BBS01 Controller Upgrade 36V to 48V

[Doran]

I've seen this question asked many times, but have not seen a definitive answer, so maybe someone here can help.

Can I replace my BBS01 350W 18A 36V controller with a 48V controller, limit the amps to 18A and so get some more power from my motor?

I know that a 48V version of the 350W BBS01 motor was available previously, so in theory this should work OK.

Any responses will be highly appreciated.

 

[amberwolf]

If you have a 48v battery to go with the 48v controller, then the answer is sort-of-yes.

But there are two catches:

--the motor will then spin faster than before for the same throttle setting (meaning you'll have to shift to lower gears to get the same output speed (but higher torque at that speed).

--the motor may run hotter, which could damage it.

Also, any display or LCD that came with the orignal kit may not work with a differetn controller (or voltage).

 

[Doran]

Thanks Amberwolf,

What you are saying makes a lot of sense.

The motor currently spins to max 80 rpm, do you think it will go up significantly with an increase in voltage?

 

[amberwolf]

It's always proportional. So whatever the ratio of your new voltage to the original voltage is, is what the speed ratio (unloaded) would also be.

With a load while riding it might be slower than unloaded (offground), and that's where the heat buildup happens (the difference is wasted as heat)

 

[Doran]

I achieve the speeds in the 80 rpm column exactly in all 8 gears.

So 48/36 = 1.333
1.333 * 80 = 106 rpm

So theoretically I should be able to get to the speeds in the 105rpm column?

Not bad if this is how it works out.

 

[Lurkin]

Motor speed and pedal cadence are two different things, although they are roughly related.

Yes, you can do this. The difference between BBS01 250w and BBS02 350w is the controller only. The rest is the same.

Would I bother? No. Probably play with the programming settings to be more aggressive.

Would I bother? No. I think the em3ev settings on mine are pretty much, perfect. If I wanted more speed, I would (and I am) putting together a higher speed setup and leave this as a really, really nice commute set up.

 

[Doran]

Hey Lurkin,

You are probably right, it runs very well and reliably at the moment.

I have done 4000km trouble free on it.

Maybe just invest time and money on a new project (New bike with BBSHD and 52V battery)

Now to find the right donor bike ...

 

[Lurkin]

If you can get hold of one, test it and I think you will understand why I am encouraging you to look at different options. There isn't a huge difference between them and the controller + battery cost > benefit received.

If your looking at higher power, I would be looking at Tangent Dave's Astro kit. Very, very nice with forum support? doesn't get much better than that. Bit nosier from what I can work out, but also supports something 'homegrown' and quality on the forum.

 

[Doran]

Just a quick report back on my original post. I did exactly what the post said.

Ordered a 48v controller and swapped out the 36v controller. I then built a small 4s4p battery (16.8v fully charged) which I run in series with my 36v (42v fully charged) battery.
This gives me a 52v (58.8v fully charged) battery.

The bike now runs like a rocket, the difference is absolutely amazing.

It is very obvious that the motor is spinning much faster.

I have it programmed to 16a and this more than enough.

Cheap upgrade but highly effective.

 

[Bombus]

I have also done the same, I am just using a 10p 3s booster pack made out of old makita cells.
I found that the 36v 350 watt motor had too slow a cadence.It was about 65 to 70 RPM in the real world which was too slow for my knees.

Once I put the 48v controller on, the cadence goes to 80 up to 105 rpm, depending on the PAS settings. Full throttle will give me around 50+ kph. I have had it up to 65 kph in top with a tail wind and 120 rpm for about a minute.

I am running on a Rholoff so have the low and high gears. My current is set at 18 amps but will try 20 amps once I have finished making my new 52 volt 4p 14s battery pack. My 36 volt pack can't handle more than 18 amps as the voltage sag is too much. The motor seems to go OK and doesn't over heat but I don't push it too hard. Usually running around 3 to 6 amps with unlimited speed on the controller.

So as Doran reported, a good cheep upgrade that seems to work so far.

 

[Mündawg]

Just a quick report back on my original post. I did exactly what the post said.

The bike now runs like a rocket, the difference is absolutely amazing.

It is very obvious that the motor is spinning much faster.

Haha awesome! But also, no duh!! hehe you went from 36v to 52v silly!!! I believe the best way to increase speed is to increase voltage.
Glad it worked out! Keep an eye on temps, are you using a CA or temp sensor?

 

[Doran]

Hey Bombus,

65kph sounds insane on a bike. I have the stock 44t chain ring and 11-32t 8speed rear sprocket.

I've had mine up to 46kph in 7th gear (13t), so reckon 50-55 in 8th (11t) is possible.

