Bafang 250Watt setup advise

Hi there!

I'm a newbie about the sell my motorcycle and embark on the path of becoming a cyclist (again) with a ebike Mid drive engine for health reasons (i use to be 90 kgs as a cyclist) and gained about 30 kgs riding a motorcycle since you can just drive right up to anywhere you want to go and just park there.

Due to legal reasons here, we can only have ebike engines upto 250 watts and i live in one of the hilliest places in Australia. So i'm looking for some feedback if a Bafang 250watt mid drive engine + a battery pack from say http://em3ev.com would be sufficient / would have enough torque to reliably get me up hills with my weight with some pedal assistance. The bike i'm planning to use is a decent (not too heavy) hybrid bicycle. My concern is whether or not this engine would have overheating issues or simply is upto the task to getting me multiple hills from a aprox 20km (12.4miles) journey.

I'm not too fussed about speed, I'm more concerned about the assistance that a 250watt mid drive engine can give me uphill... Can someone sort out the kind of experience i would get from this setup? Would i much better off with a 500watt setup?

Your feedback would be very much appreciated!

The great thing about the 250 watt version of the Bafang mid-drive is that it is stamped 250 watts which will meet your laws, but it actually puts out 540 watts - 36volts X 15 amps.

I have a BBS02 and use it regularly set between 400 watts and 500 watts and it provides enough power for my commutes for me to rid along at about 20 miles an hour with easy pedaling on a hybrid upright bicycle.

mclark999 said:

The great thing about the 250 watt version of the Bafang mid-drive is that it is stamped 250 watts which will meet your laws, but it actually puts out 540 watts - 36volts X 15 amps.

I have a BBS02 and use it regularly set between 400 watts and 500 watts and it provides enough power for my commutes for me to rid along at about 20 miles an hour with easy pedaling on a hybrid upright bicycle.

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Thanks for the info mclarke999! Good to know haha, i did some reading about the BBS01... It seems some people had overheating issues with it? Has it been updated with the the safety systems that the BBS02 has?

Also, I've got another question if the bafang will any issues with bicycle that has two chain rings in the front... And in regards to providing the bafang engine with more amps, do i need an after market controller? If so any suggestion on controller?

Thanks!

The continous output of my Bafang 250 W up a steep hill at max load is over 400 W. I measured 400 W output with a close to empty battery at 15 A. A full battery would yield a higher rpm and thus more power. I used a rear wheel power meter. I measured the overall efficiency of the motor to ~78%. Mine has yet to overheat when used in the summer in hilly terrain.

The same goes for other OEM mid drives and hubs, For example the Bosch, so it's not unique for Bafang. The nominal power rating is 250 W.

And in regards to providing the bafang engine with more amps, do i need an after market controller? If so any suggestion on controller?

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Nope. It's rated at the higher amperage. As another person added, it will run at 400 watts continuously without overheating.

Hi guys! Thanks for the information. I've been looking at the Bewo Kit and there's an shop here that stock it and have it on their bikes... I'm going to give it a test drive... It looks like a good bit of kit, the metal internals of the engine looks more durable?

Got a few lumps and bumps round me in Perth - the 250w systems certainly helps up hills never dropping below 20 km/h and the BBS01 is good.

I have a single ring on the front, 9 on the rear - mate said my cluster at the rear looked like it had problems as it was rusted....Quick down shifts solved the rust discolouration - then I realised that I had only used the highest 5 out of the 9 cogs on the rear in 3 months......you may therefore not need 2 chain rings on the front - how hilly is hilly?

Tats said:

Got a few lumps and bumps round me in Perth - the 250w systems certainly helps up hills never dropping below 20 km/h and the BBS01 is good.

I have a single ring on the front, 9 on the rear - mate said my cluster at the rear looked like it had problems as it was rusted....Quick down shifts solved the rust discolouration - then I realised that I had only used the highest 5 out of the 9 cogs on the rear in 3 months......you may therefore not need 2 chain rings on the front - how hilly is hilly?

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Hi Tats! Sorry about the late reply... I didn't really know how to describe the degree/grade of the incline of the hills around my area... But i have now found a graph via http://en.wikipedia.org/wiki/Grade_%28slope%29. I would estimate 30% (16.70) to 50%-70% hills that go one for a few go on and on a few kilometers at a time

Another question for you all, I'm looking for a battery + battery rack (pannier rack) that i can use for a bafang / Bewo kit... Any suggestions?

That's pretty hilly but a 250w will help if you get a crank drive running through your gears. Standing while pedalling will help heaps and shouldn't be too draining for you.

My 10ah 36v ping battery is in my topeak mtx rack back on a topeak rack connected to the seatpost.

I have the exact kit referenced in the first post, from em3ev, for the same reasons. It's better than nothing but leaves a bit to be desired on the power front. Bear in mind em3ev also program to a max of 30kmish. Thats slower than on the roadie without assist and pedalling above it has the drag of the motor unit and the weight of the additional unit.

I'm now planning/ building a much higher power build (regardless of legality )..... and my commute doesn't involve any decent hills.

