Lighter weight Battery Pack suitable for Tongsheng TSDZ2B 48 Volt 750 watt

IrlDaveBlue

10 mW
Joined
Sep 19, 2022
Messages
26
Location
Galway, Ireland
Hi,
I enquired about weight of battery packs suitable for the Tongsheng TSDZ2B 48 Volt 750 watt from pswpower.com

But they said that the 48volt battery pack 12.5ah and also the 15ah and also the 17.2ah all weigh 3.8Kg.

Does anybody know a lighter weight battery pack suitable for this motor that can be mounted on the down tube? Even if it has lower power ah.

Ideally with Samsung batteries inside.

Thanks in advance,
Dave
 
Hi,
I enquired about weight of battery packs suitable for the Tongsheng TSDZ2B 48 Volt 750 watt from pswpower.com

But they said that the 48volt battery pack 12.5ah and also the 15ah and also the 17.2ah all weigh 3.8Kg.

Does anybody know a lighter weight battery pack suitable for this motor that can be mounted on the down tube? Even if it has lower power ah.

Ideally with Samsung batteries inside.

Thanks in advance,
Dave
 
When you buy a generic downtube battery you are pretty much going to get the same thing from any Chinese vendor. They will all use the same case and the same number of cells. The only significant difference is going to be the cells they fill them with. Those can be anything from no-name generic to name brand (like Sansung or LG) to counterfeit name brands. The difference in capacity comes down to the rating of the cells used in the pack. Regardless the individual cells are not going to have any significant weight difference.

There are some different Lithium-Ion chemistries that could make a difference (like LiFePo4 ot LTO) but you are not likely to find those in generic E-Bike batteries as they have lower power densities and are more expensive.

We are beginning to see some packs being manufactured with 21700 cells as opposed to 18650 cells. There may be a slight difference in the weight of those. However it is likely less that if you decided have an extra cup of coffee with your breakfast.
 
With ebikes, weight is of way less concern.
A pound here or there is really nothing, toilet bowls seen more in a sitting.
10's of pounds dont count either

- Dont get to little but dont get to much.
 
The bike I want to build is 10 Kg + the motor 3.6 Kg and I am hoping I could find a batter for 2 Kg.

That would make the total weight 15.6 Kg

I plan to ride 50% of the time with the motor off... which is why the double clutch in the TSDZ2B
is important to me.

Is there a downtube battery... even 8AH ... that would be less than 2 Kg ?

If not, I might give up on this and just buy the highest capacity battery such as a 19.2 ah.

Many of my rides will be less than 10 miles (16 Km) on tarmac.

But I have read that the weight of the battery very much depends on it's capacity... so thought that a lower
capacity battery could be significantly lighter.?
 
IrlDaveBlue said:
The bike I want to build is 10 Kg + the motor 3.6 Kg and I am hoping I could find a batter for 2 Kg.

That would make the total weight 15.6 Kg

I plan to ride 50% of the time with the motor off... which is why the double clutch in the TSDZ2B
is important to me.

Is there a downtube battery... even 8AH ... that would be less than 2 Kg ?

If not, I might give up on this and just buy the highest capacity battery such as a 19.2 ah.

Many of my rides will be less than 10 miles (16 Km) on tarmac.

But I have read that the weight of the battery very much depends on it's capacity... so thought that a lower
capacity battery could be significantly lighter.?

Number of cells is dictated by the voltage you need (14s/15s for 48/52v) and the Ah/current draw you need (p)..

so a 14s4p has 14 parallel groups of 4 cells - so each cell in the parallel group gives a quarter of the current draw... for 750W = roughly 15A - so if you only have 2 cells in each group - each needs to give 7.5A continuous... more cells - less load on each cell = less voltage sag and more capacity.

Too few cells in each parallel group (p) and you'll have a light battery that has really bad voltage sag which results in a bike that isn't very fun to ride - as I learned the hard way when I made a 14s2p battery pack using samsung 21700 50e cells... it was useless! :(
 
Thanks Beemac!

Does that mean that there might be a 'rule of thumb' of what would be the lowest ah capacity that would be useful for a 48 volt 750 watt motor?

What size battery did you try that was not so useful? And for what Voltage and Wattage motor?
 
IrlDaveBlue said:
Thanks Beemac!

Does that mean that there might be a 'rule of thumb' of what would be the lowest ah capacity that would be useful for a 48 volt 750 watt motor?

Ah doesn't matter - it's the voltage sag you need to worry about and that depends on the cells and their rating for current draw. Look for the data sheets and the graph showing voltage against load... but if you're anywhere close to the continuous max current rating the voltage sag is going to be pretty bad.

IrlDaveBlue said:
What size battery did you try that was not so useful? And for what Voltage and Wattage motor?

"as I learned the hard way when I made a 14s2p battery pack using samsung 21700 50e cells... it was useless"

I have TSDZ2s running casainho's OSF - so I can draw up to about 1000W (18A @ 58.8V)

You might be able to make a 14s2p pack that isn't awful using cells like the molicel inr21700-p45b/p42a (45A continuous rating) but it might also be an expensive paperweight...
 
IrlDaveBlue said:
Does that mean that there might be a 'rule of thumb' of what would be the lowest ah capacity that would be useful for a 48 volt 750 watt motor?
More like a rule of "market demand". Too little market demand to make it profitable. There are a few e-Bikes with small capacity batteries but they also are equipped low powered motors and controllers (250 watts or less at 36 volts) and those batteries are likely to have proprietary mounting.

