will i make it!

[sil4ps]

Hi all,

I have just bought a 500w bafang with a 48v 15ah high C rate li-on battery,

my journey is 15 miles each way and i can charge at work, there are a few big hills each way but i will be pedaling with the motor.

Having no experience of any of this I would just like to know if this is suitable.

Will this be ok or do i need more amps.

I'm hoping bms will provide the correct controller for the battery and kit that i have ordered or should i specify any particular controller.

Thanks for any help or info.

 

[103Alex1]

Hi all,

I have just bought a 500w bafang with a 48v 15ah high C rate li-on battery,

my journey is 15 miles each way and i can charge at work, there are a few big hills each way but i will be pedaling with the motor.

Having no experience of any of this I would just like to know if this is suitable.

Will this be ok or do i need more amps.

I'm hoping bms will provide the correct controller for the battery and kit that i have ordered or should i specify any particular controller.

Thanks for any help or info.

Is that a 48V rear driving Bafang motor you need to buy a freewheel for

(Bafang BPM 48V500W Rear Driving E-Bike Motor Wheel - BMSBATTERY)

If so it tells you to select either S09P, S12P or S12S controller in the order comments and you also need to specify the appropriate RPM for the wheel size you are using. The appropriate controller will depend on whether you are running the motor sensored or sensorless (S12P runs higher amps than S09P and both mean you need to run the motor sensorless) and also whether you want to order an LCD (in which case you need S12S - only for motors with hall sensors).

... or have you ordered 270RPM 36V Bafang CST 500W cassette spline motor kit to be run at 48V, which doesn't need freewheel :

http://www.bmsbattery.com/ebike-kits/589-q11-48v1kw-front-driving-hub-motor-e-bike-conversion-kit.html

Is this the battery you ordered ?

High C-Rate 48V15Ah Li-Ion Alloy 07-Case Battery Pack - BMSBATTERY

Don't forget torque arms, a spoke key for tightening, extra thumb throttles as spares and HWBS if running cable brakes. Also if you buy the Bafang 500W rear driving kit rather than the CST you'll need to get a freewheel. Also you may want to order an extra Hall Sensor connector just in case. They are very hard to find here if BMS don't send one (or send the wrong one like they did with mine).

 

[Deleted member 4366]

You need to be very clear about which motor you've ordered. If youordered the 48v BPM, the default is 201 rpm, which jumps from 0 to 14mph in about one second, but won't go any faster. If you're unsure about what you've ordered, please post the details here so that we can advise you. There'es lots of other things to order besides what you've mentioned. If you ordered a BPM kit, you get the KU123 controller, which is OK for what you want.
Your battery should be OK for the return journey as long as you don't go too fast. I used to commute the same distance at about 18mph, and used 15 to 20wH/mile. You have 750wH, so, at the same speed, you can do at least 37 miles, or you can go flat out and charge at work.

 

[sil4ps]

alex d8veh
sorry didnt make it clear

i ordered 48v 328rpm rear bpm kit with freewheel
lcd disp. hwbs and torque arms. extra thumb throttle.

not sure if it has hall sensors or if i need them
should i order them with the extra connectors as recommended???

the battery is their li- ion 48v 15ah high c rate and my
main concern was will it be powerful enough for my 15 mile each way
journey with hills. this was my main concern!!

and it seems it will thanks to d8veh.
and i have no probs charging at work.

as i presumed the controller will be suitable
as its part of the kit but wasnt sure what to expect.

im sure there will be some fitting issues to solve and look forward to sharing with you all
shortly

many thanks

 

[Deleted member 4366]

alex d8veh
sorry didnt make it clear

i ordered 48v 328rpm rear bpm kit with freewheel
lcd disp. hwbs and torque arms. extra thumb throttle.

not sure if it has hall sensors or if i need them
should i order them with the extra connectors as recommended???

the battery is their li- ion 48v 15ah high c rate and my
main concern was will it be powerful enough for my 15 mile each way
journey with hills. this was my main concern!!

and it seems it will thanks to d8veh.
and i have no probs charging at work.

as i presumed the controller will be suitable
as its part of the kit but wasnt sure what to expect.

im sure there will be some fitting issues to solve and look forward to sharing with you all
shortly

many thanks

That's a bit clearer, but still some things don't make sense. Did you order this one? If so, What's the LCD for? It doesn't work with the KU123 controller. If you want to use the display, you need a S12P or other controller plus a wheel-speed sensor for it to work. If you want to use the LCD,you can always buy the extra controller and keep the other as a spare or sell it on Ebay, or, if you email them and offer to pay the extra, they'll probably swap it. All the controllers with a "12" in the number work at both 36v and 48v.

