying to recalibrate cause it was to pessimistic.(build to do so).

So if the Battery does not behave like the model that is bulid in the BMS your charger is turned off at 98%
Normally this happens in the winter or when the battery gains a lot of temperature while loading in the summer.

Does not mean you have less range after the charger shuts off.

In the newer charger models they gave up.
They took the balancing right out of the procedure.
My charger displays 100% for about 15-25 minutes while it is balancing the Battery.
(Still charging it with 1/3 of the max current!)

The SoC climbs from 99,1% to 99,9% in this time.
For the old ones it went from 95% to 100% and sometimes cut off at 98% cause the battery had reached the max voltage.

1 Like

Thank you for that explanation. Most helpful.

Best explanation I’ve ever read, thank you

Nice and easy way of explaining Grossstadtfahrere.
I have questions would the power box solve the traction battery issue of holding the charge or balancing the charging power.

I also have a 2018 Twizy and the battery cuts off at 98% all the time. In Winter it cuts off at 92%. I have to unplug it a few times for it to show 100%.