Safe to run 24v Tongxin motor on 36v?
- Thread starter Geebee
- Start date
Motors don't really have a voltage rating, TBH, just a maximum safe current rating and a maximum safe RPM. All that happens when you run a motor on a higher voltage is that the RPM increases, roughly in proportion to the difference in voltage (so 24V to 36V gives about a 50% increase in no load RPM).
Power output increases in proportion to the voltage increase, but motor torque (the ability to climb hills and accelerate) is set by the motor current, so won't change unless the current is altered.
My controller preference is the Xiechang range. These are sold under several pseudonyms (Lyen, e-crazyman, infineon, etc) but are all basically the same. These controllers can be programmed with some free software and a PC serial lead to change the settings, which is extremely useful.
For the Tongxin a small 6 FET controller would be ideal. The cheapest source is probably Keywin (Shiejji Ge) who has been trading on ebay as e-crazyman for several years. This controller: 36V 350W brushless controller for E - bike & scooter | eBay at about £28 including shipping, would be fine (the 25A current quoted is the peak current, as supplied it will run at around 12 to 15 A, and can be programmed to any reasonable current you want fairly easily if you need to change it).
You can also get any other parts needed, like a throttle or pedelec sensor from e-crazyman, if it's not listed on his ebay shop just email him and he'll probably be able to help. He speaks good English, so you can skype him if you want more info.
Power output increases in proportion to the voltage increase, but motor torque (the ability to climb hills and accelerate) is set by the motor current, so won't change unless the current is altered.
My controller preference is the Xiechang range. These are sold under several pseudonyms (Lyen, e-crazyman, infineon, etc) but are all basically the same. These controllers can be programmed with some free software and a PC serial lead to change the settings, which is extremely useful.
For the Tongxin a small 6 FET controller would be ideal. The cheapest source is probably Keywin (Shiejji Ge) who has been trading on ebay as e-crazyman for several years. This controller: 36V 350W brushless controller for E - bike & scooter | eBay at about £28 including shipping, would be fine (the 25A current quoted is the peak current, as supplied it will run at around 12 to 15 A, and can be programmed to any reasonable current you want fairly easily if you need to change it).
You can also get any other parts needed, like a throttle or pedelec sensor from e-crazyman, if it's not listed on his ebay shop just email him and he'll probably be able to help. He speaks good English, so you can skype him if you want more info.
I ran my Tongxin on 63v for ages with no probs - just kept the amps down to prevent clutch slippage.
Just to add to what Jeremy has posted, the last two controllers I purchased from e-crazyman (keywin) came from a warehouse in Heathrow. They are also 'universal' voltage now so can be over-volted within reason if required without worrying about cap and FET voltage.
Hi, I'm using a 24V Tongxin myself at 45V but I'm a little worried about output motor current.
What current limit did you set for your motor? I don't mean battery limit, only motor current limit to prevent slip.
I've been running 20 amps for a while with no problems but I'd like to increase output to 25-30amps if safe.
My controller is very gentle and does not feed any sudden current peaks no matter how I treat my bike.
Anything over 650w and the clutch slipped and the motor got to hot. Is your battery 45v fully charged? Or is it 50.2v (12s lipo)?
If it's 50v, then that's approx 13amps peak.
I'm suprised your tongxin is still going @ 20amps - that's 900watts @ 45v.
How long have you been running it like that?
If it's 50v, then that's approx 13amps peak.
I'm suprised your tongxin is still going @ 20amps - that's 900watts @ 45v.
How long have you been running it like that?
Is the 650W limit of yuors measured at the batteries or motor, that's a big difference.
My own controller limits both battery current to 12.8amps and motor current to 20amps.
The output motor limitation is adjustable between 10-20amps by a pot while riding.
E'g at hill climb or standstill start I can set the motor current to 20amps yet it will only
consume 5-10amp from the battery due to the lower voltage required by the motor
at lower RPM's. Meaning 5A at 45V from the battery will supply 20A at 11.25V to the motor.
Even though the battery limits is 12.8A at 45V (576W) the controller never lets the motor
comsume 576W at low RPM's due to the motor current limit of 20amps.
At high cruising speeds it will of course see 576W at a high motor voltage at lower current.
My question: Would the motor handle e'g 30amps at low 12V whithout slip (360W drawn from the battery)?
My own controller limits both battery current to 12.8amps and motor current to 20amps.
The output motor limitation is adjustable between 10-20amps by a pot while riding.
E'g at hill climb or standstill start I can set the motor current to 20amps yet it will only
consume 5-10amp from the battery due to the lower voltage required by the motor
at lower RPM's. Meaning 5A at 45V from the battery will supply 20A at 11.25V to the motor.
Even though the battery limits is 12.8A at 45V (576W) the controller never lets the motor
comsume 576W at low RPM's due to the motor current limit of 20amps.
At high cruising speeds it will of course see 576W at a high motor voltage at lower current.
My question: Would the motor handle e'g 30amps at low 12V whithout slip (360W drawn from the battery)?
Controllers have no way of actually measuring phase current (which is what I presume you mean by "motor" current) unlike battery current - it's all an estimation based on linear interpollation. You might think the controller is limiting phase amps to 20a but in reality, especially on a low resistance motor like a Tongxin, it could actually be pumping out twice the limit you think you have set.
