ERIDER Scooter 5000W Lithium with BMS on each cell

Well I have been away for work for 2 weeks. I left it charging so it could balance the cells.

I came home last night and I was excited to see if it had balanced. Off charge it was only 73.4v Uh-Oh

It struggled getting up to 20km/h in the car park :(

Ah well. Back to the drawing board. I noticed one cell near the front of the bike was down to 1.7v before I left anyway. I hoped it would all balance out....nope :(

Anyway, I called Eric from eRider in Melbourne again, and I must say he really stands behind his products. Without hesitation he said he will send another 4 cells. WOW!!

My Scooter is expected to arrive around mid July. The scooter I am having all this trouble with is just the "Loan" scooter while 'waiting' for my scooter. As it turns out, I have had no riding experience, but I have gained a LOT of experience pulling the bike apart :)

My High current shunt has arrived for my Cycle Analyst so I can't wait to connect that baby up. That will tell me INSTANTLY the voltage sag I'm getting as well as the power input. I wonder just how close to 5000w this bike REALLY is.

The dealer tells me of all these good stories where people just ride their bikes and charge them. I'm just starting to think that the technology just isn't ready. The BMS on BOTH my eBikes is perfect. It balances the cells and protects them. It seems the bms on this bike is not doing its job. Maybe it's faulty, or I'm just lucky to have all these problems :-)

Is there anyone out there with one of these scooters that has any good stories?

Well here is a good story. I have the XTreme 4000li, no BMS, in the same brilliant red color as your bike, and I love it. I purchased it in January as a "showroom display" from XTreme for $1900. It had 14 miles on it. I now have 2011 miles on it that have been completely trouble free. I plug in, and I ride. The end. It has been a dream. At full charge my voltage reads right around 79.8 V. My top speed is around 53 mph. And my best range to date is 47.6 miles on a single charge. The 5000 watt version should do even better.

Your story makes me wonder if the complexity added by BMS is worth it. I usually leave mine plugged in over night, and doesn't the Thundersky charger go into "pulse mode" after 3 or 4 hours, thereby bringing up any of the lower cells into balance with the higher cells?

Well here is a good story. I have the XTreme 4000li, no BMS, in the same brilliant red color as your bike, and I love it. I purchased it in January as a "showroom display" from XTreme for $1900. It had 14 miles on it. I now have 2011 miles on it that have been completely trouble free. I plug in, and I ride. The end. It has been a dream. At full charge my voltage reads right around 79.8 V. My top speed is around 53 mph. And my best range to date is 47.6 miles on a single charge. The 5000 watt version should do even better.

Your story makes me wonder if the complexity added by BMS is worth it. I usually leave mine plugged in over night, and doesn't the Thundersky charger go into "pulse mode" after 3 or 4 hours, thereby bringing up any of the lower cells into balance with the higher cells?

Garrrr! That is exactly all I want to do. Plug in, ride, plug in some more. Just out of interest, my bike has 24 thundersky cells (72v pack) and it hits 80.1v hot off the charger. Yes the thundersky charge does go into a pulse mode, but without a bms or shunts, it will not be able to "bring up" flat cells, you run the risk of over charging all the other cells.

Does your bike have Thundersky 40Ah cells or 60Ah cells? Because 75km (47mi) sounds like a fantastic range! Also 85km/h (53mph) is also very good. That's about what my scooter does when the needle hits 100km/h (60mph). Even though the needle says 100km/h the gps says 85km/h

The dealer is sending another 4 cells for me to swap out but I have a bad feeling this bike is just never going to go more than 1 or 2km before it dies again. My partner doesn't even want to ride it anymore because we have both lost faith in it. I have had better reliability from my electric bicycles, but they have BMS boards too. I think all the problems started when the bike was send with the BMS not connected. Who knows how many cells were ruined.

When I get my new Scooter, Hopefully in July I will start a new thread as it won't have thundersky cells, it will be using the new GBS-LFMP cells from Electric Motorsport. The BMS even has an LCD, what it displays exactly I'm not sure.

