Anti-regen Rides
deerfencer1
down Quaker Hill and back again. I only had 1/2 hour or so to ride, so
tried something different, and came up with some interesting results.
Basically I sprinted up the hills with full power demand, then did the
downhills as fast as possible by bypassing regen but pedaling hard in
freewheel mode to give the battery a break. IOW, on the downhill (3.5
mile) stretches I tried to keep the current draw minimal, somewhere
around 100-300W, just enough to bypass regen, and pedaled hard in my
top (54/11) gear to maximize my speed.
Results: I averaged between 20-22 mph on the uphill portions with max
pedaling and current draw, then very close to 33 mph on the downhill
stretches with virtually no regen and minimal current, though with an
occasional minor e-goose on the flats between downgrades. I averaged
around 1.4 miles/Ah after 14 miles of this fast up and down riding.
Here's the significant part: the lipo packs were almost stone cool at
the end of the ride, even though I had been riding them to the max on
the two 3.5 mile climbs. The last part of the ride was downhill but
still I was very surprised at how cool the packs were to the touch at
ride's end considering how I hammered them on the climbs.
Conclusion: This whole Regen debate is a very worthy one as I'm
starting to think regen may indeed be a major stress on our packs. IOW
I'm ascribing the cool packs to the fact that I overrode regen for
pretty much the whole ride--and kept my average speeds very high by
just pedaling hard on the downhills and freewheeling. 33+21/2=27 mph
average, which is very fast.
I plan on investigating this further by bypassing regen as much as
possible and am very interested to see what my average speeds and
range come out to be riding this way over longer distances.
Larry
PGrace
and out. Charging peaked a tad over 19Amps. From my 8.5Ah "A" pack,
I took out 11.9Ah, and put in 3.9Ah through regen (the difference .5
was lost to heat). Obviously that ride would not be possible without
Regen.
But yes, 19.02A charging is a very high charge current for an 8.5Ah
pack. (more than 2C, it would charge the battery from flat in less
than 30 minutes) so this would affect the life of the battery compared
to the slow charge on the shelf. Also, we would be charging an
already warm battery, which is not as good as charging a cold battery.
So:
If you want your battery pack to last longer, treat it as gently as
possible. No turbo, no high-rate regen. With turbo shut off, regen
also is much lower.
Discharging the pack at 19A is every bit as bad as charging it at 19A.
But, 3.9Ah on an 8.5Ah pack in regen is a huge gain in efficiency, it
makes rides possible that would otherwise be impossible.
LiPos can probably tolerate more regen, as they have better current
handling, and more Ah to play with.
Be aware that any charing issues discovered with Regen would apply
identically to fast-charging of LiPos.
Nimbuzz
can be a more sensitive indicator of stresses. On my 3 mile up hill is
the only time the pack gets warm.
I'll get my DB hooked up again soon.
A
deerfencer1
30% of your overall Ahs! My DB usually reads all of 6% regen gain
after a long ride, even with active use of regen. How do you get yours
so much higher? What's your riding style and average speed?
I hear you re the high discharge/recharge issue but cannot live
without my turbo or CC, especially on the climbs, as this to me is the
essence of what makes these machines great, and a joy to ride. There's
nothing like cleaning a significant hill @ 16-20 mph, and with the
double packs I'm usually drawing no more than 15-17A continuous per
pack, about half their rating.
So what I'm thinking here is max demand on the hill climbs where I
need it, then rest/cool the packs on the downhills by overriding regen
and coasting/pedaling/freewheeling AMAP. I noted last night that the
bike is capable of some very high speeds on its own downhill once the
big mo kicks in and regen is locked out. Very curious to see how this
style of riding effects my range since my regen gains are minimal even
when I actively use it. Average speeds should be a notch higher, which
may well translate to modest range gains as well; we'll see.
Larry
Joe
Stone Cold Larry, it's good to hear our packs take this kind of use in stride!
PG, that's awesome high regen data.
All good stuff.
Although I have no detailed riding data from any meters, I do have
extensive experience with the standard A hub in daily use on an X
bike.
First some bad news about my hub pack. I haven't been riding since
the fall, but I have been experimenting in the hub lab. My hub pack
has continued to degrade rapidly since charging it in a hot
environment after riding on a hot day. I suspect if I open it I will
find the swollen cells reported by LEVT. My hub is down to about 1/3
of it's original 8.4Ah capacity. Slow draining with a light bulb only
knocks out 2 of the 5 LEDs with the Voltage going from 42.5 at full
charge down to about 35. I may eventually open the battery hub to get
a better idea of what happened.
