4000Li - Passed 6000 mile mark

Pete, I was reading some of your posts and wonder if you check ALL of your cells when you charge. Those voltages over 3.7 and up in the 4s don't seem right. If your range was dropping before, then your charger went, and now you are seeing those high numbers on some cells could mean you have 1 or more dead cells. The charger may have been straining to get the pack up to full voltage and that's what killed it. Is your new charger the same as the old one? Most packs end up about 3.4 and change average per cell without a BMS in my experience with several xm3500li (20 40ah TS cells). You must be running 24cells Right? As 20x 3.2vnm=64vnm or about 70v fully charged. I hope you aren't using a 24cell charger on 20cells. As 80v/20batts= about 4v a cell. I've read a few posts with people saying their xm4000li pack was about 80v charged, this doesn't make sense for 20 cells.

Yes, I thought about it and I remember the same thing about the end of charge. I had hooked up little RC/hobby balancing cards as a makeshift BMS. I had some high cells too, but they would come down right away. I top balanced mine with some little 3.6v single cell chargers and that helped. I agree, it's best not to push the charge to long. Sounds like you've got a well matched pack. The most primitive (and simple) form of BMS, or really disaster prevention is to leave the plastic seat compartment off and get in the habit of feeling the batteries once and a while. If one is going bad it will get hot. Eventually you will smell it. Nice job! Keep crankin out the miles!
Bill

At 55 degree temps, the meter will drop all the way to the red, and will even flash the red light, so the batteries seem under more stress in the colder weather. Is this normal?

Sadly yes - LiFePO4 like it warm and cuddly, much like us humans :-) Below about 59F battery temp. (not ambient) you will notice serious degradation every 9F colder, and below 41F battery temp. forget it if you need to drive up anything worth being called a mountain. I personally haven't had anything below freezing yet, but at 32F it is a real drag to even just accelerate to sub-highway speeds without read lights all over the dashboard. I need to put in a battery heating means, because I am sure I have won my bet against my GBS cell pack that it will chicken out way before I do in this winter weather :-)

Hi

I ride an XM 3500 Li running 22 TS 40 AH cells and live in Portland OR. I don't ride in temps below 40 F and certainly the cells have reduced range and more sag in cooler temps but it won't hurt them. If you look in the Thunder Sky manual there are some specs for cell voltages at different temps. All voltages go lower including the voltage at which cell damage will occur. My bike has no flashing lights and no BMS but do have a Pactrakr and it never gives any warnings unless I go too far which I avoid. In 75 F temps I get 45 mph and a practical range of 30 miles. In 40 degree temps it is reduced to 42.7 mph and 25 mile practical range. Distance and speeds are from a GPS calibrated bike computer which is the best $12 I ever spent. Well almost the best, lol. Acceleration and hill climbing is also reduced. I have thought about some kind of battery heater but to burn up electrons heating my batteries seems to to go against the green in me. Probably just a thick blanket that hangs to the floor and a 100 watt light bulb would be an effective heater. At any rate these lifepo4 cells have lead acid beat all to hell !! Range on my SLA scoots is reduced to half !

Garry

That sounds about right. Did you add the two extra cells?

Sadly yes - LiFePO4 like it warm and cuddly, much like us humans :-)

Yes my bike loved it in Florida. It's perfect for them there, warm and flat. I rode it to a shuttle launch, 40 miles each way, loved it! I'm just finding out how much the batteries really don't like this cold. They're fine if I warm them up, but that's not so efficient. Maybe if my wife wouldn't mind if I kept it in the living room. It won't leak oil. Hmmm. If you don't hear from me for awhile, you know what happened.

Do you notice a huge variation in "sag" during colder weather?

Yes, definitely.

i

No I didn't add the cells. I bought this from EPED who used to be very active on this site. A very nice guy I might add. He did a bunch of really nice upgrades. He built a battery charge balancer that I still use and modified the stock charger to charge the 22 cells. I have about 4500 miles on it now. Had a motor bearing go out and a front caliper leak so not bad for a cheap scooter. The motor bearing replacement was interesting and some work but only cost 12 bucks for both bearings. All in all I'm happy. I'd like to replace the tires though, slippery as heck in the wet !!! They look brand new after 4500 miles and would probably last forever if they don't kill me first !

