BBS02B/750w: First Build

[Gionnirocket]

Good day all.
I thought I'd start a thread to consolidate the inevitable tens of questions with added trials and tribulations of my first build.
I'll be adding a 750w BBS02B to my 12 year old cheapo' mountain bike that quite honestly has served me well.
First situation is due to the full suspension the typical water bottle mounting place for the battery will not work. I've got several rear racks ordered so I can see which works best. The racks that they sell with batteries looked ridiculously large to me.
That said my AliExpress 17.5ah battery arrived today. It came fully charged, with the new 5 pin plug on the mounting plate and a mid February 2020 build date tag so I'll take that as a plus. The charger is a plastic cheapo 2amp, but it does have a fan and XLR connector.
Ok.. First question.. I'd like to open up the case to confirm it was built with Samsung 35E cells. I see the screws around the bottom of the housing....Anything that I need to be aware of to pop off the top cover?
Danke in advance

 

[tomjasz]

Yes, the base screws will allow opening. Just be slow and gentle. Many aliexpress sellers reward batteries. The are a number of sites that even sell cell shrink wraps to disguise b and c quality generics. All depends on who you purchased from.

 

[tomjasz]

Please remeber a BBS02 needs to be ridden like a regular bike. Lugging the motor and taking off from a stop without having shifted like you would without a motor can overheat and trash a controller. Great motors if you treat them right.

 

[Gionnirocket]

Yes, the base screws will allow opening. Just be slow and gentle. Many aliexpress sellers reward batteries. The are a number of sites that even sell cell shrink wraps to disguise b and c quality generics. All depends on who you purchased from.

Thanks Thomas.
You mean there's a chance that my Raulex Watch isn't real?
Yeah it's a shame that that is the situation. I don't know how even reputable seller can keep from getting duped when the fakes can look so convincing.

As for using the BBS02B.. Yes my intent (at least a the moment) is to depend on it as little as possible.
So just to clarify, are you saying don't put it under heavy torque situations like starting from a dead stop in a high gear or riding it fast/hard up hill?
Would always starting in PAS 1 solve the problama?

 

[tomjasz]

Proper shifting as if you had no motor is important.

 

[Gionnirocket]

Proper shifting as if you had no motor is important.

I'm always shifting... just keeping enough stress on my legs to feel it but not enough wear myself out.
I guess I'll treat the motor the same.

 

[tomjasz]

I'm always shifting... just keeping enough stress on my legs to feel it but not enough wear myself out.
I guess I'll treat the motor the same.

Perfect

 

[Gionnirocket]

I'm assuming one way to get a feel for the strain on the controller and to provide some protection for it is to monitor its power draw.
If the display can be trusted for accuracy I'd say keeping it under 80%, 20amps at peak and under 60% 15 amp continuous "should be" an acceptable load for the controller to handle.

edit: I'll add the addition of an easily replaced 20amp fuse between the battery and controller can be a cost effective means of protection for the controller.

 

[Gionnirocket]

Seems finding a properly rated fuse is becoming a bit of a task.
Automotive fuses are only rated at 32v and outside the automotive industry things go straight to the industrial scale.
So is anyone fusing their motors and if so, what type of fuse?

 

[Gionnirocket]

While I wait for my motor which the UPS says should be here Monday, I thought I would see if there is enough room for placement of a fuse holder in the battery mount. And though it was nice to see a little silicone around the terminal connection, the lack of a strain relief or bushing where the cable exits leaves a little bit to be desired.
At least the screw holes and space allowance is there to add them easily.
I'd guess these would be included on better builds.
Anyone know what it looks like coming from reputable suppliers such as EM3ev?

 

[Gionnirocket]

Overkill or what?
The old man has too much time on his hands

 

[harryS]

Your battery should already have a max currrent limiter in its BMS. That needs to be more than what your controller can draw, or you'll constantly be frustrated by battery resets. It's not uncommon to spike current occasionally when riding an ebike, and a fuse will just be an irritant if it's too small.

If you place a fuse that is too small somewhere where tools are needed to access it (like inside that battery cradle), you'll be walking home often.

If I were to install a fuse on my bikes, it would be a big one for catastrophic/dumb wiring errors, not to control the nut on the handlebars.

 

[Gionnirocket]

Thanks Harry
I realize that fusing the controller may be more of a problem than solution... but I do like to experiment and if it proves to be more of a nuisance, it's easy enough to increase fuse size or eliminate. I'll definitely be adding a fuse for the cheap light/horn/button add on.
If the specs are accurate my battery is rated @ 30a continuous / 60a Peak and the controller @ 25a. I'll leave it to someone here if this is a good match.
My reason for trying is I've read a few times that the most common fail on the BBS02B is the controller. So to try and baby it a little I'll preemptively cut current with an easily replaceble fuse. Without all in hand I'm think somewhere on the rear rack that the battery will mount on. Good point though... I always travel with some basics, a Leatherman, allan keys, screw driver, small pump.,etc.... I may add a few wire nuts now
One thing to note is that I wouldn't consider myself a typical eBike user at this time. I don't plan on using the throttle and just using PAS at maybe 30 - 40% max. I'm just looking to extend my daily exercise riding day with a few electrons.
Granted this estimate comes before ever having ridden an eBike. I may end up going full throttle junky!

 

[tomjasz]

My reason for trying is I've read a few times that the most common failure on the BBS02B is the controller.

