BBS02 pre-purchase advice

[Claymore]

Hi there, I posted here a while ago enquiring about a Bosch bike for my daily commute, but I think I've decided that a Bafang BBS02 750w at 48 volts is the right way for me to go.

I have a reliable and reasonably nice Boardman hardtail MTB that I currently commute on and I want to convert this with the BBS02.

Firstly, what are my buying options? I've been looking at EM3ev in Hong kong and Eclipsebikes in the UK - are there any other retailers I should be looking at?

EM3ev appear to have more options for the buyer and a provide the ability to specify exactly what I want (such as a C963 display), but some options mystify me (low voltage cut and ebrake options - I want to keep my very good hydraulics). Can someone explain? I also imagine import tax could sting me hard?

The last piece of the puzzle is the battery type, size and charger, I'm more than happy to spend the required money here, but I don't want to lug around battery weight that I don't need. My journey in is on road and 7.8 miles with 338 ft of elevation, the journey home is the same distance with 600 ft elevation. So give or take 16 miles a day and 1,000 ft of climbing.

I don't want to have to charge at work, but will consider it if anyone thinks it's a good idea. I want a bit of power so 48 volts is required, but any suggestions for amp hours required? I am frustratingly sometimes fit to ride and sometimes not, so my assistance can't always be relied upon due to health issues.

Finally is there anything else I need to consider?

Many thanks for any assistance provided.

 

[KirstinS]

The 750w 48v needs a battery capable of giving up to 30a.

I wouldn't worry about shaving a couple of kilos of battery weight. Sort of meaningless with an ebike as you simply won't notice the difference.

To really reduce weight and retain the ability to get the required 30 a you'd need to go Lipo. This requires extra safety measures, a reasonable level of electrical knowledge ( or time and willingness to learn). It is a more dangerous battery Tech and is not plug and play. Plenty of diy ebikers do use them but they are certainly more hazardous.

Woosh bikes in Southend sell these kits , a matching normal lithium battery using top notch Samsung cells and charger. They have an excellent reputation on this forum.

Id post the link but I cannot seem to find it on their mobile version website

 

[Deleted member 4366]

The 09 bottle batteries are often used with that motor. If you get one with branded cells, they're rated at 20A continuous, so will be OK for occasionally reaching your 25A max. 11. Ah should be enough. Keep away from LiFePO4 batteties because they're very heavy. The weight will spoil your ride, especially if you can't get it in the triangle.

 

[delboy55555]

I am about to take the plunge and order one of these kits myself. Am put off by the thought of customs charges also? I like that em3ev say they are using the updated mosfets in the controller now though. Also how much difference would a 52v battery make over a 48v one?
Been reading this article where they recommend going for 52v; https://www.electricbike.com/bafang-bbso2-750w-mid-drive/

By my calculations its only going to make a difference of 100w over a 48v battery and the 52v batteries are harder to find so it hardly seems worth it. And what is the hot rodding thing all about will that make much difference?

 

[delboy55555]

Another thing to consider is the chainwheel size. em3ev recommend 42t? anyone know what sort of speed would that top out at with an 11t on a back wheel 26 inch?

 

[Deleted member 4366]

Unless you're involved in off-road racing, a bog-standard 48v BBS02 will have enough power. They all have the higher power mosfets now as long as you don't get an old one. Everybody keeps running out of stock, so I doubt that there's any old ones still in circulation.

As general advice, I would always say that you should stick to standard stuff that you can buy anywhere, otherwise you're knackered when things go wrong.

 

[Fordulike]

Another thing to consider is the chainwheel size. em3ev recommend 42t? anyone know what sort of speed would that top out at with an 11t on a back wheel 26 inch?

Around 30mph on a fresh battery. Only get a 42T if you have chain alignment issues, intend to ride slow technical trails, or will be climbing very long steep hills on a regular basis.

The standard chainring that comes with the kit should be fine for most riders.

 

[delboy55555]

Unless you're involved in off-road racing, a bog-standard 48v BBS02 will have enough power. They all have the higher power mosfets now as long as you don't get an old one. Everybody keeps running out of stock, so I doubt that there's any old ones still in circulation.

As general advice, I would always say that you should stick to standard stuff that you can buy anywhere, otherwise you're knackered when things go wrong.

That sounds good plan Is it true that a 48v battery with a 25a controller could put out a peak of 1200w?

Around 30mph on a fresh battery. Only get a 42T if you have chain alignment issues, intend to ride slow technical trails, or will be climbing very long steep hills on a regular basis.

The standard chainring that comes with the kit should be fine for most riders.

Is the standard chainwheel 46t? I wonder if theres anyway with a bit of custom fabrication to get a dual chainwheel setup, besy of both worlds....

 

[Deleted member 4366]

Why not change your rear cassette if you want lower gearing? That's a 5 minute job. What size gears do you have on your cassette now?

48v 25A is 1200w from the battery. Max output power will be about 900w to the chain and maybe 850w at the back wheel. My Xiongda at only 15A can get a 100kg rider up a 31% hill with moderate pedalling. That's about 350w output power from the motor. There aren't many hills that steep.

 

[delboy55555]

Why not change your rear cassette if you want lower gearing? That's a 5 minute job. What size gears do you have on your cassette now?

48v 25A is 1200w from the battery. Max output power will be about 900w to the chain and maybe 850w at the back wheel. My Xiongda at only 15A can get a 100kg rider up a 31% hill with moderate pedalling. That's about 350w output power from the motor. There aren't many hills that steep.

The rear cassette is a Shimano HG-50, 9-speed, 11-34 Tooth Range, I rarely use the smallest gear with the 22t chainwell up front but sometimes i need it for the steepest hills. Thing is i want to be able to go really fast downhill too lol. I guess its not possible to have the best of both worlds.

