Kalkoff Battery Problem?

[oriteroom]

"In the plot below, my battery is the round orange blobs, and my wife's is the square black blips. My battery has had a total of 65 charges since 1st Feb 09. My wife's battery has had a mere 17 charges in the same time."

Hi Fecn

My recharge data seems to fit on your chart quite nicely. I've only been monitoring recharges since March 2009 - prompted I think by an earlier post of yours back then?


My Battery (total charges 21)

lights left----- A/hr used---- mA/hr/mile

2------------- 8.2------- 29.9
2------------- 7.5------- 46.7
2------------- 7.3------- 39.2
2------------- 7.7------- 42.8
3------------- 5.1------- 29.4
2------------- 7.5------- 29.9
2------------- 7.4------- 20.3
3------------- 5.2------- 53.5
2------------- 7.3------- 44.1
1(flash)------- 7.8------- 38.4
1(flash)------- 6.5------- 50.6
0 (fast flash)- 10.4------ 362.8 test ride constant power assist

Wife's Battery (15 charges)

lights left----- A/hr used---- mA/hr/mile

3----------- 5.5-------- 41.9
2----------- 6.8-------- 48.8
2----------- 7.5-------- 50.6
4----------- 4.3-------- 27.4
2----------- 6.8-------- 23.5
3----------- 4.7-------- 34.0
2----------- 6.5-------- 40.5
3----------- 5.0-------- 26.8
3----------- 6.4-------- 46.6

Regards.

Mike

 

[flecc]

Everyone - What's the assembled wisdom on what mileage a 'decent' Kalkoff battery should assist for on 1:1 assistance. Is my battery looking about right?

Rider dependent of course, but I found 35 miles continuously used on a Kalkhoff Agattu during testing.

This was with standard gearing, rider 71 years, temperatures varying on the runs, 7 to 13 degrees C, low wind speeds, moderately and very hilly mixed terrain.
.

 

[Fecn]

Rider dependent of course, but I found 35 miles continuously used on a Kalkhoff Agattu during testing.

With an 14stone-plus unfit rider (called Matt) on my wife's agattu with factory gearing, on the 1:1 medium assistance level, he got 36 miles until the battery ran out. It is arguable whether he really needed a new battery at that point, or if it was just the fact that he'd managed to buckle my wife's back wheel from jumping up/down so many kerbs.

Myself, on my own Aggattu with modified gearing (for 18.5mph) at under 14 stone, can kill a battery in around 20 miles.

The Panasonic system is so very sensitive to the gearing you use on it. I've seen my one of my mates (Si) get 62 miles out of a battery.... but then again, I've managed to drain my own battery in under 10 miles.

 

[Fecn]

Fecn - I'm going to see how all my recharge data fits on your graph (will put data in a separate note). We seem to be living in similar 'time dimensions'!. You and your wife both have Kalkoff's, your battery's been recharged more than hers, you measure recharge characteristics as well!!! As an aside, was it you who also bought a Thule towbar bike carrier designed for pedelecs - if so how's it going, I've still the earlier EuroClassic.

Guilty as charged on all counts. Thule towbar is still great, if somewhat underused lately. My missus is trying to get back into shape this year, so hopefully some more bike explorations on the cards once the sun is shining again.

 

[Old Timer]

I dunno! what I gather from reading all the bumph is to not keep letting your battery go into deep discharge and if you have a fairly long commute then carry an extra battery and swap before that happens. I agree with some of the writings in that article that it`s not a bad idea to keep an eye on your lights and give the battery a rest and allow it to recover.


Tony(onmebike) has just fitted an extra output cable on my Alien battery so that I can use it on my Alien and also on my Powertrek so that on my main distance bike (Powertrek) I can carry my spare Alien battery and swap them about. That should more or less double my range and also prevent those deep discharges.This is better than purchasing a new battery that can only be used on one bike when you take into account that batteries degrade with time as well

Image here IMG_0462.jpg photo - david chilvers photos at pbase.com

Thanks Onmebike

Dave

 

[NRG]

I guess don't care about the warranty Dave?

 

[Old Timer]

I guess don't care about the warranty Dave?

What warranty To be honest if something works as well as this battery for a few months then chances are it will fade into the big battery graveyard a lot earlier than it should and almost certainly outside the warrany period and there are better solutions that are cheaper should I need one.

If that battery fails then I`ll convert the powertrek battery so that it works on the alien as well

I`m taking my car in for an MOT in a minute now that is something to get anxious about!

 

[onmebike]

I dunno! what I gather from reading all the bumph is to not keep letting your battery go into deep discharge and if you have a fairly long commute then carry an extra battery and swap before that happens. I agree with some of the writings in that article that it`s not a bad idea to keep an eye on your lights and give the battery a rest and allow it to recover.


