Build of Bafang BBS02 from Greenbikekit

[darth_elevator]

Here are some more details on my lipo battery packs.

24.4 Amp hours in all. I haven't decided yet on a bag to use if I ever take everything I've got on a single long-distance ride.



Even though I call these my "main" pack and "reserve" pack, I've been taking both with me on nearly every ride, because I like the security of knowing I've got all that extra juice. So the reserve pack is only a reserve pack in the sense that I have to unplug the main pack and plug in the reserve pack to use it. I debated about whether to make an additional adapter that would let the entire 15Ah plug in at the same time, but for now I opted not to do that; even if I rarely used such an adapter whilst riding, I still will probably make one because it could be used to bulk charge both packs together.



I'm using the same connection method as hie2kolob used on his second build. The bullet connectors are in a square configuration with the three packs connected together in series (positives to negatives) and then the harness plugs into the last two spots. The electrical tape might be unecessary, as the connectors fit together quite snuggly, but I think it's a good precaution. I can post a closeup picture with the electrical tape removed if anyone wants one. This method greatly simplifies the wiring of the harness, but at the risk of causing kentucky fried fingers if I accidentally plug + and - of one battery into the - and + of another (hence, I pay VERY close attention when reassembling the pack).



I already had a bunch of 3-cell lipos on hand that I use for RC planes, so I made a harness that lets me easily plug in any 4 lipos of equal capacity to make an instant reserve pack. The four larger packs on the left are 5Ah packs and the eight smaller packs are 2.2Ah packs, giving a total of 9.4Ah in reserves.

 

[0utrider]

Here are some more details on my lipo battery packs.

Boy oh boy is your method a far more affordable approach to batteries. Even with 9 packs, it's under 250 bucks!

Since you have much experience with RC batteries, it's second nature for you to go this route.
I paid over twice as much for a 16s 15ah Headway pack. I guess I just need to get over my fear of the complexity of using these types of cells.
Is using about 45 volts instead of 48 volts any issue? Apparently not since you have ridden quite a bit with these packs with no problems!

 

[darth_elevator]

....Even with 9 packs, it's under 250 bucks!....

Yah, counting shipping it came to about $82 per 5Ah. That "one time offer" in your picture makes me laugh. To make the "one time offer" come up any time you want, you just have to leave the page open for awhile and it'll pop up. LOL. Or I just login and it shows me the lower price to begin with.

I had no idea a Headway pack would be twice as much. Wow! I never priced any other setup because I basically just copied hie2kolob's setup. He showed me how to wire can lights in my house, so, yah, I know I can't go wrong if I copycat him on all things electrical.

Is using about 45 volts instead of 48 volts any issue?

I would assume there wouldn't be any issues with 45 volts or lower -- aren't some people running their Bafangs with 36 volt setups? I haven't run any of my packs all the way down yet, so I can't really speak to 45 volts or lower. The lowest I've ever run my pack down to was 45.6. So all I can speak to is that I have 77 miles so far without problems running in the range of 45.6 volts to 50.2. Those are, of course, resting values. I'm guessing the voltage likely may have sagged below 45.6 under load, but I can't say for sure how much. I don't want to routinely run my individual packs to below 3.5, which comes out to 42 volts. But it will be interesting to see if I get any issues if I ever run them down below that. I do carry a low-voltage alarm with me in case I get down to the bottom 20% of the battery capacity; it plugs in to any of the balancing leads and beeps at about 120db upon a low voltage occurrence. My experience with those alarms in RC planes is that you can start getting intermittent alarms near the end of the pack. When the pack's low, if I hit full throttle, the voltage can sag low enough to make the alarm go off, then when back off the throttle, the alarm turns back off. I have a tricopter that has two voltage alarms on it; if the alarms go off when I'm using low throttle, I know it's time to land immediately; if the alarms go off intermittently with throttle spikes, then I know I've actually got at least 2 more minutes of flying time if take it easy on the throttle.

What is the nominal and maximum voltage with your setup?

 

[darth_elevator]

Woohoo! 100 miles and still rolling!

 

[0utrider]

What is the nominal and maximum voltage with your setup?

Nominal for this headway pack is 51.2. It charges to about 58.4 but quick charging kicks off after the first cell hits 3.6-3.7 then it balances and trickle charges until disconnected. At least I think this how it works. I'm learning and all this battery stuff is rather new to me.

