Battery cutting out

[Rosie]

Hi all,

My Urban Mover 55 is 9 months old, has done about 350 miles with 40 charges. The battery has cut our now five times, the latest being today. It simply stops giving power, but when I stop and turn it off and on again it works fine. Not an enormous problem unless you are crossing a busy road when it could cause an accident as I am virtually unable to pedal the bike without the power.

When I pointed this out to the dealer a few weeks ago he said the battery was under too much pressure. This I find hard to accept as, taking today for instance, I had ridden 6 miles on a fully charged battery on mostly flat terrain at a pretty slow pace using low power only when it cut out. Two of the previous incidents have happened on canal paths, again pretty flat. I do use the throttle to start off but not otherwise, and when the cut outs have occurred the monitor is showing four lights, therefore a pretty full battery.

Any thoughts on why this is happening or what I might do to solve it.

Your help is greatly apprecaited.

Rosie

 

[Deleted member 4366]

There's a couple of common reasons why it happens, but they all are really the same thing. The motor is demanding more current than it can get.

The battery management system electronics have a current limit. If the controller demands too much current, the BMS trips out to protect it.
The controller has a low voltage control system to protect the battery from going too flat. When the battery voltage goes down to a certain level, the controller switches it off.
If you have a weak battery, i.e it can't give enough current that the controller is demanding, then the battery voltage will drop and so the controller thinks it's flat and switches off. Then, when you switch on again, you aren't demanding any current, so the voltage rises and it works ok again until you go up a hill, then the current rises, the voltage goes back down and it switches off again.
The root cause can be a worn out battery, abused battery, or a battery that's under-specified and was never really up to the job.
I suspect that yours is the latter and that the cure is a replacement battery. You could tell the shop to fix your bike so that it doesn't cut out, as it's still under warranty and shouldn't do it. Take it to the shop with a half flat battery so that you can demonstrate the problem.

 

[Rosie]

Many thanks for this d8veh, i will take the bike back to the dealer as you suggest. One previous 'cut out' about two weeks ago occured after only a mile on a full charge and I then rode the bike for a further three miles without further problem, so it looks like there is some fault. Hopefully the dealer will be able to help.

Best wishes

Rosie

 

[Deleted member 4366]

OK Rosie, I hope they do something. Just tell them that you believe that the low voltage cut-off is activating when it shouldn't. They may try and fob you off and say that you're using too much throttle up hills, or that you're not pedalling hard enough, so tell that it used to be OK when it was new and that your friend's £360 Cyclamatic doesn't do it, and he weighs 100kg. Let us know how you get on.

 

[steveindenmark]

Rosie, is there a small magnet on one of the rear spokes?

If there is, take it off and try to ride the bike.

This was the problem with Jannies Tonaro but it may not be the problem with your bike. It is worth a try.

Steve

 

[Rosie]

Thanks both for this.

I do have a magnet, but it is on the front wheel as part of the trip computer. This is something I added, so will remove the magnet and give it a try. Nothing to lose and it may save me a trip to the dealer. If it makes no difference will brave the dealer anyway and report back on how i get on.

Best wishes

Rosie

 

[Fordulike]

Rosie, how does the battery supply the power to the bike?
Does it slide into a docking station, like the Cyclamatic, or do you have to plug in a kettle type lead once the battery is in place?
If it is the former, then clean the battery and bikes power contacts with some rubbing alcohol, white vinegar or vodka.
Sometimes, poor conductivity of the connection from battery to controller can cause symptoms similar to yours.
Happened on my Cyclamatic a while back, and cleaning cured the problem

 

[Deleted member 4366]

Don't bother with the magnet. Some bikes (Tonaros) have a magnet on the back wheel for speed control. You don't have one on your bike. The one for the computer has nothing to do with the motor and controller.
Fordulike's right. Sometimes the battery connections get worn, dirty or bent, so see if you can clean them -especially the ones in the battery. On one bike I had, they had spread a bit so there wasn't much contact. I bent them back with a small screwdriver until they were a tight fit again and no more problems.

 

[Rosie]

Thanks to both, my bike has the docking station type of connection so will follow your recommendations for cleaning the contacts of the bike and battery and give it another try to see what happens. Don't have any vodka though, will white wine do? Just kidding, I have plenty of white vinegar.

 

[Fordulike]

Thanks to both, my bike has the docking station type of connection so will follow your recommendations for cleaning the contacts of the bike and battery and give it another try to see what happens. Don't have any vodka though, will white wine do? Just kidding, I have plenty of white vinegar.

You can get inside the battery contacts with a cotton bud dipped in your favourite tipple, if white vinegar's your thing
Dry it with the other end of the bud.
Doing what d8veh mentioned with bending the contacts inwards for a tight fit is also a good idea.
If these things don't cure the problem, then at least you've eliminated one thing from your checklist

 

[Rosie]

Just wanted to say thanks, I've followed your suggestions about cleaning the heads with vinegar, and after four rides so far so good and no further cut outs. Will continue to keep these clean, so fingers crossed.

Best wishes

Rosie