Getting back onto the topic of this discussion, I frequently rode my
X bike in Turbo mode and let regen do its thing. It lasted fine for
over 2 years under this type of use and abuse. There are some
problems though. In warm weather the battery will quickly overheat
and the BMS will kick in and start cutting you off and otherwise
misbehave once the hub is hot.
I believe it's the BMS and the heat sensor(s) that work very well to
prevent premature destruction of our packs through overheating from
regen. I don't think it's too risky to use regen normally with our
hubs under typical average riding conditions. I suspect there may
also be a regen current limiter in the BMS. Anybody know?
Things I've learned about regen:
regen is actually stronger if you apply some throttle then if you cut
the throttle off. I'd be interested if someone could measure this
difference, I can feel it. To see for yourself, go down a hill at
over 20 mph till regen comes on with no throttle. then apply some
throttle, but not enough to turn off regen. you will feel the bike
slow down more, and if you release the throttle you'll feel the bike
speed up (with regen still on). This is useful if you have a non X
bike and you want to go over 20 mph - cut the throttle off and
pedaling will be easier.
I have learned never to use regen BRAKING for extended periods while
going down hill.
Turbo regen seems stronger than non-turbo regen, but I'm not
absolutely positive because I sometimes get inconsistent results. If
somebody could measure these it would be interesting.
On long distance rides with only my hub I typically leave Turbo OFF
and let it gently regen whenever I go over 20 mph on downhills and
flats. I'm sure I recouped a lot of Amp hours since I've gotten close
to 50 miles with power to spare.
Regen can be very useful.
Best,
Joe
PGrace
life.
And the data I gave was from a test designed to exercise Regen. (so
no power-robbing wind) Details below.
One other point, is that NiMH packs LIKE to be charged at high rates
(1C or more) they do NOT like to be trickled (see
BatteryUniversity.com) I have not researched LiPo charging limits,
and LiFePO will be completely different too.
Here is the old mail regarding the regen test:
I have a local dirt trail of 1.4 miles, a relatively constant 5%
grade. I rode up and back 7 times, with CC set to about 6mph, Turbo
on. I added pedal power both ways at my leisure, keeping speeds at
6-9mph. I lapped until I felt I couldn't make another lap and still
make it home. The test is only designed to gather data about what
Regen does. Two "Watt's Up" meters hooked up "back to back" monitored
current flow in each direction separately.
Distance: 21.7 miles
Time: 2.6 Hours
Peak Amps Out: 51.2
Peak Amps Regen: 19.0
Peak Watts Out: 1,605.8
Peak Watts Regen: 795.0
AmpHours Out: 11.9
AmpHours Regen: 3.9
WattHours Out: 406.2
WattHours Regen: 153.8
-Without Regen the ride would not be possible. The 8.5AH battery
delivered 11.9AH, the deficit had to be made by Regen. Regen gained a
good deal from the 5% slope, as I never pedaled that hard.
-Regen hit 795 Watts without being driven at high speed. The
Wavecrest motor is HUGELY efficient.
-Speed kills. My speeds remained quite low, CC was set to 6mph, and I
never went faster than perhaps 12mph. By doing so, I minimized air
resistance, by FAR the largest inefficiency. Also by riding slowly,
the amount of time spent in Regen is maximized.
PGrace
the "part throttle" trick. I think (my theory, no hard data to
support):
Regen is an algorithm that operates like this:
Is Throttle on?
If yes, the shut off REGEN.
If no, Is Speed > CC setting? or is left brake on?
If yes, then increase REGEN amount.
If no, then Is Speed = CC?
If yes, then leave REGEN where it is.
If no, then Turn off REGEN (since we now know Speed < CC)
Loop
So when you give it a little throttle, you speed up the bike, without
triggering the "Is throttle on" setting. (This may be a mis-
adjustment, or a flaw in the scheme, or by design) which the algorithm
interprets as "increase regen", slowing the bike.
It feels to be like REGEN exists in discrete steps, maybe 4 or 5. At
it's peak rates, there is no way I can pedal through it on the level.
Hardly a surprise, it can crank out 800Watts, I'm lucky to hit 300W
briefly.
Joe
I think there are also differences in the logic based on the hub
battery. My bike seems to go into regen at lower speeds as the SOC
gets lower. There's definitely different logic
Forgetting about CC (I rarely use CC unless my hand/wrist/thumb gets
tired) I don't think my regen normally comes on until the speed's over
19.5 MPH on a full battery. That's weather or not the throttle is on.
But I'd have to test it to make sure as I'm not absolutely positive.
I agree there seem to me to be only a few descreet levels of regen.