Discharge recommendation the pack 48amps continuous with an instantaneous 150amps. I don't understand what these numbers mean in consideration that the BBS-02 which is supposedly rated to 25amps. Till I'm better educated I'll assume I'm not taxing the pack with current drain amps with the kit being used.

I'm planning to reduce the max charge voltage to 56 by adjusting a potentiometer in the charger. From my understanding, this along with keeping the batteries stored in a cool environment should lead to a long pack life.

The pack's BMS (the one represented in the pictured below is what this particular pack uses) supposedly will cut off the pack when the first individual cell drops to 2 volts or an ideal pack 32v if the cells are perfectly balanced. I'll probably not run it down to that extent often if at all. I'd like to get a user guide or manual to this BMS. No documentation came with my pack other than how to charge it.

 

[0utrider]

Woohoo! 100 miles and still rolling!

Congratulations!

 

[0utrider]

By the way, I think the company from which I got my kit got his stock from Greenbikekit as well. The item I have uses the same BMS. It’s also about the same price with shipping so he must be getting a dealer discount to be worth his while to resell it to me.
It appears my kit may be from Greenbikekit too!

 

[darth_elevator]

By the way, I think the company from which I got my kit got his stock from Greenbikekit as well....It appears my kit may be from Greenbikekit too!...

Cool! What's your serial number? Mine's 1407286971 -- first two digits mean it was built in 2014, next four digits mean it was built on July 28, and the last four digits mean it's unit number 6971. I can't remember where I saw the post explaining the serial number, nor can I remember whether the unit number means that it was 6971st unit built on that day, or the 6971st of all time.

....The pack's BMS (the one represented in the pictured below is what this particular pack uses) supposedly will cut off the pack when the first individual cell drops to 2 volts....

Thanks, I was wondering what a BMS is. I've seen lots of references to it on ES.

 

[0utrider]

Cool! What's your serial number? Mine's 1407286971 -- first two digits mean it was built in 2014, next four digits mean it was built on July 28, and the last four digits mean it's unit number 6971.

Here's the Walgoose's number: 1408077394


I guess that makes it number 7394. So that's 423 units on a production run between July 28th and August 7th. They don't seem to have a run or batch number; interesting. I guess they can assemble about 1,500 of these things a month assuming they are in continuous production.

Thanks, I was wondering what a BMS is. I've seen lots of references to it on ES.

Yep, but I still check the cells individually. Since this thing has no indicator lights or interface that I'm aware of, I don't know how to verify its proper operation unless I spot check the cells often. If it's behind a curtain, it's magic to me.

 

[darth_elevator]

1408077394

Yours is the latest production date I've seen posted.

Here are some serial numbers I found on ES. The last four digits appear to be an absolute count of all units produced. When they get to 9999, I wonder if they'll add another digit or reset the count and start counting up from 0001 again.

1310240062
1311270098
1402200272
1403110792
1407256876
1407286971
1408017088
1408077394

 

[mushymelon]

I can 1 up that just slightly.

 

[joshseitz]

Not sure that it matters, but since we're all whipping them out to compare...

1408237823 received in the States from EM3EV about two weeks ago.

 

[darth_elevator]

I can 1 up that just slightly.

Not sure that it matters, but since we're all whipping them out to compare...

1408237823 received in the States from EM3EV about two weeks ago.

LOL, awesome! It's like an auction....except with serial numbers.

Mushymelon & Joshseitz, what are you guys powering yours with?

 

[0utrider]

I have to order another one just to compete!

 

[0utrider]

Out of curiosity, I wonder if someone has a survey that can tally how many members of ES have an EBike, which type, brand, model etc.
It would be interesting to see the statistics. It seems that quite a few people are ramping up and jumping on the Bafang bandwagon and I'd like to see some trending date over time.

 

[wineboyrider]

Can't wait for the funds to come to build mine!
I have/had ezip mtn trails a cyclone setup, a bafang geared motor setup, a bmc geared motor, 9c setup and now mxus yescomusa setup. But, a BBS02 is on Santa's list right now??????

 

[joshseitz]

Mushymelon & Joshseitz, what are you guys powering yours with?

I'm using a 50V 16.5Ah (14S6P) Samsung 29E pack from EM3EV. I actually ordered a rectangle pack to go in my camel back, but was sent a triangle pack instead. Working with Paul to get it resolved. The triangle pack fits in the backpack, but is not ideal. I really wanted the Samsung 25R pack (15Ah, much higher discharge), but after a long wait the cells never emerged.

