ERider 8000W scooter - Australia (similar to xm5000li)

Yes, I've seen short peaks of 10.3kw (138 max amps on cycle analyst) to my 3.5kw motor. I've never seen any data that would show that regen braking shortens battery life though. If you have any please post. I'm not sure about the relation between % of braking power (amps back from regen) and rated peak amperage from controller. In other words, if you used 100% braking at 100kmh ( which would be very unlikely) I don't think you would see 350amps of current back to the batteries. Can anyone clear this up? I think there is a max current from regen but I'm not sure it correlates as you indicated. I can watch the regen current on my C/A but haven't done any high speed brake tests and noted the -amps from regen. If anyone can provide more info on this subject it would be very helpful.
Usually the only other difference between the higher kw rated motors (besides the leads) would be in the windings I believe. Heavier Gage wire I think. Not sure though.
I have to say, my 3500kw motor runs nice and cool with my pack voltage at 92v and has held up great. I have a little IR heat sensor that I used to carry with me to measure motor and controller temps. After 10 miles at 55MPH my controller was cool and the hub motor about 120%F.

Here's an old link to the thread where I started monitoring temps.
http://visforvoltage.org/forum/6320-hub-motor-temps-28-cell-3500li
There are very few big hills where I live so that's probably why I haven't fried my motor yet. :-) (full disclosure)
This has some helpful info on hooking up variable analog regen braking, if anyone is interested.
http://visforvoltage.org/forum/6494-kelly-controls-throttle-response-much-smoother

Sorry if my posts are a little amateur, but I am learning as I go.

This isn't really a good thread to be discussing the intricacies of Kelly-speak in their programming, but here goes: Anything to do with current percentages is always to be understood in relation to max rated current of the controller. However, it must be clear that in regeneration for instance the motor becomes a generator, and will only be able to generate electrical current in relation motor rpm, coils and cable resistance, generator efficiency and battery voltage. So even if I programmed a max regeneration limit of 100%, i.e. 350A in my case, my motor could never muster that much current at the speeds my bike can reach, even at empty battery. Even my 60 something A will only come about at speeds above around 40km/h, below that rpm is too low for the motor-turned-generator to put out that much current, and it is continunously reduced down to standstill.

What I HEARD (not own experience) is that LiFePO4 batteries are not very happy about constant cycling of discharge and charge, i.e. what happens in the life of the usual automobile battery, particularly in cold winters.
As long as this is quick cycling - like in city stop-and-go riding - and regen currents are in the region of 1C it is said to not be detrimental to cell longevity, but at higher regen currents in such quickly cycling driving conditions longevity is SAID to be compromised. I have heard that an opportunity charge should last at least half an hour to be effective and also not unnecessarily stress the battery. But I have no scientific proof (yet) for these assumptions. Maybe our member CHL Lithium could elaborate on this aspect of LiFePO4 electrochemistry?

...... Maybe our member CHL Lithium could elaborate on this aspect of LiFePO4 electrochemistry?

LFP is nothing special electrochemistry,I think all batteries charging and discharged character are mainly depend on its impedance

LFP is nothing special electrochemistry,I think all batteries charging and discharged character are mainly depend on its impedance

Ummm, I was more interested in your experiences concerning intermittent charging and discharging as is the case in heavy city driving with a lot of stop and go and slowing down with regegeneration. Unlimited regeneration that is, i.e. with the highest regeneration currents that the motor and battery are capable of at the respective speeds.

I have heard that high discharging and regeneration currents in quick succession are detrimental to battery life. Of course cell impedance is important here too, but it IS more of an electrochemical issue if quick changes of charge/discharge should have a negative effect on cell life expectancy, for example like electrode plating when charging with too much current at lower battery temperatures is also an electrochemical issue.

On my exprience,frequently regenerative current do good for battery life. no matter lead acid or lithium battery.It active electrolyte all the time !

On my exprience,frequently regenerative current do good for battery life. no matter lead acid or lithium battery.It active electrolyte all the time !