Given all the problems I've had with this loan bike (well it was a store demo) I would NEVER buy from overseas. I will always buy from an Australian dealer, and this guy in Melbourne will certainly help you anyway he can. I'm just 'lucky' enough to get a bad one, but at least I'm becoming very familiar with stripping down the bike :)

My 4000Li is 40ah and 60v. I frequently measure the voltage using a digital voltmeter and I was very suprised to see the voltage reach 79+ volts at full charge. My 48 volt 700li would only reach 53+ volts at full charge. I also felt that 47.6 miles on 40ah and 60v was exceptionally good.

I will take to heart what you say about the possibility of overcharing my stronger cells, and will only charge it for 3 or 4 hours I wasn't sure if the Thundersky Charger had diagnostics that would take over when BMS was absent. Thanks for the input!!

UPDATE:

Just had a call from UPS delivery company and they have delivered my 4 new cells. Looks like I'll be installing some new cells and the Cycle Analyst today.

Well, So far so good. I replaced another 2 dead cells at 0v. All seems to be going good now (for the moment). I was unable to connect the cycle analyst because the shunt resister has 12mm bolts and the scooter has 10mm lugs. I'll fix that later.

Today I rode into work for the VERY first time and a fellow worker spotted I was electric from the traffic lights a few blocks before I got into work. He was on a noisy BMW and he could still tell I was silent?! He just filled up for $33 and got 270Km from his tank...That it!! I told him I filled up last night for 18c

So here's a picture of my scooter in the $8 a day car park at work. Motorbikes have free parking :)

Hi all.

Well I've mounted the Cycle analyst on the bike and noticed from a flat battery the charger stopped after putting in just 23.5Ah rather than 40. The thundersky batteries are 40Ah cells so it should have taken 40Ah or close to it. This only gives me a range of 25km.

I worked out that I use around 0.911Ah per km

Anyway, heres a photo.

Note: The 10Amp charger is connected and charging the battery at 10.7Amps

The charger only puts back what you have taken out, so to speak.

when you rode, and discharged 25Ah, was the bike starting to cut out?

Matt

The charger only puts back what you have taken out, so to speak.

when you rode, and discharged 25Ah, was the bike starting to cut out?

Matt

Hi Matt,

Yes My scooter just started cutting out on me 2 streets away from my house so I limped home and reset the cycle analyst and then plugged in the charger. Then in the morning it read only 23.5Ah was put back into the bike. I rode to a friends place today and used 5.8Ah and plugged in and the cycle analyst started counting DOWN the Ah :) After a cuppa and cake I came out to find it had put in the 5.8Ah plus an extra 0.5Ah because the cycle analyst read -0.5Ah. Cool, that's an extra 500m range.

Anyway the scooter seems to be going ok now but the voltage sags to around 67.5v whilst accelerating. The bike also doesn't seem to have the same amount of pickup it did in the past so I think 1 cell may be sagging too much. Because at a red light the voltage sits on 77v but when I get home it sits on 77v but by the time I pull off the seat etc to access the cells it has risen to 79.6v. But hot off the charger the bike is drawing 100 amps with a 105Amp peak at 71.5v. That's OVER 7kW power in! But after 2 km the power settles to around 5.8kW

Anyway, I had a chance to take some good shots with my SLR camera today by the lake. Here's a nice one.

Well I am happy to say the scooter is still working and running nicely. I only pulled it part twice today :-)

I have ridden over 65km today trying my hardest to make the BMS shut down but the bike passed with flying colours. Even at 7am this morning in -3c cold weather the voltage sagged down to 66.0v under full throttle but nothing cut out and I could still ride as per normal.

I was still not happy with the voltage sag under load so I decided to add 1 extra cell to the pack to make is 25 cells, a 75v pack. I noticed the charger peaked at 86.8v just before it finishes charging the 24 cell pack and then settled down to 80v so 1 extra cell should be fine.

I made up an extra cable and installed 1 extra cell to the pack.....WOW!!

The extra power it has made is very surprising!! The charger can still charge the battery pack (24.5Ah capacity now) with the extra cell. Hot off the charger it peaks at 87.5v and then settles to 84v. That's fine, BUT, under FULL throttle instead of the voltage sagging to 66v or 67v it only sags to 71v now and is able to pull a nice 114Amps to make a healthy 8Kw of power. The acceleration is only slightly quicker but after 40km/h things are VERY different. Instead of struggling to get up to 80km/h to keep with the cars, the bike now Scoots up to 105km/h with NO hesitation! I find it a lot safer now with the quicker speed and I have ridden nearly 25km today with the extra cell connected and nothing is getting hot, smells funny or bloated. In fact the extra cell seems to be helping the other cells with voltage drop.

