Focus Whistler-battery turning off

[Old skool]

Hi there
Looking for some help with my focus pedelec. Going to work and the battery was fully charged... But every time i went over the pedal assist speed 25kmh instead of just the motor sleeping the battery turned off.
I turned it back on every time and it would work fine until i hit the max speed again and off the battery went.
It is a very simple bike with no controller or screen. Everything just built into the battery which is a Derby Cycle 35v 7ah battery.
Any ideas?
There are no faults on the battery it charges fine. 2 year old.

Thanks Jane

 

[Jonnyando]

Hello

Can I ask did you find a resolution to this problem as I've come across the exact same on my Focus whistler 3.9.
Jonny

 

[vfr400]

How do you know the battery is switched off?

 

[Jonnyando]

It goes from full green light to no lights while riding and then no power at all.

 

[vfr400]

It goes from full green light to no lights while riding and then no power at all.

That sounds like it's knackered.
What voltage is it hot off the charger?
What voltage is it after it cuts out?

 

[Old skool]

Hello

Can I ask did you find a resolution to this problem as I've come across the exact same on my Focus whistler 3.9.
Jonny

Hi Jonny

Yes I did get it resolved in the end. I took it to my local Focus dealer and they contacted Derby the UK supplier. They said it was a motor fault so they posted out a new rear wheel. Bike shop fitted it and the problem was resolved. Battery is fine.
They did it all under warranty so was very pleased.
Hope yours is as simple.

Jane

 

[Old skool]

It goes from full green light to no lights while riding and then no power at all.

Does it switch back on when you press it?

 

[Jonnyando]

Does it switch back on when you press it?

Ye it switches back on and goes for another couple of mins and then dead again.

 

[Nealh]

Ye it switches back on and goes for another couple of mins and then dead again.

Sounds very much as vfr put it ' knackered cells' an indication of voltage collapse when current is asked of the battery. Cell aging/ capacity loss due to high internal resistance of the cells, it doesn't matter how one paints the picture time for a new battery or a re-cell.

If the battery was healthy the lights would stay on.

 

[Jonnyando]

Thanks for all your advice. I'm going to take it back to the shop for them to have a look at.