Bafang BBS02 750W Mid Drive on Craigslist Hardtail

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teslanv   100 MW

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Bafang BBS02 750W Mid Drive on Craigslist Hardtail

Post by teslanv » Jan 12 2014 12:30pm

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This was my very first ebike build, after becoming interested in the technology last fall.
I was looking for a set-up that could handle the numerous hills I have on my 20-mile round-trip commute from my Home in Bellevue, WA to the jobsite where I work on Mercer Island.
After some research and some excellent feedback from forum members like dogman and spinningmagnets, I decided that I wanted the versatility of a Mid-drive that could take advantage of my bicycle's rear gears.
I also am experimenting with recycled laptop cells and building my own battery, but after some persuasive arguments from dogman in particular, I caved and went with HK LiPo's - And I am glad I did. They have an excellent power to weight ratio and are very reasonably priced. - Be aware that LiPo's can be more dangerous (i.e. - fire) than other battery types, so following safety precautions like monitored charging, fireproof enclosures/bags and careful electrical connections is a must.

The Battery:
Here is the HK LiPo pack I assembled.

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The Cost of this 12S - 10AH pack is $165 SHIPPED from the US Warehouse. (not including the custom wiring harnesses or charger)

And here is the web link for the packs I purchased:

http://www.hobbyking.com/hobbyking/stor ... _pack.html - If you are in the US, make sure you select the US Warehouse, otherwise you'll pay a boatload to have it shipped from China.
My Pack is (6) of these 4S packs run 2 parallel and 3 in Series for a total of 12S (44.4V nominal/50.4V Max) and 10AH

Charge & Connection Harness:
I tried buying a harness kit from iceman http://lipoconnectionsolutions.com/ but he had quite a backlog at the time, so I built my own harness. His videos and photos are quite helpful, and I had no trouble assembling the harness. Parts sourcing was from hobbyking - mostly the 4mm Bullet connectors and Silicone wiring. - The 4mm Bullets are quite easy to solder - much easier than soldering a Deans (T) connector, which I used on some of the other connections.

I made 3 sets of parallel harnesses that join two LiPo packs, plus one extra connector on each harness for a third parallel pack for future upgrades. (I taped off the extra connector on each parallel harness so it won't accidentally get connected until I am ready).

Image

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Then I made a 3S Serial Harness. The Serial harness is routed through a small hole in the triangle pack and stays in there at all times. (I can't charge it at 12S anyways, since my charger will only charge up to 6S Packs.)

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When I am ready to charge my pack, I remove the serial harness and set my pack in a fire-proof enclosure (repurposed Brinkman BBQ/Smoker) Then I just have to connect the three parallel leads from the pack to a parallel charge cable which is connected to my charger and plug in the 6P Balance cable harness if I want to balance the pack.

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The connections to the charger are ALL parallel, so the charger only sees one big-ass 4S, 30AH battery pack.
This set-up makes it nearly impossible for me to connect the pack wrong - (The main cause of KFF - Look it up if you want to see pics).

The Charger:
For charging, I started out with an Imax B6 Charger. It's only rated for 50W, so it took a LONG time to fully charge the 12S-10A Pack. (I charge it in 4S x 6P) The pack has 444 WH of capacity, so it took almost 9 hours to fully charge at 50Watts. I have since upgraded to a 200W iCharger 106B+ as shown here: https://www.hobbyking.com/hobbyking/sto ... arger.html - 5 times the power. Except that my power supply (an Old Asus Desktop PS) could not handle the 250W for some reason - it made a terrible screeching noise.. So I bought a 700W Dell Server Power Supply off ebay and converted it to power the HK Charger. - Again iceman sells these pre-built for RC Chargers and has good photos of how to convert them.