As I said before, the free-wheel's useless unless you can get a 53T chain-wheel, but that might be a more expensive option.

I keep forgetting about the spoke key. Anybody that orders a kit from them should order the spoke key, which is only 60p, and saves a lot of messing about later.

 

[sil4ps]

hi d8veh

i assumed if i order the kit they will send what I need for the kit
i did order the speed sensor. i will check what controller and pay difference.

will order spoke key.

bit confused about cassette over freewheel
i can prob put a 53 tooth ring on but is the problem the 14 smallest sprocket on a freewheel
the smallest on my cassette is 12 or 13 i think.

Hall sensors. will they be in the kit and do i need them
still learning about this bit.

many thanks for all your advice.

 

[averhamdave]

The cassette type as with Bafang CSt motor will take a cassette that has a 11T top gear. YourBPM will only take a 14T freewheel so you'll either have to find a 52/53 front chainwheel or pedal like mad!

 

[Deleted member 4366]

It's difficult to find free-wheels with less than 14T top gear, which is much too low for a 500w electric bike with the normal 42T or 44T chain-wheel. You can sometimes get a DNP free-wheel with 11T from Cyclezee, so check with him. The 7 spd one is fairly easy to fit, but I think the 8 spd is wider, so a bit more jiggery pokery to get everything right.

Cassette gears are easy to get with 11T top gear, plus you can get decent ones like Shimano XT, which is why some of us are now prepared to pay extra for a CST motor. The DNP free-wheel will cost at least £25, so you have to add that to the cost of the motor.

You don't need to order any hall sensors. They're inside the motor. With Alex's kit, the plastic housing for the connector pins went missing, and it was difficult to find a replacement, but I think that was a one-off, so I don't think you should worry about it. I've probably got one you could have if it happened to you, but I'm sure you'll be OK. I think you've got everything covered now.

 

[sil4ps]

hi, d8veh, Alex,

I think I would like to change my order to the cst 500w 36 volt wheel as I have the cassette on my bike with 12T top gear which should be ok and keep my 9 speed.

I'm confused now as it says 36V but can this be run at 48V as I have order the 48V battery Also does it matter if I get the s12p or S12s, will this wheel will have hall sensors? I still don't understand about hall sensors and If I need them.

Hopefully Bms will understand what I want and not end up with a kit that is a mish mash of parts that wont work together,

many thanks.

 

[Deleted member 4366]

The 500w CST is 270 rpm, so does about 22 mph at 36v. At 48v it'll do 29mph. It would probably be better with the S12S controller at 23 amps. I think the 30 amps from the KU 123 or S12P at 48v will make it into a bit of a brute, but it depends what you want.

 

[Cyclezee]

If you are looking for a screw on Freewheel, we can supply 7, 8, and 9 speeds with an 11t top gear and recently supplied an eZee kit with a 10 speed.
They are manufactured by DNP and Sunrace.
We can also supply inner and outer spacers if required.

 

[sil4ps]

The 500w CST is 270 rpm, so does about 22 mph at 36v. At 48v it'll do 29mph. It would probably be better with the S12S controller at 23 amps. I think the 30 amps from the KU 123 or S12P at 48v will make it into a bit of a brute, but it depends what you want.

d8veh

so the 500 w cst will run 36 or 48w on the same
controller.

my 15 mile journey will be 8 minutes less with the
48v so im happy with 22mph 36v

will the 36 v 15ah high c have a better range than the 36v 20ah
or will it deplete quicker?? the 20 ah has a 15a continuous the 15ah has 30a continuous.

 

[Deleted member 4366]

d8veh

so the 500 w cst will run 36 or 48w on the same
controller.

my 15 mile journey will be 8 minutes less with the
48v so im happy with 22mph 36v

will the 36 v 15ah high c have a better range than the 36v 20ah
or will it deplete quicker?? the 20 ah has a 15a continuous the 15ah has 30a continuous.

All their controllers with a "12" in the number are switchable between 36v and 48v.

Range depends on wHs. Watt-hours = average volts x amp hours. The 20aH battery has approx 800wH and the 15 aH has 600wH. Discharge rate (amps) has nothing to do with range. The 15 amps continuous for the 20aH battery is incorrect. It should be double the 15 amps quoted for the 10aH version. The rate at which you use current depends on the controller, not the battery.
KU123 30 amps
S12P 29 amps
S12S 23 amps

 

[103Alex1]

I think the 30 amps from the KU 123 or S12P at 48v will make it into a bit of a brute, but it depends what you want.