Thanks for that! How high a regeneration current could still be o.k.? 1C? 2C? 3C? More? Or would you say there is a limit to where regeneration might get higher than the cells would like? Or would you say the normal charging limtis would apply to regenration currents also, without causing a reduction in battery life?
This is getting interesting :-)

Our CHL battery is designed for E-car,so that 10C short time REGEN current is not problem. and 6C constant charging current would be acceptable too.

A bit too pricey for me, but Woot.com has what looks likea good helmet cam on sale today (12/17/11) only. You might want to check it out.

http://www.woot.com/

Anyone have a request of a video I can make with the glasses?

Yep: taking off from standstill and accelerating up the steepest gradient you can find in Canberra. And of course anything about zooming along at full "throttle" :-)

Ah, it's Christmas, the glasses are here - good to hear (and to see?) :-)

Now only the final Christmas gift is missing, the 24 cell inductive BMS from CHL!

You should ask your dealer to switch over to using the throttle off for regen to see if you like it. You can do it from the laptop, no mechanical changes nessisary. Say have throttle off regen at your 18% then BR/SW regen at say 30% or whatever feels good. You can download the program from Kelly and you should have got a cable with your controller. It's sounds like you know enough not to get yourself in trouble. Just don't raise the % of battery power.

The variable regen on pccarlsons bikes sound interesting. As he said it would probably take some time getting used to. I tried the throttle regen but found it a little annoying to glide. Maybe if there was a larger Zero spot it would be better. Anyway I'm having fun catching up on what everyone's been up to.

Thanks for the great posts.
Bill-

Forecast here 35F and rain : (
Have fun tomorrow!! Just heed the warnings, take it easy towards the end of charge until you get the BMS.

You should ask your dealer to switch over to using the throttle off for regen to see if you like it. You can do it from the laptop, no mechanical changes nessisary. Say have throttle off regen at your 18% then BR/SW regen at say 30% or whatever feels good. You can download the program from Kelly and you should have got a cable with your controller. It's sounds like you know enough not to get yourself in trouble. Just don't raise the % of battery power.

The 18% brake-switch induced regen is perfectly fit for the slippery road conditions around here at the moment, and they are gentle enough to get some continuous regen power down the steepest hill on my normal routes, and strong enough to serve as a good braking replacement for most traffic-related stops, so I don't really have have any reason to do anything in that respect. But I WILL tear the thing down over the Christmas break to try to install a heating means for my GBS battery, and clean and insulate the balancer boards on my cells as they tend to shut down the BMS and thus charging as soon as just the tiniest bit of moisture collects on one of them... And all cells will be voltage tested, 3/4ths empty and an hour after charging ends.

Pcarlson, thanks for the quick as lightning repsonse! You are far faster than youtube - I still just get their usual rectangular grumpy "smily" face instead of your video :-)

New youtube address: http://youtu.be/tjbION8Ey1A

Doesn't work for me.

Great video!

Only 480p was available just now, maybe later HD?

Another matter, maybe you have mentioned it before, but what is the relation between the bikes speedo and the CA?

Right now I really envy you, haven´t been riding for some weeks, we have had between 0-5 Centigrades here for a long time now, too cold for me..
By the way, that´s unusually mild...

Johnny

http://youtu.be/tjbION8Ey1A
works now :-)
Thanks Phil for the personal dedication! That scooter sure has punch!!! But I do reckon that at 20°C my beefed-up 5...8kW Thunder could keep up with you at least for the first 5 or 6 seconds, but those CHL sure seem to have some more life in them at the upper end than my GBS set. How much does your speedo exagerate? If I remember correctly it was around 14% fast towards the upper end? So the peg at 106km/h would be real 93km/h :O That would be a full 7km/h more than my ride can muster. But can you also do 106 on level terrain?
0-80 real km/h would be 15 seconds then, in test no. 4 slightly downhill. Uphill was only slightly longer, around 19 seconds. And all of that while taking into account that above around 70km/h back-EMF begins to kick in and dampens the urge to accelerate. Awsome performance!!!
Your new video gadget is also quite superb, I must say! Thanks again!