The Frame:
I had originally planned to install a kit on my '98 Giant Rinkon. - I spent a Saturday afternoon making my 20-mile round trip commute on this bike, just to assess the difficulty without electricity. - I am 5'10" and 190 lbs - Not particularly in shape, but not obese, either. - The ride kicked my ass. With no suspension and V-Brakes, I knew there had to be better options so I started scanning my local craigslist for a Hardtail with disc brakes, and I found this Iron horse Maverick SE 5.5 (well-used) for $100 http://www.performancebike.com/reviews/ ... usive.html
The Rear Cogs and chain were pretty worn, and I knew the Mid Drive would be working those components pretty hard so I replaced them with an SRAM PG850 11T-32T 8-speed Cassette and PC 850 Chain, as well as replaced the derailleur/shifter cable. The suspension forks are nothing special, but the headset is standard, so I can change those out when my budget allows. - The Giant Rinkon had a non-standard headset, so not many options there to upgrade.

The Kit:
I wanted a motor that could handle the numerous hills I have on my commute. The options finally came down to a MAC 12T Geared Hub or a mid-drive. The issue with the Geared hubs is the high-power requirements for the steep, long hills I have to contend with. - And I did not want to tax the battery to get up the last big hill on my way home - So it was down to the mid-drives.
I looked at the GNG Mid Drives, but after reading reviews about the cranks being of low quality, I decided against the GNG drives.
Spinningmagnets wrote a great article on Electricbike.com http://www.electricbike.com/bafang-bbso ... mid-drive/ which convinced me to go with the Bafang BBS02 750W Unit.
I ultimately found it here http://lectriccycles.com/products/750-w ... ersion-kit from lcrewse. - Cheaper purchasing options from China do exist, but I believe in supporting the local (USA) economy and also value the added service and responsiveness of a US Supplier, and http://lectriccycles.com/ has been wonderful to work with. And the reality is that for $750 SHIPPED, It wasn't that much more than a cheaper Chinese motor or geared hub, once you factor in about $150 for shipping either of those from China.
I chose to order the Bafang with the speed limited to 31 MPH (50KPH) but lcrewse can also program it for unlimited speed. I also had the LVC set to 38V, since I was using a 12S (44.4V Nom) pack, but after some further research, I think that LVC is too low for a HK LiPo battery - 42v LVC is probably more appropriate for a 12S pack. - I added a wattsup meter to monitor the pack voltage.
Performance has been great, although we are still working through some minor details with regard to the PAS Settings. According to lcrewse, the 5-level PAS Settings should correspond to 20% increments in current between the levels, but a couple of us have experienced slightly different increments. I find the best PAS setting for me is on level 2 of 5, but since the number of PAS levels is user-selectable, I am going to try increasing to 9 levels to see if I can get a finer range of assist wattage. The lag of start and stop for the PAS is noticeable, as it is based on cadence and not torque. Bafang is reportedly working on a torque sensor option, but is having difficulties with it.
Up-shifting under power worries me, and I try not to do it. Using the PAS exclusively, this means having to pause your cadence briefly before you up-shift. Down-shifting seems to be less of an issue. - Of course this is all about the quality of your drive-train. A reliable IGH would be a sweet set-up with this mid-drive in my opinion.

The Details:
I bought the largest Triangle Bag I could find on Amazon. This one fit my bike nicely and also fits the battery pack comfortably. http://www.amazon.com/gp/product/B006JA ... UTF8&psc=1
It is very streamlined and keeps the bike agile and well-balanced. The bike with the motor & battery weights in at 49.0 lbs., which I think it quite reasonable for an ebike.
I have plans to add a rear rack and mount up a 50-Cal Ammo Can for the battery enclosure. - This would allow me to fit up to 30AH of HK Lipos or to house my hybrid HK LiPo/laptop LiCo pack when I complete the Laptop Pack. - It's also very fire-proof as battery enclosures go. - But I would probably not ride like this unless I had a really long ride planned. The triangle bag I have now is a great solution for my planned 20-mile commute.
I also added a knock-off wattsup meter http://www.amazon.com/gp/product/B00C59 ... UTF8&psc=1 since the Bafang Display does not provide detailed battery info - just a battery meter bar.

