Hi all
I recently had an issue with my mid drive cutting out intermittently. This post is just to show the diagnosis and result in case I may help a other
So the cutout was Totally unpredictable, sometimes under load and sometimes not. Sometimes on bumps, sometimes when near stationary on the flat, sometimes would switch back on and sometimes not. No LCD errors
At the same time both my 36v batteries starting sagging horribly according to the lcd ie from 100% to 70 in under a mile and then bounce back. One pack was all but new and performed flawlessly until the cutouts started.
My order of testing (based on my own thoughts on likelihood)
1. Battery connections to rail and to controller.
2. Welds inside battery pack itself
3. Bad cells in a cell string
4. Phase bullets
5. Wiring harness dodgy/broken wire
6. on/off and PAS switch
7. BMS (output side only as was charging /balancing perfectly
8. Lcd
I spent an age manually testing balancing the cells using a turnigy lipo charger and there was no more than 150mah between each 21,000mah cell string
Finally and somewhat astonishingly a change of lcd solved everything!
So the sagging batteries was a total false reading and a total red herring! I've never come across this kind of weirdness from an lcd. It was a good couple of years old and lots of wet miles plus the odd minor knock... But still
Big thanks to Brighton Ebikes for loaning me some spares from their workshop to help me diagnose. And I bought a nice new lcd from them too
Good to be back on the road again. And even better that my batteries are actually fine!
I recently had an issue with my mid drive cutting out intermittently. This post is just to show the diagnosis and result in case I may help a other
So the cutout was Totally unpredictable, sometimes under load and sometimes not. Sometimes on bumps, sometimes when near stationary on the flat, sometimes would switch back on and sometimes not. No LCD errors
At the same time both my 36v batteries starting sagging horribly according to the lcd ie from 100% to 70 in under a mile and then bounce back. One pack was all but new and performed flawlessly until the cutouts started.
My order of testing (based on my own thoughts on likelihood)
1. Battery connections to rail and to controller.
2. Welds inside battery pack itself
3. Bad cells in a cell string
4. Phase bullets
5. Wiring harness dodgy/broken wire
6. on/off and PAS switch
7. BMS (output side only as was charging /balancing perfectly
8. Lcd
I spent an age manually testing balancing the cells using a turnigy lipo charger and there was no more than 150mah between each 21,000mah cell string
Finally and somewhat astonishingly a change of lcd solved everything!
So the sagging batteries was a total false reading and a total red herring! I've never come across this kind of weirdness from an lcd. It was a good couple of years old and lots of wet miles plus the odd minor knock... But still
Big thanks to Brighton Ebikes for loaning me some spares from their workshop to help me diagnose. And I bought a nice new lcd from them too
Good to be back on the road again. And even better that my batteries are actually fine!
