Mid-Motor - highest assist level and no speed restriction - battery life

[DavidSWP]

Hi,

I'm currently reviewing the Tongsheng TSDZ2 250w 36v Mid Drive Conversion Kit which I bought from ebike-sales.co.uk. Not many people seem to have this motor so I want to be fair to it (and the battery). I never used a BBS01/2 or any mid-drive bike. I did cycle on an AlienBike Bafang 250w hub motor for 1000s of miles around 8 years ago, so that is my main frame of reference.

So I set off with TSDZ2 with highest assist level and speed limit turned off. 10.4ah battery was fully charged although I did use it for about 20 mins the night before climbing a steep hill (about 100 meters). The route had some long sweeping hills, but not steep (about 1 in 10) and a lot of downhills too. I was pedaling strongly all the time. Max speed reached was about 34mph downhill. The route was about 18 miles. After 13 miles the battery was down to 1 bar. I turned it off and did the last 5 miles unassisted before using it for the last 100m climb up to my house (about 2.5 in 10).

Mathematically this sounds about right. 10.4ah battery will put out 10.4 amps for 1 hours (I think?) and assuming it was putting out close to the maximum 16amp for 13 miles which took about 45 minutes, that sounds about right.

However, comparing this to my old AlienBikes Bafang front hub motor with 10ah battery the range was disappointing. I did 20 miles every day on a similar route averaging 18mph and there was enough for 5-10 miles left over at the end.

The Alien would do 17-18mph on the flat without pedalling and some days I hardly pedalled and still did the 20 miles. TSDZ2 does 14-15 on the flat with considerable pedaling. I got up to about 24mph on the flat really going for it.

Some positives:

• Going up a steep hill from a standing start - very strong assistance off the bat, the hub motor would have been useless.
• 18.5mph assist was the max on the hubmotor but I felt the same level of assist on TSDZ2 no matter what speed I was doing. Of course when going 30mph the assist doesn't exactly improve the speed that much because it takes exponentially more power the faster you go.
• Very smooth assistance - you put torque on the pedals and maybe move them 2 inches and it kicks it. I read somewhere else that it would cutout while pedals were in the horizontal plane, I didn't find that at all.
• Nice and easy to install. Nice Display. One problem (will post full review soon)
• Constant power delivery
• In Turbo Mode - considerably faster journey.
• For very weak peddlers the motor does supply proportional assistance. I tried to simulate this by pedallig very weakly and the motor does provide weaker assist. However, I am typically pedaling providing 250 watts so its a bit unrealistic to expect a 250 watt motor to multiply my input.
• Modes - ECO, TOUR, SPEED, TURBO - you can really feel the difference between these.

Negatives:

• Subjectively range worse than 8 year old hub motor and slightly smaller battery while assist level was no better (apart from standing start on hills and assist over 18.5 mph).
• When I fitted the cranks to TSDZ2 but hadn't fitted the chain yet I found that moving the cranks by hand there was considerable resistance. Old front wheel hub Bafang Alien kit apparently had considerable motor drag but I could spin the front wheel with it on and it would spin for minutes. TSDZ2 with cranks fitted and trying to move them - don't get me wrong I can move the them with 2 fingers but its STIFF and there is a lot of resistance. I am pretty sure that turning the cranks = turning over the motor, there is no way to pedal without turning over the motor.
• ECO mode (lowest level of assist) is ok if you want to go really slow (< 5mph) and it can help you up hills if taking them real slow or on the flat with no wind at slow speed, but I feel if you use it while going a reasonable speed you are battling the motor pedal resistance and extra weight. ECO Mode and even the higher TOUR mode doesn't compensate for the pedaling drag and extra weight - you would be better off without the kit.
• Have to use SPEED or TURBO mode for reasonable assistance. Battery drain in these modes seems high.

Does this seem reasonable or is my battery knackered, is BBS01/02 better ?

 

[Nealh]

I have been considering the Tongsheng as being a torque sensor cd I would have thought range should be quite good, however your review doesn't sound great. However tonking it on full assist unrestricted will not be good for range you now need to repeat the trip restricted and in a lower assist to see how it fairs.
Hard to say if bbs01 is better without trying both to compare, the GSM was in my view a good equal if not slightly better then bbs01 in speed and performance but found was lacking in reliability with heat issues .

 

[Geebee]

If the battery is new or unused for an extended time it will take 3~5 charges to reach normal life, my Tonaro more than doubled range first to second charge!

Turning a crank vs wheel is like comparing apples and oranges due to leverage, fly wheel effect etc. also the crank should free up with a bit of use.

Try to maintain a high cadence and shift down early will extend range greatly, my BBS01 draws about 7~8 wh per km with close to no rider assist (speed unlimited) over variable terrain with 300 m plus climbing over 16 km as an example.

 

[DavidSWP]

Thanks for the replies, I will do some more testing after the battery has been recharged a few times.