I ran 63v and battery amps was set to 10.5 amps and phase current was set to 15 amps - any more phase amps and the clutch slipped.
I also had to have block time set to 0.1s as any higher it allowed the controller to overshoot the limits and again clutch slip occurred.
I suggest you get an amp meter on your install, sit at the bottom of a hill, flick the throttle on full and switch off within a second. It wouldn't surprise me if the meter shows the full 576watts being drawn even at low rpms, not the 360watts you have calculated.
I ran 63v and battery amps was set to 10.5 amps and phase current was set to 15 amps - any more phase amps and the clutch slipped.
I also had to have block time set to 0.1s as any higher it allowed the controller to overshoot the limits and again clutch slip occurred.
I suggest you get an amp meter on your install, sit at the bottom of a hill, flick the throttle on full and switch off within a second. It wouldn't surprise me if the meter shows the full 576watts being drawn even at low rpms, not the 360watts you have calculated.
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Hehehe, my controller is not bought of shelf but a design of my own that is 110% correct in all readings.
When I set the output to a certain level that is the true output without any overshoots or current spikes.
It also ramps up output currents very gentle with no jerky forces at acceleration. It will never exceed any set limits.
I work as Power Management Designer and I spent several hours on perfecting this controller. Final release is v5.0.
The controller use no micro chips or any software of any kind, it's entirely an analog design with precise functionality.
I intend to release the schematics and gerber files soon, just need some more testing until I'm 1000% satisfied.
Back to my question, but is seems like no one here can tell what currents is feed to the motor in reality......
But if you make an qualified estimate from your experience, will 30amps induce to much torque in the Tongxin?
Of course 30 gentle amps with no hiccups ...... I know 20A is being OK but I'd like somewhat better hill climb capability.
Bye the way, I do use ampmeters to monitor and verify all currents during the ride.
When I set the output to a certain level that is the true output without any overshoots or current spikes.
It also ramps up output currents very gentle with no jerky forces at acceleration. It will never exceed any set limits.
I work as Power Management Designer and I spent several hours on perfecting this controller. Final release is v5.0.
The controller use no micro chips or any software of any kind, it's entirely an analog design with precise functionality.
I intend to release the schematics and gerber files soon, just need some more testing until I'm 1000% satisfied.
Back to my question, but is seems like no one here can tell what currents is feed to the motor in reality......
But if you make an qualified estimate from your experience, will 30amps induce to much torque in the Tongxin?
Of course 30 gentle amps with no hiccups ...... I know 20A is being OK but I'd like somewhat better hill climb capability.
Bye the way, I do use ampmeters to monitor and verify all currents during the ride.
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Well, you should have really mentioned that first 
In that case, you're in uncharted territory. You'll have to try it and tell us if it works
In that case, you're in uncharted territory. You'll have to try it and tell us if it works
Honk, your controller sounds very interesting, i hope you share the details with us.
I have managed to destroy about 3 tongxin motors. Amigafan has probably put the most power through one and it survived. I broke a compression ring just by gradually accelerating from a low speed. I couldn't say why it broke....it just did. I think i managed to get the ring to slip once but overall i was pretty gentle with it (about 400W max). Good luck with yours.
I have managed to destroy about 3 tongxin motors. Amigafan has probably put the most power through one and it survived. I broke a compression ring just by gradually accelerating from a low speed. I couldn't say why it broke....it just did. I think i managed to get the ring to slip once but overall i was pretty gentle with it (about 400W max). Good luck with yours.
@ amigafan2003
I simply thought modern of shelf controllers could monitor motor currents and therefore I asked about folks experience. Now I know better......
@wurly
I will certaintly share all details. I initially bought 3 Tongxin motors back in 2008 but never got around to
finish my ebike. During this time a lot happened in a short timeframe, I got a family, bought a house,
got a son, got a boat, renovated the house, developed an 8hp electric outboard....and so on.
Meanwhile all this I now and then developed and tested the controller with improvents in every revision.
At the moment I'm testing controller v4.1 by an everyday 20 mile ride to work. I found a few small issues
and that will take the nest revison to v5.0. Then it's ready for release.
It could be Tongxin themselves that have a certain percentage of badly built motors in their production line.
Amigafan might have gotten lucky by getting a good and strong top end Tongxin.
I guess I will have to find out myself the hard way what a regular Tongxin can handle.
I simply thought modern of shelf controllers could monitor motor currents and therefore I asked about folks experience. Now I know better......
@wurly
I will certaintly share all details. I initially bought 3 Tongxin motors back in 2008 but never got around to
finish my ebike. During this time a lot happened in a short timeframe, I got a family, bought a house,
got a son, got a boat, renovated the house, developed an 8hp electric outboard....and so on.
Meanwhile all this I now and then developed and tested the controller with improvents in every revision.
At the moment I'm testing controller v4.1 by an everyday 20 mile ride to work. I found a few small issues
and that will take the nest revison to v5.0. Then it's ready for release.
It could be Tongxin themselves that have a certain percentage of badly built motors in their production line.
Amigafan might have gotten lucky by getting a good and strong top end Tongxin.
I guess I will have to find out myself the hard way what a regular Tongxin can handle.
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I'm looking to rejuvenate an old Salisbury which has a 200w 26v motor, how would you use the controller listed above with a pedelec sensor? Note, my old salisbury has an inoperable torque/pedelec sensor.
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