Failures with the controller have nothing to do with a fuse. Most were with cheapo FET's, Updated to higher quality with the BBS02B or due to user abuse, 99.9% of the time. Ride it like a bike and remember to not get lazy being heavy on the throttle in the wrong gear lugging the motor. We don't sell as many controllers for the BBS02B. Most are for the BBSHD. But that is a relatively rare occurrence. Careful that you don't cherry-pick issues from the internets! Few post the positive experiences so many posts amplify the problems

 

[tomjasz]

I may end up going full throttle junky!

With a dead controller. As I described several times.
I still ride a 2014 BBS01 36V 350W that runs as fast as I care to ride these days. Lots of use but riding like a bike with assistance. I only use the throttle when in the fastest gears. 42T x 11T

 

[Gionnirocket]

Failures with the controller have nothing to do with a fuse. Most were with cheapo FET's, Updated to higher quality with the BBS02B or due to user abuse, 99.9% of the time. Ride it like a bike and remember to not get lazy being heavy on the throttle in the wrong gear lugging the motor. We don't sell as many controllers for the BBS02B. Most are for the BBSHD. But that is a relatively rare occurrence. Careful that you don't cherry-pick issues from the internets! Few post the positive experiences so many posts amplify the problems

Thanks Thomas
I'm sorry, I think I may have given you the wrong impression.
I'm of the impression that the BBS02B and even earlier versions are quite robust. And of the few failures that do occur, it's usually as you say, the lower quality mosFet' in the earlier version, coupled with user abuse and a lack of understanding of the units capabilities.
Now will a fuse solve the problem of abusing the controller inadvertently... I lack the experience to comment.
But adding a properly sized fuse in theory is always good practice. If not for overlad, but at minimum for wiring faults. When ever I wanted to protect a piece of hardware, whether it be a car stereo amplifier or a 75 horsepower pump motor, a fuse is always your safest bet. In this case will doing so be more of a nuisance than solution... it may very well be. But as someone with an electrical background and inquisitive mind, I'm curious. Especially when what I've read on what and how people are fusing these things... like the use of AC rated glass fuses or 32v automotive fuses gives me great pause.

I still ride a 2014 BBS01 36V 350W that runs as fast as I care to ride these days. Lots of use but riding like a bike with assistance.

In this respect we are definitely on the same page.
The full throttle junky was a flashback to a younger and dumber me

This said... the UPS says my BBS02B is out for delivery today. I'm now flashing back to a kid on Christmas morning

 

[Gionnirocket]

It's alive!

Well as anticipated, the BBS02B was delivered this morning. I plugged it all in to bench test before starting the install and for the most part all is well. She turns, PAS changes speed and the break leavers cut off the motor. Seems all the pieces are here and it has a build date of Dec 20, 2019
On the plus side... The bolts for the "crappy cranks" as well as the motor mount came with blue and red threadlock on them respectively.
On the negative side... The bullet connector on the motor's negative wire was not matched to the extention wire provided. When trying to get a temporary connection the cheap crap snapped off. No worries as I intend to butt splice this anyway.
The motor lock ring tool that was supposed to be provided, wasn't. Somehow I got lucky and bought one on eBay while I was deciding on where to buy the motor as most vendors didn't include it.
In a somewhat related negative, the rear rack that I plan on mounting the battery on was to be delivered this morning as well. Seems USPS has decided it needs to do a few laps around surrounding zip codes first. Hopefully it will be here tomorrow as I'm hesitant to start installing the motor until I'm sure I have a home for the battery.

 

[harryS]

I should amend my comment. No need to walk home if you blow a fuse you cannot access, The BBS02 clutch has fairly low drag on the pedals as you may have noted by now.

In fact, on the first big ride with my BBS02, 32 miles up and down the Chicago lakefront. I lost power 50 feet after leaving the parking lot. My battery worked on my wife's bike, as did hers. But nothing worked on mine. So I pedaled the whole 32 miles. When I got home, I found the battery receptacle was just loose. Whew. An easy fix.

 

[tomjasz]

I use the voltage limit in the programming there’s no way to tell what the BMS limit is. On several BBSXX drives I own the BMS limit was lower than I’m comfortable with. Depending on an unknown value from the BMS is risky at best

 

[Gionnirocket]

I should amend my comment. No need to walk home if you blow a fuse you cannot access, The BBS02 clutch has fairly low drag on the pedals as you may have noted by now.

In fact, on the first big ride with my BBS02, 32 miles up and down the Chicago lakefront. I lost power 50 feet after leaving the parking lot. My battery worked on my wife's bike, as did hers. But nothing worked on mine. So I pedaled the whole 32 miles. When I got home, I found the battery receptacle was just loose. Whew. An easy fix.

Thanks Harry... That's good to know.
Maybe keep a length of rope in your emergency kit so next time she can tow you
I live in a bit of a valley and my daily ride on the rail_trail near my home has a 3 mile hill with a varying degree of slope from 10 - 30° to start off.
On a good day I power up it and can still handle a 25 mile round trip with a smile.
On a bad day it sucks the life out of me and turns my legs to overcooked egg noodles. If I end up doing 14 miles with 2 or 3 stops I feel lucky.
I'm hoping the BBS02B will help me have more good days.

I use the voltage limit in the programming there’s no way to tell what the BMS limit is. On several BBSXX drives I own the BMS limit was lower than I’m comfortable with. Depending on an unknown value from the BMS is risky at best

You lost me Thomas?
I know that you can buy a programming cable and there's a way to modify parameters of the BBS02B... but that's all I know. I figured that was something to look into after I've had the unit for a few months.
Can you elaborate on why you made the changes?
Is the software to make the changes download'able somewhere?
Danke Schoën!