My bike is a 2006 Cannondale Prophet full-suspension (5.5" front/rear; 67.5 degree head angle). I originally thought it had a 73mm BB, but it turns out it has a 68! Chainline is near perfect with the popular (and spendy) Italian 42T chainring. With elevated chainstays for large chainring clearance, this is close to an ideal frame for this conversion. Very comfortable and stable at speed.



There is even a little triangle-shaped section in the frame near the head tube that contains the surplus cable. I plan to cut some carbon fiber or abs panels to cover that section which will also contain a little 2S lipo pack for my headlight.

I also used the left-hand paddle-style thumb throttle from Lectric Cycles. Very worthy upgrade from the standard cheapo thumb throttles we've all grown accustomed to. Throttle response is still a bit abrupt, but I plan to smooth things out once I build a programming cable. I'm just enjoying it now. I'll do more tweaking once the rain comes. I also bought Lectric Cycles' universal brake sensors for use on my hydraulics. Unfortunately they're not compatible with the latest 9FET controllers and software for some reason. LeGrand is looking into this known issue and working on a new solution. I hope he sorts it out, as they appear to be the only plug-and-play solution for hydraulic brakes.

Other upgrades coming soon include a 10-speed 11-36 Shimano Zee short cage derailleur and chain/shifter/cassette to match. Also moving to 203mm rotors and new pads. Might also end up building a heavier-duty DH wheelset. I'm heavy (220 lbs), and with the added weight of battery and motor, and my propensity for stair drops and the like it's only a matter of time before I pancake these rims.

 

[darth_elevator]

....close to an ideal frame for this conversion....

Wow! I agree! That is a SWEET ride.

 

[0utrider]

My bike is a 2006 Cannondale Prophet

Interesting! There is a person selling one on the local Craigslist.
Whoops! Make that was selling. It's gone now.

Whoops again! It was a Cannondale Scalpel Lefty not a Prophet. I got visually confused with the single downtube.

 

[joshseitz]

Scalpels are pretty sweet, but not as upright/laid back as the prophet. More cross country. Probably decent conversion candidate though.

 

[mushymelon]

Mushymelon & Joshseitz, what are you guys powering yours with?

I currently just have a test pack. 12s 5 ah lipo It makes a nice light setup. 49 lb Uphill ebike Oh Ya

I'm not sure what to go with yet maybe 29e's but my bud has just built up a battery with them and there very saggy at only 35 amps 14s 6p. Hopefully something like the 25r's or equivalent will pop up soon.

Unfortunately i'm having controller problems. Only 25 kilometres of testing on the bike stand and it crapped out.
I will post about it when the issue is resolved, thats going well so far no worries. 8)

Heres a pic of the work in progress.

 

[darth_elevator]

Sorry to hear about your controller. Is the vendor replacing it under warranty or are you doing the mosfet fix?

 

[mushymelon]

Yes there sending one out next week.

Thanks

 

[KINNINVIEKID]

Here's the Walgoose's number: 1408077394


I guess that makes it number 7394. So that's 423 units on a production run between July 28th and August 7th. They don't seem to have a run or batch number; interesting. I guess they can assemble about 1,500 of these things a month assuming they are in continuous production.

My serial is 1408087483 so thats at least 89 units in a day!
Only 48 miles done so far(built it 4 days ago) but after checking todays strava http://www.strava.com/activities/197075289 I noticed my top speed was 49.9Mph!!

So not in the 50Mph club yet but not far off and to be honest I could have gone quite a bit quicker but the bikes currently got the original Clarks CMD9 mechanical discs and they are not a patch on the hydraulics fitted to my Dillenger/Trax bike.
The bike itself is brand new and though a cheapie at £149 it seems ok apart from those brakes.

Its a hardtail unlike the Trax and to be honest I thought the Trax suspension didnt really do much until comparing it to this one,despite having an air saddle fitted its very uncomfortable on my spine and the battery rattles like mad now which it didnt on the Trax (same battery and rack).

I have quietened it a bit with a rubber bar towel but need to get some thicker rubber blocks to silence it totally.

I live in the hills of Teesdale England and this motor has opened up a lot of roads and tracks for me that I could not touch with the Dillenger 1000 watt kit.

 

[easyryder]

Nice built darth_elevador!

I'm thinking of building an electric bike.

Can you tell me how fast your bike goes?