 

[amigafan2003]

The rear cassette is a Shimano HG-50, 9-speed, 11-34 Tooth Range, I rarely use the smallest gear with the 22t chainwell up front but sometimes i need it for the steepest hills. Thing is i want to be able to go really fast downhill too lol. I guess its not possible to have the best of both worlds.

I have a 10spd 11-36 cassette with a 42t chainring on my BBS02 - it'll climb anything I point it at and will still do 30mph on the flat* and spins out at nearly 40mph going down hill**.

*You're power limited @ 30mph on the flat - so even with a bigger chainring, you wont get above 30mph on the flat

** max rpm on BBS02 is 110rpm so 42t x 11t @ 110rpm - 38mph. 46t x 11t @ 110rpm gives 42mph - so not that much difference.

 

[delboy55555]

I have a 10spd 11-36 cassette with a 42t chainring on my BBS02 - it'll climb anything I point it at and will still do 30mph on the flat* and spins out at nearly 40mph going down hill**.

*You're power limited @ 30mph on the flat - so even with a bigger chainring, you wont get above 30mph on the flat

** max rpm on BBS02 is 110rpm so 42t x 11t @ 110rpm - 38mph. 46t x 11t @ 110rpm gives 42mph - so not that much difference.

That sounds good enough for me I think I might buy a couple of extra chainrings anyway maybe a 46t and a 52 just to try out for fun

 

[Kinninvie]

That sounds good enough for me I think I might buy a couple of extra chainrings anyway maybe a 46t and a 52 just to try out for fun

I wouldnt bother with a 52T on a standard bike as you run a big risk of overheating the controller.
Better getting a standard 44T and maybe a 48T for speed .
I run a 44T with an 11-34T casette on my 29er and it pulls my 17 stone and 6Kg of batteries up even the biggest hills up here in the Pennines.
My batteries are 44.4V nominal and my BBS02 maxes out at 1150W.
It will do 34Mph on the flat as long as there is no headwind..

 

[delboy55555]

I wouldnt bother with a 52T on a standard bike as you run a big risk of overheating the controller.
Better getting a standard 44T and maybe a 48T for speed .
I run a 44T with an 11-34T casette on my 29er and it pulls my 17 stone and 6Kg of batteries up even the biggest hills up here in the Pennines.
My batteries are 44.4V nominal and my BBS02 maxes out at 1150W.
It will do 34Mph on the flat as long as there is no headwind..

Thanks for the info, what kind of range do you get? and what AH are your batteries?

 

[Kinninvie]

I use 16Ah Multistar LiPo and have 6 so thats 48Ah.
I get around 150 miles out of them.

 

[delboy55555]

Why not change your rear cassette if you want lower gearing? That's a 5 minute job. What size gears do you have on your cassette now?

48v 25A is 1200w from the battery. Max output power will be about 900w to the chain and maybe 850w at the back wheel. My Xiongda at only 15A can get a 100kg rider up a 31% hill with moderate pedalling. That's about 350w output power from the motor. There aren't many hills that steep.

My cassette is a 11-34t i believe, Ive tried riding the bike as it stands with the 44t chainwheel up front and using the
34t at the rear and getting up some of the very steep hills where i live takes some serious effort. I am fairly fit but would like to make life easier and not turn up at work sweating and knackered before a 10.5 hour shift, then having to repeat the journey home. I magine the electric motor will make a big difference but will it cope with some really silly welsh gradients? Plus have some battery life left? I currently
About a 10 mile hilly commute using trails and staying off the roads obviousy for legal reasons
( i just hate getting off and walking it feels so defeatest lol.)

I really like the look of the Xiongda, I wonder would it be poweful enough off road tough and only two gears?

 

[delboy55555]

I use 16Ah Multistar LiPo and have 6 so thats 48Ah.
I get around 150 miles out of them.

That is some serious battery capacity respect! is that a bbso2 setup? what sort of power are you running and how does it cope with serious hills offroad?
must weigh a bit though?

 

[delboy55555]

I wouldnt bother with a 52T on a standard bike as you run a big risk of overheating the controller.
Better getting a standard 44T and maybe a 48T for speed .
I run a 44T with an 11-34T casette on my 29er and it pulls my 17 stone and 6Kg of batteries up even the biggest hills up here in the Pennines.
My batteries are 44.4V nominal and my BBS02 maxes out at 1150W.
It will do 34Mph on the flat as long as there is no headwind..

Thanks for the information, the em3v site seems to be big on the 42t chainwheel due to alignement issues and the chain coming off is that a problem? also do you ever break many chains?

 

[delboy55555]

Ps. to Claymore sorry if it feels ive hijacked your thread hopefully most of my questions are helpfull for you to know also

 

[Deleted member 4366]

My cassette is a 11-34t i believe, Ive tried riding the bike as it stands with the 44t chainwheel up front and using the
34t at the rear and getting up some of the very steep hills where i live takes some serious effort. I am fairly fit but would like to make life easier and not turn up at work sweating and knackered before a 10.5 hour shift, then having to repeat the journey home. I magine the electric motor will make a big difference but will it cope with some really silly welsh gradients? Plus have some battery life left? I currently
About a 10 mile hilly commute using trails and staying off the roads obviousy for legal reasons
( i just hate getting off and walking it feels so defeatest lol.)

I really like the look of the Xiongda, I wonder would it be poweful enough off road tough and only two gears?

I think I'm missing something. Aren't we talking about a BBS02, which should be able to drive a heavy rider up the steepest hills without even pedalling on a 30T rear sprocket?