Kalkhoff retro fit possibilities?

Babsbike

Finding my (electric) wheels
Sep 29, 2019
16
11
I am probably one of many ( 100s ? ) with perfectly serviceable Kalkhoff bikes where we have run out of patience with failing Impulse motors. Is there an after market motor/controller option to recover the use of these bikes. At the moment I am faced with £2000 of scrap after only a couple of years. (See the 50 cycles story! )
 

anotherkiwi

Esteemed Pedelecer
Jan 26, 2015
7,845
5,786
The European Union
A Bafang to Impulse adaptor kit would be a great market opportunity. Surely someone could design a bolt on adaptor for a BBS0x and have it CNC cut. It might not be extremely pretty but there is possibly a way of making something reasonably good looking with some kind of fairing (CF or 3D printed PETc).
 

soundwave

Esteemed Pedelecer
May 23, 2015
16,895
6,507
unless the motor mount is custom made for the frame then there is no option to fit another motor you can still get the motors to fit the frame but there not cheap.
 

anotherkiwi

Esteemed Pedelecer
Jan 26, 2015
7,845
5,786
The European Union
unless the motor mount is custom made for the frame then there is no option to fit another motor you can still get the motors to fit the frame but there not cheap.
That is what I was saying. 2 pieces of waterjet cut aluminium welded to a BB shell is not rocket science. Then a couple of bits of plastic to fill in the gaps.

Will the battery work with another controller than the stock one is probably where the problem lies...
 
  • Agree
Reactions: soundwave

anotherkiwi

Esteemed Pedelecer
Jan 26, 2015
7,845
5,786
The European Union
32855

Oh look! They designed a motor with a hole in the top, I bet water can't get in there...
 

vfr400

Esteemed Pedelecer
Jun 12, 2011
9,822
3,993
Basildon
You need a battery as well as the motor because your battery won't work with a Chinese motor unless you do some internal modifications.
 

Baboonking

Pedelecer
Nov 4, 2006
147
6
Watford
I think its a good idea to do something like that - bolt on plate to attach the bafang motor, hookup to the original battery. Is the company that made the Impulse motors also dead like 50 cycles? Kind of a shame for all the bikes to become toast as being Kalkhoff I imagine they are good. Given that many more Kalkhoff ebikes are sold on the continent I wonder what they are doing there, it might be worth checking the German pedelec forums to see how they are handling the situation.
 

vfr400

Esteemed Pedelecer
Jun 12, 2011
9,822
3,993
Basildon
I think its a good idea to do something like that - bolt on plate to attach the bafang motor, hookup to the original battery. Is the company that made the Impulse motors also dead like 50 cycles? Kind of a shame for all the bikes to become toast as being Kalkhoff I imagine they are good. Given that many more Kalkhoff ebikes are sold on the continent I wonder what they are doing there, it might be worth checking the German pedelec forums to see how they are handling the situation.
II just said in the previous post that you can't use the original battery without a substantial modification (replacement BMS).
 

vfr400

Esteemed Pedelecer
Jun 12, 2011
9,822
3,993
Basildon
Open the battery and peal back any heatshrink or tape to get full access to the BMS, then unplug the power wires and pull out all the connectors. Purchase a Chinese BMS and solder on the charge and power wires. The connector for the 10 sense wires most likely won't fit, so you'll have to cut it off and solder the one that comes with the new BMS being careful to get the correct connection sequence shown on the diagram that comes with it. Reassemble the case, then you have a battery that you can use with anything. Your old charger won't work, so you have to buy a standard one for about £12.

The terminals on the battery won't be much use, so it would be better to drill a hole and run the power wires to an external connector. Also, the Chinese charger won't have the right connection, so drill another hole in the case and add a standard 5.5mm jack socket and solder the charge wires there.

It sounds like a lot of work, but as long as you can solder and measure voltages, it's fairly straight forward.