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Overall Impressions:
I am so glad I went with the Bafang BBS02 750W Mid drive for my first ebike project. It was incredibly easy to install as a novice builder, as all the wiring connections are idiot-proof as well as water-proof, the controller is built into the drive unit and the display unit is quite useful and included in the purchase price. lcrewse is great to work with, and I highly recommend that you purchase from him, especially if you are in the US. And this bike is a blast to ride. - I find myself smiling uncontrollably every time I peg the throttle.
Last edited by teslanv on Mar 30 2014 4:28pm, edited 11 times in total.
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Re: Bafang BBS02 750W Mid Drive on Craigslist Hardtail

Post by spinningmagnets » Jan 12 2014 1:55pm

I am so glad I went with the Bafang BBS02 750W Mid drive for my first ebike project
I'm afraid you're going about this all wrong. You're supposed to buy a super cheap hub-motor that is completely ill-suited to the commute that you intend to use it on, then, in order to "save some money", you're supposed to buy a generic "no name" battery pack that's way too small. Then...when you have one problem after another, you would truly appreciate a good kit when you finally get one...after a seemingly unending series of component failures.

If you buy a good kit right off the bat, and immediately pair it with a good battery, then...your posts will end up being short...with no questions for any of us to answer. How do you expect to make any friends if you don't let us help you out, huh?

I tell you...these new posters?...sometimes I just don't know what to think about them.

edit: get a suspension seat post: http://www.electricbike.com/suspension-seat-posts/

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Re: Bafang BBS02 750W Mid Drive on Craigslist Hardtail

Post by teslanv » Jan 12 2014 3:07pm

spinningmagnets wrote:
I am so glad I went with the Bafang BBS02 750W Mid drive for my first ebike project
I'm afraid you're going about this all wrong. You're supposed to buy a super cheap hub-motor that is completely ill-suited to the commute that you intend to use it on, then, in order to "save some money", you're supposed to buy a generic "no name" battery pack that's way too small. Then...when you have one problem after another, you would truly appreciate a good kit when you finally get one...after a seemingly unending series of component failures.

If you buy a good kit right off the bat, and immediately pair it with a good battery, then...your posts will end up being short...with no questions for any of us to answer. How do you expect to make any friends if you don't let us help you out, huh?

I tell you...these new posters?...sometimes I just don't know what to think about them.

edit: get a suspension seat post: http://www.electricbike.com/suspension-seat-posts/
Yeah, I guess that's what I get for reading up on ES BEFORE I Made my purchase. - Lesson learned :D
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Re: Bafang BBS02 750W Mid Drive on Craigslist Hardtail

Post by teslanv » Jan 12 2014 7:43pm

I test-rode my commute today and here is the latest performance data:

Adjusted the PAS setting to 9 levels.

My Commute is quite hilly.

First half of Ride I used only PAS Level 3 of 9, and no throttle.

10.2 Miles, 45 minutes, 13.6 MPH average including stop lights & hills.
2.7AH of my 10AH Pack Consumed
136WH Used
13.3 WH/mile (8.33WH/km)
612W Max Watts
300-500 Watts average
Estimated Range at this PAS Level: 33 Miles

Second Half of the ride I used PAS level 4 of 9, and no throttle.
10.2 Miles, 35 Minutes, 17.5 MPH average including stop lights and hills.
5.08 AH Consumed
226 WH used
22.2 WH/Mile (13.85 WH/km)
752W Max Watts
16.5A Max Current (1.65C)
500-700 Watts Average
Estimated range at this PAS Level: 20 Miles

Full Ride
20.4 Miles, 1Hour, 20 minutes, 15.3 MPH including stop lights and hills
7.78 AH of my 10AH Pack Consumed
362 WH used
17.75 WH/Mile (11.1 WH/km)

For me, PAS Level 3 of 9 seems to be the sweet spot for exercise and range.

This Kit & Bike are AWESOME!!!
Last edited by teslanv on Jan 12 2014 11:06pm, edited 1 time in total.
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Re: Bafang BBS02 750W Mid Drive on Craigslist Hardtail

Post by teslanv » Jan 12 2014 7:50pm

Stealth:

Today Going down the largest hill on my commute, I got the speed up to ~40 MPH (64 km/h).

(I wasn't using electric assist at that time.)