I realise that moving a crank vs spinning a wheel is not a direct comparison due to leverage and flywheel but I think I have a good intuitive sense of this type of thing to extrapolate outwards and I am sure that if the crank was the same radius as a 700c wheel and had the same weight as a rim and tire on it, it would not spin at all. There is definitely a lot more resistance there. Hopefully it will loosen up.

Does anyone know if these are kits have a free wheel for pedalling when the motor is off. Information on the TSDZ2 is very limited and I heard mixed reports about BBS01 with some saying that there is not much resistance and others saying that there is a lot.

 

[D8ve]

My BBS 01 is now circa 50% remaining on plugin tester 3.7 volts per cell or one bar off on the display. After 125 miles.(16ah Lipo) I'm dreading a sudden cutoff and will monitor the battery as the charge falls. But 3.2volts is my definite limit.

 

[anotherkiwi]

You lose a whole heap below 36 V D8ve. The lipo cliff on my Multistars is around 35.4 V (3.54 V per cell).

 

[Kinninvie]

You lose a whole heap below 36 V D8ve. The lipo cliff on my Multistars is around 35.4 V (3.54 V per cell).

Yup,
If I take my Multistars below 3.6V they start to wander apart and have to be balance charged.
Keep to 3.6V and they have been used for over a year without going out of balance at all.
I tested them yesterday when the alarms went off at 3.6V and reset the alarms to 3.5 and I got less than 1400 yards before they went off again!
I average around 20Wh per mile according to my Cycle Analyst.

 

[Geebee]

There is definitely a lot more resistance there. Hopefully it will loosen up.

At 20 mph you wheel is required to spin at ~240 rpm as opposed to the cranks doing 80 ish, so drag is multiplied.

My BBS01 crank will spin about 3 revolutions with the chain off after sitting for a few weeks in a cold area, I just went and tried it, the drag is very minor in the real world to the point of being unnoticeable and I am extremely touchy about drag.
Hopefully yours has a free wheel as well and just needs a bit of use to loosen up.

 

[D8ve]

Ok so I'm looking at 1.5 volts left. From 5 volts I have had 125 miles so thinking perhaps 40 miles left.
I carry a spare 3ah battery so I will keep going.
It looks like charging every 100 miles will be easy system.

 

[DavidSWP]

I repeated the same trip with another full charge and the kit has gone really weird. I noticed from the start that something had changed even though I've not changed any settings. The assist was noticeably weaker and patchy. It is now like someone mentioned in a post on endless sphere. The motor is only providing power now when pedaling very strongly, on the flat this basically means that you get no power assist unless constantly accelerating, so in practice no assist during normal cruising on the flat. It is also not providing smooth assist anymore, but only on the pedal downstroke. Then after 5 miles the battery suddenly turned off and I had to wait for several minutes before it would turn back on. After it came back on it seemed to be back to normal for a few minutes but then the batter turned off again and when I was able to turn it back on again there was literally 0 power assistance. I was thinking maybe the motor/controller was placing power demands on the battery that it couldn't provide so I changed the AMPS down from 16 (which it was set to when delivered and I've never set it higher) to 13 and it worked for a few more minutes with feeble assistance and then the battery turned off again and I couldn't turn it on for about 10 minutes. So I put the Amps down to 10 and it lasted until I got home but still with this new uneven power delivery, and only when accelerating or going up hills.

Any ideas what could be causing this? I think I'll have to contact the seller.

 

[D8ve]

Ok fell of the lipo cliff at 143.4 miles and circa 3.25 volts per cell.
Switch to backup battery and cycle home.
Did a full charge and watt meter says I put 630 watts or 16.6 amps into the battery. That's around 4-5 watts per mile.
I'm quite happy with this. It was full assist and I didn't spare the battery or speed. Averaging over 16 mph.
Sticking to a charge every 100 miles should be easy.
Using less power .....well why have assist at all.
BBS01 conversion appears good. Got the new Alfine 8spd hubed wheel in today so that's the next job.

 

[anotherkiwi]

Did your cells stay balanced? If you don't care about battery pack life you can take them down to 3.5 V over that you are flirting with one of the cells falling below the others and failing. You should re-read the ES RC-Lipo tutorial

I have made up my mind on my "big" pack - 4 x 5S 8000 mAh nano-tech in 2P2S for a 16 Ah battery. Expensive (340 €) but if I take care of them (charging to 4.15 and discharging to 3.65) they should last a while because they are 25C and I will only be using 1C or just over. Them all being the same type makes swapping one out an easy choice and charging the same size is less fiddly. And the format 194x45x47mm makes it easy to fit them on the bike.

And I will have a 10 Ah every day round town/backup battery.

 

[D8ve]

They went lower than I wanted but remained ok.
Currently going through a balance cycle then it will be recharge every 100 miles.
I have 4 3ah 5s for backup.

 

[DavidSWP]

Did your cells stay balanced? If you don't care about battery pack life you can take them down to 3.5 V over that you are flirting with one of the cells falling below the others and failing. You should re-read the ES RC-Lipo tutorial

I have made up my mind on my "big" pack - 4 x 5S 8000 mAh nano-tech in 2P2S for a 16 Ah battery. Expensive (340 €) but if I take care of them (charging to 4.15 and discharging to 3.65) they should last a while because they are 25C and I will only be using 1C or just over. Them all being the same type makes swapping one out an easy choice and charging the same size is less fiddly. And the format 194x45x47mm makes it easy to fit them on the bike.