I must say that I am very pleased with the new 25 cell battery, 24 was not quite fast enough. I would like to try 26 cells but without knowing what capacitors are in the speed controller, I won't try because if it has 90v capacitors then a peak of 87.5 + 3.5 = 91v...poof!

Does anyone else have a 5000w scooter? Do you find you use about 1Ah per km? I was really hoping for less power consumption than that.

Well I have some news...

Even with 25 cells, the battery is still struggling with this cold Canberra weather.

Last night it dipped down to -1°c

My ride into work today started at 84.1v off the charger, after just 4.8km the bike started to "cut out". The cause was under load the voltage was sagging to 67v and that's about the cut-off limit. It seems that these Thundersky cells just do not like the cold weather. I don't care what the manufacturer says, these are NOT 3C cells. In cold weather they are more like 2 C cells. That means 40Ah x 2 = 80Amps maximum. With a voltage of 68v that means my bike will max out at 5.4kW. Now to maintain 80km/h requires about 5.7kW so trying to maintain this speed will overload the batteries. My advice to people with thundersky batteries, treat them as 3C cells in summer and 2C cells in winter.

My scooter arriving in July has 60Ah cells by GBS motorsport, not Thundersky, so even with this very cold weather, 60Ah x 2 = 120Amps!! With a voltage of 72v it should supply 8.6kW in Winter and 13kW in summer. On a warm weekend I tested the scooter and 8.1kW was too fast for me! It flew up to 106km/h (gps certified) no problem. So 8.6kW should be enough to get me around town while freezing cold. As for 13kW I wouldn't know what to do with all that power?

Maybe I should get a side car and put in 200Ah cells???? :)

Today wasn't as cold, it was only 4°c

I have learnt a few things whilst riding this temporary scooter. In cold weather, believe it or not, you need to 'warm' the batteries up. This means for the first few hundred meters SLOWLY roll on the throttle and the voltage stays above 70v because if I go FULL throttle instantly it dips to 68v. AFter about 2 km of slowly rolling the throttle I get to the merge lane where I'm forced to get up to 80km/h quickly. At this stage I FULL throttle and the bike only dips to 71v and still accelerating all the way up to 85km/h to merge I ease off the throttle and keep my 80km/h and the battery stays at 70-72v.

Now I am aware of this, I take a different route to work. A few back streets to warm the batteries and then the fast lanes. But I know exactly what the EV grin is all about now....riding all over the place for next to nothing. Dashed off to the shops last night to get freezer bags...25cents and I didn't have to burn 2Litres of petrol to do it!

The voltage of battery set drop too much after full throttle because of bad impedance of yellow battery,if you come to CHL battery,the voltage would dips less than 5V with 50AH batteries. Its 0.20mΩ is only 1/5 impedance of yellow battery.

Hi CHL Battery!

I thought these Yellow Thundersky batteries were not that good. The scooter I have bought will be coming with GBS Motorsport LiFeMnPo4 batteries. Have you tested these cells? If so, how do they compare to CHL cells? The GBS battery comes with a BMS with an LCD screen readout. Once again, these are supposed to be 3C cells, so 3x60Ah = 180Amps maximum, if the voltage can stay at 70v at 180Amps then thats 12600 watts! That will be lovely acceleration. This temporary scooter has a 90A controller but it can handle loads of up to 115A for short bursts but settles down to 88-92Amps on full throttle.

GBS originally was one branch of Thundersky,so that I think they are almost same technology

UPDATE:

Well it has been 3 weeks and 1 day since I started getting the scooter going, and in that time have put on 987km! I'm sorry to say that this morning was a little cold and only 1km from home riding into work the BMS started shutting down the bike all over again :(

It looks like there may be yet another dead cell. I noticed the voltage sits at 80.1v at rest but sags right down to 67.1v under mild acceleration so it looks like the impedance of the pack is too high and just can't deliver the power required. I will check the cells tonight if it stops raining, I have a feeling which cell may be the problem. Still a month until my scooter comes. Should I try and fix the temporary bike again?

