New member here, first question: 48V TSDZ2 kit on 36 Battery?

[neixian]

Hello guys,

I am new to e-biking and this forum.

I recently purchase a 48V 350W TSDZ2 with VLCD5 kit and read a lot about it here but couldn't find the answers I am looking for.

What I am trying to do is to use this kit on my dual suspension MTB, to pair with a 36V 13ah battery I have already which fit on my bike tube just about right. (48V 13ah would be too big.)

The question is, can this be done? If yes, would it be very much underpowered?

To increase the power, can I flash the firmware as many of you have already done?

Thanks in advance.

 

[amberwolf]

By "can this be done", what specifically do you mean?

If you mean, will the 48v system work with a 36v battery? Maybe, if it's LVC is changed to that needed for a 36v battery. It will run proportionally slower with the lower voltage battery, if that's not a problem. You can test if the system will work with your battery just by hooking it all up before mounting to the bike; if it won't run the motor or won't turn on at all, you'll know there are things you'll have to modify to make it work, or that you'd need a 48v battery to use it, or that you'd have to return the 48v version and buy a 36v version.

If you mean, will it fit the bike you have? Can't answer that without knowing exactly which bike you have to find dimensioned drawings or at least good pictures that might show if there's clearance around the BB/downtube area where the TSDZ2 unit has to go, or if you measure things yourself to check and see if they will clear the known dimensions of the TSDZ2 unit.


If you mean something else, you'll need to state it.

 

[neixian]

By "can this be done", what specifically do you mean?

If you mean, will the 48v system work with a 36v battery? Maybe, if it's LVC is changed to that needed for a 36v battery. It will run proportionally slower with the lower voltage battery, if that's not a problem. You can test if the system will work with your battery just by hooking it all up before mounting to the bike; if it won't run the motor or won't turn on at all, you'll know there are things you'll have to modify to make it work, or that you'd need a 48v battery to use it, or that you'd have to return the 48v version and buy a 36v version.

If you mean, will it fit the bike you have? Can't answer that without knowing exactly which bike you have to find dimensioned drawings or at least good pictures that might show if there's clearance around the BB/downtube area where the TSDZ2 unit has to go, or if you measure things yourself to check and see if they will clear the known dimensions of the TSDZ2 unit.


If you mean something else, you'll need to state it.

Thanks for the reply.

Sorry I wasn't clear enough.

I meant to run this 48V kit on a 36V battery.

And if it can turn on, will it be under powered? Can I increase the power in that case by tweaking the firmware?

 

[nicobie]

It should run the same but much slower and will drain your battery much quicker.

Can you cut and solder new plugs?

And that is just if it will even switch on and run for more than 10 minutes.

Worth a try though. You might think of adding a 12V boost battery in series.

 

[docw009]

The low voltage cutoff for a 48V battery is about 40-41V, while the full charge on a 35V battery is 42 volts. You may have a problem with the 48V TSDZ2 shutting off quickly on a 36V battery, or not even starting up.. I don't believe you can change the low voltage setting on a VLCD5. It's programmed into the controller.

I am sure you could address this by loading in the OSF/embrusa firmware. I have done that on my TSDZ2's. I could program to run on my 36V batteries by setting the low voltage alarm to 30V instead of the default 40V. I probably will, one of these days, so I can mix batteries.

 

[neixian]

The low voltage cutoff for a 48V battery is about 40-41V, while the full charge on a 35V battery is 42 volts. You may have a problem with the 48V TSDZ2 shutting off quickly on a 36V battery, or not even starting up.. I don't believe you can change the low voltage setting on a VLCD5. It's programmed into the controller.

I am sure you could address this by loading in the OSF/embrusa firmware. I have done that on my TSDZ2's. I could program to run on my 36V batteries by setting the low voltage alarm to 30V instead of the default 40V. I probably will, one of these days, so I can mix batteries.

Thank you very much.

I will give it a try. Hopefully it doesn't lose too much power if I increase the amperage.

 

[Epithemeus]

From what I've read the tdsz motors struggle to give much assist at higher pedal cadences (around 90 rpm I think) Running the 48v winding at 36v is going to be 75% slower than that. So you're not going to get much assist above 67.5 rpm. Which is really slow... My cadence is usually around 80-90.

 

[neixian]

From what I've read the tdsz motors struggle to give much assist at higher pedal cadences (around 90 rpm I think) Running the 48v winding at 36v is going to be 75% slower than that. So you're not going to get much assist above 67.5 rpm. Which is really slow... My cadence is usually around 80-90.

Can we change it in the firmware?

 

[Blacklite]

Can we change it in the firmware?

No - it’s a consequence of the motor wind.

 

[neixian]

No - it’s a consequence of the motor wind.

Thanks.

How slow is 67.5 rpm? I am not planning to ride above 25km/h, which is the legal limit in Australia.

 

[neixian]

It should run the same but much slower and will drain your battery much quicker.

Can you cut and solder new plugs?