Tony(onmebike) has just fitted an extra output cable on my Alien battery so that I can use it on my Alien and also on my Powertrek so that on my main distance bike (Powertrek) I can carry my spare Alien battery and swap them about. That should more or less double my range and also prevent those deep discharges.This is better than purchasing a new battery that can only be used on one bike when you take into account that batteries degrade with time as well

Image here IMG_0462.jpg photo - david chilvers photos at pbase.com

Thanks Onmebike

Dave

Your most welcome Dave. Not sure your guarantee would be affected as any court in the land would judge me over qualified to do a simple conversion like that.
As you know I've been involved in building and flying model aircraft for many years. Battery charging and usage has always been an area of concern, especially with Lithium Polymer batteries which have a certain amount of risk involved in their use, over charging or discharging and you have a fire or small explosion on your hands as several friends have discovered, one losing his home another his workshop together with thousands of pounds worth of model aircraft including jet turbines and other equipment.
I'm not sure about the E-bike controllers but those used in R/C models are mostly programmable for the type of battery used, Ni-CD, Nimh, Lipo, Life or Pb [lead acid] and will cut off at the appropriate level before damage to the cells occur.
E-bike controllers do have this feature but are not programmable as far as I know. So, if the controller was designed for lead acid or Nimh's, changing to Lithium batteries would carry some risk of over discharge because Lithium batteries can't generally be discharged to the lower levels Lead acid and Nimh's can be and as set in their controllers. If the controller was designed for Lithium batteries then it should be perfectly safe to discharge to the cut off point set by the controller, which by the way is surprisingly high. I can't remember exact figures but on a single lipo cell of 3.6volts the cutoff is around 3.1volts so a 36volt E-bike battery will be in the region of 30Volts I would imagine. I actually think it better to use the battery until the controller cuts it rather than charge mid cycle. Its actually impossible to deep discharge these batteries under normal use, as in deep discharging Ni-cd's to overcome memory effect. Also never attempt to discharge Lithium batteries by any means other than the controller and normal use, never connect external means of draining the battery such as Light bulbs , resistors or the like.
Regarding charging, trying to speed up the process by fast charging beyond the capability of the battery can cause damage and it can also give false readings, an example of this is the charger can be fooled into thinking the battery is charged to capacity because the cells can't take the elevated charge rate. If in any doubt consult the battery spec sheet or manufacturer for advice.
By the way, Cyclamatics are back up to £499.00. What shall I do with the cheque?

 

[flecc]

I can't remember exact figures but on a single lipo cell of 3.6volts the cutoff is around 3.1volts so a 36volt E-bike battery will be in the region of 30Volts I would imagine.

The general practice is to set the low voltage cutout at 31.5 volts on nominally 36/37 volt e-bike controllers.
.

 

[NRG]

The newer controllers are programable...for speed HVC, LVC etc. However, LVC in the controller is not much good for Lithium Polymer becasue it only monitors the pack voltage and not individual cells. So a weaker cell may be hidden within a pack and whilst the pack voltage seems OK the weaker cell may be running into problems...which manifest themselves at the next charge.

So with Lipo individual cell LVC monitoring is recommended using devices such as the Celllog8 device. These little devices monitor cell, pack and cell delta voltages and have programmable settings plus an alarm out put that can trigger some sort of protection scheme or device for the pack. The alternative is to embed a good BMS into the pack that performs the same function and communicates with the controller to provide pack protection.

 

[onmebike]

The newer controllers are programable...for speed HVC, LVC etc. However, LVC in the controller is not much good for Lithium Polymer becasue it only monitors the pack voltage and not individual cells. So a weaker cell may be hidden within a pack and whilst the pack voltage seems OK the weaker cell may be running into problems...which manifest themselves at the next charge.

So with Lipo individual cell LVC monitoring is recommended using devices such as the Celllog8 device. These little devices monitor cell, pack and cell delta voltages and have programmable settings plus an alarm out put that can trigger some sort of protection scheme or device for the pack. The alternative is to embed a good BMS into the pack that performs the same function and communicates with the controller to provide pack protection.

HI NRG, thanks for that info. I have several chargers for R/C use that have built in cell balancing for 2,3,4,5 or 6 cell lipo packs and I've made some adapters up to suit other chargers. I keep my lipo's in steel Ammo cases because of the fire risk, although the dangers are more due to the charging and use than the storage. Thankfully the newer lipo's are safer than the one's I've been using.

 

[Old Timer]

What warranty To be honest if something works as well as this battery for a few months then chances are it will fade into the big battery graveyard a lot earlier than it should and almost certainly outside the warrany period and there are better solutions that are cheaper should I need one.

If that battery fails then I`ll convert the powertrek battery so that it works on the alien as well

I`m taking my car in for an MOT in a minute now that is something to get anxious about!

The Bloody car failed the MOT, front drive shaft gaiter and both rear disks and pads and I was going to bid for a E bike as well

 

[onmebike]

The Bloody car failed the MOT, front drive shaft gaiter and both rear disks and pads and I was going to bid for a E bike as well

Sorry to hear about the car. Bid for what ebike, aren't five enough?

 

[Old Timer]

Sorry to hear about the car. Bid for what ebike, aren't five enough?

I need eight, I`m training our pet Octopus to ride the Cyclamatics

 

[Old Timer]

Latest headlines: E-bikes need to comply to MOT regulations only exemption turning up at MOT station with proof of age or telegram from the queen

BTW who is the oldest on the Forum? I`m 65 + a week or so.

 

[timidtom]

Latest headlines: E-bikes need to comply to MOT regulations only exemption turning up at MOT station with proof of age or telegram from the queen

BTW who is the oldest on the Forum? I`m 65 + a week or so.

Any advance on 74 (wef tomorrow!)