Kalkhoff Power Problem

[Cyclezee]

Following on from the drive problem that I had with my Agattu a couple of weeks ago which seemed to be fixed with the help of 50cycles, who supplied me with a new drive sprocket. I replaced the chain and rear sprocket at the same time.

I have new problem, power and therfore drive is cutting out intermittently. I am wondering, without having examined it yet if could be a loose or poor connection or something more serious?
I also feel the pedals judder slightly, again intermittently, I assume this is part of the same problem.

Have any other Kalkhoff owners experienced this?

Incidently, my battery, 21 months old now is now down to 8 amps according to the inbuilt battery meter test.

My third rear mudguard has now snapped off, I really should have fitted 'proper' stays after it happened the first time.

In fairness, this bike gets used by my son on almost a daily basis for commuting and between us has covered getting on for 4000 miles over some less than perfect cycle routes.

The Agattu is my sons favourite, so he is 'roughing it' on a Forza for the time being until I get the Agattu fixed and back in action.

J hn

 

[Cyclezee]

Update

I just tried the almost new battery from my Pro Connect S in the Agattu and took it for a short spin and the problem seems to have disappeared. OK, so next I tried the battery the old battery from the Agattu on the Pro Connect, again a short spin and same result, no problem

Clearly I need to do a couple of longer runs to verify these findings, but what could be wrong, wear on the battery connectors and/or the connection plate prongs?

J hn

 

[flecc]

The battery life is roughly what I'd expect for a good quality lithium battery John, since they do all lose capacity year by year. At one and three quarter years a loss of only about 20% total is very good indeed, seeing that the industry still expects anything up to 33% per annum.

I can't give an answer on the power problem without seeing it all in action. If any gear slip takes place in the rear hub you'll lose pressure on the pedalshaft torque sensor so the power would drop and a jerk be felt in the pedals, but the power loss would only be as momentary as the gear slip. If the loss is continuous for any period it would have to be another cause, related to the motor unit internals or handlebar control and connections.
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[Cyclezee]

I just tried the almost new battery from my Pro Connect S in the Agattu and took it for a short spin and the problem seems to have disappeared. OK, so next I try the battery from the old battery from the Agattu on the Pro Connect, again a short spin and same result, no problem

Clearly I need to do a couple of longer runs to verify these findings, but what could be wrong, wear on the battery connectors and/or the connection plate prongs?

J hn

Tony,
Not sure whether you saw my 2nd post on this thread regarding battery swaps?

J hn

 

[flecc]

No, I hadn't seen it John.

There could be a connection problem causing the drive snatching problem.

If you mean the capacity is corrected as well, others have reported this sort of apparent capacity recovery on these batteries, so it could be a meter zeroing thing. The meter zero capacity and charge measuring point is set by the initial conditioning charge and full discharge, but over time drifts out. Many authorities recommend running the battery to empty every thirty or so charges to reset the zero point. It could be that your battery swapping has reset the zero point.
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[Cyclezee]

Thanks Tony,

I will check that tomorrow.

J hn

 

[Cyclezee]

As suspected it is a connection problem.
The Agattu performed perfectly today using the newer battery from the Pro Connect S and as I reported earlier the Pro Connect S also performed perfectly using the the older Agattu battery. This sounds odd, but I am fairly sure I know why.
On close examination the rearmost of the 3 steel battery connection poles or pins has a horizontal grove which would match perfectly with the contact point of the brass connector in the battery base.
This must be as a result of electrolitic corrosion/errosion. I can also see some pitting of the rearmost brass battery connector.

I guess the solution is to fit a new connector plate to the Agattu and repair the brass battery connector. The latter will be difficult as it is almost impossible to access it to clean it or to adjust the tension on it to bring into better contact without opening the battery. As it is still under warranty, I won't be doing that, but I will give 50cycles a call on Monday.

Has any one else had this problem?

I will post some photos if I get time later.