@Mündawg, yes voltage is the way to go, but as you said, temperature can be a problem. I don't have a CA or temp gauge, so it's all done by "feel".

I have to say, the motor does get quite hot after a 15km ride, but so far so good.

I am planning to install a temp probe in the controller though.

 

[Bombus]

Yes 65 kph is fastish, but that is not sustainable, cruising is 40 to 45 kph with a tail wind on the flat in 13 or 14th gear on the road. (46 tooth front and a 16 tooth rear)
On the river trails around 25 to 30 kph drawing around 3 to 4 amps.
I have a watt meter installed and max watts is 800 with a fully charged battery at 54 volts. Cruising is around 200 to 300 watts which is the same as the 36 volt controller, just at a higher cadence.
I've no temp gauge but the motor just gets warm (after 20 ks) to touch so should be OK.

 

[sannder]

(bringing this thread back to life...)

The upgraded model in question was the new BBS01B ?
I ask because I got the information that the model B 36V and 48V controllers are incompatible.

36V controller could go up to 12S with 80-90% charged battery anyway but it's a rather odd voltage for an ebike battery.

 

[Doran]

Sannder,
my upgraded motor is BBS01 Version A. Still running very well after the upgrade with no issues so far.
I have now done just shy of 8000km in total with the motor of which about 3000km since the upgrade.

 

[sannder]

Thanks Doran. Mine is a little 250W - I will probably get a new controller from Luna and check if it fits.

The idle current on my BBS01 is 70 mA without a screen and 80mA with the screen mounted (3-4W).

Did anybody measured the 9 FET 48V controller for the idle power consumption ?

 

[ghill13]

I am looking at doing this same thing, I have a BBS01B and want to make it 48v. The problem is I can't seem to find a 48v 350w controller. I read somewhere that a 48v 500w controller is the same once you adjust some settings. Is that true? If not where did you find a 48v 350w controller?

 

[pomah]

Kicking this thread back to life another time, anyone want to report on long term use for a bbs01 with 48V?

Any mechanical issues?

What do you limit the current to?

Thinking of going with a 48V 500W controller and limit that to 15A

EDIT:

UPDATE:

Well I got a 48V controller, installation was without issues, since the original 36V bbs01 can take up to 18A, I decided to limit the 48V to 14A, that should give similar power input/output and hopefully the mechanical and technical parts will hold up.

Now I am waiting for m eggrider v2 that got lost in the post and I hope that I will be able to put this setup through a few km of riding and get back with some longer term review.

But for now a legal 250W 48V system

 

[Doran]

I can confirm that my BBS01 is still going very well after the upgrade to 48V at around 5,000km on the clock. It is now approaching 23,000km without any mechanical issues. My original chainring (44T) is quite worn and dropping the chain frequently, so I am in the process of replacing that and installing a new chain.

The controller is limited to 16A, and I run a 52V (58.8V fully charged battery).

 

[pomah]

Ok I did my first real run today, to work and home. The way home is around 10 km, with the last 1km with an increase in height of around 86m, I live on a big hill. When getting home the motor was warm, but not hot. It is cold out here now, around +5 degrees celsius.

It is running at 48V and 14A right now. I am still waiting for my eggrunner so that I can get some good stats out of it.

I am running a 104 bcd adapter and a 38t chainring, max speed today was 42km/h, that is what I was aiming for.

27,5x2,4 inch wheels, impressed today, espceially compared to my old setup using a mac-motor and phaserunner.

Update 2:
Using the eggrider I changed the offroad mode to 16A, removed the throttle completely and have done some trail runs, it is working perfectly after around 16km run with a very high incline last bit the engine is a bit warm to the touch. I will double check duing the summer when the temperature is above 0 degrees Celsius, but so far it seems the 48V controller switch is safe enough. A total of 400km on the motor now.

 

[eagercyclist]

What settings are you guys running (Keep Current, speed limit)? I will be making the same conversion soon. Hoping to assess temperature and slowly go up on current depending on temperature.

Currently running 36V at 9A which until I get used to it is already awesome (but wanting the top end cadence offered by higher voltage). That is with 100% Keep Current so it runs at that current for most of the ride, rather than for just short periods as no doubt intended by Bafang.

 

[dorndi]

I have a similar question:
Currently I have a BBS02 36V 500W (manufacured 2022, so newest model with gear sensor).
I run it sometimes for a short time at the limit (25A) for steep MTB climbs but when doing so I keep a high cadence too avoid too much thermal stress.
As most of you know there is also a 48V 750W 25A BBS02 available, so the motor is capable of more power (at least as long as l avoid overheating)

I am wondering what is the maximum possible voltage with the original 36V 25A controller?
Can I run it with 11s or 12s or even 13s without extreme high risk (currently 10s)? I have no glue about the specs of the electronic components in this controller and have no Bafang programming cable available so I can't check the possible voltage settings in the Bafang software at the moment.

