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[skadamo]

Cool interview with Todd Kollin.



http://blog.wired.com/gadgets/2008/10/anotger-great-e.html

I like this...

Customizable rigs indicate that a user could buy the bike with an efficient battery and engine build today, and when the next cycle of improved batteries is released, he'll be able to swap in the new one without investing in a new one. 

[Gardener]

I'd like to test ride this bike if it becomes available in Chicago. The price seems just right and it would be a nice machine to ride to work and back - a 12 mile ride either way every day for me. Let's see if they begin to sell them over here.

Cheers!

[skadamo]

+1.  I am in the Chicago suburbs.  Would be cool if we had an eDealer around here.

I am looking forward to hearing some owner feedback on this one.

[Gardener]

Skadamo,

I came to know about your forum when you visited my blog. 

Great forum and I have invited visitors to my blog to register and participate here.

Yes, I hope we'll see some of these machines at Rosemont in Feb. I woud love to do a test ride - am planning to buy an MC next spring and an electric one would be fun.

Cheers!

[skadamo]

Cool, thanks for the referrals!

Feel free to put your blog in your signature if you want.  Might get more of us out there.

[gridnack]

I bought one of these (EMC/Electric Motorsports GPR-S), but I can't provide any usefull feedback since it's been in the shop since I got it titled.  I was trying to get used to it and finding the range but it never went more than 35 mph and I was only able to ride it for a total of 4 miles.  It seems the charger had a blown fuse and some of the batteries were bad.  The interesting thing is there isn't an apparent indicator of a problem, unless you know what the voltages should be.

Now EMC is telling me it's going to take up to 25 days for the batteries to balance and during this time it can't be ridden faster than 20 mph and a certain voltage can't be exceeded.  Martin at EMC hasn't emailed the voltages yet, so I don't know what they are.  If I ever get the bike back I'll be sure to answer any questions you may have.

The manual is lack luster and provides very little useful information.

I just hope they start my warranty from the time I get the bike back (if ever) and not when they delivered it. 
I've almost sent the bike back several times, but they have convinced me they just about got it fixed.  It will go back this week if they don't email the speicifcs of the voltages and warranty. 
I've made seven payments on this thing and have nothing to show for it except for a lot of aggravation.

[skadamo]

Hey gridnack, hope everything gets sorted out.  That has gotta be tough.  Let us know when your back on the road.  Interesting about the batteries balancing.  I would like to hear more about how that works.

[TK]

Hi my name is TK,

I am Electric Motorsport and I am going to see if I can help shed some light on Gridnack's issue. 

Electric Motorsport GPR-S Recalled the on-board speed chargers on 24 of the first 100 bikes it sold.

The reason for this recall was because the 1.5 kW on-board charger kept popping its fuse.
All of these 24 chargers have been replaced.  If someone was unfortunate enough to experience one of these blown charger fuses they would not hear the audible charger fans running or see the green LED charge light. Their batteries would not be getting a charge.  If they tried to ride the bike uncharged the controller would immediately hit low voltage cut back and current limit them to half speed (35mph) until the vehicle would eventual come to a stop.   Luckily most customers were able to have the replacement charger installed and the battery pack was not effected.  Some however ended up damaging some battery cells.   Electric Motorsport had these customers batteries replaced free of charge.

BALANCING

The solid state BMS on the Electric Motorsport GPR-S shunt balances about 100 milliamps.  That is equal to 2.4 Ahr of balancing over a 24 hour period. This is fine for balancing a matched and pre balanced pack of LFP batteries but if one or more cells are being replaced in a pack it can be a different story.   When changing cells in a series pack it is possible that the new cells are not at the same state of charge as the rest of the pack.  we recommend if changing a cell in a Lithium Pack either parallel balance the pack first with the new cells or install cells that have somewhat equal state of charge.   If not what Gridnack is experiencing can be the result.

   If a fully charge battery cell of 50Ahrs is put into a pack that is depleted to 20% state of charge the new cell will be holding 40 Ahr more capacity then the rest of the pack.  This is BAD because the charge will irremediably turn of when the charged cell hits max voltage and the rest of the pack will not charge that is until the BMS bleeds down the newly installed cells to match the rest of the pack.  This however would take an abnormal long time

The math goes like this

40 Ahrs  / 100 milliamps  = 400 hours to balance.

When we heard the installer at a local electric vehicle repair shop put fully charged replacement cells into a depleted pack and reset the BMS we immediately new the customer was not going to be happy with the fact that they would have to wait so long before they could ride their bike.   If it was in our shop we would have parallel balance the new cells prior to installing avoiding such a abnormal long balance time.


VOLTAGE AND STATE OF CHARGE METERS FOR LFP BATTERIES.

Standard state of charge meters do not work very well for LFP batteries.   The reason is that the voltage drop is not as linear with state of charge like Lead Acid batteries are.   This means most state of charge meters for LFP would stay almost full up to about 10% state of charge and then would drop like a rock.   This is why we put a Cycle Analyst on every  Lithium bike sold.   The Cycle Analyst as explained in the GPR-S Owners Manual reads both Amp hours used and watt hours used.  Both of which can count down state of charge like a precision instrument to the thousandths of a percent.   If the battery pack ever gets to low the controller also has a limiter that cuts back power and speed along with a distinct low pitch current limiting sound.   Riding in low voltage current limit is not good for the batteries.   This is the same with every Electric Motorbike or Scooter on the Market.   Gridnack was complaining there was no RED danger you are low light.   This is somewhat true.   A new rider may not recognize the sound of the low voltage power cut back.   They may be just wondering why am I only going half speed.  Indeed there is a red warning light Alltrax puts on the controller itself but the rider can not see the controller under the fairings.   that is why we now have a fiber optic cable upgrade for the GPR-S that goes from the controller LED to the dash so people can see the RED LED low voltage light that comes on simultaneously with the current limiting feeling and sound.

Hope this helps.


[/quote]

[frodus]

TK = Todd?

Welcome to the forum... this is Travis.... good talking with you today.

That was a great post on the BMS/charging of Lifepo4, not just for your bikes.

[gridnack]

Sorry guys, I forgot to return post that my bike is working a whole lot better now.  I haven't ventured too far from home due to having to walk it back once and I'm still a little gun shy.  It is fun to ride.