UPDATE:It looks like there may be yet another dead cell. I will check the cells tonight if it stops raining, I have a feeling which cell may be the problem. Still a month until my scooter comes. Should I try and fix the temporary bike again?

Guy's, I hope you don't take this the wrong way, but although I found your journal fascinating, and just as Mik's struggles with his 'Vetux' are equally interesting, what do you think an ordinary consumer, say your fiancé,would react to all these technical setbacks? Especially, when the dealer is 600klms from being able to fix the problem?

What do you think an ordinary consumer, say your fiancé,would react to all these technical setbacks? Especially, when the dealer is 600klms from being able to fix the problem?

Hi Marcopolo,

It pains me much to say this, as much as I love the idea of electric vehicles, I certainly would NOT recommend these chinese scooters (erider, xtreme, zap, etc etc) to non technical people at this stage. I will be able to give you more information once our 2011 model scooters arrive from China. New GBS LiFeMnPo4 batteries with new BMS, new cevcon controller.

I pulled the bike apart AGAIN last night to find another 3 cells had died. The supplier happily sent another 4 cells overnight but with the sun setting at 5:45pm I just don't have enough time to replace the cells after work now so it'll have to wait for the weekend.

I put 3500 miles on my XB-700li and now 2700 miles on my Xtreme 4000Li. And while I would agree that being a very technical person definitely helps (Mechanical Engineer here) the 4000Li has been a very trouble free dream. The only problem I have encountered is a rear flat tire, which was not the bike's fault. And yes it takes an act of God and Engineer to replace one of those rear tires. But the rest of the bike has been flawless.

My 700Li had numerous part failures from alarm to throttle, and I was able to fix or replace each of them with help from very good customer service from XTreme. But the 4000Li has been simple plug in and drive. Awesome.

I put 3500 miles on my XB-700li and now 2700 miles on my Xtreme 4000Li. And while I would agree that being a very technical person definitely helps (Mechanical Engineer here) the 4000Li has been a very trouble free dream. The only problem I have encountered is a rear flat tire, which was not the bike's fault. And yes it takes an act of God and Engineer to replace one of those rear tires. But the rest of the bike has been flawless.

My 700Li had numerous part failures from alarm to throttle, and I was able to fix or replace each of them with help from very good customer service from XTreme. But the 4000Li has been simple plug in and drive. Awesome.

You're kidding! A flat tire! Oh man, why am I so unlucky.

After the kind man at eRider sent me yet another 4 cells. I found 3 dead and one weak in the pack so I changed 4 cells and gave it overnight to charge and balance. I rode 5km the next day to a friends place and on the way home (7km now) the BMS is shutting the bike down all over again. The voltage is STILL sagging down to 67v or lower! I just can't believe how absolute rubbish these THUNDER-SKY cells are, either that or they are old cells?

Anyway, I'll send the supplier an email tomorrow and just tell him not to worry about anymore cells as it's a waste of time and money.

Ah, I just hope my new scooter will be like your xm4000li story. Just plug in and drive. And have the ability to ride more than 25km!

After the kind man at eRider sent me yet another 4 cells. I found 3 dead and one weak in the pack so I changed 4 cells and gave it overnight to charge and balance. I rode 5km the next day to a friends place and on the way home (7km now) the BMS is shutting the bike down all over again. The voltage is STILL sagging down to 67v or lower! I just can't believe how absolute rubbish these THUNDER-SKY cells are, either that or they are old cells?

This might be an obvious question, but, are you sure the BMS is actually doing balancing and charge termination when the cells hit full?
Ie checked no cells are going over voltage with a volt meter at end of charge?

do you balance the cells at all before installing them?

a failure rate this high is nearly unheard of......

Matt

This might be an obvious question, but, are you sure the BMS is actually doing balancing and charge termination when the cells hit full?
Ie checked no cells are going over voltage with a volt meter at end of charge?

do you balance the cells at all before installing them?

a failure rate this high is nearly unheard of......

Matt

Hi Matt,

Yes I have a 1 cell 5Amp charger and before every cell goes in, I take nearly nearly 4.5 hours to charge each cell to a nice peak of 3.7v. The 40Ah cells all take around 23Ah or less when they were sent to me.

