Help me identify and upgrade 36V controller to 48V

Hi all,

I was hoping you could me identify my *Bafang?) 36V250W ebike-kit so I can find out how to upgrade it to 48V.

Or maybe it already supports 48V.

Some photo's:

Motor:





New controller:



View attachment 5


As you can see, there's no obvious known branding anywhere.
The guy has some contacts in China and managed to get his own brand on it.

I guess it's just a Bafang front hub motor? I got it in The Netherlands (where I live).
It's a 245RPM motor.

Rated power is 250W. The battery is a 36V11Ah LifePo4 (Pouch cells).
Controller max A is 12A, so motor is possibly a 350W? Maybe 500W?

The goal is to run it at 48Vs instead of 36Vs.
The reason is that my other bike will become 48V kit (BBS02 48V750W).
With a big battery pack. I want to share this pack with the bike above for more range.
I can get rid of the 36V11Ah (bulky/heavy) battery

Question: can this motor run at 48V and 8A? That would be similar to 36V12A ?

Question 2: can this controller handle this?
You'll see two controllers in the pictures. The first is an old one. The newer is an enhanced version of the same controller, supporting better top speed (20mph).

My supplier says both engine and controller can't handle this.
For the motor I don't believe him. The controller I don't know.

I can get better pictures of the controller if needed, maybe open it up?

The supplier doesn't want to tell me what exact engine/controller it is.
He doesn't want me playing around with it because of the warranty.

Plan:

Plan would be to buy a new controller that support 48V (and maybe 36V at the same time?).
I have been googling, but I haven't found a controller that matches the display.

The display has 9 speed settings and display Volts, Amps. Seperate +/- control and seperate thumb throttle.

This china supplier looks to have similar looking display, but no similar spec controllers.

http://www.fdm-ebike.com/Electric-Bicycle-Kit-LCD-Display-with-Computer-Bluetooth-p74355317.html

Thanks for any help,

Opper

The controller has (at least) the following connectors:

- throttle
- walk assist 6km/h
- lcd display
- motor
- hall sensors
- battery in
- head light out
- brake sensor (2x)
- pas sensor

1. Motors don't care about voltage, just watts. If' it's a 250W rated motor, that means it's rated for 250W continuous operation without damage 24/7. That could be 36V, 48V , 72V, whatever, as long as it's not more than 250W. Higher the voltage, the faster rpm. Problem with increasing volatge on the same controller is that it increases the watts, which increases power and speed.It also puts more strain on the gears. I don't use geared motors so I'm not sure how well it will handle 48V, but it should be ok as long as you don't increase the amps past 20A. That would allow ~1200W to the motor under heavy load.
2. Most 36V controllers will support up to 63V max because of the caps and fet limits. Only way to know for sure would be to open the controller and look at the parts, But if you put a 48V pack on it, the LVC will still be set for a 36V pack @31V, so you must either change the lvc, or monitor the pack voltage and don't run it down that low or change the LVC in the controller. If you don't change the lvc, then you could use either a 36V or 48V pack on the controller. If you knew what you were doing, you could install a switch to switch between different lvc settings so you could use a 36V, 48V, or any other voltage you wanted to safely with the flip of a switch.

Thanks, i was thinking the same about the motor.
Any good sources to buy a similar controller for 48V with proper LVC?
Most controllers seem to be missing some features.
And how will I know if the display will work?
Is that a standard interface or reach controller type different interface to display?

open the old one up
with 9 speeds, it should be easy to find a lower speed to keep the watts in the normal range, if the parts check out, which they should. add a LED DVM and use your mind for lvc.

Matt Gruber said:

open the old one up
with 9 speeds, it should be easy to find a lower speed to keep the watts in the normal range, if the parts check out, which they should. add a LED DVM and use your mind for lvc.

Click to expand...

By LED DVM you mean digital volt meter?
The display shows voltage and amps. I can also set speed and amp limit inside the display).
I can keep watts to 400W just like now, don't need extra speed. Just need 48V to work.

If I open up the controller, what do I look for? Or just post picture here

I could be unlucky and the controller is to weak for 48V?