Or would you recommend to buy a new 48V controller if I aim for at least 20% more short peak power?
Will the 48V controller work fine with the 36V version of the motor because of other windings of both motor versions?

 

[pomah]

I have used a 48v controller with a 36v motor, works great. But I do not know what the voltage limits are for the 36v controller

 

[amberwolf]

I am wondering what is the maximum possible voltage with the original 36V 25A controller?
Can I run it with 11s or 12s or even 13s without extreme high risk (currently 10s)? I have no glue about the specs of the electronic components in this controller

In general, for any controller in any system, assuming the software or hardware has no HVC that prevents operation above a specific voltage (many do), then the "maximum possible voltage" will depend on the specs for any and all parts that are directly connected to the battery voltage bus.

This includes (but may not be limited to) the phase FETs, the main capacitors (all the ones connected from battery positive to negative, they may not all be the can-style electrolytics but those are the most vulnerable to overvoltage, unless it uses any tantalum caps), and the input side of the low-voltage power supply that creates 5v, 12v, etc., from the battery voltage.

I don't know if there are any diagrams that show these parts, but you can find them by using a multimeter on continuity or it's lowest ohms setting, with no battery connected to the system or controller, and connect hte meter black lead to batterynegative input of the controller, and touch the red lead to each lead of every part you suspect is connected to the battery, making notes for anything that shows a connection. Then do the same for batterypositive input. Any part that has a connection to both + and - is probably going to need to be rated for as high a voltage as you intend to use.

Note that most parts have some "absolute max" limits in their spec sheets, and that is what they are guaranteed to handle. Anything beyond that may cause it to fail, but there's no hard line where the failure will occur--there is batch variation.

 

[dorndi]

Thank you very much for your replies.
I found this interesting thread which answered my main question and shows the needed mod:

BBS01B 36V 250W - trying with higher voltage [success]

Hello everyone, I tried in a different forum, but did not receive any help, so I would like to ask you. Is it possible to make my motor BBS01B 36V 250W to work on 52V with standard controller (if not 52V, then 48V?)? I know about "error 07 - overvoltage protection", but everything else looks...

endless-sphere.com

Modify Bafang BBS01B 36v for 44v

This may help some people who like me are handicapped by the 78 RPM limit of the Bafang BBS01B motor. My natural cadence is around 90 RPM and I select a gear which allows me to spin at that speed when climbing. If you do spin at 90 RPM the motor becomes a generator (back EMF effect) and stops...

www.velomobilforum.de

As I mentioned I have a BBS02B 36V 500W.
But the stock 36V controller of this motor is capable of a lot more:
The parts on the controller are rated for 63v (same voltage rating of electric components as the BBS02 48V 750W).

To sum up:
But if >44.x volts go through one wire to the display the display (called "P+") will show an overvoltage-error-message (shows the 07H error message) and prevents the controller from working.
The workaround is to install a TVS diode before the display to stay below 44.6V with the fully charged battery.
Or in other words: without a mod the stock 36V controller will only work with 10s batteries.
But as long as the display will "see" at maximum 44.6V with the help of the TVS diode mod also 11s-14s batteries are possible with this 36V BBS02B controller.

Picture from @anotherkiwi:


My plan:
I have in addition to my 10s 36V batterly also a 13s 48V battery.
Order a display extension cable (so I don't need to modify the wires of my display but only a cheap extension cable).
Order two TVS diodes (probably one with 5V and one with 6V) to reduce the voltage which the display "sees/measures" by 11V (fully charged 13s=54,6V-11V = 43,6V = <44.6V = no 07H overvoltage error).
Thanks to @Wizzeros and @fechter for sharing this mod.

Benefit for me:
Don't need to buy a new 48V controller (which is expensive).
Can use my existing 48V battery with the existing 36V motor.
I prefer the higher cadence of more voltage (especially when my currently in use 10s battery is nearly empty and the motor load is high the cadence of my motor is not satisfying for me as my natural cadence is around 90).
By removing the display extension cable I would theoretically be able to switch back from the 13s setup to the 10s setup.

Possible benefit for others with 36V BBSxx:
Increase battery voltage to 11s or 12s by adding cells to the existing 36V setup.
This higher voltage can slightly increase the motor efficiency, cadence and peak power (and no need to buy a new 48V controller + battery).

Be aware:
Not sure but I think most BBS01 or older BBS02 (without B) have 50v Caps (so limit on these is 50V, not 63V).
So only fully charged 11s or nearly fully charged 12s (instead of stock 10s) might be safe with this TVS diode mod on lower spec/older BBSxx controllers.