Hauling heavy loads in steep hills.

[Renax]

Hi, I'm Jonatan from Norway.
I'm looking to buy a ebike kit for my wife, we recently moved back to my home town, which is made up of some steep hills with only some small inclines connecting the hills. My wife takes the kids to kindergarden in a bike trailer, and then rides on to get to work, and the same to get back again. She has a 250w kit on her bike today, but this isn't nearly enaugh to get her up the hills. I can bearly do it and I'm exhausted after a 2km trip to get the kids with the ebike.
The kids in the trailer are about 50kg together, and growing fast, (the oldest I hope will start to ride herself soon, but I'm not holding my breath..)
I've tried searching around, but I can't really find any info on what is the best solution, All the "road legal" kits are too weak (I haven't tried all, but I've tried some high end bikes, and they do not make the cut)
And all the "not road legal" kits seems to be made just for speed. (I would like one ot those, but if it can't haul a heavy load up a steep hill its no good for her)

Anyone here tried biking with upwards of 170kg total weight? (thats, the bike, trailer, kids and herself combined.) Speed is not the issue, if she can go 10km/h uphill without pedaling like a maniac she would be extatic. speeds on flats doesn't matter, she can pedal herself fast enough there.

Budget is pretty low, but not rigid around 300£. I was looking at the cyklotricity 1000w kit, but read somewhere that its made purely for speed and therefore wont be any good in her uses.
Then I have had someone say that crank motor is the way to go, but I'm a bit afraid it will be a maintenance nightmare to keep up with the wear of a high power motor going trough the drivetrain? I've seen its not a big problem with the 250w units, but what of higher power motors hauling heavy loads every day. And can anyone link me to a good kit, its a jungle out there and I don't want to end up with some overpriced junk from china.

Sorry for the long post, hope someone reads most of it and can help

 

[tommie]

170kgs weight?

£300 isnt going to cut it,

you`d be looking to pay that at least on a battery.

BBS02/HD would do it, but best part of £1K

 

[anotherkiwi]

What kit do you have now? In Norway you can buy a perfectly legal Bafang 250 W BBS01 which is called the 500 W BBS02 in other countries.

You want a 500W geared hub that has a 250 W label on it and a 25 Amp controller otherwise.

Don't neglect the battery, at least 15 Ah if you don't want it to sag too much.

 

[flecc]

There's some details on the BBS kits that Another Kiwi mentions in this link.
.

 

[Renax]

170kgs weight?

£300 isnt going to cut it,

you`d be looking to pay that at least on a battery.

BBS02/HD would do it, but best part of £1K

Forgot to add, I already have a good 48V 17AH battery..

I will do some reaserch on those BBS kits,

You want a 500W geared hub that has a 250 W label on it and a 25 Amp controller otherwise.

Sounds like a good plan, bu its 36V only? and 500w gonna cut it? the price difference between the 500w and 750w kit is so little.

 

[anotherkiwi]

No you can use a 48 V controller and battery on a good quality 36 V hub.

https://bmsbattery.com/44-36v

 

[Deleted member 4366]

A Xiongda kit would do the job perfectly. They're very cheap to buy direct from Xiongda - I think about £250 without battery. You need to build the wheel or get somebody to do it for you. The motor is two-speed. In low gear, it's like a winch. The 48v version is best, but then you probably need a new battery. The 36v one is the same if you solder the shunt in the controller up to 20 amps, like I did. the standard controllers are 15 amps, which might be enough for you anyway.

The motor is quite wide if you use a disc brake and 7 or 8 speed gears. you can still fit it, but you have to stretch the frame a bit, but with a 5 or 6 speed and/or rim brakes, it'll go straight in. What bike does she have?

Edit: I see you already have a 48v battery. That's perfect: Your problem is solved. I'm 100KG and my bike is about 20kg, but I have carried as much as 20kg shopping. The motor has no problem winching me up fairly steep hills with hardly any pedal effort. Without shopping, 30% hills are no problem, but you need low gears because the speed goes down to about 6km/h on 30% hills:

https://xiongdamotor.en.alibaba.com/product/1557178214-220560510/New_Invention_2_speed_Ebike_Motor_Amazing_Torque.html

 

[Artstu]

Start them young I say and before you know it they'll be winning every race they enter.

 

[Renax]

What bike does she have?

Popular question. and the answer is many different, but the one I'm planning to convert has 29" wheels, disc brakes and 8speed derallieur..

@Artstu those looks like about the same age as my kids, still a couple years before they're propelling themself 2+km to school....


I'm looking at the BBS kits. Are there any reason other than the legal ones to go for the 500W option rather than the 750w? 500w is still illegal if they test it.

 

[Artstu]

those looks like about the same age as my kids, still a couple years before they're propelling themself 2+km to school....

Both her and her brother were doing 5 km a day from age 3 or so. Both did around 50 races each last year, including a few competitive hill climbs like this one, the youngest competitor there at just 9-years-old.

 

[Renax]

Props to you for raising your children as cyklists, thats the way I was raised. at the age of 6 I rode Denmark from North to south on my little 6speed bike.
However, this thread is more about streamlining the daily commute and less about getting 5yearolds to ride a bike 2km each way in 5cm snow

 

[D8ve]

...............

I'm looking at the BBS kits. Are there any reason other than the legal ones to go for the 500W option rather than the 750w? 500w is still illegal if they test it.

As an innocent customer who buys a 250 watt marked legal motor in good faith. Unless you deliberately mod it there's no proof that it's not legal.
And the tests are beyond your innocent skills so use away.
The extra strain on the chain and drive system makes little difference to maintance requirements.
So enjoy.

 

[Renax]

Small update: went for BBS02 750w after reading a bit more. I'll just remove any obvious evidence (stickers etc) of it beeing over 250w. and it will be limited to 25km/h.
Will post updates when I get it and get to try it out, incase anyone later need a ebike for the same purpose..

 

[Fordulike]

Small update: went for BBS02 750w after reading a bit more. I'll just remove any obvious evidence (stickers etc) of it beeing over 250w. and it will be limited to 25km/h.
Will post updates when I get it and get to try it out, incase anyone later need a ebike for the same purpose..

You will not be disappointed with its hill climbing ability, believe me

Give me a shout if you need help with programming the controller.

 

[Deleted member 4366]

I'll just remove any obvious evidence (stickers etc) of it beeing over 250w. and it will be limited to 25km/h.

It's engraved into the casing underneath - not easy to hide!

 

[tommie]

It's engraved into the casing underneath - not easy to hide!

*cough*

 

[Deleted member 4366]

You're lucky I'm not a Policeman!

I must say that I like the 250w decal on the side, which is a bit more convincing than the plate.

 

[Fordulike]

*cough*

View attachment 17139

You little tinker

 

[anotherkiwi]

Excellent work, very well done!

 

[Renax]

*cough*

View attachment 17139

Thats just what I need, can you get a set for me?

OT, her old bikes battery (36V) shorted out today, all 50 18650cells right in the shitbox, just because the charge checker got a bit moist and shorted out.
I have some 12V MC batteries, they are rated 9Ah each, but how are such batteries compared to lithium ones? Will it be a complete waste of time and zipties to fit 3 of them in series to get her around?