You Might try looking for "bottle batteries" ... as I recall those were usually low capacity.
Golden Motor has one that is 2.5 KG at 36 Volts, 8 Ahr
https://www.goldenmotor.com/

P.S. they also have very high shipping charges
 
Listening to all the replies, I think it is not worth reducing the capacity of the battery, in order to save at maximum 1 Kg.

I think the best strategy might be to try to get the bigger battery of 19.2ah for the 48 volt 750 watt motor.

Thanks for your replies!

Best Wishes,
Dave
 
IrlDaveBlue said:
Listening to all the replies, I think it is not worth reducing the capacity of the battery, in order to save at maximum 1 Kg.

Likely a wise decision. Not to beat a dead horse but I have one last comment ....

I tried to find a reference to these earlier but they have disappeared from listing in Grin's store:
"Grin's LiGo battery"
https://ebikes.ca/product-info/grin-products/ligo-batteries.html

These were individual 36 volt 2.7 Ah modules that could be connected in series or parallel. They are no longer available.

"Unfortunately several key IC's used on the LiGo BMS boards became impossible to source in 2021 due to the semiconductor shortages. We had enough stock to produce one final batch of 2000 BMS boards for LiGo and LiGo+ batteries over winter, and sold the last of these in July 2022."
 
I'll tell you what happens with my pswpower 500W 48V TSDZ2 this week. Installed on a steel 10 speed with upright bars.

EDIT.
Just got it running yesterday. Initially excited that it works after sitting in a box for years.
 
And on day 2, I am pretty disappointed with torque sensing as a way of life on a bike,

Of the four power modes, Eco is showing peak current of 3A and Touring is 6A. That's 150W and 300 watts peak, but I can barely detect assist. The next two levels show peak currents of 9A and 15A.

I can't read my wattmeter while riding, so I have to stop and see the peak numbers. Based on how it feels with my hub motors, I think I'm getting 250-300W continuous in the upper power modes, but I'm pedaling way too hard to coax it out.

Anyway, it sucks. Looks like I either pursue the firnware alternative or stick it back in the box.
 
tongsheng is pretty weak i was disappointed at first too after coming from 500w geared hub motor , it felt weaker. if u dont get assistance please turn motor off then on again and let it start for around 30sec so torque sensor can calibrate.
 
Check out other TSDZ2 threads. However, I had an early TSDZ2 and IMO the newer version is a different animal. Much improved.
 
I read the VLCD5 manual and realized the default settings were holding me back. Removed the 16mph speed limiter, and raised the current from 16A to 25A. Now it's more like an ebike, although still mild mannered.

I'll be seeing if my two 48V7AH packs I have will work, One is 2P Sanyo Ga cells, which are only 10A per cell. Might be too small. The other will be 3P with Eve cells, 2500mah and rated for 20A per cell,
 
I know very little about this, but I have done a lot of research.

If anybody thinks the power from the Tongsheng is weak, please read about the OpenSource code that
can change the setting to improve the power.

https://github.com/OpenSourceEBike/TSDZ2_wiki/wiki


And for anybody who has not bought a TDDZ2 to consider buying the 750 watt 48 volt model.

Please be aware that some countries have limits on the Watt power... but good to read the review below;

Very good review at
https://edrivenet.com/tongsheng-tsdz2-review/
 
IrlDaveBlue said:
I know very little about this, but I have done a lot of research.

I bought the 500W model from PSWpower because I didn't think there was anything different between it and the 750W in 2019. Throttle is 16-18 mph. That's kind of sad for a 48V bike. My 36V 250W hub motor bikes will go faster than that.

I have the ST-link V2 that I must have bought at the same time. This plus some solder, wires and a connector to fit the speed sensor cable will allow me to reflash my TSDZ2?

I also have an unused LCD3, but it looks like best to buy the 860C display, rather than try to reflash it as it's no longer supported?


View attachment F9260907.JPG
 
I agreed with Doc and actually donated my 48v TSDZ2 to a poor fella living on $600 SS. A life charger for him but my BBS01 36V 350W are a better motor for me. 20 mph with a 250lb guy and 50lbs of groceries. PAS works well for me. But the TSDZ2 hasvtaken a lot of abuse, easily repaired and reliable with $150 in parts over 3000 miles.
 
I did a longer 10 mile ride this morning on a bike path. Started to appreciate the TSDZ2 more for a low assist Euro pedelec type of bike. under 10 mph, I could feel more of the assist though I believe I'm doing more than half the work. It's OK and climbing some of hills/dips along a little river, I knew I couldn't have ridden my regular bike out that far.

Coming home I realized I was climbing our steepest hill at 15 mph as at easy cadence. My other bikes are faster but I'm pulling 600 watts out of a 36V pack on throttle. Haha. Then a guy on a Lectric Lite, which is 750W 48V and only one speed passed me easily.

10.3 miles. Max current was 13A. Max voltage sag was 48V out of a freshly charged 13S-2P pack with Sanyo NCR18650GA cells. That's 1/2V per cell. Hmmm, new GA's should do better than that. Wattmeter says I pulled 1.36 AH for about 7WH/mile. The battery I used will do about 6AH (rated 7AH), so I guess 40 miles should be possible.

My battery probably is too light duty. I will try a 13S-3P with 2500 mah 20A cells. Gotta build it though.
 
In my recent experience, 21700 cells are better suited to minimalist cell packs. I’m really liking 50E cells. Waiting for NESE winter sale to make the move to home built.
 
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