BBS01/BBS02 differences

[Lurkin]

I currently have a BBS01 250w kit.. which is fine.

Just wondering:-

- If I want to switch to a higher power unit, do I need a new loom/display etc or is it just a matter of replacing the motor unit (given the controller is attached to it)?
- are the insides of 350w/500w unit different or could they be crammed into a 250w stamped motor shell?

 

[dusan]

BBS 2 has wider stator because more robust motor winding to keep rational cadence when pedaling with 48V. It means, it's 5mm wider.
There is also different controller with 9 Fet.
You could probably run BBS1 safely at 350W, it means max current 18A instead of 15A.

 

[Lurkin]

It's able to be run above 350w currently, according to the Bafang display. No idea of how accurate this is. I'm wondering how long it will last like that though.
Hmm.. we'll see.

 

[ziltoid81]

It's able to be run above 350w currently, according to the Bafang display. No idea of how accurate this is. I'm wondering how long it will last like that though.
Hmm.. we'll see.

The stock BBS01 15A, 250w will pull around 500w max. out of the battery.
The 250w is just a rating from bafang.

The 750w BBS02 also pulls up to 1400watts........

I think your controller is locked to 15A.

 

[Lurkin]

Any ideas on how to do that?

How will I know if I'm about to roast the battery by trying to draw more from it than it's designed for?

Do you know where the temperature reading comes from on the display i.e. is this actually the temperature of the motor?

 

[ziltoid81]

Any ideas on how to do that?

How will I know if I'm about to roast the battery by trying to draw more from it than it's designed for?

Do you know where the temperature reading comes from on the display i.e. is this actually the temperature of the motor?

Doing what?

Your controller is not capable of doing more than 15A i guess, so your battery is safe.

Maybe comparing your temperature in your display, while driving and the local temp in your weatherapp is not an option?
If its significantly higher, its the motor temp, if not its not.
Not too hard to figure out....... :wink:

 

[Lurkin]

How can I change my controller to allow more than 15a?
If so, how can I tell if its going to draw more than the battery is capable of providing?

 

[ziltoid81]

Get a BBS02.......swapping the controller makes no real sense.
I mean you can do this but i would not.
The little BBS01 will not operate at significant higher power levels, at least not really long i guess.

You need to know the cells in your battery, a samsung inr18650 25r delivers easily twice or 4 times the amps of cheap cells.

 

[Lurkin]

As suspected.

Which brings me back to the original post question:-

- If I want to switch to a higher power unit, do I need a new loom/display etc or is it just a matter of replacing the motor unit (given the controller is attached to it)?

 

[Tats]

G'Day Lurkin - I have a 36v BBS01 from Ewan Maxwell's emax-ebikes here is Aus and it is delivering current as follows.

9 levels of PAS, highest PAS assist is 10.5A - full throttle at all levels of PAS, highest full throttle amps is 17.5A. I have a CA V2.

This is the "350w" BBS01 controller that is a direct swap for the "250w" BBS01 controller and may in fact be an identical controller just programmed differently.

The bike is plenty quick enough with this setup for me and the lumpy bits around me - Strava keeps chucking me out of KOMs as the rides are flagged as being with a vehicle. Personally I think less than 100 bucks for a second controller, meaning you have a spare, is a better investment than swapping from a BBS01 to a BBS02 - which probably requires a 48v change too to fully maximise the benefit. Unless of course you have two bikes and are putting the BBS01 on that.

Are you looking for more torque or top speed or both? I can sit on the flat in the low 40 km/hs on PAS at the 10.5A assist level. The extra beans with the throttle gets about 10% more speed, though I'll sometimes use the throttle as a boost when climbing.

So, the BBS02 on my cycling routes would be of minimal additional benefit to me personally, and make the bike heavier - ymmv. I can recommend you give Ewan a call, he's a good guy and when I explained what I was looking for he recommended I go with the BBS01 over the BBS02. Couldn't be happier with the system I have.

 

[mfj197]

The 250W and 350W BBS01 versions are identical, just with a different maximum current programmed into the controller - 250W is set for 15A and 350W is set for 18A. You can easily change this yourself using a programming cable (see this thread on programming the controllers. I think the 15A setting is fine for me but it's easy to change if you want to.

