Maximum normal regen? Is CA V3 correct?

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niwrad

1 W
Joined
Jun 16, 2019
Messages
57
Hello all

I've started my daily commute with my finished DYI ebike kit along with a cycle analyst V3. Someone said that the regen I'm getting is unrealistic. Is this correct or is there something potentially wrong here?

cycling thru CA stats in link
https://imgur.com/a/ygaNQfT
(22%)
 
This is the exact same question with the exact same data as your other thread. Same answer. It's probably high, depending on the specifics of your ride.
 
flat tire said:
This is the exact same question with the exact same data as your other thread. Same answer. It's probably high, depending on the specifics of your ride.
Click to expand...

what other tread? Maybe you're confusing me for someone else, this is the first time i posted here about this Q
 
Oh, well your regen is probably high. Unless you're riding down a mountain. Most likely your current consumption isn't zeroed or you left the bike sitting for a while with a small nonzero consumption due to limits in the device's accuracy and it accrued more regen than you really got.
 
nope, riding the urban jungle of NYC. Tallest incline is either the Manhattan or Brooklyn bridge
 
re-zero your current consumption (in the menu you get by holding left button somewhere) and it should go away. Make sure if the temperature changes a lot to re-zero.
 
edit: nevermind, but will see to re-zero it
 
That might have been me. I just recharged the battery and will see how my figures look for the next "trip". It's a good tip, I typically do get -4W read-out when coasting, and now it's typically 0W. I have a hunch that will knock the numbers down a little, but not a lot.

For me, though, since my question was about my regen read-out, I thought it would suffice to just write what it was (18%), in my post, rather than require the reader to watch a video to find out. (22%)
 
niwrad said:
I've started my daily commute with my finished DYI ebike kit along with a cycle analyst V3. Someone said that the regen I'm getting is unrealistic.
Click to expand...
Verify your shunt value is correctly entered in the CA setup.

Verify that you've zeroed the measurement while in there, so that when no current is flowing, the CA reads zero Amps.

If you are charging thru the system in a way that lets current flow backwards thru the CA shunt, then it will read as regen. So you have to note your regen info before you recharge, in that case, or you'll get incorrect data.


Otherwise, the readings you get are probably correct (though they seem pretty high if you're not regen braking down long hills).
 
I’m using the CAV3 with the direct plug into the motor controller. Also I plugged in my battery and the electrical readout said 0 amps. Left the shunt value at the default 1 mOhm.
 
amberwolf said:
Otherwise, the readings you get are probably correct (though they seem pretty high if you're not regen braking down long hills).
Click to expand...

Just thinking out loud, maybe it’s just counterintuitive. To go downhill, you have to go up. Going up hill is less efficient due to losses (heat, etc). This increases total consumption. Regen on the other hand only cares mainly about wheel speed, and probably doesn’t have the corresponding effect on efficiency, although there is greater potential and kinetic energy due to the hill you’re descending. So, if you’re riding fast and efficiently on flat ground, and total consumption is low (the denominator), the the regen percentage may be higher (regen = numerator). As I said, just thinking out loud with only a half cup of coffee. I think maybe with improved throttle technique to reduce total consumption, the OP may even get his numbers higher?



Sent from my iPhone using Tapatalk
 
Yeah I have it set up so my bike is solely controlled by pedal assist and an AUX input which changes the degree of assist. I think I use about 300-400 watts while traveling around 20 mph. I estimate that I can continuously output 200 watts depending on what kind of incline I put into the Grin Tech simulator. I like how much regen I get so I feel like I can come to a complete stop at each red light without having “wasted” any effort, and often with pedal assist I can easily catch up with any non e bikes that jumped the light
 
niwrad said:
Yeah I have it set up so my bike is solely controlled by pedal assist and an AUX input which changes the degree of assist. I think I use about 300-400 watts while traveling around 20 mph. I estimate that I can continuously output 200 watts depending on what kind of incline I put into the Grin Tech simulator. I like how much regen I get so I feel like I can come to a complete stop at each red light without having “wasted” any effort, and often with pedal assist I can easily catch up with any non e bikes that jumped the light
Click to expand...

Ya, without using throttle, it's a lot harder to waste power on acceleration. On the other hand, there are ways to combine throttle and pedaling without PAS that can even be more efficient, but that's more work.
 
i never really understood how you use throttle and pedal assist at the same time though
 
I've seen as high as 25% regen on flat terrain. That's with lots of stop-n-go, no pedaling and ebraking as much as possible. 22% regen in the city with lots of pedaling seems quite reasonable to me in city riding where cruising at a constant speed is almost non-existent.
 
niwrad said:
I’m using the CAV3 with the direct plug into the motor. Also I plugged in my battery and the electrical readout said 0 amps. Left the shunt value at the default 1 mOhm.
Click to expand...
The CA DP doesn't plug into the motor, but rather the controller (just to make sure you've got it in the right spot. ;) ).

Then, unless the controller's shunt is actually 1mOhm (most aren't), then that directly affects all current and wattage readings in the CA, including regen.

You have to set the value to the *actual* shunt resistance, or all readings will be wrong. Some controllers (like the Grinfineons) have this printed, written, or etched on the casing or labelling. If yours does not, you can go here
https://endless-sphere.com/forums/viewtopic.php?t=68747
for methods to measure yours. If you can't do it via the methods there, one of these should be possible
https://www.google.com/search?q=how+to+measure+a+controller+shunt



This, however, won't change the *percentage* of regen, just the total value you get.


If you were using the Grin Tech SA shunt, then it is 1mOhm, so leaving the CA at the default would be ok.
 
Ah okay fixed my post

according to Grins user manual it’s 1.000 mOhm so it should be correct already.
 
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