Possibly extra strain on the gears in the motor too so more prone to wear out faster ?

my 15 mile journey will be 8 minutes less with the
48v so im happy with 22mph 36v

will the 36 v 15ah high c have a better range than the 36v 20ah
or will it deplete quicker?? the 20 ah has a 15a continuous the 15ah has 30a continuous.

You likely won't run the motor at max speed for the whole journey - stopping and starting and natural road and off-road hazards see to it that marginal speed gains have little real impact over a few miles. So in real life conditions your average speed probably won't be that different. Run 48V @ higher amps (30A) if you are in the over 85-90kg+ range and want to sustain higher speeds/much more push help up steep to very steep sustained hills. Obviously at a cost of considerably more power consumption. This is where the extra input watts will show. Running 48V @ 23A = max power input 1104W. Running 36V @ 30A with a KU123 (sensored) or S12P (sensorless) controller = max power input 1080W. There is genuinely very little in it between the two.

As d8veh says, the 20ah can sustain 28-30A for a good few minutes up a steep hill with pedal assist along with during acceleration so to all intents and purposes it is good for 30A continuous. In practice range will most likely be higher due 720W/h as compared 540 W/h on the 15Ah high discharge battery. If you buy a 20Ah battery you are extremely unlikely to need to recharge it at work for your round trip - unless you actually want to. With a 15Ah battery, you’ll most likely be at lower voltage on the trip home if running maxed out on power assist all the way so might be less punchy without a recharge. But probably not much real difference.

On the flat you only need a high discharge battery if you need to run high amps continuously and motor speed is probably maxed out well before the motor actually needs that, so capability would not be called on much in any event....

but if you use the S12S 23A LCD-compatible controller @ 23A with a 36V battery then as compared to a KU123 30A/S12P 29A controller (or a 48V battery with S12S 23A controller), power will be considerably lower during steep climbing and acceleration so climbing speed may drop considerably more - but the battery will likely take you further the more sustained steep climbing and accelerating from low speed at full power you do, simply because less power can be drawn during these 'greedy' elements of a max-assist ride.

 

[sil4ps]

All their controllers with a "12" in the number are switchable between 36v and 48v.

Range depends on wHs. Watt-hours = average volts x amp hours. The 20aH battery has approx 800wH and the 15 aH has 600wH. Discharge rate (amps) has nothing to do with range. The 15 amps continuous for the 20aH battery is incorrect. It should be double the 15 amps quoted for the 10aH version. The rate at which you use current depends on the controller, not the battery.
KU123 30 amps
S12P 29 amps
S12S 23 amps

d8veh, Alex,

you guys are great, Answers at 1.30 in the morning, 24hour technical help Brilliant.

The s12p says for 750Watt motor which is why I didn't look at it. But as you both advise that model then i'll get the s12p and the s12s and try them both.

D8veh, you say the 48w 20ah is 30a continuous, so their website info is wrong or is my lack of knowledge confusing me???.

their website shows the 48v 20ah to be 15a continuous discharge and the 48v 15ah high c to be 30a and that's the same with the 36v also which is why I went for the high C option

1. 1Pcs 48V20Ah Li-Ion NiCoMn shrink tube electric bicycle battery pack. Included 13s polymer cells, 1pcs 15A continuous discharge current smart BMS.

1. 1Pcs 48V15Ah Li-Ion NiCoMn Aluminum Alloy shell 07-case ebike battery pack. Included 13s polymer cells, 1pcs 30A continuous discharge current smart BMS

for the extra few dollars i'm going for the 48v 20ah, so hopefully will have plenty in reserve and with the 2 controllers can decide which is better for me.

much appreciated.

 

[Deleted member 4366]

There' one more slight difference between the controllers. The S12P is sensorless, so in theory, might be a bit less efficient and not so good from a start, but Alex runs his CST sensorless with the KU123, and it doesn't seem any different to mine, which I run sensored.

You're correct. There might be a difference in the BMS, but between us, we have several of those 20aH shrinktube batteries with 500w CST motors at 30 amps and nobody has experienced a cut-out. It will be absolutely fine with the controllers mentioned.

The 48v 20aH battery is 30% heavier than the 36v 20aH and 48v 15ah, There's always a down-side to every up-side. You need to think where to put it. 5kg on a rear rack is manageable, but 7kg can make the bike unwieldy. You'd be surprised at the effect of that extra 2kg. Definitely no good on a bike with rear suspension. Taking the battery out to charge at work is not easy, and I wouldn't recommend it. If you can bring a charger to the bike, charging at work would be an option. I reckon that the two smaller batteries will have a range of about 40 miles at an average speed of 20mph. If you want to sustain speeds faster than 22mph, you'll probably need the bigger one.

