Kalkhoff battery question

[lordvincent]

Hello experts!

I have a Kalkhoff agattu 2013 model and the battery was recently replaced under warranty.

Under the instructions for impulse 1 bikes (the one I have), the battery should have a 'learning cycle' where it is run down to empty for the first cycle.

However under the instructions for impulse 2.0 there is no such learning cycle recommended for the battery.

I believe that the battery I now have is the type which are used on impulse 2.0 bikes. Since the learning cycle is for the battery's onboard meter, the type of motor is probably not relevant, rather the type of battery.

So my question for the experts is, do I need to run this battery to empty? I would rather not do this as it is highly inconvenient, living as I do in a hilly area.

 

[flecc]

Only those few with intelligent battery meters normally need this running to flat to set a zero point for accurate metering. If yours has the battery integral meter it would probably be best to do it for perfect accuracy.

I know how inconvenient this is, living in a hilly area as well, so try it without doing this. Since from what you say you never run near to zero charge the meter's accuracy probably doesn't matter too much and you could probably manage by basing charges on experience of the bike. In any case lithium batteries prefer to be recharged often rather than being run low so you could probably just rely on the frequent charges to ensure not running out.
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[lordvincent]

Many thanks for your reply flecc. I have appreciated your informative posts on here for a while. Thanks also for giving the right answer! I had to run the old battery to empty a couple of times, by request of 50cycles, while we were trying to find out what was happening with it, and for the last few miles I had to stay close to home doing circuits which was very boring.

I thought I had spotted a loophole when the impulse 2 did not require a learning cycle, and maybe they have new meters with the new sony cells. Also the handlebar meter seems to be independent of the battery meter..do you know if this is the case?

So I will prob not do a learning cycle, so long as this will not limit the overall capacity of the battery in any way. Is there any advantage in doing one apart from the calibrating the battery meter?

 

[JohnCade]

Why not ask 50 Cycles if this new battery needs it? I don't think the batteries have changed at all on the Impulse 11 so any change in the service manual might be sales led. I have the same bike as you and I also had a new battery from 50 Cycles just before Christmas. I also live in a hilly area and it is a pain but I did it anyway, and like you I had to run the old one down for diagnosis too. The manual suggests it should be done every six months which I think I will stretch a bit....

You can do it over a couple of days if your battery is one of the larger capacity ones. As a matter of interest what was wrong with your battery? There have been a few on the forum having problems with them recently.

 

[flecc]

Is there any advantage in doing one apart from the calibrating the battery meter?

No advantage at all apart from the meter zeroing. Since the metering can drift out over time, it is recommended that the zeroing be carried out from time to time to keep it accurate. However, since completely emptying a lithium battery is best avoided, that should only be done quite rarely.

You probably know that these batteries also have a capacity check function by keeping the button pressed for a longer period. Obviously if the meter isn't zeroed that will also not be precisely accurate. However, capacity is temperature dependent and at the present with very cold weather the reading will often be lower by one LED anyway. It follows that thinking a meter inaccurate during cold weather should not prompt an emptying to zero to correct the meter since it may not be necessary. Emptying the battery for zeroing is best only done when ambient temperatures are around 20 degrees C or more with the battery at full efficiency.
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[JohnCade]

Yes that's the reason they give to do it. To reset the battery parameters and they say prevent the battery losing charge unexpectedly by the LEDs getting out of kilter with the actual charge level, so misleading the rider. The battery is never completely flattened by riding it until it stops giving assistance though. You just ride it to system shut down and at that point there is still a safe amount of charge in it.

 

[lordvincent]

Thanks flecc and John.
I asked 50cycles and they said run it down every six months. I am still unsure as to the reason for this advice being missing from the impulse 2 instructions. The batteries might be different as per this page so I was thinking that this might be the reason.
The problem with my battery was a drop in capacity, noticeable in terms of range as well as dropping to 4 LEDs, and an error light sometimes (on charger) when charging.
Btw John, my replacement battery was a bit darker and more glossy than the original, and they don't seem to have any stock of the stickers for my model, which do help in blending the battery in with the bike; was it the same for your new one?

 

[trex]

..
I asked 50cycles and they said run it down every six months. I am still unsure as to the reason for this advice being missing from the impulse 2 instructions. ...

it's sensible to do so to make sure that all the Lithium circulate between the two electrodes. If you recharge every few miles, only a small portion of the Lithium moves between the electrodes. The immobile Lithium then tends to stick to the electrodes and form dendrites, reducing your battery capacity.

