I contacted Tony at Whoosh, he said the hub motors wouldn't stand up to doing 28mph for prolonged periods of time and that a bafang mid drive motor would be better.
Advice on ebike conversion kit for 30mile commute
- Thread starter Hilly
- Start date
The geared hub motors in my kits are not up to the job, but you can use much cheaper direct drive motors.
The internal gearbox is the weak link, they are made for 250W continuous use.
If you put 1,000W into it, the nylon cogs will melt in a few minutes. Direct drive motors don't have internal gearbox so they are much better suited to your target speed (28mph).
Even a Bafang BBS01B cannot run at 28mph for long.
You need a BBSHD for that speed.
The motor a bbshd will do it without a doubt ,but the biggest problem I see is the battery size capacity vs duration /reliability 25amps constant for one hour plus = dead cells quickly .
A life of probably months not years on a cheap battery even with top grade cells 10+ charges a week and drain ride till empty is not ideal for a long lifespan perhaps two packs.
Also if you go legal dvla etc have you looked into insurance on a conversion as it does not have type approval
I have to agree a 50cc moped will be cheaper in the long run
A life of probably months not years on a cheap battery even with top grade cells 10+ charges a week and drain ride till empty is not ideal for a long lifespan perhaps two packs.
Also if you go legal dvla etc have you looked into insurance on a conversion as it does not have type approval
I have to agree a 50cc moped will be cheaper in the long run
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Hi Hilly, another thing to consider when deciding whether to go centre drive or hub motor is what type of wheel hub the donor bike is set up for (in terms of the frame). The Planet X London bike that you linked looks like it has a QR through axle on the front, but can’t see what is on the rear from the pictures. Centre drive looks like it would be easier to fit.
Looking at this from a different viewpoint
You want to cover a 30 mile commute (including 2 hills) & would like a top speed of 30mph.
What type of roads & traffic will you be facing?
If you are cycling in SE London, then the top speed is irrelevant, as its all stop/start & you do not have the acceleration nor stopping power of cars.
The alternative is side roads where you can maintain a higher average speed, but 30mph might be too fast for local traffic, used to cycles at 20-25mph.
You want to cover a 30 mile commute (including 2 hills) & would like a top speed of 30mph.
What type of roads & traffic will you be facing?
If you are cycling in SE London, then the top speed is irrelevant, as its all stop/start & you do not have the acceleration nor stopping power of cars.
The alternative is side roads where you can maintain a higher average speed, but 30mph might be too fast for local traffic, used to cycles at 20-25mph.
That's absolutely not true. It makes no difference whether you have a hub or crank motor. You can get both that give enough power to drive a bike at 100mph. You just need to choose a motor that can sustain the speed you want.
What he means is that the hub-motors he sells won't stand up to continuous 28 mph.
Regarding my post a short while ago on reduced capacity of my bbshd52v 30Q battery.ie 58.8v permanently down to 57.5v.The motor a bbshd will do it without a doubt ,but the biggest problem I see is the battery size capacity vs duration /reliability 25amps constant for one hour plus = dead cells quickly .
even with top grade cells 10+ charges a week and drain ride till empty is not ideal for a long lifespan
Do you think this is why after 1500 miles in a year that happened? Not just because it never got balanced.due to me not knowing it had to be switched on when charging. But the inevitable consequence of a bbshd s demand ,even with good high drain 30Q cells?
I wasnt hammering it continously on high PAS/throttle on rides , but i wld use it a lot in the early days.
These days im always on 1 & 2 out of 5 (carls special sauce) rarely give it any more except the steepest hills.
30Q has poor cycle life according to threads on ES from users who have cycle tested them and use them.
ES is known for power bikes with high current demand, a lot of diy packs are made, you have to read between the lines to see what spec they build and how many parallel cells.
ES is known for power bikes with high current demand, a lot of diy packs are made, you have to read between the lines to see what spec they build and how many parallel cells.
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Battery tec is such that even if only one cell is off in a string the overall capacity drops we use simple a bms in most of our bike packs and are space/weight limited
The high spec bms that live monitor via blue tooth show more data but still cannot overcome that one duff cell out of many , even in the car and bus battery packs a few faulty cells needs a whole new battery cell our local bus company are to phase out the electric buses all 6 of them due to unforeseen cost
I have a 36v pack with a 100 cells it weighs a ton but the load is split over 10 strings
The high spec bms that live monitor via blue tooth show more data but still cannot overcome that one duff cell out of many , even in the car and bus battery packs a few faulty cells needs a whole new battery cell our local bus company are to phase out the electric buses all 6 of them due to unforeseen cost
I have a 36v pack with a 100 cells it weighs a ton but the load is split over 10 strings
Most of the ride is long straight roads with the occasional town. I work in willesden so only the last bit of the journey is urban and even then they're main roads.
