18% regeneration?

General Discussion about electric bicycles.
niwrad   1 W

1 W
Posts: 57
Joined: Jun 16 2019 9:12pm

Re: 18% regeneration?

Post by niwrad » Aug 03 2019 4:02pm

been riding around and I usually get between 10-15% regen myself. 18% is definitely within reason. using the brompton kit from grin. I've been able to come to a complete stop every time
Jersey City, New Jersey, USA

Cephalotus   10 kW

10 kW
Posts: 723
Joined: Jun 18 2012 12:27pm

Re: 18% regeneration?

Post by Cephalotus » Sep 08 2019 5:28am

The regen quote on CA3 is measured different from industry standards.

The "quote" in CA3 is not Energy regen/ Energy consumed as usual, but Energy regen / (Energy consumed- Energy regen)

So in industry standard if you consume 100Wh but gain 50Wh from regen your regen quote would be 50%
On the CA3 the regen quote calculated under the same conditions is 100%

So the CA3 gives higher numbers than industry standard, especially for high regen numbers. (in reality CA3 shows range extension, not regen quote)


Besides this regen quote is based on your terrain and how you brake

All my numbers are with BionX D motors in 28" wheels, 13s battery and 30A BionX controller

For my bikes with a system weight of around 100kg you gain around 0,5Wh when braking from 30km/h to near zero and around 0,9Wh when braking from 40km/h to near zero.
In moderate hilly terrain I gain around 1Wh/km from braking downhill and in stop and go city traffic I also gain around 1Wh/km from regular braking to standstill. In mountainous regions regen can reach up to 4-5Wh/km going downhill, in flat terrain without the need to stop regularly regen is obviously close to zero.
Overall 1Wh/km is realistic with my bikes and BionX D system.

So the quote depends on how much you consume. Touring with a 25km/h Pedelec consumption can be as low as 3Wh/km, so regen at 1Wh wold give you an industry quote of 33% (CA would show 50%)
On a 45km/h speed pedelec consumption can be 10Wh/km, so regen quote would be only 10%.

Here is a picture from braking at 40km/h with BionX-D (regen limited to 8A, you don't gain much if going up to 12A)
190723_RekuTest_RC3_40kmh.jpg (81.5 KiB) Viewed 165 times
So this is from part of a trip that I made this summer through Switzerland and France.

This is how our bikes looked like, my system weight was around 120kg. Motor drive was a BionX D limited to 45km/h, 25A and 10A regen. Battery in my case a 13s8p with Panasonic PF cells (Ri around 100mOhm)

This are our speed pedelec: (battery is in the frame bag)
sPed_Frankreich01.jpg (326.74 KiB) Viewed 165 times
sPed_Frankreich03.jpg (210.75 KiB) Viewed 165 times

This are statistics for this part of the trip. Overall regen by industry standard in Wh regen / Wh consumed (named "Rekuquote") has been 14,3%. During some days it was lower, during some days significantly higher. Maximum eneryg gained on one day with regen was 200Wh. Regen overall was 1,2Wh/km. A bit higher than the rule of thumb, but the system weight was 20% higher, too, because of the luggage for camping.
Reku_sPed_Tour_2019_Teilstück.jpg (112.41 KiB) Viewed 165 times
And here you get the link to a large jpg with all the logged currents over those 1000km+:

https://www.bilder-upload.eu/upload/861 ... 277969.jpg

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