 

[flecc]

The problem with my battery was a drop in capacity, noticeable in terms of range as well as dropping to 4 LEDs

As I noted that will happen when the weather is very cold and the battery drops to very low temperatures. Then it's quite common for a capacity check to show only four of the five LEDs lit, but a return to milder weather usually recovers it to a five LED reading. Hence my warning not to run to flat then since it may not be necessary in those circumstances. Just do it if the reading is still low once milder temperatures return.
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[JohnCade]

Thanks flecc and John.
I asked 50cycles and they said run it down every six months. I am still unsure as to the reason for this advice being missing from the impulse 2 instructions. The batteries might be different as per this page so I was thinking that this might be the reason.
The problem with my battery was a drop in capacity, noticeable in terms of range as well as dropping to 4 LEDs, and an error light sometimes (on charger) when charging.
Btw John, my replacement battery was a bit darker and more glossy than the original, and they don't seem to have any stock of the stickers for my model, which do help in blending the battery in with the bike; was it the same for your new one?

Yes, mine is the same. Just a plain black one without the stickers. No idea why that isn't on the Impulse 11 manual, maybe it just got left off by mistake. As I said I don't think there is any difference between the batteries. But ask them if you're still not sure.

I ran the bike to shut down when I got the new battery, and the new one ran a lot better at low charge than the old one did and then shut down suddenly. The old one had very low power for miles before it shut down. Both batteries ran for the same mileage though.

 

[flecc]

it's sensible to do so to make sure that all the Lithium circulate between the two electrodes. If you recharge every few miles, only a small portion of the Lithium moves between the electrodes. The immobile Lithium then tends to stick to the electrodes and form dendrites, reducing your battery capacity.

Do you have a source for this Trex? Metallic lithium which can form dendrites is only used in the anodes of primary (non-rechargeable) lithium cells, our rechargeable lithium ion batteries use intercalated lithium compound for the cathode instead. The formation of metallic dendrites in these usually only results from poor manufacturing techniques and was responsible for the fires and explosions of many past ones, particularly in laptops.

Here's two quotes from the ex-industry Battery University source:

"Lithium-ion is a low maintenance system, an advantage that most other chemistries cannot claim. There is no memory and the battery does not require scheduled cycling to prolong its life."

"Manufacturing methods become more critical the denser the cells become. With a separator thickness of only 20-25µm, any small intrusion of metallic dust particles can have devastating consequences. Appropriate measures will be needed to achieve the mandated safety standard set forth by UL 1642"
.

 

[trex]

you are correct of course. The word 'dendrites' carries slightly different meaning to 'dendritic', the latter suggests a smaller formation than dendrites.

sources:

http://phys.org/news/2014-10-stanford-scientists-smart-lithium-ion-battery.html#inlRlv
http://phys.org/news/2015-01-aims-lithium-based-batteries.html

In some batteries, dendrites are lithium formations that grow while batteries are being recharged, adding layers that resemble tree rings, with each layer representing a single recharge. Because they grow faster when exposed to a high current needed for fast recharging, the dendrites limit recharging speed.

 

[flecc]

Thanks Trex.
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[lordvincent]

As an update, I emailed Kalkhoff and they said that the learning cycle is still required and that the omission in later manuals was due to language and translation issues (?).

So I finally decided to do a learning cycle since the weather is somewhat milder now. The result was that the new battery had significantly better mileage, under similar terrain and weather conditions to when I did the same with the old battery. As a rough calculation, the old battery had about 75% of the capacity of the new one, so the four lights showing for the capacity was an accurate reflection of this.

My experience was similar to JohnCade's in that the low battery cut-off happened in a convincingly sudden manner so did not have to plough on at low and reducing assist for miles; it seems they have improved the implementation of this.

So it was worth doing, not just because they still recommend it and the reasons for this, but also to demonstrate that the old battery was indeed faulty (75% capacity with only about 15 cycles on it) and to give me a good idea of the mileage that can be expected from the new one.

 

[mike killay]

My Phillion battery on the Tonaro is 3 years old and still going strong, as is the 1 year old battery on my Woosh Gale.
I always recharge after the smallest use because I never know how far my next journey might be.
There is no battery meter on the Tonaro, although the Woosh has one, but because it is behind the saddle pillar I never look at it.
This cold weather has affected both batteries. The assistance uphill is noticeably down and the lights nearly all go out under full throttle signifying voltage drop.
My experience suggests that frequent recharging does not harm the batteries.
Perversely, the 12 year old lead acid battery on my Astra is still going well!