Kalkhoff Agattu - a high power puzzlement

Most of the time, unless I'm feeling particularly idle, I ride with the power setting on "low". If I come to a significant gradient, I switch to "med", and when I do that, the additional motor assistance is always obvious.

So far so good. What is puzzling me though is what happens (or rather doesn't) on steeper gradients. In short, after two months with the bike, I have yet to notice any effect when I switch to the "high" power setting.

Even when towing our Roland trailer up a gradient which is enough to get me working hard* in, for example, third gear, I find that switching to "high" makes no odds. I don't notice any change.

The same applies with my wife and her Agattu, which would seem to make this a rider issue rather than a bike one. My question therefore is - under what circumstances might we expect to notice an obvious change in assistance level when switching from "med" to "high" power?

* a relative term, given that I am old, somewhat overweight, and not as fit as I once was.

I have a Pro Connect and my usage is similar to yours in that I use Low Power nearly all of the time. However, I do notice a distinctive difference in the level of assist in all three modes.

My bike is quite old (2008), and I think the motor power starts to reduce at much lower speeds than the newer Panasonic units. Maybe this somehow makes the different power levels feel more distinctive. Do you go up hill faster in high assist mode? Maybe you are putting in the same amount of work, but travelling faster as a result. The false perception being no difference in assist level.

Flecc has posted a detailed account explaining the power delivery system in the Technical section:

http://www.pedelecs.co.uk/forum/technical/1957-panasonic-system-power-delivery-explanation.html

Flecc has posted a detailed account explaining the power delivery system in the Technical section:

http://www.pedelecs.co.uk/forum/technical/1957-panasonic-system-power-delivery-explanation.html

And I've just read it, so thank you for that.

OK ... I've also just got back from a ride on which I tried out different combinations of gear and power setting on a couple of long gradual hills into a bit of a headwind.

Using combinations of 3rd to 5th of 8 Nexus gears with med and high settings, I could feel no difference in assistance at a road speed of between 7 and 9.5mph. Flecc's explanation leads me to guess that's because my speed and/or cadence was too high.

So, the question now is this - if faced with a significant hill whilst towing the trailer, what would be the optimum gear (of 8) to be use, and what sort of speed should I be moving at , to gain maximum assistance?

There's two aspects here. One is the cadence one of course, needing to change up sometimes to achieve full power. However, I think the other one might be at the heart of this problem, depending somewhat on the age of your bikes, and the clue is in the high effort you put in when climbing.

At the root is that the motor's peak power is 400 watts. If you put in a high 300 watts effort for a very short period, in normal mode the motor can match that to total 600 watts with your effort. If your bikes have the 2 times high power mode, clearly the motor can't deliver the 600 watts that 2 times demands, it can only short change you with 400 watts. Therefore the power gain isn't very obvious in high power mode then.

What year are your bikes?

The high assist setting definitely gives more help on my 3 speed Agattu purchased at the beginning of 2011. I agree with the other replies here, you have to be riding below the cutoff speed for the gear you are using.

It is hailing at the moment, but I have to go out when it stops. I will try the bike on a 5% hill at 12mph in top gear and I will then report back on how much easier it feels as I go from medium to high.

i don't notice much difference from med-high but is it not that the assitance is low 30 % med 50% and high 60% so being half that of low-med it isn't as noticeable ?

It's been changing over the years. Eco mode is always 25% of rider effort, Normal mode is always 100% of rider effort, but High Power mode hase changed through three settings. At first 130% of rider effort, later 150% than finally at 200%.

These are usually expressed as 0.5 times (or 0.5 to 1), 1 times (or 1 to 1), and similarly for the high mode, e.g. 1.3 times (1.3 to 1), 1.5 times (1.5 to 1), 2 times (2 to 1).

What year are your bikes?

Purchased Feb this year.

It's been changing over the years. Eco mode is always 25% of rider effort, Normal mode is always 100% of rider effort, but High Power mode hase changed through three settings. At first 130% of rider effort, later 150% than finally at 200%.

 

These are usually expressed as 0.5 times (or 0.5 to 1), 1 times (or 1 to 1), and similarly for the high mode, e.g. 1.3 times (1.3 to 1), 1.5 times (1.5 to 1), 2 times (2 to 1).

and thats why they newer bikes can't achieve the same distance from the batteries as mine...even though it is modified...but i think we have been there before !

Purchased Feb this year.

That fits my second case then, both have the 2 times high power mode, so can fail to deliver twice the motor power in high mode if your pedalling input was over 200 watts before changing to high power.

Best to make sure you are not pedalling too fast to make sure you are getting everything you can, if in doubt change up a gear to slow your pedalling rate for the given speed.

Purchased my Agattu in Dec 2010 (to avoid the VAT rise)

Don't know what my power figures would be, the paperwork/manual was not very good

Back from my tests. Basically I agree with danfoto that when you go medium to high I sometimes dont notice much immediate change. But the bike does tend to gradually speed or get easier a little when on a hill. The change seems much noticeable and definite when you switch the other way.

I have no doubt that high is high judging from my much longer runs at speeds around 15mph.

I know I can out put much higher power for short anaerobic sprints of up to one minute. I think you really have to do the comparisons over long distances, but then it is almost impossible to compare how hard you have been pedalling. It just shows up in overall timings on long hills or long undulating routes.

Here is a picture the label on my Panasonic motor

I interpret 10/12/17 to mean that the motor was made on 17 December 2010.

Just had my chain guard off to check the date 10/01/18

So almost a year old when i purchased it 'New'

So what would be the top power on that flecc, any idea?

Just reporting back that we seem to be getting somewhere here. On my way home from the shops this morning, I sailed up a steep hill which I know well in 5th, having switched to "high" before I started climbing. When I've previously tried it in 5th and "med", it's been hard work, and switching to "high" whilst climbing has resulted in no power increase.

Didn't have time (or indeed the weather) to test further, but it certainly seemed to me that I was getting more assistance than I've had hitherto.

I think you have to stop pedalling when selecting different power modes. When climbing hills I've noticed lack of extra power when just switching up. If I can manage to self-propel bike a few yards without any input and then change mode, all is fine.

Rob

Edited April 12, 201214 yr by robelee

Just had my chain guard off to check the date 10/01/18

 

So almost a year old when i purchased it 'New'

So what would be the top power on that flecc, any idea?

I can't be certain but I think 2 times in high power mode. 2007/8 bikes had 1.3 times, 2009 had 1.5 times and my impression is that was for a short period before quickly changing to 2 times, I think for all the 2010 bikes. I do have a summer 2010 Kalkhoff document stating 2 times, so that's very likely to be for all that season's bikes.

I can't be certain but I think 2 times in high power mode. 2007/8 bikes had 1.3 times, 2009 had 1.5 times and my impression is that was for a short period before quickly changing to 2 times, I think for all the 2010 bikes. I do have a summer 2010 Kalkhoff document stating 2 times, so that's very likely to be for all that season's bikes.

My 2010 PCS has a 1.75 mode! The others 0.7 and 1.3...

Oh and no mention at all of any need to stop pedalling to change levels in the Derby Cycles handbook...

Edited April 12, 201214 yr by NRG