Rescue a failing Kalkhoff?

[Kamakiriad]

My lady has a Kalkhoff Pro Connect with the Xion rear hub motor which she relies on for commuting. We bought it secondhand so there is no warranty. It has served her quite well but over the past year has been getting less and less reliable. The mechanic at 50 Cycles has been very helpful but the time has come to replace or rescue the bike.

She is thinking of getting something like a new Woosh Krieger or a Wisper 905 SE, but would be struggling to afford one. The Kalkhoff is such a nice bike it would be a tragedy not to be able to keep it. Great construction, hydraulic rim brakes, nice gears etc. The battery seems to be in great condition. It just seems to be the motor which keeps cutting out at inconvenient times.

So we are wondering if it is possible to get a kit which will allow us to keep the original battery? Wheels 622 x 21. Happy to go to 350W or stay at 250. We'd really welcome any ideas.

 

[spanos]

So may I ask if 50 cycles confirmed it was the motor?

I ask because the issue you describe is rarely the motor. Far more common is a bad connection (either in wiring our battery itself- often the battery connection point)

Can you describe inconvenient times?

Generally bumps causing cutout is a connection fault.

On hills or startup (especially when battery isn't straight off charger would indicate a battery issue - specifically weak cellb string which brings pack voltage down past the protective cut off point). Short rest brings it back up.... Until you go again then cut out

Can you define a bit better?

Then , do you have a multi meter to test battery voltages?

 

[Kamakiriad]

Pretty sure it is the motor. 50 cycles said there had been troubles with the Xion motors and they introduced a new type.

First problems were about three minutes into commute, near top of a hill. 50 Cycles upgraded the software on the console and gave us a used replacement wheel/motor. This worked fine at first but now problems occur any old where and are not caused by bumps. Now we get the dreaded triangle with the "C" before she rides it all the time.

Yes I have a multimeter and also my bike's battery will fit.

 

[Nealh]

Does your battery work O.K on your lady's bike ?

 

[Kamakiriad]

No, same warning symbol.

 

[Deleted member 4366]

IIRC the controller is in the motor and you have to split the wheel to get at it. If your battery is OK, you could try a Q128C motor and a S06S controller from BMSBattery. You'll need a PAS and throttle to go with it.

 

[Nealh]

A Q100c or Q100H or Q128 C or H fromBMSBattery with a KT controller /lcd kit from PSWPower might be an option though you would have to have the hub laced and trued in to your existing rim. Kit parts cost approx. $220.

 

[Kamakiriad]

D8veh, Nealh, thanks for the advice. We will check out this stuff over next few days. I am quite good at DIY and fixing things but am a total newbie to all this.

We have two rear wheel/hub units. Have taken spokes and rim off one but can't see how on earth you get inside the motor!? Do the two halves unscrew like a jar lid? Mechanic at 50 Cycles said motors have "no user-serviceable parts."

Happy to chuck the hubs out and buy replacements.

 

[Nealh]

If no visible face plate screws then yes the face plate screws off, some torque/force may well be needed to do this. A lever will usually need to be fabricated to open the hub, for my Q hub I made one in true Heath Robinson style but it worked.
A pic may help.

The SO6S is all but the same as the PSW POWER 15a controller both are KT models, then main difference is the PSW models have a speed restriction which you can enable or disable by a wire connectorand they have extra wires for lights and a peep peep horn.

 

[Deleted member 4366]

I think they split down the middle like a Bionx.

 

[Kamakiriad]

We have bought the Cyclotricity rear motor kit plus a console and PAS ring.

Alas I don't think it's going to be a straightforward plug-and-play job. First hurdle is the rear wheel has no freewheel. I bought a 9-speed freewheel but it is too tall. There only appears to be room enough for a 5 or 6-speed freewheel.

The Kalkhoff had a 9-speed cassette, 11T smallest ring. I believe if we move to a 5 or 6-speed freewheel we may need to change derailleur, shifters etc.

Anyway I have asked Cyclotricity which freewheels they use themselves or recommend and await their reply.

 

[Deleted member 4366]

You'll have trouble with your gearing. You should have bought a cassette motor, like the Q128C, which would take your existing cassette. with a free-whel motor, you're more or less limited to 7-speed, which won't match your derailleur or shifter. You could try replacing just the shifter with a cheap 7-speed to see if your derailleur will work with it. It'll probably be OK.

Even with a 7-speed, you might find that your rim is off-centre, so you'll need to dish the wheel.

