Intermittant Power!

[Eaglerider]

Last night The Eagle was being naughty. Power started up fine for a few minutes riding, then coasted down a hill. At the bottom, when I started pedalling again, no power! Stopped, switched off the power at the key and turned it back on. Nothing, not a sausage. Tried again a minute later and all was fine again for 2 or 3 miles, then power dropped to level one or less and would not provide full power. I switched to throttle and full power was restored. Closed the throttle, and on twisting the throttle back again only very low power available.

Stopped again, switched everything off and back on, all was fine. I pedalled another mile or so under full power, stopped at a junction, then no power at all on throttle or pedelec function when I went to move off again. This morning I have disconnected the throttle and both brake switches, and just turning the pedals the problem persists. Mostly it will start on full power just fine, but if I stop pedalling and restart again, only very low power is available or sometimes none at all.

If I switch off and on again, it usually cures the problem until I stop and restart, it would seem there is a problem with the start up circuitry in the controller. When it doesn't want to go at all, there is an audible click but no power. Its as though just as the power is starting it gets switched off or reduced to very low power only.

The effects seem about the same whether I use throttle or pedelec function, a random chance of starting up or not!! When it runs properly, there is full power available and the bike rides normally, the problem starts when I stop applying power and then set off again. I have checked inside the controller compartment (in a box underneath the rear of seat battery) and it was pretty dry in there and all connections appear sound.

The battery is showing four lights and seems fine and provides full power without problems. The motor seems normal when its running. Seeing as the intermittent problem occurs without throttle or brake switches connected, my meagre analysis suggests some component in the controller is breaking down!

The bike has been out in some heavy rain lately but I cant find any water anywhere. The bike was fine 4 days ago?

Are there any further tests I can do to further isolate the fault? Is my controller toast?

Its a Freego Eagle with 250 watt Bafang.

 

[Deleted member 4366]

I would say that you have water where you shouldn't ough-ta.
I would also bet on the multi-pin connector to the motor, and if not that, then the connections at the controller end. Look particularly at the hall-sensor connections if you have them.

Other than that, check that there's no damage to the motor wires.

 

[hech]

Try checking the fuse, they can melt partially giving a sporadic connection which may result in symptoms you describe, otherwise you will have to open up the controller and check for burned out mosfets or worse, malfunctioning thingymabobs.

 

[Eaglerider]

Thanks chaps.

I have checked the motor plug to the back wheel, its bone dry and the copper prongs appears clean and shiny.
Should I unscrew the end plate off the the controller box itself and check inside. The steel end plates are lightly corroded, but I am reluctant to remove the end plate as its sealed against moisture with black sealant glop. Perhaps if I tried this and left it open to dry out in case there is any residual moisture causing the problem?

I just took a quick test ride and all was normal until I pressed the + button on the handlebar controller thingy to go from medium to full power. Immediately power dropped to less than minimum driving the bike at about 4 mph. Stopped, switched off and back on again, all was fine. Got back into the garage and the problem returned again. A bit frutrating as the sun has come out for the first time in ages!

I took the back wheel out and inspected the power cable entry, all appears dry and normal. Strangely, the problem seems to be slowly improving, cutting out less often. I am (in my ignorance) convinced the problem is either inside the controller box itself or in the handlebar controller switch.

I do have a good multimeter and a basic (and I mean basic) knowledge of electrical things, is there any mileage in checking any circuits with the tester. I have no idea about 'mosfets' and the like. The bike is 14 months old and has done about 2000 miles.

I'm now going to check the fuse, I guess you mean the big one at the top of the battery?

Hall sensors? Which are they, the motor is a Bafang 250.

Thanks again for your suggestions and help.

 

[banbury frank]

Hi If the bike runs ok then it cant be any off the problems you have tried if it was water in the controller it would have the fault permanently

I think it is the battery management as this will rest if you disconnect and reconnect the battery

So I think the fault is in the battery BMS or Faulty Cells or cells out off balance

Frank

 

[Deleted member 4366]

Open up the controller box. Personally, I don't think it's a good idea to seal up controller boxes because it stops the water getting out. I'm sure your problem is in there. Is the dry motor connector pushed fully home?

I can't see it being a battery or fuse problem unless you noticed the throttle LEDs go out or flicker when it cuts out.

 

[Eaglerider]

I just checked the main fuse at the top of the battery. All appears normal, no evidence of damp or corrosion or melting and passes the connectivity test on the multimeter. Mostly, I get the fault whenever a change of power occurs. I just ran it up the road on full power and all was fine, when I pressed the minus button to go to medium power again it slowed right down and did about 3 mph. Just stopping for a few seconds, without turning off the key, the problem goes and full power is restored until I make another adjustment to power ot close and reopen the throttle.

Frank, thanks for the suggestion, I'm clueless on BMS systems, but the battery seems to provide full power no problem for ages, its when I change something the fault re-occurs, perhaps I'll have to take it to the shop!

Its a bit strange.

 

[Eaglerider]

Open up the controller box. Personally, I don't think it's a good idea to seal up controller boxes because it stops the water getting out. I'm sure your problem is in there. Is the dry motor connector pushed fully home?