To be honest, I'm not sure if the BMS is actually balancing or not? At the end of a full charge (overnight) the pack voltage is always 80.2v (3.34v on every single cell measured with a multimeter by hand. The problem is every cell sags down to different voltages. Good ones sag to 2.8v and poor ones sag to 2.3v and the bad ones sag to 1.8v and INSTANTLY once they hit 1.8v the BMS shuts down all power until the pack voltage rises.

I have now replaced a total of 12 cells in the 24 pack. I called the dealer in Melboune and he was amazed as much as me. I've been using LiFePo4 for 3 years on ebikes without a hitch. We have both agreed to just leave the bike and just wait until my scooter comes from China.

ETA for new scooter: July 15...but now pushed back to July 30

Yes I have a 1 cell 5Amp charger and before every cell goes in, I take nearly nearly 4.5 hours to charge each cell to a nice peak of 3.7v. The 40Ah cells all take around 23Ah or less when they were sent to me.

Thats good practice, for a pack that is top balanced
FYI - brand new cells have a bit over 110% of rated capacity when brand new.
This increases to 120% after ~200 cycles, and eventually falls back off to 100% of rated at 1000 cycles.

The cells always come from the factory at bang on 50% SOC, mainly for balance reasons.
When running without a BMS, you are best off balanced at 50%, as it puts half the difference at either extreme.
The only downside to running without a BMS and just Ah counting on discharge is when the cell capacities drift too far apart.

At that point you have to top balance to prevent the smallest cell suffering from overcharge (and rapid failure)
This can be worked out by checking the cell voltages during the CV stage during preventative maintenance.

If you stay balanced at 50% with significant capacity difference, there is a fire risk from the small cells being overcharged.
It takes around 1000 cycles to get to that stage.

a full cell is above 3.4v at rest (actually if you charge letting the current fall to 0, it holds whatever voltage you have charged it to nearly indefinitely)

To be honest, I'm not sure if the BMS is actually balancing or not? At the end of a full charge (overnight) the pack voltage is always 80.2v (3.34v on every single cell measured with a multimeter by hand. The problem is every cell sags down to different voltages. Good ones sag to 2.8v and poor ones sag to 2.3v and the bad ones sag to 1.8v

3.34V is neither fully charged nor balanced, I think your BMS is letting your pack charger overcharge the full cells.

when you overcharge a cell, its internal resistance goes up and its capacity comes down.
when you overdischarge a cell, it develops internal shorts (high self discharge)

When marrying a new cell into a top balanced pack you need to fully charge every cell,
so if you were to do this again, I would use the single cell charger to charge every cell, not just the new one.

From a testing the BMS and pack point of view, it would be quite illuminating to see what the pack voltage is doing, and what the individual cell voltages are doing, during charge.
especially when a single cell reaches full charge.

Its a shame I can't come round a pull it apart....
I wonder if the manufacturer would be interested in taking the bike back, a great deal can be learned from the failures......

Matt

actually, just reread your last post and you already recharge the whole pack individually with that charger,

now I'm even more intrigued.....

do you know what the termination current is on that 3.7v 5A charger?

whats the termination current and voltage on the pack charger?

Matt

Hello.
I'm a Spanish owner of a Bereco voltio 6.500 watt. It's the same motorbike that you are speaking about (and the same that is named Tokyo iEdison...in Europe), so I'm very happy for having find you. Afer a few months (tree) of good results (80 km/h; 70 Km autonomy, in hi-speed mode), and a pair of cells changed, the battery has failed. I can't go over 15 Km with no acceleration and over 50 Km/h. It's very dangerous for me because I need to travel by road.
The seller has promised me that they are going to change the hole battery becouse there is a problem with the actual battery all over the world. But...I don't know if it is the truth, moreover I'm convinced that this won't be the only problem that I will have with my e-scooter.
I'm very interesting in knowing wath I have under my legs...(my other motorbike is a Harley Davidson 1300cc) and how to deal with it.
If I can help you in any way tell me, I would be an active member because I think that there is a lot of things that we can do for improving ours motorbikes.
Best regards and a lot of miles