Bafang from BMS battery advice?

[aussietc]

Hi
New to the whole scene here.
Thinking of ordering a 36V250W Bafang front kit from BMS Battery. It's the SWXU model.
Or I could purchase the 36V350W front kit - BPM model?? (Two RPM options - 201 or 393??)
And ordering the bottle style battery 36V8.8Ah.
Any suggestions/advice?

Thanks

 

[amberwolf]

order from cell_man instead; http://www.emissions-free.com/. BMSBattery doesn't have quite the perfect reputation, if you search the posts here on ES.

Or from ebikes.ca, or Methtek.

You could ask any of them for which kit would be best for your needs, too (since not every kit will work best for every terrain, commute, riding style, etc.)

 

[neptronix]

agreed, avoid bmsbattery whenever possible. You won't get any support or documentation from them.
They do not speak good english either.

 

[aussietc]

Thanks for the heads up.
What I'm looking for:
Must: a simple installation
Must: motor that can freewheel on the flats and downhill
Like: a battery within the frame (like a bottle)

 

[d8veh]

We use BMSBattery a lot on the Pedelecs UK forum. Personally, I've made about 10 orders with them and have had no problems. AFAIK no other forum members reported any problems although some got a bit nervous after waiting 5 weeks for their stuff. Their delivery times seem to be reducing from previously 5 or 6 weeks to 2 to 4 weeks for a motor built into a wheel or a battery. The rest of the stuff that's in stock takes 10-12 days.
The BPM motor is much more powerful than the SWXU and it needs 20 to 25 amps (It'll go as high as 40), so that bottle battery won't be able to supply that current. You need at least 15aH or lipos or A123 cells if you want a smaller battery. The SWXU motor is also quite good up to about 15 amps, which is which the KU63 controller supplies. That motor will go up to about 20 amps, but you wouldn't want to run it up very long hills at that current. You can get that power out of the KU63 controller if you solder the shunt, which makes it better at hill-climbing but not any faster. The 393 RPM motor is for 16" wheels and won't be suitable unless your ride is fairly flat and/or you don't weigh very much. The 201 RPM does just about 20mph. if you need more speed run it at 48v, which will give you a 33% speed increase.

To summarize:
If you want "legal" or if your lightweight and your journeys are flat get the SWXU with 8 to 10aH battery
If you have steep hills or you're heavy get the BPM with 15 to 20aH battery.

 

[miuan]

I've recently ordered a BPM kit, rim, spokes, controllers and a couple chargers with custom voltages and plugs.
From the order date to delivery in Slovakia, it all took 6 business days. Very fast! But sadly they are very poorly aware of what they sell. Don't try to ask techy questions, they don't really care.
For an e-assist bicycle, I could also recommend the MXUS geared hub. I have a MXUS DD and the lacing is very solid with thick 12G spokes. The geared is said to deliver decent torque, probably a bit more than the small Bafangs, if not as high as the BPM or MAC.

 

[neptronix]

Cell_man MXUS 350w kit or MAC 500w kit.
FalconEV triangle bag.
Add a ping pack if going lower power.. a123 pack from cell_man if you want higher power.. that's what i'd recommend.

Those bottle batteries are usually on the junky side.. don't buy cheap no-name lithium batteries; good way to end up with a multi hundred dollar useless lump down the road.

 

[aussietc]

"You get what you pay for" eh!?
Thinking of a rear rack and bag from Topeak. Wonder if his battery will fit?
Does the 500W freewheel/coast as well as the 350W?

Lower power? Ping or a123 - What is the difference?

 

[d8veh]

"You get what you pay for" eh!?
Thinking of a rear rack and bag from Topeak. Wonder if his battery will fit?
Does the 500W freewheel/coast as well as the 350W?

Lower power? Ping or a123 - What is the difference?

Don't waste money on an expensive bag. Buy a football boot bag for about $10, cut a piece of plywood the same size as the inside base. Put the plywood in and bolt the whole lot to your rack. get one with a zip that runs round the top as it's easier to open.
The 500w motor is mechanically the same as the 350w one. They all coast very well.
Ping battery normal running is IC. However, it can give 2C max, i.e. 20 amps for a 20aH battery or 40amps max. So for a 25 amp motor you need ideally a 25aH battery, but as long as you don't go too hard on it, you could get away with 15aH.A123 cells can go up to 30C, which is as much current as you want, so you choose your battery size by how far you want to go, and if you don't want to go far, you can have a much smaller battery. It's the same for lipos, but they're more tricky to use.

 

[aussietc]

Sorry, I don't understand. I want to use a Mac motor (350W or 500W ... still undecided). Would like to commute 25km a day.

39.6V 9.2Ah from cell man
or
36V 10AH V2.5 LiFePO4 Battery Pack from Ping?

 

[cwah]

The batteries sold by Cellman are A123. They are somehow "better" version of Lifepo4 because they have higher discharge rate. I recommend you getting the A123 if the price is similar.

If you have 25 km/day commute with 360wh (36V10AH or 39.6V9.2AH) battery, you better get the 350W motor. It will be less powerful but you'll be able to complete your journey with 1 charge.

 

[d8veh]

Sorry, I don't understand. I want to use a Mac motor (350W or 500W ... still undecided). Would like to commute 25km a day.

39.6V 9.2Ah from cell man
or
36V 10AH V2.5 LiFePO4 Battery Pack from Ping?