 

[103Alex1]

d8veh, Alex,

you guys are great, Answers at 1.30 in the morning, 24hour technical help Brilliant.

The s12p says for 750Watt motor which is why I didn't look at it. But as you both advise that model then i'll get the s12p and the s12s and try them both.

D8veh, you say the 48w 20ah is 30a continuous, so their website info is wrong or is my lack of knowledge confusing me???.

their website shows the 48v 20ah to be 15a continuous discharge and the 48v 15ah high c to be 30a and that's the same with the 36v also which is why I went for the high C option

1. 1Pcs 48V20Ah Li-Ion NiCoMn shrink tube electric bicycle battery pack. Included 13s polymer cells, 1pcs 15A continuous discharge current smart BMS.

1. 1Pcs 48V15Ah Li-Ion NiCoMn Aluminum Alloy shell 07-case ebike battery pack. Included 13s polymer cells, 1pcs 30A continuous discharge current smart BMS

for the extra few dollars i'm going for the 48v 20ah, so hopefully will have plenty in reserve and with the 2 controllers can decide which is better for me.

much appreciated.

The 48V 20Ah is 960 W/h as compared 720 W/h for the 15Ah.

Couple of things if you fit the 48V battery with the S12P - do bear in mind the physical size / weight of the 48V 20Ah exceeds the 36V 20Ah .. and the 36V one is pretty hefty .. so will most likely wind up rack mounting on the rear. This means you need to be more careful with cornering etc. due to effect on handling and probably will benefit from making your own rack to minimize impact on centre of gravity. Make sure your brakes are decent too.

Your controller will most likely benefit from direct air flow cooling so some extra weatherproofing running on the S12P likely to be beneficial if you're riding in heavy rain / all year round.

EDIT : - just crossed with d8veh !

 

[Deleted member 4366]

Great minds think alike!

 

[sil4ps]

There' one more slight difference between the controllers. The S12P is sensorless, so in theory, might be a bit less efficient and not so good from a start, but Alex runs his CST sensorless with the KU123, and it doesn't seem any different to mine, which I run sensored.

You're correct. There might be a difference in the BMS, but between us, we have several of those 20aH shrinktube batteries with 500w CST motors at 30 amps and nobody has experienced a cut-out. It will be absolutely fine with the controllers mentioned.

The 48v 20aH battery is 30% heavier than the 36v 20aH and 48v 15ah, There's always a down-side to every up-side. You need to think where to put it. 5kg on a rear rack is manageable, but 7kg can make the bike unwieldy. You'd be surprised at the effect of that extra 2kg. Definitely no good on a bike with rear suspension. Taking the battery out to charge at work is not easy, and I wouldn't recommend it. If you can bring a charger to the bike, charging at work would be an option. I reckon that the two smaller batteries will have a range of about 40 miles at an average speed of 20mph. If you want to sustain speeds faster than 22mph, you'll probably need the bigger one.

Hi yes i was a bit concerned about the 7kg weight, is there a central mount or bag i could use or is it too heavy for that?
Charging at work next to a plug is no problem as i have a warehouse with easy access to plug sockets, so would'nt remove at work or at home.

i don't have suspension but am a bit concerned about the extra weight and the weight of the motor and my 90kg all on the back wheel.

I've changed my order 3 times now, so not sure what the hell i will end up receiving and hope my pigeon english will have explained well enough to translate into chinese.

 

[103Alex1]

Hi yes i was a bit concerned about the 7kg weight, is there a central mount or bag i could use or is it too heavy for that?
Charging at work next to a plug is no problem as i have a warehouse with easy access to plug sockets, so would'nt remove at work or at home.

i don't have suspension but am a bit concerned about the extra weight and the weight of the motor and my 90kg all on the back wheel.

I've changed my order 3 times now, so not sure what the hell i will end up receiving and hope my pigeon english will have explained well enough to translate into chinese.

20Ah 48V is not too heavy for a centre mount system using a box/bag-type enclosure but it's quite likely too bulky (won't fit as too big). Don't know the dimensions of a 15Ah high discharge one.

This was my box for the 36V 20Ah battery in progress - you can see how tight the fit is at the bottom right corner where the box frame has been cut out :

http://www.pedelecs.co.uk/forum/uk-off-road-s-pedelecs-overseas/13813-cst-its-all-working-11.html#post180773

It's a Trek frame which has a relatively big triangle too.