Michael

 

[Tats]

I reckon the 15A is pretty good anyways, I ride PAS at 10.5 99% of the time and 15A would be sufficient as the 'boost' button for me.

To determine whether or not you're going to 'roast' the battery you need to know your specific cell, the 'C' discharge curve and the total Ah (or configuration if you don't have it eg 10s4p so you can work it out).

The battery will provide power and the volts will drop in relation to the amount of current being drawn. I have a 10Ah "Ping" LiFePo battery and it has a very flat discharge curve at 2C. Meaning at 20A current drawn from the motor (Current / total Ah = 2C I think is the formula) I am on the 2C discharge curve and the voltage doesn't drop much over time. I can look up the 2C discharge curve for my cell and it will tell me how long the battery will hold a voltage level for at that discharge rate. If I had a 20Ah battery, 20A draw would be 1C so I'd be looking at the 1C curve. I can look along the curve and when the volts hit my low voltage cut-off level configured in the battery management system I know this will operate to prevent over-discharge and potential damage to any of my cells. If I had a 2Ah battery discharging at 20A I'd be on a 10C curve and my volts would drop very quickly and BMS LVC cut-out would happen very quickly.

This is why sometimes full throttle can cause system shutdown even though there are a few bars left on a crude battery display and rebooting and riding on PAS can go for several KMs further until you hit a hill or open the throttle again - work out your C rating based on your controller settings and battery configuration then reference your cells discharge curves to get your answer. Always try to run at a C rating that is less than your your battery's continuous discharge rate C rating to extend battery life - and more Ah is better. Hope it helps, Rich

 

[Lurkin]

The 250W and 350W BBS01 versions are identical

As suspected. I will just get a programming cable.

I have a CA V2.

Can you post a pic of your set up? which CA version (DPS etc) do you have? I've been thinking of buying one of these for a while. In another thread I was encourage to buy celllog instead, but frankly it's a bit of a fail. I really like the idea of being able to get (pretty much) any metric desired from the CA.

low 40 km/hs on PAS at the 10.5A assist level

a higher top speed would be ideal if possible. This is the main attraction to changing. This way I can keep the "250w" stamp yet crank out over 350w up to 40km/h.

the battery is a Samsung 36v 16.5Ah 10S6P 29E using INR18650-29E cells... Says the pack is rated to be able to discharge at 20A continuous (or potentially up to 30A)....

http://em3ev.com/store/index.php?route=product/product&path=35&product_id=160

 

[Tats]

I have the CA V2.3 DP-S with a CA Shunt-SA.

The Shunt is connected with Anderson connectors in series between the battery and the controller. The CA plugs into the JST connector on the shunt and has a magnetic speed pickup off the front wheel. I'll add a pic later.

Good battery cell for your system and one I nearly went with - here is the discharge curve http://lygte-info.dk/review/batteries2012/Samsung%20INR18650-29E%202900mAh%20(Blue)%20UK.html the Ping allowed me to get my bottle cage back.

My system configured stock by Ewan for 17.5A is pretty quick with 40km/h easy on the flat - have a check on the "programming thread" to see what the upper limit should be for reliability though. I think some have nuked a controller by running too high a current at too low a cadence i.e. straining the motor up hills. Higher current = more heat.

 

[Lurkin]

hmm your link doesn't seem to work.

Very interested in your CA set up. I read up on the shunt, but wasn't really to sure how it worked. I take it it's a sensor which the electricity actually passes through, measuring both voltage and current without having to run them directly through the CA itself.

 

[Tats]

Sorry about the link, try googling "Samsung INR18650-29 battery test discharge curve" and you should get it near the top.

The Shunt is a passive resistor that's all, no active components - it is a set resistance value and a Y-Cable that serves the purpose of calibrating the volts/amps sent to the CA in order for it to read correctly as well as providing some level of protection for the CA in the event of any faults. The value of the shunt resistor is derived from electrical circuit formulas when running parallel voltage/current paths. Nothing special, just very well built wiring and connectors with a fully sealed resistor so it won't be impacted by water/dirt ingress - saves making one yourself and doing a lot of soldering/crimping. I crimped Anderson connectors on mine and it sits in series between my battery and the motor - the little JST connector connects to the CA - the parallel connectors and resistor are in a sealed block.