Bravo! That was nicely done. I love how you could hear that bike going off forever in the distance. Funny, we have them same car to, even to the color. I can't believe how quiet that sevcon is! Loved how you demonstrated that you came to a full stop using the regen braking. I really envy you as well. I like where you mounted the C/A too. I put mine right over the panel since none of it read right anyway, but it can be a little hard to read in there sometimes, mine is the smaller version.
Thanks for all your reporting, those are some nice scooters, for sure! Great job, I thought it would be to shaky, but it looked great.
Long may you run- Bill

That's right, I forgot, it's not exactly balmy where you are right now, here either. I'm glad you mentioned that about the GBS as I need to buy a set of batteries soon and was thinking of trying them. I don't ride much in winter. With my original tires I'm not crazy about winter driving. My TS cells sag like crazy in low temps also, so it's not a great feeling. I just thought I would mention it because you can switch it with the push of a button. Pretty nice! Another approach I read about that I thought was clever was to have the throttle switch from THR to Brk when you pull the brake handle. Then just twist the throttle as you want more brake. My problem with that system was that if you forget to return the throttle to 0 before you let off the brakes... SURPRISE!!! That's why I ended up mounting the thumb brake like I did. Anyway, sounds like you are up there with the best that's available right now by adapting and improving, that's all you can do. Keep up the good work!

So, here is your uphill and slight downhill acceleration graph over time. I put the approximate "real" speed on the vertical axis:

The scooter does have a rather serious current limitiation up to about 30km/h, above that it really takes off! I have also noted the times for 50 and 80km/h. What I find particularly interesting though is the marginal difference between uphill and downhill acceleration from standstill to about 45km/h. This may be due to the already slightly discharged battery for the downhill test.

Thanks for the kind words :-) I enjoy doing such research!

I have some news about my speedo dial now. Today I pulled it apart to make a new background for accuracy and then I found the needle has not been set correctly. Long story short, the speedo needle is now within 3% accurate

As for your speedo needle, what exactly do mean by "the needle has not been set correctly"? Does this mean it was reading like 10km/h at standstill? I think not, as the 10-mark was passed several times in your newest video...
With the slightly larger winter tires my speedo needle is pretty much spot-on, but the odometer is slightly on the slow side, i.e. it shows less than actual distance travelled. But this is also only in the 3% range and will be more than offset with the Cheng Shin once it gets warmer around here.
My hands are all chapped now and my body aches from head to toe due to two days spent mainly in the garage (at 2...6°C) tearing down my Thunder for the first time - on my own, not at my dealer. I am extremely grateful to my dealer though from whom I learned valuable tricks to make things a little easier and safer. Basically the whole upper part of the body is hooked together and simulataneously screwed to the frame and to one-another, sometimes in hidden places. It will be hell to put the thing together again, even though I was meticulous at keeping all screws of a panel in one spot and writing down the order in which I worked myself down into the bowles of my scooter - the battery pack. Plus pics of particularly tricky spots.
I am doing this for several reasons:
1. to find the leaks through which moisture came onto the cells, and despite the lids on the GBS cells (which are extremely thoroughly engineered, from a mechanical standpoint) had befallen some of the balancer boards which had caused the BMS to tell the charger to go into failure mode. I had blown into the front grill with an electric heater for 8h to get things dry enough for the BMS to allow the charger to resume operation.
2. to clean and seal the balancer boards so this kind of fault does not happen again even if I cannot modify things enough to get the battery compartment watertight enough
3. to measure all 24 babies, first at 3/4 empty, then 1h after termination of full charge (both measurements showed a pretty healthy and well balanced team)
and 4. and most importantly to assess the possibilities of either just insulating or even installing electric heating for the battery pack. The odds of the latter have declined sharply due to masses of wires in the way and the middle rows of battery packs I cannot get unstuck to be able to slide them fist completely to one side to insert insulation/heating on the other, then slide them over again as far as possible to do the same on the other side.

But for the next couple of days this will have to rest - MERRY CHRISTMAS everyone :-)

I will also take my Thunder apart when the BMS arrives, could you possibly e-mail me the "key" pics of the disassembly?

Johnny

I am alsoin the process of taking down my thunder. Remarkable how many clips they can fit...
Will measure my cells as well...
/k