18% regeneration?

General Discussion about electric bicycles.
niwrad   100 mW

100 mW
Posts: 44
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: 603
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
190723_RekuTest_RC3_40kmh.jpg (81.5 KiB) Viewed 46 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
sPed_Frankreich01.jpg (326.74 KiB) Viewed 46 times
sPed_Frankreich03.jpg
sPed_Frankreich03.jpg (210.75 KiB) Viewed 46 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
Reku_sPed_Tour_2019_Teilstück.jpg (112.41 KiB) Viewed 46 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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