Here's a picture. Basically, you can chuck everything on the left, leaving the cell-pack with its red and black power wires and the multipin sense wire connector. It's those nasty thin green, yellow and white wires bottom left that stop you from using the battery as is.

 
Last edited:
  • Like
Reactions: Baboonking

flecc

Member
Oct 25, 2006
53,193
30,599
I am probably one of many ( 100s ? ) with perfectly serviceable Kalkhoff bikes where we have run out of patience with failing Impulse motors. Is there an after market motor/controller option to recover the use of these bikes. At the moment I am faced with £2000 of scrap after only a couple of years. (See the 50 cycles story! )
There's another solution that's been used a few times on Giant Lafree bikes with failed Panasonic motor units.

Open the Impulse unit and remove everything inside except the pedalshaft with its redundant pedelec sensor. That leaves the quite light alloy casing as the bottom bracket.

Then fit a hub motor kit, using either the existing battery modified or a new battery if yours is getting on a bit. With a bit of stretching a BPM front hub motor or possibly a CST rear hub motor would match the Impulse power previously enjoyed.
.
 
  • Like
Reactions: E-Wheels

vfr400

Esteemed Pedelecer
Jun 12, 2011
9,822
3,993
Basildon
There's another solution that's been used a few times on Giant Lafree bikes with failed Panasonic motor units.

Open the Impulse unit and remove everything inside except the pedalshaft with its redundant pedelec sensor. That leaves the quite light alloy casing as the bottom bracket.

Then fit a hub motor kit, using either the existing battery modified or a new battery if yours is getting on a bit. With a bit of stretching a BPM front hub motor or possibly a CST rear hub motor would match the Impulse power previously enjoyed.
.
Better still, keep the electronics in there. Just chuck the motor and primary drive, then pick up the motor hall and phase wires and run them to a hub motor. That way, the battery, charger , LCD and torque sensor can still be used.

The only flaw is that it's often the bearings that go, and if you're going to open the motor, you can probably repair it anyway.
 

flecc

Member
Oct 25, 2006
53,193
30,599
Better still, keep the electronics in there. Just chuck the motor and primary drive, then pick up the motor hall and phase wires and run them to a hub motor. That way, the battery, charger , LCD and torque sensor can still be used.

The only flaw is that it's often the bearings that go, and if you're going to open the motor, you can probably repair it anyway.
If the innards are stripped out and/or original motor not in use, bearings are no longer a problem since there's only the two pedalshaft bearings left in use which won't cause trouble with rider power only.
.
 

Babsbike

Finding my (electric) wheels
Sep 29, 2019
16
11
If the innards are stripped out and/or original motor not in use, bearings are no longer a problem since there's only the two pedalshaft bearings left in use which won't cause trouble with rider power only.
.
I had considered the hub motor conversion but from a theoretical point of view as I do not have detailed knowledge of how all this works in terms of the electrics. ( I previously did a hub conversion on a regular bike and that worked just fine ). However given the random nature of my power failures I rather suspect my controller is at least partially responsible so I want that replaced. Thanks for the advice above, given me further food for thought.
 

cyclebuddy

Esteemed Pedelecer
Nov 2, 2016
1,640
770
Beds & Norfolk
I am probably one of many ( 100s ? ) with perfectly serviceable Kalkhoff bikes where we have run out of patience with failing Impulse motors. Is there an after market motor/controller option to recover the use of these bikes. At the moment I am faced with £2000 of scrap after only a couple of years. (See the 50 cycles story! )
I know this doesn't help your predicament at all, but it's related. The first article says that Kalkhoff are phasing out their own Impulse motor to replace it with a new motor made by Conti (as in Continental Tyres etc) for their new Kalkhoff 2020 range of ebikes. And the second article says that Conti will be stopping all involvement with e-bikes including production of these same motors in "the first quarter of 2020"!

Kalkhoff really know how to pick 'em, don't they?

 

Nealh

Esteemed Pedelecer
Aug 7, 2014
20,917
8,533
61
West Sx RH
The biggest cock up they ever made was dumping Panasonic.