Advise on First ebike build

HI all, im new to the ebike scene and after getting a store bought ebike and finding the limitations or customisability (namely not being able to use a bigger battery) I want to build a custom one for commuting purposes and hopping you can help me out.

My use case is:

• 30 - 33 Mph max speed

• 50 miles one charge (cruising at average speed 20-25Mph)

• mostly flat with a couple steep hill (I don't know the incline % but its not too terrible nor too long)

• regen breaking (saving the breaks really appeals to me)

• I weigh 100kg when wearing all my gear.

• I prefer disk breaks.

• Being able to switch between road legal and off road would be a big bonus (im thinking CA3 for this job)

Im thinking a hardtail mountain bike with front suspension (I need to get a new bike for this so suggestions are welcome).

I need the 50 miles due to a 25mile one way trip with no chance to charge, I realise this is a long distance but im happy to put in the effort on the way home at a slower cruising speed.
On that note, I have a 50V 27.9Ah triangle battery on its way to me from em3ev as it was the biggest I could find.

I dont want to spend too much, im thinking £500 ish for the bike and similar for the motor kit.

I really like the idea of a variable regen break of some kind.

Im thinking that a 1000w DD motor should do the job but I really dont know where to buy from, whats good or bad.

Any help/advise on this and where to get the parts is most welcome.
Thank you in advance.

Should be able to find a suitable kit here. Any bike with steel rear dropouts would be best.
https://www.ebay.co.uk/sch/i.html?_from=R40&_sacat=0&_nkw=48v%201000w%20rear&rt=nc&LH_PrefLoc=1&_trksid=p2045573.m1684
The 27.9ah (1440wh) battery pack should be plenty for 50 miles if you stay around 20 mph.

I'm far from an expert, but here are some thing's I've gathered:

Geared hub motors have moving parts which can fail, and no regenerative braking unless the clutch seizes up. They tend to be more powerful for their size and weight, or lighter and smaller for the same power. If you're frequently accelerating, they're often more efficient, meaning you'll get more range with the same batteries. These motors may be more noisy due to having spinning gears inside. These motors can freewheel, so there's virtually no drag when you're not applying throttle; your bike can be ridden like a normal bike when the battery is dead.

You can get a complete kit (rim, motor, controller, throttle, brake levers, PAS sensor, battery meter) from ebikeling for around $140 shipped to the US, and the motors seem to be pretty reliable up to around 500w. I've built several bikes with these. I can't speak for UK suppliers. https://www.ebikeling.com/shop

MAC hub motors are larger and heavier (though still less than most DD motors), and can take considerably more power. 1600w seems to be a safe upper limit, but I have one I've been beating on with 72v/40a (3000w) for a few hundred miles now and the internals still look pretty good. These are not cheap motors; expect to pay $3-400 for one. I bought the one I have from https://em3ev.com

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DD motors are more robust and will generally not fail unless you overheat them. They offer regenerative braking, but tend to produce less power for their size and weight. Some DD motors can be more efficient at cruise, and are typically quieter. These often have noticeably drag when not being powered, so it can be unpleasant to ride a bike with a DD motor and a dead battery.

There are a ton of suppliers of cheap but inefficient (80%) DD hub motors. Leafbike is one supplier I'm familiar with which makes much more efficient (~90%) DD motors, but you'll pay a bit more for it. I have one on order to play with: http://www.leafbike.com

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I'm not super familiar with controller options, but some are more efficient than others. You can spend more on an efficient controller, or less on an inefficient one and put the difference into more batteries. I have some cheap ebay contollers, a few that came with various ebikeling kits, and a Phaserunner from ebikes.ca, which is a pretty expensive controller. The CA3 + Phaserunner combo is capable of having a ton of presets to govern speed and power.

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One battery config I've been favoring lately is a seller on eBay selling 36v/4.4ah packs with BMS. I have reason to believe they may be used cells (or possibly B-grade), but testing shows them to have near their advertised capacity and if the pack is sufficiently large, current isn't an issue.

https://www.ebay.com/sch/alarmhookup/m.html?_nkw=&_armrs=1&_ipg=&_from=

For a while I was getting Samsung ICR18650-22F-based packs for ~$25 each. It seems he only has LG cell based packs now for $45 (which I probably wouldn't buy), but I think it's worth keeping an eye on. I was able to put together a pack for my velomobile with ~850-900wh usable for around $150.

Any speed over say 17-20 mph and you are going to want a Full Suspension Bike.


Any speed over 17 mph and you are going to be using 200 on up to perhaps 500 watts or even more power because of aerodynamic drag. That pack you ordered might do if you can keep the speeds down to under 20 mph.

Then you live in England ?

For all you want to do ... Higher Speeds, Long Range, using every day,
I would look into a type of velo mobile or on of those three wheel trikes that are in Europe . I forgot the name of them now.

Regen braking is more for saving brake pads then gaining electricity back into battery.

Buy the Leaf 1500W motor kit, www.Leafbike.com and get the KT display and you will be over-joyed!

Buy some torque arms from www.ebikes.ca

Then you need to concern yourself with battery and charger. LiPo needs to be carefully thought, DIY packs, Home Depot type stores that sell battery powered lawn equipment: like the EGO 56V 5Ah or 7.5Ah packs would be as easy as going to the local store and buying the battery and charger. 10Ah or 15Ah is better to have.

Thank you all for your advise.

@ScooterMan101 yep I live in England.

@marks yep thats the reason I want regen, also the extra 5%ish (that people seem to report) might come in handy on a bad day.


The parts that im currently considering are:

• 1500w leaf motor – it seems a few people seem to like this one.

Then from http://www.ebikes.ca:

• C4835-GR controller

• CA3 with the 2 button and the potentiometer

• ebrake

• T throttle

• PAS 12p

• and of course a TorqArm_V4

what do you guys think of that setup? Am I missing anything? (other than battery)

Is there any benefit to using a certain wheel size? Or just get the size to fit the bike its going on?

I'd get the size that fits your bike.

With a given motor winding, a smaller wheel will have a lower top speed but better acceleration. Most direct drive motors I believe will be more efficient with a smaller wheel, because they can run at higher RPM, but it's not like you can run a 20 inch wheel on a frame designed for 700c.