I went with one of the above. It's not a 2016 model though. The Impulse 2 drive is awesome.

My three year old Panasonic crank engine just gave up the ghost recently.

The dealer says that the engine shorted the battery and vice versa. So I'd need both components as new or used.

The battery costs 600EUR or less depending on capacity. http://www.amazon.de/Derby-Panasonic-Motoren-Kalkhoff-Ladegerät/dp/B007GBD8RS/ref=sr_1_1?ie=UTF8&qid=1450190851&sr=8-1&keywords=e-bike+batterie+24v+panasonic

The engine I could not find at a glance.

So my question is. Do you think it is worthwhile for me to try to fix the electronics of the engine / replace the battery of a 3 Year old bike that was used daily for climbing hills. Or rather just get a new bike that costs 2600,-EUR with newer technology. Impulse 2 system from Kalkhoff.

And would it make sense to remove the engine and use the bike as a non e-bike instead?


Just to clarify the battery seems to be charging fine in the charger. Pressing the check charge button works as usual. Only when the battery is in the bike, pressing the check charge button makes all charge lights on the battery flash in sync. So I do think the electronics on the engine are gone.


this looks like the motor and the electronics are one part that can be swapped.

So the question is, do I want a brand new bike with brand new technology or refurbish a well worn 3 Year old bike with an aluminum frame that had several falls, lot's of pot holes and one accident running from behind into a car.

Since aluminum does tend to just break without much of notice I'd rather go with a new bike even though it is a heavy investment. The e-motor on the new one and the whole riding experience is superb.

  • 2
    FWIW, You may find people more knowledgeable on this topic over at endless-sphere.com/forums
    – renesis
    Dec 15, 2015 at 19:21
  • 1
    Before you count it a loss, try the standard TV repair strategy of taking it all apart and putting it back together again. Sometimes the problem is a poor connection, and this often fixes it. Dec 16, 2015 at 17:09
  • Thanks for the update - please continue to contribute to SE Bicycles in the future.
    – Criggie
    Jan 9, 2016 at 10:32

2 Answers 2


Answering the other part of your question - Yes you could take the electric bits off and use it as a normal bike.

You'll want to take some links out of the chain to account for the skipped/missing motor drive cog. Depending on the rear dropouts you may be able to tension the chain using the parts of the motor drive, or if they come completely off then by adjusting the rear dropouts.

You might elect to remove all the electronics from the handlebars. This would be pretty terminal for restoring ebike functions later, unless you can unwire it rather than chopping the wires.

The battery fitting should be removed, it will likely give you access to the mounts for a drink bottle cage.

Recycle the bits, or list them on ebay. Someone may want it for the battery alone, or spares for their ebike.

Why castrate your ebike? Your bike will be lighter than with the motor. It will not perform as well as a non-electric bike because its likely built a bit heavier, especially around the motor mounting points.

Why not? If you ever want to restore ebike functionality, all this would need to go back on the bike. You bought an ebike because you wanted an ebike, and it would be a shame to go back to a normal bike. IE you get slower and much sweatier!

Delay If you don't use the battery for a while, it will loose capacity. Lithium batteries are a lot better, but leave it untouched fr a year and it will have so little capacity its junk. You should look at charging the battery every two months, especially because its not used.

Do let us know what you end up doing... SE Bicycles doesn't have a lot of info in ebikes, and they are a growing sector of cycling.

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    Thanks, so far I'm contemplating giving it to the dealer sans saddle. The bike is 3 years hold has had several crashes and with an aluminium frame I'd rather have a new bike to be rather safe than sorry. The only downside is the new one is pretty expensive. Dec 30, 2015 at 17:20

First up - I know nothing about your specific bike model. However 3 years is a pretty good run for batteries especially if used for hill climbing, and it could be they're just past it and need replacing.

600 euros sounds a lot, but its one of the consumables. Do you know how far you're ridden? 10,000 km would be 0.06 euros per km, which is a lot cheaper than a car.

Its highly unlikely the battery shorted the motor and the motor shorted the battery killing both.

If you're handy, try and find two working 12V batteries (car ones would do) and hook them up in series to the leads, with your powered wheel off the ground. Do mind the polarity and watch for shorting. The bike should run like normal on 24V. For this test, battery type doesn't matter but current will need to be at least 10 amps so small batteries are unsuitable. If this works, the motor is fine. You might be able to use a mains PSU adapter, provided it supplies 24V DC at 10-15 Amps.

If this doesn't work, the motor or controller may be damaged and you need some more skilled local help. Google about for an ebike retailer or specialist in your region.

Best to google about for a replacement battery pack or find a battery specialist who can repack your existing battery.

A bike is not a cellphone to be replaced every couple of years, with normal maintenance it should last for decades.

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    Yeah, it's worth trying an external supply. Do be careful, though, as the large batteries put out A LOT of current and can throw some amazing sparks if you short something. (As I learned working on my 24V lawnmower.) Especially note that jewelry (rings and watch) should be removed before working on the stuff. The real problem is the controllers -- there's generally one in the battery pack and another near the motor. These could be fried and there'd be no way to diagnose, outside of the factory. Dec 16, 2015 at 0:25
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    Thanks. Yeah, just to clarify the battery seems to be charging fine in the charger. Pressing the check charge button works as usual. Only when the battery is in the bike, pressing the check charge button makes all charge lights on the battery flash in sync. So I do think the electronics on the engine are gone. Dec 16, 2015 at 9:54
  • 2
    All lights blinking is typically a fault indication. According to the Gazelle manual for a Panasonic power assist bike there should also be a display with fault codes, but that may be a different model. But it sounds like service centre time either way. The good news is that your battery may be fine.
    – Móż
    Dec 17, 2015 at 1:11
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    @ChrisH When I got an ebike motor of unknown provenance I poked it with a meter. The readings made no sense, and it turned out that the motor was 90 volts three phase AC. The batteries were 36V DC, so the controller was doing a whole lot of magic power conversion. I'm glad I persevered though.
    – Criggie
    Dec 17, 2015 at 1:37
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    @Criggie that's weird but I guess it was driven off a variable frequency inverter. The 36V bike my wife rides seems to be a DC motor with a simple PWM circuit. At 36V with the UK power limits that's only 6A and even I could design the circuit. The 2 small wires are for a speed sensor as the motor has to cut out above 15mph.
    – Chris H
    Dec 17, 2015 at 8:05

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