Sorry for posting a new topic but could someone help advise

[JustinClementsUK]

Hi, I am a total noob to electric bike conversion and just need some general advice. I've been having a good look around the forum but have struggled to find any of the basic general information I need to get started.

Starting with my needs: I want to commute about 10 miles to work each day over some fairly steep hills. I'm not too worried about speed but do want to get up those hills with ease!!

In the UK we are limited to a motor of 250w with a top speed of 15mph. Looking at the forums I get the impression that a 250w motor will only give minimal assistance with hill climbing so am considering getting something bigger.

There doesn't seem to be a huge variation in cost between a 250w kit and a 1000w kit so should I just go for 1000w or is that just overkill? Other kits are available at 500w and 800w. For what I need, (a good helping hand climbing hills) what would you recommend?

The kits come with a choice of battery voltage, 24v/36v/48v I assume the higher the voltage the heavier the battery due to the increased no of cells but then a high voltage will draw less amps so less power loss in creating heat is this correct? What are the pro's and cons of higher voltage to lower voltage systems and what would best suit my needs for getting up that hill?

Travelling 20 miles a day over hills for a fairly light person 10.5 stones who is reasonably fit and will be pedaling constantly would a 10ah battery be sufficient or should I get something bigger. Again there is a pro of less weight against a con of reduced mileage and I think longevity of the battery.

The best value combinations I've found so far are:

Kit: http://www.ebay.co.uk/itm/48V-1000W-Front-Wheel-Electric-Bicycle-Conversion-Kit-E-Bike-DIY-Cycling-Motor-/170941463949?pt=UK_SportGoods_CyclAcces_RL&hash=item27cce7bd8d

Battery: http://www.ebay.co.uk/itm/48V-10ah-water-bottle-type-lithium-Li-ion-electric-bike-battery-/140939248087?pt=UK_Bikes_GL&hash=item20d0a241d7

Do these seem reasonable?

Hoping someone can advise.

Thanks

Justin

 

[sabongi]

http://em3ev.com/store/index.php?route=product/product&path=36&product_id=55

 

[Drunkskunk]

Welcome to the forum.

The motor kit you listed is a good example of what a basic kit should be. Thats a 9C/GM901/MXUS motor of some kind. (they are all basicly the same) Most of those motors get listed as 500 watt motors, but that vendor is basing his 1000watt rating on the controller. That could mean 1000 watts peak (48volt, 20amp limit) or That could mean 1000 watts nominal, though thats less likely.

They are also high priced. thats $330 USD. I've never paid over $250 with shipping max for one of those kits in the U.S. But where you are that may be reasonable. Do keep looking.

As Sabongi sugests, em3ev.com is a good source. They sell a similar motor, listed more accuratly as a 500 watt (nominal rating) with a choice of speed options. The lower RPM options would handle climbing a hill better. The motor he was suggesting is a geared motor. more expensive, but a good option for hills. Youll have to read more here on Direct Drive Versus Geared Hub motors. Both have benifits. Both have liabilities.


That battery is interesting, to be sure. but its cheap enough to set off my junk alarm.
This may sound counter intuitive, but the battery is far more important than the motor.
A good battery choice can make up for a bad motor choice, but a bad battery choice, and you'll be walking home.

A battery's voltage is just one dimension of how much power it will have. Generaly, more voltage on the same motor will make it faster, but you may find a 36 volt battery paired with a good motor is better than a 48 volt battery paired with a diffrent motor. Its all relitive. The Amp hours are also important, and are related to it's range, and the amount of currant it can safely provide. The current directly affects your torque and acceleration. A battery's true rating is given in watt hours. that Volts X Amps. The Watt hour rating is like the gaallon rating on a car's gas tank.

Still.... With any motor mentioned so far, I'd recomend a 48 volt battery.

 

[d8veh]

The best value combinations I've found so far are:

Kit: http://www.ebay.co.uk/itm/48V-1000W-Front-Wheel-Electric-Bicycle-Conversion-Kit-E-Bike-DIY-Cycling-Motor-/170941463949?pt=UK_SportGoods_CyclAcces_RL&hash=item27cce7bd8d

Battery: http://www.ebay.co.uk/itm/48V-10ah-water-bottle-type-lithium-Li-ion-electric-bike-battery-/140939248087?pt=UK_Bikes_GL&hash=item20d0a241d7

Do these seem reasonable?

Hoping someone can advise.

Thanks

Justin

The answers are a bit different in the UK. You really need to limit your speed to about 22mph and pedal all the time, if you don't want your collar felt. Big pancake motors will also get noticed. if you want to go over 250w, stealth becomes more important.

That bottle battery is only rated at 10amps. You can take a lot more current out of it, but it'll probably sag a lot. Also, look at the length of it. I'd be very surprised if it fits in your frame. You have to allow extra room at the top corner so that you can get the battery into the holder. Look at this one, which is only 36v 8.8aH. If it were 5mm longer, you wouldn't be able to get it in because you lift the top front upwards to unclip it. Also, have a look at Pedelecs forum that has a lot of useful stuff if you're in the UK - in particular, this thread, which shows how to make a stealthy good climber that does about 22mph, and a range of about 50 miles:

http://www.pedelecs.co.uk/forum/electric-bicycles/13226-new-build-carrera-kracken-conversion.html

 

[dogman dan]

EM3 for the win. You don't win ES endorsements from guys like DS or myself easy. Cellman has done so. Paul is native English speaking, so not like dealing with alibaba or random ebayers from china.

I can't recommend highly enough that you get a motor with some power for the hills. 250w sounds like a lot, but enough of it will waste into heat to make it less than you think.

Get a larger motor, such EM3's affordable direct drive, or the Mac. Get the slower version, so you won't stick out while you are riding by traveling 50 kph. The slower motors climb hills quite well, and for most people a 20 amps controller running 48v will be plenty. It's about 1200 watts.

 

[dogman dan]

True enough about stealth. Especially a big motor up front.

But the Mac tucks very neatly behind disk brakes in the rear motor version.

Much depends on how steep a hill you need to climb. the smaller motors can take 4-800 watts fine, and at that power will climb 5-6% grades no problem. The bigger motors in the slow windings are what you want for 10% -15% grades.

 

[whereswally606]

Im not sure how many police want to catch people with large pancake motors. both my and my girlfriends bikes have largish pancake rear hubs. They are noise wise far more discreet than an RC mid drive. RC drives can be less visible but you would definitely hear them. a mid drive tongxin would be quieter and have awesome hill climbing through the gears. whatever you do its gonna cost a bit more than you think it will so do the research first and compare some different setups and their costs.

I like old DH full sus since they ride well at speed and carry the extra weight well on the downside they are heavier and i find you need more battery to move to move the bike.