Resurrection from the dead of the Euro (pedelec, not currency)

[Cuthbert Dibble-Grubb]

My sister bought an old Powabyke Euro, didn't get on with it ("too heavy") and left it outside all winter. Now it doesn't work. She said if I can fix it I can have it! I charged the battery overnight and it has 39V, which I assume is OK. I connected the battery directly to the front hub and it revved up with gusto so the motor's OK too. Thanks to the very helpful diagnostic guide at http://www.ebikes.ca/learn/troubleshooting.html I tested the twist grip throttle. It was a bit confusing at first because the wires were not red (+5V), black (earth) and some-other-colour (signal) but red, green and yellow. Once I'd worked out that the yellow wire carried the signal I was fine. The throttle is not, however.

I'm about to order a new throttle from China which should be here in a few weeks' time. I know that's a long time to wait in such sunny weather but it's only £8.48 and it comes with a fourth wire to connect to the +ive battery terminal. This powers a row of LEDs on the throttle to indicate battery voltage. Before ordering I'm waiting for the vendor to confirm the diameter of the grip. You'd think they would put that in the ebay advert.

I've wire-brushed the rust off the mudguard stays and sprayed them black to match the frame. I've also welded up the broken double-leg centre stand. I should be out and about on it by the summer!

 

[Benjahmin]

Welcome, go for it and good luck.
As others will probably confirm, I think 39v is a little low for a fully charged battery, think it's more like 41 and a bit. But hey, if it works.......
Happy pedaleccing.

 

[flecc]

Welcome, go for it and good luck.
As others will probably confirm, I think 39v is a little low for a fully charged battery, think it's more like 41 and a bit. But hey, if it works.......
Happy pedaleccing.

They're SLA in the Euro Benjahmin, 3 x 12 volt lead acid in series, so the 39 volts probably ok.
.

 

[Deleted member 4366]

That bike has some strange way of operating the throttle. IIRC, there's two modes, selectable from a switch, and both require you to pedal first before it starts to operate.

If you want to check that it's working, go to its connector. There will be three wires: 5v (often red);ground (often black); signal (any colour). Check that you have 5v between the 5v one and ground, then check between signal and ground, which should go from about 1.4v to 4v as you open the throttle. You have to check with it connected and powered up.

 

[Cuthbert Dibble-Grubb]

Thanks for the advice everybody. The torch on the bike had 4 tired AA batteries in it producing 4.8 volts so I used that as a power supply to test the throttle. With 4.8 volts between the red and the green wires the voltage on the yellow wire varied from 0.1 volts to 0.1 volts as I opened the throttle. Spending the winter outside must have ruined it. I ordered a new one today, but from Coventry rather than China because I want to get on with it, despite what I said earlier.

Keith Palmer from Powabyke has been very helpful. He sent me the manuals as pdf files. One describes a self-test procedure: "Open the throttle then turn on the ignition. The 6 LED’s will light 3 times cyclically." but I have been unable to get mine to do that. All six LEDs just come on and stay on. Perhaps mine is an early model that predates the self-test function.

[edit] DOH! I just realized that the self-test procedure requires a working throttle!

 

[Cuthbert Dibble-Grubb]

I have a problem. The new throttle has arrived with red, black and green wires. Presumably the red is +5V, black is ground and green is signal. The connector is the wrong size so I've soldering the old one to the new throttle. The old connector has red, yellow and green wires coming out of it. When connected to the PCB I get a potential difference of 5V between the red and the yellow, so I connected red to red, green to green, and yellow to black. The good news is that the self-test procedure now starts when I turn it on. The bad news is that it indicates a throttle fault. When I turn the pedals the electric motor drives the front wheel, but the throttle is operating backwards. When I twist the new throttle I get low speed, and when I release it I get full speed. Further investigation shows that the signal on the original Powabyke throttle goes from 4V to 1V as you twist it but the new one goes from 1V to 4V as you twist it. Hmmm, I guess I'll have to buy an original Powabyke throttle after all.

On 8 August 2015 d8veh wrote "When brushed controllers fail on their own, it's normally the output fets that go, which causes full speed as soon as you switch on." So Itested my FETs. This very helpful guide shows how: http://www.bcae1.com/ampfail.htm. I tested mine and one of them failed the first test. It leaks current from the gate to the drain so I have ordered four B20100G FETs from China for the princely sum of £1.35 including P&P. I have no idea how they can produce, pack and post them so cheaply.

So I don't really know if it starts on full power due to a backwards throttle or to a dodgy FET.

 

[D8ve]

Try reversing the red black wires. I may then go 4-1v