When I get to a stop light at the end of the run, a cop pulls up beside me and says, "You were going over 35 MPH [posted speed limit] down that hill." Then he smiles, gives me the peace sign and drives off.
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Re: Bafang BBS02 750W Mid Drive on Craigslist Hardtail

Post by Rollodo » Jan 15 2014 4:34pm

teslanv wrote:When I get to a stop light at the end of the run, a cop pulls up beside me and says, "You were going over 35 MPH [posted speed limit] down that hill." Then he smiles, gives me the peace sign and drives off.
We need more of these here in NY.
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Re: Bafang BBS02 750W Mid Drive on Craigslist Hardtail

Post by teslanv » Jan 15 2014 5:01pm

Rollodo wrote:
teslanv wrote:When I get to a stop light at the end of the run, a cop pulls up beside me and says, "You were going over 35 MPH [posted speed limit] down that hill." Then he smiles, gives me the peace sign and drives off.
We need more of these here in NY.
Easy going police or Bafang Mid Dives? - I am guessing both ;)
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Re: Bafang BBS02 750W Mid Drive on Craigslist Hardtail

Post by teslanv » Jan 17 2014 10:11am

2nd day of commute and I upped the PAS assist to level 4 of 9, and used the throttle on occasion.

Distance of 10.2 Miles
243.4 WH consumed
23.9 watts per mile
Approx. 45% of battery life remaining for the ride home, but I brought a charger to recharge. - Otherwise I could have stepped the PAS down to level 3 and comfortably made it home.

Next on the purchase list is a full-face helmet. It was <40 degrees F and quite foggy this morning. My face went numb and watery eyes reduced vision.
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Re: Bafang BBS02 750W Mid Drive on Craigslist Hardtail

Post by Rusty123 » Jan 17 2014 12:32pm

teslanv wrote:Next on the purchase list is a full-face helmet. It was <40 degrees F and quite foggy this morning. My face went numb and watery eyes reduced vision.
I've had to adjust my clothing as well (higher speed, less exertion). Before you invest in a full face helmet, you might try a balaclava (I use one from Pearl Izumi, which is thin enough to fit under my helmet without adjustment). I also wear wrap around glasses (I use photo-sensitive safety glasses, which are clear at night, and tinted during the day), which prevents the watering eyes.

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Re: Bafang BBS02 750W Mid Drive on Craigslist Hardtail

Post by teslanv » Jan 17 2014 12:38pm

Yes, definitely the balaclava would be nice.

I wear prescription glasses, so I am not sure how to deal with the wind-burned eyes, though... Might just have to go back to contact lenses and wear ski goggles or something.
Last edited by teslanv on Feb 22 2014 10:28pm, edited 1 time in total.
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Re: Bafang BBS02 750W Mid Drive on Craigslist Hardtail

Post by Rusty123 » Jan 17 2014 1:27pm

teslanv wrote:Yes, definitely the baklava would be nice.

I wear prescription glasses, so I am not sure how to deal with the wind-burned eyes, though... Might just have to go back to contact lenses and wear ski goggles or something.
A set of prescription sports glasses (I like the wrap-around style) might be a good investment (and not just for cycling).

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Re: Bafang BBS02 750W Mid Drive on Craigslist Hardtail

Post by teslanv » Jan 19 2014 12:44pm

Reading through the Nuvinci Developer Kit string on ES and am starting to warm up to it.

http://endless-sphere.com/forums/viewto ... &start=360

@drewjet claims it has an efficiency loss of ~8%, which seems acceptable if it dramatically improves the ride by eliminating the shifting.

Purchased a kit from ebay, and now trying to decide if I want to install it on this bike, save it for a different build or just off it. (Overall I can't find much to complain about with this bike - Just something inside me want to keep tinkering.)

I think overall the Nuvinci is well-suited to this bike, If I am willing to give up a little efficiency.
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Re: Bafang BBS02 750W Mid Drive on Craigslist Hardtail

Post by Tom L » Jan 20 2014 4:08pm

The N360 won't shift under load. http://turbobobbicycleblog.wordpress.co ... les-style/

EDIT: just noticed you meant the previous version not the N360. Sorry.
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Re: Bafang BBS02 750W Mid Drive on Craigslist Hardtail