And that is just if it will even switch on and run for more than 10 minutes.

Worth a try though. You might think of adding a 12V boost battery in series.

Interesting idea. I have no problem making connectors and I do have a 4s 5ah drone battery as spare.
The question is, will they discharge at the same rate? I mean, if one battery has still power and the other is empty, then they will stop work as together, right?

 

[Epithemeus]

Thanks.

How slow is 67.5 rpm? I am not planning to ride above 25km/h, which is the legal limit in Australia.

The road speed is mostly irrelevant here as you can gear it differently depending on wheel size etc. You'll be power limited for speed so get the same road speeds as a 36v kit. What I'm talking about is how fast your legs are spinning the cranks around. This is called your cadence. One should aim for a cadence of about 70-90 for the maximum efficiency of your legs. The kit will probably be below that range and so you'll probably find the motor very underwhelming in normal operation. It's not cause you don't have enough power though, it's because it can't deliver it properly.

If you install the open source firmware it does have field weakening that could help, but it's not the best solution, it makes the makes the motor a bit less efficient. You're better off getting the 36v motor wind if you can.

 

[999zip999]

No you're 5ah won't work.
You must try it in the firmware and see if you change your low voltage cut off yes it'll be slower..

 

[amberwolf]

Interesting idea. I have no problem making connectors and I do have a 4s 5ah drone battery as spare.
The question is, will they discharge at the same rate? I mean, if one battery has still power and the other is empty, then they will stop work as together, right?

A drone battery is probably just a bare RC Lipo pack with no protection So if you drain it first, current will still flow thru it from the other pack, and reverse-charge it, which will permanently damage it (and could cause catastrophic failure of it immediately or at any later time).

If the system LVC triggers before the drone battery empties, then it will stop trying to drain the batteries, but if it does not then the above can happen.

I would use at least two or three of those drone batterys in parallel if you want to series them with a pack that is between two and three times their capacity.

 

[nicobie]

Like everyone has said, You need to have a battery that at least comes close to what your original battery Ah is. Remember that you can only use as much energy as your least capacity battery holds. A cheap Wattmeter or even a Voltmeter can do that. It is not as complicated as it sounds.

 

[neixian]

The road speed is mostly irrelevant here as you can gear it differently depending on wheel size etc. You'll be power limited for speed so get the same road speeds as a 36v kit. What I'm talking about is how fast your legs are spinning the cranks around. This is called your cadence. One should aim for a cadence of about 70-90 for the maximum efficiency of your legs. The kit will probably be below that range and so you'll probably find the motor very underwhelming in normal operation. It's not cause you don't have enough power though, it's because it can't deliver it properly.

If you install the open source firmware it does have field weakening that could help, but it's not the best solution, it makes the makes the motor a bit less efficient. You're better off getting the 36v motor wind if you can.

Thanks. As long as I can get assistance to ride 25km/h with ease. I really don't care how much power it delivers and how fast I pedal.

I have ordered the st-link cable, hopefully I can tweak it so I don't really have to buy new battery, because the 36v one will be wasted.

 

[neixian]

Like everyone has said, You need to have a battery that at least comes close to what your original battery Ah is. Remember that you can only use as much energy as your least capacity battery holds. A cheap Wattmeter or even a Voltmeter can do that. It is not as complicated as it sounds.

Thanks, looks like a new 48v/52v battery is better.

Will experiment 36v and see if new battery is definitely needed here.

 

[nicobie]

Yes, I would go with a 48/52V one too.

 

[999zip999]

I seconded but I'll just go with the 52 and get it over with 10ah or more if you are going to over amp it meeting put in a high or average demands of the controller for more power means a stronger battery I always get quality name brand sales and nowadays they have Bluetooth BMS which is extremely handy. Of course you have to pay for these things remember buy it with a charger from the same company as a package deal. The kit price and everything matches. Plus depending how cheap a a connector they put on is how cheap they are.
What country are you from as it makes a difference ain't here in United States they have a company battery hookup that sometimes have what you need properly made for an automobile with that type of specs for a good price.

So tell us where you live

 

[neixian]

I seconded but I'll just go with the 52 and get it over with 10ah or more if you are going to over amp it meeting put in a high or average demands of the controller for more power means a stronger battery I always get quality name brand sales and nowadays they have Bluetooth BMS which is extremely handy. Of course you have to pay for these things remember buy it with a charger from the same company as a package deal. The kit price and everything matches. Plus depending how cheap a a connector they put on is how cheap they are.
What country are you from as it makes a difference ain't here in United States they have a company battery hookup that sometimes have what you need properly made for an automobile with that type of specs for a good price.

So tell us where you live

I am in Australia and we do have a few ebike shops. But nowadays everything is made in China and you don't know the quality control there.
I am juggling between a 52v 10ah and a 48v 15ah, both of which are about the same size, with 21700 lg/Samsung cells.

I can't go bigger as the full suspension bike has limited space in the frame.