And I will have a 10 Ah every day round town/backup battery.

I am not sure if you are talking to me or D8ve. I don't know anything about balancing cells, I am just using the charger provided.

Does anyone have any idea what could be causing my problem? I think its the battery. The motor behaves completely differently when I set it to 10 amps via the LCD display - only assists when you are very strongly pedalling and accelerating, whereas when set to 16 amps it has very strong smooth assist with moderate pedalling. I think that when I was having the former behaviour even with it set to 16 amps the motor/controller mustn't have been able to get what it required from the battery. I think the battery is either defective or isn't up to the demands of this kit. Can anyone verify?

This is the motor kit: http://ebike-sales.co.uk/product/tongsheng-tsdz2-250w-36v-mid-drive-conversion-kit

This is the battery: http://ebike-sales.co.uk/product/rocket-ebike-battery-36v-10-4ah-silver

Bought from the same place at the same time. I would have though the seller would have warned me if the battery wasn't suitable because they have been very helpful and seem very knowledgable.

 

[D8ve]

Sorry technically I have been stealing your thread.
My apologies. I was repling to others. And drifting off the BBS 01 free wheels very well hence my 140+ miles in a 16ah battery

The battery should be good for full assist.
But there is a big difference in power between 10 and 16 amps 60% stronger.

 

[anotherkiwi]

I am not sure if you are talking to me or D8ve. I don't know anything about balancing cells, I am just using the charger provided.

Does anyone have any idea what could be causing my problem? I think its the battery. The motor behaves completely differently when I set it to 10 amps via the LCD display - only assists when you are very strongly pedalling and accelerating, whereas when set to 16 amps it has very strong smooth assist with moderate pedalling. I think that when I was having the former behaviour even with it set to 16 amps the motor/controller mustn't have been able to get what it required from the battery. I think the battery is either defective or isn't up to the demands of this kit. Can anyone verify?

This is the motor kit: http://ebike-sales.co.uk/product/tongsheng-tsdz2-250w-36v-mid-drive-conversion-kit

This is the battery: http://ebike-sales.co.uk/product/rocket-ebike-battery-36v-10-4ah-silver

Bought from the same place at the same time. I would have though the seller would have warned me if the battery wasn't suitable because they have been very helpful and seem very knowledgable.

Sorry replying to D8ve notorious thread stealer at large

You are asking too much of your battery at 16 Amps. They say that these batteries are capable of 2C (20 Amps) but in fact they usually aren't I have turned mine down to 11 Amps max and get more range now.

You also have a torque sensor which explains your problem in the quoted message.

If you want to use 16 Amps best bet is to get a 17 Ah battery. That is what D8ve and I are doing but with Lipo.

 

[Alan Quay]

Sorry replying to D8ve notorious thread stealer at large

You are asking too much of your battery at 16 Amps. They say that these batteries are capable of 2C (20 Amps) but in fact they usually aren't I have turned mine down to 11 Amps max and get more range now.

You also have a torque sensor which explains your problem in the quoted message.

If you want to use 16 Amps best bet is to get a 17 Ah battery. That is what D8ve and I are doing but with Lipo.

You don't need to go that big, just get a battery that is rated to do it.

For example:

http://eclipsebikes.com/hailong-13ah-lithium-frame-battery-samsung-cells-p-1118.html

Sent from my HTC One_M8 using Tapatalk

 

[Garry Cooper]

I have not posted before : but I do have one of these units, - I suspect you have the older model, I would try and get your dealer to exchange it for the latest version with updated software and a throttle, Torque sensing in the new version is excellent and the difference in battery life is really noticeable,
A brilliant piece of kit which I suspect to be slightly more powerful than the 250 watt it is reputed to be !!!!

 

[DavidSWP]

Sorry replying to D8
You also have a torque sensor which explains your problem

I wouldn't really have expected the entire characteristics of the torque sensing to change because the amps are set to a lower value. I would have expected it to just provide proportionally less power for the same torque. What it seems to have in fact done is greatly multiplied the amount of torque needed to give any assistance at all to the point where pedalling on the flat you get nothing at all except when pushing really hard and accelerating.

 

[DavidSWP]

I have not posted before : but I do have one of these units, - I suspect you have the older model, I would try and get your dealer to exchange it for the latest version with updated software and a throttle, Torque sensing in the new version is excellent and the difference in battery life is really noticeable,
A brilliant piece of kit which I suspect to be slightly more powerful than the 250 watt it is reputed to be !!!!

I've contacted the seller. It looks like my version really needs the 16 amp. Perhaps there is some way to update the controller software though. There is a video on YouTube (can't find it right now) of someone using some software which has a ton of different profiles for the motor but it doesn't explain where to get the software or cable from.