You won't have a problem with the range, but you may well get a problem with the power. you don't say which battery from Cell Man, but I'm assuming not A123. The MAC motor will be about the same power as the Bafang BPM. Whether you destroy your battery with this motor depends on which controller you use. Those batteries are only good for about 15 to 20 amps, so no point in getting a 25amp controller, which will just cause the BMS to shut the battery down. Solution: bigger battery, A123 battery or Lipos - otherwise get a smaller motor.

 

[aussietc]

I might go for the complete kit from cell man then - motor, battery, controller ...etc and trust that it all works together well.
Sounds like the 350W rear motor is the way to go ... on a single charge.
or 500W 8T or 10T with an extra charger at the office?

 

[motomech]

D8veh is a modest sort, so I will take the liberty to post pics of his very nice BPM conversions.
The Mac is about the same size so you can get an idea of what frt. and rear installs look like.
The total review is at the Pedelecs. UK forum.
The nice thing about Lipo for your proposed build, it can be configured into different voltages to attain the speed you are seeking.
Later, when you want more, you can "throw another brick on the fire" :lol:

 

[Samd]

Where are you from Aussie? If you are near Melbourne, hope to see you on a group ride soon as per the events page on ES...

 

[aussietc]

southside of Sydney

 

[neptronix]

The A123 packs seem to be really good and i've never heard of any complaints, other than a problematic charger one time, which cell_man made good on later.

350w and 500w both freewheel really well. Better than any other geared motor i've encountered ( a few 250w ones ).

 

[aussietc]

Will I need torque arms for the rear 350W kit?

Is it worth purchasing a rear 500W torque kit (similar top speed but greater torque) instead for a few more dollars? How will the same 39V 9.2Ah A123 Pack battery cope?

Also will the battery fit into a triangle falconEV bag?

And one more question ... I have a choice of fitting out either my flatbar road bike with 700c wheels or my mountain bike with 26" wheels.
Recommendations for choice?

 

[miuan]

yes you need a torque arm and install it securely.
choose a MTB. smaller wheels, more stable chassis.

 

[motomech]

QUOTE- "Is it worth purchasing a rear 500W torque kit (similar top speed but greater torque) instead for a few more dollars?"

You are looking at the motor rating with an eye accustomed to looking at gas engines. Electric motors are different, the wattage rating has more to do with efficiency at a given rpm. The 350 watt motor will be fine for your selected battery.

QUOTE- "How will the same 39V 9.2Ah A123 Pack battery cope?"

Likewise, this battery will be fine with your selected motor.

QUOTE- "Also will the battery fit into a triangle falconEV bag?"

Easily.

QUOTE- " ... I have a choice of fitting out either my flatbar road bike with 700c wheels or my mountain bike with 26" wheels.
Recommendations for choice?"

Yes, the MTB.

From Cell/man site,

QUOTE- "As a guideline you can expect approximately the following real world speeds for the above windings on 12S LiFePO4 battery pack (approximately 38V under load) in a 26” rim on the flat, no pedaling with a rider plus bike weight of approximately 130kg total (286pounds):

8T – 39kph (24mph)

10T – 32kph (20mph)"

Sub'ing the BMC V1 for the 10T @ on the Ebike CA simulator[approx. same no-load rpm] and using Cell_man 52V 11-5 battery gives a top speed of 24.5 mph with fair climbing ability.

Bottom line, if you have small hills to negociate, the 8T @ 39V is ok.
If you have more formitable hills, the 10T combined with Cell_man's 52V 11.5 triangle battery would be a better choice.
No-pedal range would be greater, 15-20 miles, than with the 39V 9.5 battery, which would be 12-16 miles.

 

[gartmu]

I have a Bafang BPM48V500W code 11 (393rpm) bought in BMSbattery and all I can say it´s a beast. I use headway batteries 38140S (12AH) and 500W 48V controller with 30A limit. I weight 83Kg and my height is 1,80m. Last sunday I made 39Km is 54 minutes in my bike computer with lots of hills. The average speed was 43Km/h and it took 10AH from the battery. Here is the GPS record: http://www.sportypal.com/Workouts/Embed/1963547. The bafang motor is one of the best I ever seen and I never had problems with BMSbattery.

 

[aussietc]

BMS says, 201RPM is often used for 24", 26", 700C and 28" rim. 393RPM is often used for 16", 20" and 24" rim.

Is this right?

 

[d8veh]

BMS says, 201RPM is often used for 24", 26", 700C and 28" rim. 393RPM is often used for 16", 20" and 24" rim.

Is this right?

They're guide-lines. There's no right or wrong. It depends on what you want. First, you need to decide what speed you want to go most of the time and then choose the appropriate motor.

 

[edavinci]

I got the 350W front BPM at 201 RPM for 700C rim; 36V 11AH LifeP04, KU93 Controller as a kit. Me and the bike and backpack are 230 pounds. This set-up is BEAST! I can easily ride up an 8% grade at full speed and the battery is plenty for my 36Km commute at 30Kph. A word of advice if you order from BMS Battery; the wheels are laced very poorly, and the package is bulky. Buy your own rim and 13G spokes locally and lace your own wheel. Its finicky work but well worth it. This way the package from BMS is small and compact. And, make sure you tell them what charger input voltage and plug type you need; I live in Vancouver (110v single phase service ) but got 260v single phase from BMS!! You will love E-biking!!!

 

[aussietc]

What about using the existing rim on the bike and buying spokes?