Not my area of expertise but game to take a crack at it. 4 likely areas of worry. The switch, but I'd guess that does little more than tell the computer to start up. The 'intdlligence' – assessing whether there is power and more importantly whether the battery pack is balanced. The battery itself as to whether cells are all at a close enough state of function and finally whether motors, bearings etc are causing too much draw.

If you have access to the individual cells in the pack then you can assess them but if a sealed unit with in inbuilt charge controller your a bit stuffed unless able to test in another bike or prepared to open it up. The switch itself and any resistance to rotation would be easier to assess.

Pgk

If it is 6 years old and hasn't been used much, it could be the battery on the way out. Maybe get it load tested at a battery shop?

Edited By Hopper on 30/04/2022 11:56:42

I repaired one last year that had a fault in the wheel hub. The owner was compleltely mechanically inept, he was complaining about a loss of speed and range and then it wouldn't work. When I looked at it one of the bearings in the motor hub has disintegrated and bits of the cage has been floating about. and ripped off a hall sensor. I replaced the bearing and all three sensors, plus the well-knackered chain and he was off and running again.

I'm not suggesting that you have the identical problem but it might be worth checking in the hub and loom for water/foreign objects.

In my professional and personal experience, about 80% of electrical and electronic faults are caused by bad electrical interconnections, not the actual circuitry or components themselves.

My approach would be to disconnect and clean with switch cleaner spray, (WD40 now do one), as many of the electrical interconnections as you can – ideally all of them – both on the control side and the high current motor circuits. Use an old, clean toothbrush to carefully clean all the connector pins. Allow the connectors to dry out, then reconnect and disconnect a few times to 'wipe' the contacts against each other – all with the battery disconnected.

The problem might be in the controller, which might use conductive plastic switches – similar to the sort in your TV remote. These might have got condensation in the switches; causing spurious demands to the controller. They might be tricky to get to and clean. If so, maybe put the controller in a bowl of (uncooked) rice or desiccant, and/or in the airing cupboard for a week.

You might have a problem with the battery – but unlikely since you say a new battery does the same thing. Could be the battery internal control board – if you can get to it, clean all the connections as above. Rechargeable batteries usually require a few full charge/discharge cycles to achieve their full capacity; perhaps one or both batteries just need fully charging and discharging a few times – worth a try anyway. If the batteries are cheap, or if 6 years has gone by; individual cells might have become discharged, in which case a battery balancer might help, but only if the batteries and charger are designed to do this.

Finally, have a careful visual inspection of all the components and the wiring – something might have got damaged or pinched somewhere.

Good luck !

Edited By John Doe 2 on 01/05/2022 13:43:12

Yes, or simply rig up a couple of wires piggy backed onto the battery supply, so the supply voltage can be read while the bike is operating. Obviously, be careful trying to read your meter while riding the bike !! – build a secure temporary rig that doesn't need to be held or anything to see the voltage.

It might be worth knowing that some electric bike companies are taking advantage of the "green" and "eco" revolution and charging a huge mark-up.

I nearly bought an add-on electric bike kit, comprising a replacement wheel with an electric hub, the battery and control etc. The company said they normally charged £1,000 but as a special introductory offer, the price would be £500.

Some research by myself and my son revealed that the components are readily available from China for a few hundred pounds retail – presumably less wholesale. So I shelved the idea.

So I am extremely suspicious about a battery costing £600+ That sounds like blatant robbery to me. If it were mine, I would look into purchasing new cells and re-cell the battery myself. And/or research a good quality balancing or rejuvenating charger.

Edited By John Doe 2 on 02/05/2022 10:41:22