New to the forum and sudden problem with Samebike LO26: battery or controller

[robinhoodhimself]

Hi,

I'm from belgium, Arlon in the southern part of Belgium near the France and Lux border.

I've bought a samebike LO26 last year. I've made 512km with it without problems.
I had surgery in june and was not using the bike for around 4 months. I've charged the battery once during those four month but did not use the bike (due to knee surgery)
Battery was stored in my house at room temp during those four month.

When I put back the battery in the bike in was not starting when pressing the M. Nothing?

I took it back and charge it for maybe 2 mins till light is green on the charger.
After charging I put it back and then press M and the bikes start. Everything looks fine for some minutes then suddenly the LCD turn off and I can't start the bike again.
If I charge the battery it start again for some minutes then turn off.

I'm looking for help because there is no bikes shop that want to work on this bike.
What could be the problem?

Is it a battery problem or a controller problem?
How can I test the battery status without another bike?

Thanks in advance for your help.

Regards,

Vince.