J hn

 

[flecc]

I do remember someone else mentioning a one-off connection problem on one of the new Panasonic unit batteries John, but can't remember who. The old unit had a different system, spring contact blades on the battery base with relay style contacts pressing on contact posts on the unit.
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[JamesC]

John
I think that it is worth mentioning that the location of the battery can develop some play, and be a little bit prone to rattling up and down as a result. If not attended to, this does in time wear away at the connector pins.

The play allows the battery to be readily rotated out of the top clamp for recharging. The battery itself, and the supporting area around the 3 connectors are both hard plastic and unable to absorb any up/down movement that develops.

A good solution is to use one or two thicknesses of inner tube rubber, cut into a small rectangle and slotted to fit over the three connector pins. This provides enough cushioning to hold the battery tight and stop the up/down movement.

James

 

[Cyclezee]

Good tip James, I might well try that when I get the problem fixed.

Photos of battery connections





J hn

 

[Cyclezee]

I reported the problem to 50cycles on Monday and they sent me a replacement battery connector by first class post. I received it Tuesday and the Agattu is performing perfectly again using the original battery.

Lloyd also made a suggestion as to how the battery could be made a snug fit by adjusting the position of the locking barrel i.e. moving it downwards slightly. I did do this, but it can only be adjusted by a very small amount, however it does seem to make a difference as ther is no play between the battery and the mounting.

Thanks to Lloyd and 50cycles for the speedy resolution to this problem.

Photo of the offending connector. Look closely and you will see that the plastic has melted.



J hn

 

[JamesC]

I reported the problem to 50cycles on Monday and they sent me a replacement battery connector by first class post. I received it Tuesday and the Agattu is performing perfectly again using the original battery.

Lloyd also made a suggestion as to how the battery could be made a snug fit by adjusting the position of the locking barrel i.e. moving it downwards slightly. I did do this, but it can only be adjusted by a very small amount, however it does seem to make a difference as ther is no play between the battery and the mounting.

Thanks to Lloyd and 50cycles for the speedy resolution to this problem.

Photo of the offending connector. Look closely and you will see that the plastic has melted.
View attachment 895


J hn

John
Thanks for posting the closeup of the worn battery contact platform from your Agattu, and glad to hear that the replacement from 50cycles has done the trick in resolving the intermittent power problem.

Thanks also to Flecc for including this item in his maintenance section for the Panasonic drive.

However, the suggestion to adjust the battery barrel lock downwards needs a degree of caution because it can only be held in that downward position by the degree of tightening of just one M5 bolt which screws into a shallow aluminium pad, welded to the frame.

Users must NOT be tempted to overtighten this bolt as it is very easy to strip the threads from the pad. This had happened on an Agattu that I purchased second hand. Fortunately, there is enough material surrounding the M5 hole in the pad, to tap the hole out to M6, but it is neccessary to drill/tap through the wall of the seat tube to create enough, well formed threads to secure the barrel. (In manufacture, the tapped hole in the pad will have been made BEFORE welding to the frame).

I think that there are 2 important points to minimise issues in this area:

1. The complete Panasonic bottom bracket is held into the bicycle frame with 3 strong bolts which pass through a rigid mounting plate folded down on both sides of the motor.

It is crucial that these 3 nut/bolts are maintained to a high torque (say 40 lbs ft ?) so that the bottom bracket is clamped tightly between the folded sides of the mounting plate.

It is NOT possible for the little bolt that holds the barrel at the top of the battery to resist any movement that might be coming through from the bottom bracket.

I would suggest that the 3 mounting bolts are tightened after the first 100 miles, and then checked every 1000 miles.

2. The retaining barrel comes to rest against the pad in a slightly higher position, reducing the need for a very tight M5 bolt.

I would favour this position, together with a resilient rubber pad under the battery, to remove any play that might develop


Your picture clearly demonstrates the wear that can develop if there is play between the battery support plate (attached to the motor/bottom bracket) and the battery itself. I saw this begiinnig to develop on my ProConnect when the battery condition lights on the handlebar would suddenly change from 3 to 1 and then back to 3. Adding the rubber pad cleared the problem.

James

 

[flecc]

Thanks for the tips James, the maintenance of the tightness of the frame bolts was one of two things I had pending to add to my site, and it's relationship to the battery mounting is indeed crucial.
.