EDIT: Found another topic http://endless-sphere.com/forums/viewtopic.php?f=3&t=52443 looks like I need to check max voltage on capacitors. Hoping 63V
EDIT2: Even another topic (how did I miss these before?): http://endless-sphere.com/forums/viewtopic.php?f=30&t=40072

Finally found a supplier that sells the display I have: http://lipeng.en.alibaba.com/product/60023527740-800144139/LCD_Display_for_electric_bicycle.html

Another one: http://m.made-in-china.com/product/724336085

Display uses UART protocol?

This might work http://m.aliexpress.com/item/895920535.html?tracelog=storedetail2mobilesitedetail

I have tried various controllers on my mini-motors over the years, but only two that mate with a LCD(5-wire connector), both from BMS Battery.
The small SO6S and the very large S12S.
The SO6S is very low power and will not survive 48V without replacing internal componets.
The S12S will accept 48V, and at 23Amps is high power. Your Bafang probably could take smooth sine-wave 23 Amps, depending on the type of usage(your profile?).
The current can be limited, but only in PAS. It is a very large controller.

I use Lipo, and the odd voltages do not work well with the LCD displays, so I currently use non-LCD controllers.
My favorites are;
http://www.elifebike.com/peng/iview.asp?KeyID=dtpic-2012-8W-QNK2.073KQ
This simple controller is sturdy and has exactualy the right power for a 2.0 to 2.5 Kg. mini-motor(like your Bafang). It has a built-in LVC of 41V, perfect for 48V. It is advertized to be able to run sensorless, but it will not. It uses the simple LED810 display. It is sometimes acvailable on Ebay, which saves on shipping.
Fool-proof, inexpensive and durable, but a little large.
And:
http://www.ebikes.ca/shop/ebike-parts/controllers/c3620-nc.html
High quality controller, but best combined with the Cycle Analyst:

http://www.ebikes.ca/shop/ebike-parts/cycle-analysts/ca-dp.html
Far and away the best combo, but not cheap.
Unlike the LCD displays, the CA is a real computer, offering a wide array of feature and abilities.
For my application, this combo is better than the sine-wave\LCD display variants.
Highly recommended.

Just opened up the controller and it has different types of caps.

Two big ones with 63v written on them.

Three smaller ones with 50v written on them. These are close to the three (phase) wires going into the motor.

Another 50v and one 25v one.

I think the 25v is already low so I guess its won't be getting full 48v (14s, so close to 60v really).

Should I replace all the 50v ones? Or should I measure all of them while powered on on 36v to see how much v they get?

The 6 MOSFETs on the side are rated 68v.

There are also two voltage regulators close to battery power coming in.
Lm317t has max input 37v.
A 78m05 close by has 35v max input.

Any guide on which ones to replace? Just replace all of them?

no. post up pictures of the 50V caps so we can see where they are located. the 25V caps are on the charge pump or the 5V rail.

Thanks.

Two 50v close to power input, including two voltage regulators.

Three 50vs close to power output.

pictures are not much use but it looks like you have one of the blue(63V?) caps on the input and one is on the S/D buss so they will work on 14S lipo. no way to know what the black ones are but i assume those are the ones you said are 50V since they are small and they appear to be on the 12V rail and the 5V rail. but you have to look at it to determine if that is the case. i cannot make it out from your pictures.

Thanks. The black ones are 50v in between yellow blue green wires. Those are output for the motor right? Is that 3 times 36v, or 3 times 12v?
Where's the 12v rail used for?
What's the s/d bus for?

The blue ones are 63v. It's going to be 14S li-ion NCA Samsung 29e based battery pack.

the 50V caps are on the regulated voltage rails. 12V and 5V i would guess. no way to know from the pictures except to guess from their location. the source/drain busses supply the current to the mosfets.

if you go to 14S of lipo you should change that input power resistor from 160R to at least 200 or 300R. and 5W too. like that one.

For piece of mind, I'd upgrade the output caps to 63v or more. The others probably don't matter, but just to be sure, you could check the voltage accross the legs with the controller powered up. If they get battery voltage, they need to be upgraded. I'd also increase that big resisistor to be safe because I've had them run very hot when over-volting.

Can you show a high-resolution picture of the resisistors in fromt of the 12v regulator (lm317), which is probably the voltage divider for the LVC? We need to see the resistor values.