Post by Kai » Jan 20 2014 4:26pm

Rusty123 wrote:
teslanv wrote:Next on the purchase list is a full-face helmet. It was <40 degrees F and quite foggy this morning. My face went numb and watery eyes reduced vision.
I've had to adjust my clothing as well (higher speed, less exertion). Before you invest in a full face helmet, you might try a balaclava (I use one from Pearl Izumi, which is thin enough to fit under my helmet without adjustment). I also wear wrap around glasses (I use photo-sensitive safety glasses, which are clear at night, and tinted during the day), which prevents the watering eyes.
I use this motorcycle visor attached to my helmet with 3 snaps. No more watery eyes!
http://www.ebay.com/itm/UV-Light-Smoke- ... 04&vxp=mtr

To attach this your bicycle helmet, you can use cable ties, or install snaps on your helmet. They are same snaps as are used in icehockey helmets. Sport stores selling icehockey stuf have these snaps. Next I have to get a half face mask to protect my lower face from wind chill. Temperature outside is now -22 C or -7.6 F. Ouch!

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Re: Bafang BBS02 750W Mid Drive on Craigslist Hardtail

Post by teslanv » Jan 20 2014 7:57pm

Tom L wrote:The N360 won't shift under load. http://turbobobbicycleblog.wordpress.co ... les-style/

EDIT: just noticed you meant the previous version not the N360. Sorry.
Yeah, from the info I've seen the N171B units are a bit more heavy duty than the N360's, and also the automatic version uses a 4-turn vs a 2-turn gearing for the manual, which would make at twice as easy to upshift (in theory).

Still not sure about the Efficiency loss, though. Reports are all over the map on it, and I think may come down to the specific rear sprocket gearing, and how one programs the shift profile. (excel spreadsheet)

I am so temped to get mine laced up and start experimenting.
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Re: Bafang BBS02 750W Mid Drive on Craigslist Hardtail

Post by teslanv » Jan 21 2014 10:26am

Balaclava cured the frozen face. - Was way too foggy for ski goggles, though. It got pretty sketchy the last 2 miles into work. Fog was bad.
Last edited by teslanv on Feb 22 2014 10:29pm, edited 1 time in total.
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Re: Bafang BBS02 750W Mid Drive on Craigslist Hardtail

Post by Rusty123 » Jan 21 2014 11:36am

teslanv wrote:Baklava cured the frozen face. - Was way too foggy for ski goggles, though. It got pretty sketchy the last 2 miles into work. Fog was bad.
I had the same problem today -- had to take my glasses off. The fog particles in the air were collecting too heavily. I have the same problem when it rains hard.

I wonder how the motorcycle guys deal with it -- maybe the 60 mph wind clears it off.

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Re: Bafang BBS02 750W Mid Drive on Craigslist Hardtail

Post by teslanv » Jan 21 2014 12:50pm

Staring a ride log, so I can chart my efficiency to get a good baseline. Then I plan on installing and experimenting with the Nuvinci N171B Autoshifter to test efficiency.
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Re: Bafang BBS02 750W Mid Drive on Craigslist Hardtail

Post by Tom L » Jan 21 2014 5:37pm

This is probably not much good for fine fog particles but may be worth a try: http://www.rainx.com/ After a new coat I don't need to use my windscreen wipers.

For anit-fogging inside full face helmets these work great: http://www.foggoff.com.au/

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Re: Bafang BBS02 750W Mid Drive on Craigslist Hardtail

Post by hcrider » Jan 23 2014 11:17am

I have a late 70's Skid Lid bicycle helmet with 3 snaps and attach a motorcyclist bubble shield for cold weather riding, along with wearing a neck warmer and ski cap under the helmet. It really works well.

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Re: Bafang BBS02 750W Mid Drive on Craigslist Hardtail

Post by teslanv » Jan 25 2014 11:05am

Tried the ski goggles over glasses again this morning, and had better luck. No quite as foggy, and I kept the baklava over my mouth which directed my CO2 away from the lenses. Also helped that my ride was an hour later, and vision was improved with more daylight.

After 150 miles of riding I have dialed my efficiency to 14 Watts per mile, by using PAS 3 of 9 and no throttle.