I can't see it being a battery or fuse problem unless you noticed the throttle LEDs go out or flicker when it cuts out.

Thanks D8veh, The motor plug is well and truly pushed in. I will now remove the controller end plate to check for moisture inside, back soon!

The LEDs all appear to be working normally on the handlebar thing.

 

[Eaglerider]

OK, just removed the end plate of the controller and its dry, clean and shiny inside. I cant see any evidence of staining or moisture ingress of any sort. Nonetheless, I've let it dangle next to a lead lamp to dry out any hidden moisture. Other than that, there is only the handlebar controller.

I did find a grey wire that was disconnected. The wire comes out the metal box and goes straight back in. I connected it, (push fit connectors were on both ends). When connected nothing works at all so I guess its not supposed to be connected in this installation. I have disconnected this grey wire and we are back to where we were before with the intermittant fault. Failing any other ideas I'll give Freego a call tomorrow.

Thank you all for prompt and knowledgable suggestions. It's just started snowing now, so at least the incentive to go out for a ride has diminished somewhat.

 

[hech]

Must be the three/five speed switch on the handlebar shorting and switching the controller to level 1. If the switch connecter looks ok you might well have water/corrosion in the handlebar unit. Do you keep the bike inside the house or out in the shed?

 

[oigoi]

This sounds similar to a problem I had when rain got into the handlebar power switch / throttle control I would suggest dismantling the handlebar switch and throttle you will probably find water in there

 

[Eaglerider]

I put it all back together having checked everything I could and went for a test ride. At first it went like a rocket as normal, right up to when I selected medium power when it again dropped to very low (like 4 mph) power. Stopped, waited 10 seconds and set off again on full power. If I stop pedalling for a second (in pedelec mode) there is a 30% chance it either won't restart or reduces to very low power when I commence pedalling again. I repeated the process with throttle only and the same things occur.

The power system all appears ok in terms of battery and motor, it seems any switching event is likely to invoke the problem. With regard to the handlebar control unit, it seems to be a sealed unit, although I guess it may be a potential cause, but all the LED's seem to work normally.

The bike is stored in my garage which is a separate building, but its fairly dry in there.

I'm a bit stumped, the problem does seem to be getting a bit better as it seems less frequent on the last test, perhaps its the gremlins and it will fix itself in due course!

 

[oigoi]

Mine didnt look like water could have got into the handlebar unit easily at all but it did, didnt take much water on the circuit board inside to make it do funny things. I managed to dismantle it, dried it out and covered the circuit board in silicone sealant to prevent it getting damp again

 

[OldBob1]

I would try that speed controller on the handle bars, if you can get hold of a hair dryer that could help to dry thing out.
With the electrical connectors after drying them with the hair dryer I would re-assemble using a smear of petroleum gel keeps the contact clean and a bit of protection from moisture.

 

[Eaglerider]

OK, just to tie this one off, it would appear that the controller circuitry failed, and a new one has been fitted which appears to have completely solved the problem. I got the shop to do it as there are far too many wires sticking out for me to attempt it myself.

As to likely reasons for the failure, I guess we will never know. As a solid state electrical item, it should last longer than 15 months I would hope, but then I have been riding in some very wet weather lately, (who hasn't), and perhaps some water ingress brought about the failure.

I am surprised the circuit boards in these devices are not sealed in resin to exclude damp reliably, perhaps they produce too much heat, but I do think some attempt to improve water resistance is certainly desirable. I shall have to apply my thinking cap to come up with a suitable solution, I'm thinking either some hefty applications of waterproof duct tape, or perhaps I will fashion a small deflector plate to mount in front of the bottom bracket to deflect heavy water streams from the front wheel entering the controller box.

Anyway, the main thing is its fixed and I can get some riding in. I'm £69 lighter, but what the hell, I'm addicted to ebiking, and as such it's a fairly cheap 'fix'.

 

[oigoi]

My solution to the damp getting in was to cover the circuit board and components with silicone sealant. Though like you say some parts like fets get hot so not sure about sealing them up too much

 

[shemozzle999]

As oigoi said above it is known in the trade as conformal coating - it can be brushed or sprayed on but not while the circuits are live:

CONFORMAL COATING in Business, Office & Industrial | eBay

 

[Eaglerider]

Hmm! I've not heard of "conformal coatings" before, might be worth a try.

I have seen electrical contractors use a coloured two part gel which they use to fill a junction box for outside use. It goes off in a few minutes. My controller sits in a metal box under the battery like Wisper and Oxygen and many other bikes. I am minded to drill a hole in the top and fill this box with the gel stuff thus isolating the controller and sealing all associated connectors from moisture. It all comes down to how much heat is produced by the controller, and whether sealing in insulating gel would cause overheating?

 

[jateureka2]

OK, just removed the end plate of the controller,,,,
I did find a grey wire that was disconnected. The wire comes out the metal box and goes straight back in. I connected it, (push fit connectors were on both ends). When connected nothing works at all so I guess its not supposed to be connected in this installation. I have disconnected this grey wire and we are back to where we were before with the intermittant fault. ....

On the FreeGo Hawk I have, those two grey wires are for the speed restrictor: connect to restrict assist at speeds over 15MPH, disconnect to de-restric.