 

[Kamakiriad]

Well I promised a progress update, so here goes.

You should have bought a cassette motor, like the Q128C.

I take your point D8veh, but decided to buy British for speed of delivery and in case anything went wrong.

As D8veh said, I have had to buy a few extras. The DNP Epoch 7-speed freewheel is an almost perfect fit, it just needed one extra spacer washer between drop-outs to make it fit. I got a Shimano 7-speed derailleur and a 7-speed shifter is on order.

Anyway today was the big day - do a bit of soldering, connect the red and black wires from the battery and test it.

Nothing.

Most e-bike batteries have only two wires, I assume?? The Kalkhoff battery has various thin wires as well as the thick red and black, but I assumed just ignoring them or maybe connecting them together would do the job. I think the extra wires are from the controller which was in the original rear hub motor. Possibly they detect torque and vary the battery voltage (red - black) accordingly?

Stationary I am only getting 1 volt between red & black. It's 12v between black and thin yellow. Sorry I can't post any photos due to browser/Linux not working properly.

So I seem to have a choice - look inside the Kalkhoff battery where presumably there is some fancy circuit and see if there is way to bypass it, or buy a new battery. The first option is probably dangerous. If I keep the Kalkhoff battery I can always use the battery as a backup for my Kalkhoff.

A Cyclotricity battery would be an obvious choice, but there really isn't much space in the ladies frame and I doubt it would fit. (The Kalkhoff battery is tapered.)

Feeling down - can anyone cheer me up!?

 

[Deleted member 4366]

Look inside the battery. It's not dangerous. If you can show a picture of the BMS and where the wires go, there's probably a safe way to alter it.

 

[Kamakiriad]

Okay, I have downloaded a new browser and can now post photos. Might take a while to work out how to open it up without breaking anything but have made a start. Here are some "before" photos.

 

[Kamakiriad]

Are these photos any help? The four thin wires to the output are brown (pin 4), orange (pin 3), blue (pin 2) and green (pin 1).

Where the battery meets the frame holder, the orange and brown appear to be either cut doing nothing or maybe they are joined. The blue wire turns into yellow on ts way from the motor. There are various splices to the LCD display.

 

[Deleted member 4366]

OK. I was thinking it was an Impulse. I took the battery connector off one of those, and it didn't have data wires. That one most likely has data wires on the charger, but that doesn't mean that there's data wires for the power to the bike, but there probably is.

An easy and sure solution is to replace the BMS. A conventional one would cost less than £20. You would probably need to splice on a new connector to the sense wires, but the rest is easy. I've replaced loads of BMSs. It's not difficult as long as you can solder.

 

[Kamakiriad]

Yes, there are data wires (orange and brown) on the charger. At the power outlet the data wires are blue and green. The battery has a second charging socket on the side.

Yes I am happy soldering and will replace the BMS if you or someone else can talk me through it! The ones I can see on eBay look absolutely nothing like the sealed circuit on the Kalkhoff battery, but you sound like you know what you are doing. I haven't taken proper measurements, but it looks approx 6 cm by 10 cm.

Battery is 36V and something like 588WH.

 

[Deleted member 4366]

If you can open it up and show what's inside, I should be able to help you. All cell-packs work the same. There's a positive power wire, which goes directly to the terminal; a negative to the BMS, which is switched by the BMS to the terminal; and sense wires from each cell group that go to the BMS. There can be all sorts of other things in there, like sensors, charge measuring and display and USB outlets, but you don't need any of that.

The only problem I see is that your charger probably won't charge unless the battery tells it to, so you might need a new charger (£20).

 

[Kamakiriad]

Had fun getting the BMS off - accidentally touched the red and black wires together. Big flash, sparks flying, and the terminals got welded together! Luckily there is a 30A fuse which blew straight away.

Getting a 42V reading which I believe is healthy.

Okay, the BMS. It has a black translucent coating. From 12 noon going clockwise round the outside, we have

• connector for 15 very thin wires
• connector from side charging socket
  
• screw terminal to black output
• screw terminal from black battery
• screw terminal from red battery
• screw terminal to red output
• some circuit component with .470 written on it
• connector for ribbon to battery level indicator button

In the centre of the BMS is the connector carrying the four thin wires to the output, and to the side another component with 68 JFK. 2D3 on it.

A sticker on the edge says ZK 73719 #20008-2 SW 1.1_00 HW 06.00 SN 551305879. Phew! Dimensions are 67 mm by 98 mm. Hope this helps.