Garry

Hi

If you search the site with this title - Thundersky TSL60-10 XM-3500 Charger Mod for 21 Cells - and then click on it again you will come up with EPED's post about changing the charger to charge 21 cells. He later changed the resistors again for the 22 cell mod. I think I have the values for the 22 cell mod in some stuff that came with the scoot. It will have to wait till after Christmas for me to find it but I will post it soon. The charger works great and charges just to 80 volts. Not sure if you have a BMS but if not be very careful string charging with 2 new cells. They might go very high or low I'm not sure as they will react differently than the ones with 6000 miles on them.. The new cells on my bike were added with only like 100 miles on them and they balance with or without the charge balancer EPED built. My experience with SLA batteries is that when you replace one battery in a pack that bad things can happen with regards to voltages and balance. Probably the same with these cells too. You could charge the extra two cells with a separate charger but might be hard to find a 10 amp charger for two cells. I you connect them between the last cell and the circuit breaker the stock charger will only charge the 20 cells and the voltage regulator for the 12 volt supply will only see 20 cells. I have tried this and it worked with no problems. Make sure the power wire to the controller and the charge wire only go to the Pos side of the 20th cell. Be careful !! You can vaporize things with that much voltage not to mention yourself.

Good luck. Garry

One problem with doing that is that the low voltage cut off on those controllers is set at 52v or 2.6v per cell (52v divided by the # of cells). If you add 2 batteries, 52/22= 2.36v. Your low voltage won't kick in till it's to late and you will damage the batteries. Also the stock charge won't produce enough voltage to fully charge the pack. You either have to never run your pack down real low if you do this, or get a controller with a programmable LVC,BMS, or cycle Analyst. I use the TSL72-15 on mine to charge 24 cells, but it looks like they don't sell the at Elite any more.

These chargers are suitable for 24 cell charge. (87v)

http://kellycontroller.com/f7210-72v10a-charger-p-108.html

http://elitepowersolutions.com/products/product_info.php?cPath=9&products_id=205

No the stock charger won't charge to high enough voltage. On your 4000li I bet you could fit 28 cells just like this.

That's what's under the seat of my 3500li. If that can take it I'm sure your 4000 can handle the volts. To do this (if you want)Just take the circuit breaker off the seat compartment and mount it somewhere under that compartment. Two 12v car batteries will fit in that space under the plastic seat compartment. If you wire them in series, you can test to see the extra power you will get before buying the lithium batts. You'll be surprised, it's allot. I got 6mph per 4pack on my 3500li. I would just wait for the warranty to run out first probably.

This charger would be good for 28cells
http://kellycontroller.com/f8407-84v7a-charger-p-678.html
As you can see I have isolator switches and a second four cell charger in there. With the charger above, all that will be unnecessary.

Also, love the back tire! Will give you a little higher speed. Also, I hear that those controllers are regen capable. Someone needs to find out how to activate it. That thing is HUGE. Look at the size of my 250amp Kelly.

Okay, so your 3500li is really no longer a 3500li :0 In fact you have surpassed the 5000li with 28 cells, and your motor is obviously not stock.

That motor looks like the Xiamen ZAP/Erider 5...8kW 13in motor in my bike.

My rear tire actually looks larger in that picture that in real life. I went from the 130/60-13 stock size to a 150/70-13 Dunlop, which I believe increased the diameter by about 2 inches. (19 to 21) Or something like that. It rides really nicely on that tire, and the grip is outstanding. I did lose a little acceleration, and I think it helped my speedometer accuracy.

The speedo pickup is at the front wheel, so unless you put the same tire up front it's accuracy won't have changed a bit. But indeed your top speed should be a little higher with that larger circumfrence on the rear wheel, as you have effectively changed the motor's "gearing", i.e. distance covered per rpm in relation to motor rpm is now larger than before.

One possibly intersting thing to ponder: what will your insurance say if you have a speed-related accident and they realize you have mounted a rear tire that is larger in circumfrence than the vehicle CoC and related papers state? Or rather is of a different dimension altogether? Here in Germany I could get into trouble with all sorts of folks for this: police, the biennial technical checkup guys, or the insurance in case of an accident...
I must admit though that I have also entertained the thought of mounting such a 13in 150/70 tire back there for the purpose of getting my max speed closer to the promised 95 to 100km/h instead of my stock 86 at fresh charge :-)
Torque with my more powerful Kelly would surely still be sufficient for great acceleration despite the higher tramission ratio...

Hmmm, that speedo thing is intriguing indeed! What is clear is that the controller of a brushless PM-synchronous motor is at all times informed of the exact rotational location of the rotor, i.e. the wheel, and thus also of it's current RPM value. It is not entierly unlikely that a speedometer could gain wheel rpm information both from the front wheel and the hub motor and create a mean from that as long as RPM info is avaiable from both. But the reason you could not see any speedo reaction while spinning just the front wheel could also be because it may be an electronic speedo which will only show life when it is supplied with sufficient electrical power...

