newbie questions from an oldie

[padrejaume]

hello forum reader
ten years ago i converted a kettler aluminium frame with a 250w kit and was one of the first to climb the hills of vienna without (necessarily) pedaling, all the while pulling a trailer with a 50kg dog. needless to say, many interesting meetings were caused by my vehicle.
the only upgrade ever was changing the lead battery to a lithium one and the bike served me well over all those years.
unfortunately i had to leave it behind when moving countries and now i want to put another one together.
with the 250w i always wished for a little more power uphill and now i am in hillier terrain, so i would really like more pep.
the problem is, that the local law and order people are now savvy to pedelecs over the legal wattage.
i just read about the possibility of hot-rodding 250w hub motors, but do not quite know how to go about it - electricity being more or less a book with seven seals for me. is there maybe a wizard out there who can help me out.
i liked the engine in the front wheel because of weight distribution and the "awd"-feel when using the engine and pedaling.
hoping for some insight
swift and safe riding, everybody

 

[Nealh]

You can overvolt a 36v 250w hub by fitting a suitable 48v controller up to 20a ouput and a good 48v battery. Hub rpm will increase by 33%, watts at the hub will increase up to 750w or so.
Equally a company like Woosh bikes sell a 48v 250w hub kit.

 

[padrejaume]

thanks a lot for your reply. a readymade kit would be easiest, on the other hand i would like to learn more about this fascinating subject. any suggestions, as to what components would be suitable? i don't want to squeeze out the maximum, just a bit more. a while ago i saw an advert for what i think was a 350w motor in a 250w casing, but i can't find anything like that now. may have been misleading too, if i understand right that all 250w motors can take more.

 

[soundwave]

you can buy a mid drive bike and dongle it if u got the cash as long as u can spin the cranks it will pretty much fly up anything with a bosch cx motor.

 

[Nealh]

With 48v yo don't have to go mad 14 - 17a is plenty.
From PSWPower.com or they are on Aliexpress buy a dual voltage controller 36/48v with lcd screen and a choice of amps 15 -20, doesn't matter if yo get a high amp controller as thye can easily be adjusted for less amps via the lcd.
Then you need a good battery that can deliver a continuous 20amps.

 

[padrejaume]

thanks soundwave! i wish money wasn't an issue

 

[padrejaume]

and thanks Nealh! that starts to make sense, i will have a look at controllers etc tomorrow

 

[Nealh]

The best ones available for kit builds are KT (Kuenteng) also known as S series on BMSBattery.

 

[padrejaume]

excellent, i am starting to get somewhere - thanks a lot! any suggestions as for the motor? are there brands that take better to hotrodding than others?

 

[Nealh]

Problem is unless you buy a kit, it is unlikely you will get a hub marked 250w.
They will be marked 350 or 500w.

 

[wheeliepete]

The marking also differs from make to make, Bafang tend to be etched into the centre of the motor, Yose Power I think are etched on the side, but hidden by the cassette or freewheel and The Q motors from BMS Battery just have a sticky label which falls off when removed from the box. That is, if you are worried by this. YosePower front kits are 250w, but I'm not sure anyone has tried these at 48v, although they should be OK if you stay around 17 amps. The 36v Q100H from BMS Battery also works well with 48v.

https://www.yosepower.com/en/category/front-48.html

https://bmsbattery.com/ebike-kit/630-q100h-36v350w-front-driving-ebike-hub-motor-ebike-kit.html#/327-rpm-260

 

[padrejaume]

thanks wheeliepete! the issue is, that here some people had their pumped up mountainbikes confiscated plus all the trouble of driving un unregistered, uninsured vehicle without the proper helmet. that adds up! they check for etchings and are of course intrigued by size. i am not planning on doing anything silly, just a bit more power for hills and pulling a trailer. will look more into the motors you mentionned. if i get a 250w 36v kit and add a 48v battery, will the kit-controller adapt to the higher voltage? anything to look out for?

 

[wheeliepete]

On reflection, the Yose kit is prob. not a good choice because the controller is 36v only, so would need to be replaced with a 36/48v duel voltage one and they are not available with the julet waterproof connectors, which in turn means that all of the other parts in the kit will have the wrong connectors. The Q100 is a strong little motor for it's size, but I'm not sure how well it will cope with hills and a loaded trailer. I will give it some more thought, although not a huge choice of 250w front motors to suit your needs. The Bafang BPM is a good strong motor, but 350w.

 

[Nealh]

Front 250w kits are thin on the ground, Yose 250w is 36v and the hub a bit weedy at only about 20/25nm of torque.