However, I have noticed that when I pedal going downhill, I am still using watts that I really don't need, so I have adjusted my Max Speed to 22 MPH (35 kph) to cut off assist when going downhill. (I generally don't get much over 19-20 MPH unless going down hills). We will see if that helps efficiency much.
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Re: Bafang BBS02 750W Mid Drive on Craigslist Hardtail

Post by Rusty123 » Jan 25 2014 11:37am

I have a 350W/36V, vice your 750/48, but I've noticed that the PAS assist steps don't seem very even. When I had the increments set to 5, there was a big jump between 2 and 3, but not so much between 1 and 2, or between 3, 4 and 5. I switched the controller to 9 steps, and now the big jump seems to occur between 5 and 6. Have you seen that?

Also, do you have any idea what the different PAS levels actually control? I assumed they governed the maximum output in amps or watts, but I'm beginning to wonder if they actually control the max assisted speed at each level.

I don't have a wattmeter yet, or I would know for sure. I'm just going by seat of the pants. What has your wattmeter shown?

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Re: Bafang BBS02 750W Mid Drive on Craigslist Hardtail

Post by teslanv » Jan 26 2014 9:53am

Email Conversation with lcrewse a couple weeks ago, before adjust PAS setting to have 9 levels:

LeGrand,

I finished the kit install and have been testing out the kit the last few days.

I am curious how the PAS Levels are programmed, and if they could be "fine-tuned" by your software...

I have tested the 5 PAS settings and I am coming up with the following results:

PAS Level 1 - Max of 220W assist
PAS Level 2 - Max of 776W assist
PAS Level 3 - Max of 1022W assist
PAS Level 4 - Max of 1022W Assist (No difference from Level 3)
PAS Level 5 - Max of 1156W Assist (25.3A/Max Possible Current)

There seems to be a pretty big range gap between PAS Levels 1 & 2.

Can the PAS Levels be programmed to output a specific max current at a given setting?

For example, could the 5-level PAS be programmed for:

Level 1: 5A Max
Level 2: 10A Max
Level 3: 15A Max
Level 4: 20A Max
Level 5: 25A Max

and could the 9-level PAS be programmed for:

Level 1: 5A Max
Level 2: 7.5A Max
Level 3: 10A Max
Level 4: 12.5A Max
Level 5: 15A Max
Level 6: 17.5A Max
Level 7: 20A Max
Level 8: 22.5A Max
Level 9: 25A Max

In my opinion, this would nearly perfect the PAS System.

I am not necessarily looking to send my unit back in, but to optimize the user experience for future purchasers.

Overall and I quite happy with this kit, and have nothing but great things to say about it, and about your service.

Regards,

teslanv


Response:

Thank you for the input. We actually had another customer just contact us about the same issue a few days ago. We will be testing further and making adjustments as there seems to be a discrepancy in how we program these and what the actual output is. We program them in 20% increments based on current. Any other feedback you have would be appreciated. Thanks.
DD Hubs, Batteries, Controllers & Custom Ebikes.
http://westcoastelectrics.com
West Coast Electric Cycles
Bellevue, WA
USA

Rusty123   100 W

100 W
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Location: Washington State, USA

Re: Bafang BBS02 750W Mid Drive on Craigslist Hardtail

Post by Rusty123 » Jan 26 2014 10:45am

Pretty much in line with my seat of the pants observation. With the expending popularity of this kit, maybe we'll be able to do some custom programming in the field. Thank you.

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teslanv   100 MW

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Re: Bafang BBS02 750W Mid Drive on Craigslist Hardtail

Post by teslanv » Jan 26 2014 10:58am

My "scientific Testing" consisted of riding up the steepest hill in my neighborhood in 4th through 6th gear, repetitively, starting at PAS level 1 of 5, noting the max Watts of draw over the course of 3 or 4 runs, and then repeating for each PAS level up to 5 of 5.
I intend to repeat this test with the PAS now set to 9 levels, also noting max amps, since my battery gradually depletes and Amps will give a more accurate reading than watts.

Rusty123, I highly recommend buying a cheap <$30 Watt meter, as it will provide you with a lot of valuable battery info, and is pretty easy to wire in.
DD Hubs, Batteries, Controllers & Custom Ebikes.
http://westcoastelectrics.com
West Coast Electric Cycles
Bellevue, WA
USA

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