Controller Voltage Increase Past 63v

[Scottyf]

Afternoon All,
I use the forum alot but rarely post. However I have a Bafang BPM rear driven electric bike.
All pretty standard stuff using a lipo setup (44v 10ah).

Now I have the below universal brusless controller.
http://www.bmsbattery.com/controller/363-universal-brushless-hub-motor-controller.html

I've opened this up and its all pretty standard stuff really. However what I'd like to do is increase the voltage past the 63v max this controller is limited to. Ill keep the same max amp peak at 20amps but would like to see how the motor runs with say 75.6v max.

Now I know some people on the forum sell modified controllers that are pretty slick with alot of features etc. However If I was to go about changing the fets to higher rated versions what would I need.

I'm pretty handy with a soldering Iron but if there's parts I can buy from say maplins (UK based electronic shop) and litterally change an handful of parts that would be a better option.
What I'm after is a list of parts that I would have to change as such and ok my knowledge into electronics is no where near some opf the people on this forum. But the only way to learn is to ask.

Here is the controller for reference.
http://www.bmsbattery.com/controller/363-universal-brushless-hub-motor-controller.html

If need be I can open up the controller and review the parts.

 

[ZOMGVTEK]

You would need to replace the MOSFET's, since they're probably rated for 75V. Something like IRFB4110PBF would be a good choose for that voltage. Then any capacitors rated for 63V need to be replaced with 100V versions. The lower voltage ones don't need to be touched, just the electrolytic with full pack voltage on them, which should say 63V on them. Then you need to measure the current in the small red 'turn on wire' and tack some resistance onto the large power resistors that drop the voltage into the regulator. The idea here is to just drop the voltage off your battery pack into the mid-band voltage of the regulator, so that it can go a bit higher and a bit lower without dropping out. You can see whats in there stock, and determine whats needed, or just start high and go by trial and error.

 

[DAND214]

You might also consider, finding a sourch for a new set of gears for the motor. As they won't last too long on 75v, especially if you are doing any offroading. The jarring of the gears will strip them in short time.

Dan

 

[Scottyf]

I'm all on road I was hoping to keep the peak limits below 1500w even at 75.6volts @ 20amp max.
However your probably correct in pushing it a bit to far

Thanks for the reply - Ive searched the forum but its usually people who know exactly what there doing from the start.
I have a few dummy controllers to work with so don't mind a bit of trail and error.
Thank you.

 

[Scottyf]

Hello All,

Opened up the controller and did a bit of a shunt mod to increase the amps a little to get the accleration up. Now pulling peaks of 27amp instead of 20amp.

I've checked out the MOSFETS used which are http://www.ruichips.com/pic/RU7088R.pdf RU7088R
So I should be good for up to 80v.

Now could I just change the caps now without changing the mosfets to allow me up to 75v?

 

[dnmun]

the mosfets can handle it, the caps need to go to 100V. you will need to add some resistance to the power resistors you see there next to the caps. looks like two 330 ohm resistors so i am guessing you will need another 200 ohms or so, maybe up to a total of 900ohms, maybe 2x420 or 420 and 470 ohm 2 watt power resistors instead of those. but since we don't know the circuit current then it is hard to guess.

 

[Scottyf]

Excuse my ignorance buy why would I need to change the power resistors?
Is this just to throttle the amount current being passed to the capacitors at the higher voltage?

 

[dnmun]

the input power resistors drop the pack voltage 'Vcc' to a level the voltage regulator can handle. would need to know what the circuit current is to guess what to use, 900R would likely be too much.

 

[cwah]

Hello,

Any update on this controller? Is the Bafang working over 63V?

I'm planning to add a bafang 48V500W (http://www.bmsbattery.com/ebike-kits/348-bafang-350watts500watts-bpm-motor-e-bike-kit.html) to a dahon speed 20''.

I'd probably select a 201 rpm for torque and efficiency but have a wattage of around 66.6V (3 Lipo winforce at 22.2V5.2AH for their good price). What controller should I get for that and would the setup works?

 

[wesnewell]

http://www.aliexpress.com/product-gs/287758466-72V-1500W-Brushless-Speed-Controller-for-Electric-Bikes-OT100-wholesalers.html

This controller works great with 18-24s lipo. With 18s, LVC will cut off power before cells get below ~3.6V.

 

[cwah]

Thanks Wesnewell. If the bafang can handle additional voltage, I'll certainly buy this one.

 

[Scottyf]

On a 200rpm wind it should be fine.
Lyen also does 72v controllers (well up to 100v tested) the are programable.

 

[cwah]

Thanks Scottyf. I'm strongly considering the bafang now but I've heard that the new crystalyte 209 is out soon. I may wait a little bit to see which one I'll purchase

 

[Scottyf]

I've not purchased a Cheaper 72v Controller from HK. To see how well the bafang copes with those volts.
Its still in sensorless mode so will be interesting to see how it fairs with 36mph unloaded top speed.

I may run into issues but its worth trying and for £30 for the controller its cheap if it doesn't work.