Btw not sure what state your in but if your planning to use a throttle or it isn't to the European standard... the threshold is actually 200w. Meh.

Hi guys

Im running some ongoing tests on the bewo here:
http://endless-sphere.com/forums/viewtopic.php?f=28&t=48449&start=200

I'm also a Bafang dealer and perhaps BEWO soon depending on how things go. At this stage though I can't recommend over a BBS01.

Lurkin said:

I have the exact kit referenced in the first post, from em3ev, for the same reasons. It's better than nothing but leaves a bit to be desired on the power front. Bear in mind em3ev also program to a max of 30kmish. Thats slower than on the roadie without assist and pedalling above it has the drag of the motor unit and the weight of the additional unit.

I'm now planning/ building a much higher power build (regardless of legality )..... and my commute doesn't involve any decent hills.

Btw not sure what state your in but if your planning to use a throttle or it isn't to the European standard... the threshold is actually 200w. Meh.

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Haha, nice to meet a fellow melbourian! Yea... It looks like the 350w Bewo might be my easiest option, the guys from justride have their shop in Melbourne and are willing to fit the kit with battery etc for me.

I'm also interested in the 500watt bafang kit... and it looks like em3ev.com have a nice kit, but their biggest frame kit has only a 9.8AH capacity... Is this enough (my daily commute is around 20 or 40 km)? I think the most practical capacity would be 14+AH? I would like to build a bicycle with the rectangle type battery mounted on a bicycle pannier rack... any suggestions how i go about this?

chronosoft said:

Lurkin said:

I have the exact kit referenced in the first post, from em3ev, for the same reasons. It's better than nothing but leaves a bit to be desired on the power front. Bear in mind em3ev also program to a max of 30kmish. Thats slower than on the roadie without assist and pedalling above it has the drag of the motor unit and the weight of the additional unit.

I'm now planning/ building a much higher power build (regardless of legality )..... and my commute doesn't involve any decent hills.

Btw not sure what state your in but if your planning to use a throttle or it isn't to the European standard... the threshold is actually 200w. Meh.

Click to expand...

Haha, nice to meet a fellow melbourian! Yea... It looks like the 350w Bewo might be my easiest option, the guys from justride have their shop in Melbourne and are willing to fit the kit with battery etc for me.

I'm also interested in the 500watt bafang kit... and it looks like em3ev.com have a nice kit, but their biggest frame kit has only a 9.8AH capacity... Is this enough (my daily commute is around 20 or 40 km)? I think the most practical capacity would be 14+AH? I would like to build a bicycle with the rectangle type battery mounted on a bicycle pannier rack... any suggestions how i go about this?

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Make sure they use locktite on the main bottom bracket nut. It comes loose very frequently. Probably the only downside of this little kit.

We should organise a group ride at some point.

If you're planning on buying a Bafang kit, might be an idea to look to local suppliers. If anything goes wrong with the kit from Em3ev, you would either need to sort it remotely with Paul's help or ship it back to him. Dillenger Australia sells these kits. Don't just compare costs based on the first page - there are paypal fees, conversion rates etc that sting using Em3ev - need to go right through their 'add basket process' to get a 'real' understanding of what it would cost.

Having said that, Em3ev has an excellent reputation and I had no issues with my stuff from them. I will be buying any pre bulit batteries from them in the future. It might be an idea to buy the kit locally and the battery from them?... My kit was 36v so I went for the biggest 18650 cell battery they sell. I get about 80km out of each charge @ average speed of around 30km/h.

Fitting the kits isn't difficult, I installed my own. I wouldn't be paying someone else to install it unless I needed a warranty from them.

Per eMax's comments - a decent lockring spanner is a good tool to have. I didn't use loctite and it kept coming undone, until I bought a Park Tools lockring spanner (made it fit), greased the threads and then did it up (extremely tight). The grease allows a 'greater tightness' to be achieved without loctite.

I did a similar process to what you are doing - went round all the ebike shops in Melbourne to get some decent advice/see what they had. Most didn't want to know me unless I said I wanted 250w or below.

I found MySpokes in... Abbotsford? the best. The guys there have been selling bikes for a long time and are not scared of higher power. Further, they skipped the sales speak and helped me out mechanically with a few questions. Decent blokes.

As for things to check:-

- Bottom bracket width 68mm?
- Clearance around where the unit will live
- work out your battery requirements before guessing which battery to buy.

The next kit I buy will be a hub motor kit to avoid using the crank area of the frame...

You should check out the AFW kits too - they are more expensive but the weight is lower for the same product. The only reason I wouldn't go for them is that they stick out like dogs balls.. not a good combination with something illegal.... (would be greater than 200w)

Lurkin said:

The next kit I buy will be a hub motor kit to avoid using the crank area of the frame...

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+ 1 Getting tired of trying to get the programing right, the chain line right and hence the shifting reliable and now getting the right crank arm off ... One more set of attempts to get this right and if it does not work it will go the market to be replaced by a MAC rear hub build.

Andrew

We did have a good group ride in Melb last week as part of the EV show. I fit a lot of 250W units for customers at the top of our local hills. If you gear them right they can still generate enormous torque for a small amount of power.