The BMS does its balancing whether you have it switched on or not. The balancing is analogous to a row of buckets with small holes drilled an inch down from the top of the rim. When you fill them up, water will drain out of the holes until they're all at the same level.
Some modern bicycles have through-axles like a motorbike. The frames or forks are characterised by having a hole for the axle instead of a drop-out. You can only fit hub-motors in axles with drop-outs. The type of axle makes no difference with a crank or chain motor.
It makes no difference whether the axle is QR or fixed with nuts. It tends to be only the cheapest catalogue bikes that have axles with nuts these days.
Rear drop-outs are nearly always 10mm whether you have a 9mm QR wheel or not. In most cases, a motor will fit without having to file the drop-outs, though a bit of dressing to remove the paint is sometimes required. Forks are different. They often have 9mm drop-outs for a 9mm QR axle. so you have to do a bit of filing. Those cheaper bikes with bolted axles normally have 10mm axles and drop-outs.
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Thanks for that. I contacted Planet X and they said the bike comes with quick release front and rear. The guy selling the bike on ebay has changed the forks so i guess that's why it's got a through axle on the front.
Not all bms are the same most use a bleed off via a resistor crude but it works to a point others use the semi dumb charge- float- drain- trickle and repeat until balanced and require the pack to be switched on to balance and left on charge for longer once the initial charge has completed
You get what you pay for ,a fully intelligent system as used in car packs would be more than most of us would be prepared to pay but still does not show up which cell has the problem just which string and as most are glued/ bonded in the pack is still scrap mr tesla/musk might solve this at a later date
Just another quick concern big battery and higher speed will draw unwanted attention
You get what you pay for ,a fully intelligent system as used in car packs would be more than most of us would be prepared to pay but still does not show up which cell has the problem just which string and as most are glued/ bonded in the pack is still scrap mr tesla/musk might solve this at a later date
Just another quick concern big battery and higher speed will draw unwanted attention
how to estimate the result:
That particular motor is specified as 48V, 328 RPM, 500W.
On 26" wheels, 328RPM = 25.6mph, you need 650W input to maintain this speed.
On 700C wheels, 328RPM = 26.4mph, you need 700W input to maintain this speed.
That means you need to allow 650WH/25.6mph = 26WH per mile.
For your 30 miles trip, you want to arrive at destination with at least 25% reserve in your battery, that means 30*26WH/0.75= 1015WH, or 48V 20AH.
You then need a fast charger, the normal charger would take 8 hours to recharge your battery.
At this rate, your 800 cycles will be all used up within 15 months. If you use a fast charger, you may not have as many as 800 charging cycles.
That's why I think you have to buy a battery that uses LiFePO4 which can take 4A charger and still lets you have 2,000 charging cycles.
That's the requirements for a bike that does 25-26mph. 28mph will burn 20% more WH per mile.
Thanks for that. Surely the weight / aerodynamics of the bike and how much I'm pedalling will also have an effect?
8 hours charging time is not a problem.
Also as I mentioned earlier I'm not going to be doing the journey twice a day, day in day out.
At this stage I'm thinking that a more modest speed on a bike designed for road riding and and a modular kit (which won't have built in obsolescence) will be an upgrade from Haibike.
I'll probably install the kit with a smaller battery to make sure it all works the get a feel for the range and the speeds that are achievable then make a decision whether I want to put it through the DVLA test and how big a battery I will need for the commute. Only when all that's done will I sell the Haibike.
8 hours charging time is not a problem.
Also as I mentioned earlier I'm not going to be doing the journey twice a day, day in day out.
At this stage I'm thinking that a more modest speed on a bike designed for road riding and and a modular kit (which won't have built in obsolescence) will be an upgrade from Haibike.
I'll probably install the kit with a smaller battery to make sure it all works the get a feel for the range and the speeds that are achievable then make a decision whether I want to put it through the DVLA test and how big a battery I will need for the commute. Only when all that's done will I sell the Haibike.
Hmm thats interesting.Everything ive learned so far from people says the opposite.when i had my issues recently with the badly balanced bbshd battery.i trickle charged with a mobile phone charger all the cells to the same voltage,when nearly drained. Then when i charged switched on, for the first time ever it went into balancing mode.with the charger turning on and off for several hrs after the green light. Until the cells all were equal at 4.1v. It had never done this before when the battery was switched off during charging.
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