Apparently my new phone sucks at closeup pictures, also some capacitor texts are difficult to read because they are small and mounted closely to the PCB or other components. There are also 3 black small capacitors closely to the MOSFETS, they must get battery voltage right?

Here are some more pictures.

you can see the source/drain busses on the underside and they increased conductivity by soldering some copper "buss wire" onto the traces. that is your battery voltage applied to the output mosfets.

the small caps next to the mosfets are the charge pump caps that store charge above the battery voltage that is used to turn on and off the mosfet gate drivers on the hiside mosfets. they do not see battery voltage, only the voltage of the charged stored on that cap above the B+ voltage. which is only about 12V.

the input power resistor is too small i am guessing but you can power the controller up and see what the voltage is on the input to the 12V regulator. if it is above 40V then use a higher value input power resistor. if we know the voltage then we can guess how much to increase from the 150R that is used now.

Thanks.

To double check my understanding:

The only capacitors seeing full battery voltage are the blue big ones, which are 63V which should be fine with 14S.

The MOSFETS seeing full battery voltage are the 6 on the long side, which are already 68V, so should be fine as well.

The resistor on the edge of the board is used to bring down the voltage just before it gets knocked down to 12V by the LM317T?

At the moment this power resistor is the only worry and we need to make sure it brings down the voltage enough to be below the max input voltage of LM317T?

If not the resistor should be replace by one with a higher R rating, or the LM317T should be replaced?

Thanks again,

Opper

opperpanter said:

Apparently my new phone sucks at closeup pictures

Click to expand...

Magnifying glass. Even my 1.3mp nokia takes close up shots if you don't mind the somewhat tunnel vision.

this is all correct:

"The only capacitors seeing full battery voltage are the blue big ones, which are 63V which should be fine with 14S.

The MOSFETS seeing full battery voltage are the 6 on the long side, which are already 68V, so should be fine as well.

The resistor on the edge of the board is used to bring down the voltage just before it gets knocked down to 12V by the LM317T?

At the moment this power resistor is the only worry and we need to make sure it brings down the voltage enough to be below the max input voltage of LM317T?"

but you do not replace the regulator, just add some resistance to drop more voltage on the input to the LM317. you can measure the voltage on the input with your new battery and if it is too high then just swap out that power resistor with a larger one.

we know the idle current is about 55mA so from that we can guess how much to change the power resistor. most of them are 200R-220R and they used to be 300R which may be needed here.

dnmun said:

this is all correct:

"The only capacitors seeing full battery voltage are the blue big ones, which are 63V which should be fine with 14S.

The MOSFETS seeing full battery voltage are the 6 on the long side, which are already 68V, so should be fine as well.

The resistor on the edge of the board is used to bring down the voltage just before it gets knocked down to 12V by the LM317T?

At the moment this power resistor is the only worry and we need to make sure it brings down the voltage enough to be below the max input voltage of LM317T?"

but you do not replace the regulator, just add some resistance to drop more voltage on the input to the LM317. you can measure the voltage on the input with your new battery and if it is too high then just swap out that power resistor with a larger one.

we know the idle current is about 55mA so from that we can guess how much to change the power resistor. most of them are 200R-220R and they used to be 300R which may be needed here.

Click to expand...

OK Thanks. A bigger resistor means more power wastage I think, but at 55mA it's not a big deal?

How do you know it's 55mA BTW?

measured it on the infineon controller.

Found some more info in other threads, noticeably this one: http://endless-sphere.com/forums/viewtopic.php?f=16&t=19978

It calculates a 266.67Ohm resistance to be used, but this might be different for the 55mA current we're having here?

Just to be clear: I'd like my controller to still work at 36V (12S LifePo4).

Is this possible?

For 36V it states 100hms, so do I pick something in the middle?

BTW somebody here suggests that replacing the LM317 might work as well: http://endless-sphere.com/forums/viewtopic.php?f=16&t=19978#p580722
LM317AHVT works up to 60V.

i do not work from other peoples opinions. i use just the measured voltage. you have not posted up the input voltage to the regulator you measured yet.

I haven't measured yet, posting from work atm.
And I don't have my 48V pack just yet.