Say one for going too fast and another much higher for braking. These
two levels may be increased by having Turbo mode on. Otherwise within
these levels regen is also a simple (probably linear) function of
speed (faster = greater regen).
Best,
Joe
hayduke
you never know how much braking power you are going to get. IMO regen
is a near necessity for this heavy bike with relatively poor brakes.
For a bike that can go 30+ mph, brakes are the TF achilles heel. I
have considered modifying the bike by installing Magura rim hydraulic
brakes. Has anyone else thought about these brakes?
http://www.webcyclery.com/image.php?productid=16267
On Sep 21, 12:59 pm, Joe <joe...@gmail.com> wrote:
> PG,
> I think there are also differences in the logic based on the hub
> battery. My bike seems to go into regen at lower speeds as the SOC
> gets lower. There's definitely different logic
> Forgetting about CC (I rarely use CC unless my hand/wrist/thumb gets
> tired) I don't think my regen normally comes on until the speed's over
> 19.5 MPH on a full battery. That's weather or not the throttle is on.
> But I'd have to test it to make sure as I'm not absolutely positive.
>
> I agree there seem to me to be only a few descreet levels of regen.
> Say one for going too fast and another much higher for braking. These
> two levels may be increased by having Turbo mode on. Otherwise within
> these levels regen is also a simple (probably linear) function of
> speed (faster = greater regen).
> Best,
> Joe
>
Richard Papa
I just LOVE my REGEN! It's saved my butt at least once. I use it for most
braking. Also consider the Shimano XT brakes. They transform the bike for
the better. Hydraulics will be even better.
Try this. Going down a hill and gently apply REGEN. Then hold the left
brake sensor so REGEN is activated while pressing the right brake leaver off
and on. REGEN will get twice as powerful! Way cool...
Cheers,
Rich
PGrace
be handy for Larry.
Richard Papa
lever whilst holding the left on slightly).
Rich
Joe
don't forget hitting the right brake also cuts the throttle and cruise besides killing the regen. but it could be handy. I disabled my right brake switch long long ago because I want regen braking if possible when I hit both brakes. I may add a right button now with these LiPo packs installed.
Best,
Joe (mobile)
-----Original Message-----
From: PGrace <ment...@gmail.com>
Date: Friday, Sep 21, 2007 9:09 pm
Subject: [TF] Re: Anti-regen Rides
To: TidalForce Forum <Tidal...@googlegroups.com>
Richard--When I touch the right brake, it turns regen off. This would be handy for Larry.
On Sep 21, 4:16 pm, "Richard Papa" <papap...@btconnect.com> wrote:
bMF
brake or Joe's pulsing the throttle both result in increased counter-
torque.
Perhaps this may be a possible explanation.
Q. (BiGH)
However i do wonder if it would be possible to have a PIC run the
phases, and adjust the timing etc. would this allow a higher top
speed- by advancing the phases to take into account increased
rotational speed? would it be possible to make a "digital"
contoroller?
A. (Bill Von)
Phase advance can indeed do this but you introduce some new problems
(like very strong regen if you back off on the throttle.)
Since the WCL motor control PIC is doing exactly that, manipulating
the phase advance, then there's probably a delay in response to adjust
the phase advance to the new speed.
It no doubt takes a couple of revs of the motor for the computer to
get it's bearings.
By pulsing the speed, be it by throttle or brake, you're momentarily
confusing the computer throwing it a curve ball.
In this way you can keep it from 'gearing down' the advance & keep the
regen up.
Your guess is as good as mine.
_ .
_\=\_
(o)+(o)
Richard Papa
Yes my friend. Activate REGEN and use the right brake leaver to cycle the
power of the REGEN. You can try this at low speeds, say stopping at the
lights. Try this, go to 15/20mph. Apply REGEN and then cycle the right
brake leaver on - off. REGEN will increase!
The painted plate is a timing feature as I recall. If you get some dust
into the motor hub, it could effect the sensors and create problems. Our
Doug reported this some time ago.
No idea about the rest? Our Bill Von will need to chime in :)
Cheers,
Rich
-----Original Message-----
From: Tidal...@googlegroups.com [mailto:Tidal...@googlegroups.com] On
Behalf Of bMF
Sent: 23 September 2007 11:44
To: TidalForce Forum
Subject: [TF] Re: Anti-regen Rides
Joe
Joe (mobile)
-----Original Message-----
deerfencer1
to dust in the hub and dirty sensors. Kind of like me attempting
erotic :-)"
LOL!--This is what is commonly known as premature e-jerkulation,
usually most prevalent amongst younger, less experienced, easily
excitable riders <ggg>.
Uma has no patience for these pups, and much prefers an older, more
experienced mount.
L "Hef" Hayes