I cannot simply fit a larger tire in these quarters as I would get inot multiple trouble, just as I wrote. And not for speed reasons, mind you, I myself could go as fast as my two wheels can carry me, but tires on two-wheeled vehciles are taken extremely seriously here in Germany. Actually many motorcycles have a mandatory tire size AND MAKE registered in their papers, so they cannot even be fitted with another manufactureres tire of the same size and class without having to go through an individual and very costly test process.
Thankfully this very rigorous regimentation does not apply to scooters using 130/60-13 tires, so I have a large choice of manufacturers to pick from, but I cannot just put on a larger tire size :-(

Okay, so your 3500li is really no longer a 3500li :0 In fact you have surpassed the 5000li with 28 cells, and your motor is obviously not stock. How many watts are you running?

I'm still using my stock motor. I've seen short spikes to 10kw but it generally runs at about it's rated 3.5kw at top speed on level ground (48mph for 24cells). It rarely draws more than about 6kw for any length of time. The motors like yours and the ones on Some of the XM5000s that have that smaller diameter (notice the difference in the two motors. tend to overheat on long high speed runs. You would use the 72v charger for 24 cells not the 84v. Those numbers are the nominal voltage for the pack. A 72v charger actually charges up to 87v for example. You're getting good speed, maybe you should leave well enough alone. My 3500 only did 42mph when I got it, that's why I did the mods. I wouldn't really want to go any faster than about 60mph on one of these scooters. One advantage to running at higher voltage is that you draw less amps to produce the same amount of watts, as volts times amps equal watts. So you run cooler.

Here is some chat on the two different motors from a couple years ago.
http://visforvoltage.org/forum/6320-hub-motor-temps-28-cell-3500li

Bill

Does the plug on the kelly mount up with the stock plugin on our Xtreme Li Bikes?

No,you have to splice it in to the existing wires. They call it an aviation connector, But the way they can loosen up, I sure wouldn't fly anything with one. At least on my 3500, when you looked at the wiring from the controller to the motor,the big leads on the motor side appeared to be hard wired in. On closer inspection I noticed that under the shrink wrap were paddle connectors that are screwed together. For the round (aviation) connector (small wires) you have to butt splice them together. It sounds like you are doing fine as is, but if you did anything I would just add 4 batts and get a new charger to match. You might try to find a 15 amp charger like mine. It only takes me 2.67 hours to charge from empty.

Bill

Sounds like a great place for riding. My sisters both went to ASU and I remember riding my sisters scooter around Papago park (gas powered). This was in the 70's. I was 13 I think, I remember the park as being very beautiful, with lots of good rock climbing.

My controller is mounted like the stock 3500li controller was, on the 3500 you could hardly see it. Yes having yours mounted where it is must help allot with the high temps you ride in. An additional heatsink might be a cheap way to aid cooling.
http://ledsupply.com/led-heatsink.php

From what I understand one thing that determines the temperature relation between the controller and the motor is the frequency of the pulse. The controller has to work harder to chop up the pulses finer so it gets hot. If you go the other way, and program the pulses further apart, then the motor runs less efficient, and it gets hot. So it's a matter of finding a balance point where they both get warm instead of one getting hot. I could have this backwards as I am a novice at this, this is just something I heard. Maybe someone will confirm or clarify this.
Anyway glad you're having fun with your electric ride, let us know if you up your voltage and the controller temps come down. I don't know what those controllers are rated for or if they are limited. Maybe someone will know.

It is not entirely unlikely that a speedometer could gain wheel rpm information both from the front wheel and the hub motor and create a mean from that as long as RPM info is available from both.

I bet it's just a cable speedo, I can't believe they made a change like that in this model. It would have to be a digital display.
That is weird though.

MeRoller have you ever had the seat cover off your thunder and taken pictures? Is it as easy to access the batteries as the XM/E-Fun based model?

MeRoller have you ever had the seat cover off your thunder and taken pictures? Is it as easy to access the batteries as the XM/E-Fun based model?

The whole crate is currently almost naked because I intend to put in a battery heating means (you guys in Arizona are quite lucky in this respect...). And no, getting to the battery is nothing short of a pain in a.., and all sorts of other body parts are also painfully stressed when having to tear down more or less the whole bike in order to get to the battery. With the older Efun/Erider X.../ VK2008 design it is probably a lot easier to get at the innards than on the newer Thunder etc. design. Sharp as it may look...

Is your rpm limited by the controller (and thus the top speed?) Because I think you are running highter wattage than I am. 5000 watts? How many cells.

No, RPM is solely limited by back-EMF when without load and under load by voltage sag due to the rather high impedance of the GBS 40Ah cells. 24 of those are on board, and this is a 5kW continuous / 8.something kW peak Xiamen ZAP 13 inch motor. I am told that with 24 CHL 40 or 50Ah cells top speed is closer to the promised 95km/h / 59mph...