noob help

I've been reading the forums, looking at stores and it is all so overwhelming. I want to get an ebike kit soon but don't want to purchase the wrong thing. I'm the kind of guy that likes to know everything about it before he makes a decision. I just moved to a new house. Previously my commute was less than a mile. Now it is about 5 miles. I tried riding my bike but it just takes too long and I get too sweaty. What I am looking for is to get an ebike that I can ride to and from work and just charge in my office, about 10 miles total. That's it. Speed is not that important really. 15mph would put my commute at 20 minutes which is fine. It is a flat ride all the way. I'm just worried I'll get something that I think will last 15 miles and then a few days or weeks later has lost all of it's capacity.

I see all the kits with different motor sizes and battery capacities and voltages. I don't want to get something underpowered but at the same time don't want to want my money getting something overpowered. I'm just having a hard time finding out what kind/size of motor and battery will suit my needs.

Welcome to the forum.

What you want is easily attained. Any of the various 500 watt kits can exceed your need for speed and performance. The one critical factor is the battery. A good battery makes a good ebike. A bad battery makes you walk. The battery is the single most important part of an ebike. And as such, it's going to be the most expensive part.

Generaly, you need a battery sized to provide 36 watts per mile at 20mph. Thats more than you'll actualy use in normal riding, but includes a reserve for things like head winds, unexpected hills, carrying more weight, and the normal loss of capacity over time. A quality built battery sized at 36 watts per mile will still be usefull 3 years from now, and probably longer than that.

The math is simple. Volts times amps equils watts. And it just so happens that at 36 volts, you need 1 amp per mile. So a 36 volt 10 amp battery will give you a reliable 10 mile range at 20mph, and probably a good deal further in normal riding.

There are a lot of choices for motor and battery combos. many of them depend on personal taste. The simplest solution is a 305 RPM 500w direct drive motor coupled with a 6 FET controller and a 36 V 10AH battery is good for 22mph peak and at least 10 miles range. You can upgrade any part of that, and indeed most people eventualy wish they had, But those basics arwe a good starting point.

Check out EM3ev. they are known for good quality batteries and excilent customer service. There are other vendors as well, but this is a good starting point.
http://www.emissions-free.com/store/

You need to fill in your profile of where you live so that we an advise what laws apply. Then we need to know your weight, how hilly your rides are, and what bike you want to fit the kit to. Only then will you get meaningful answers.

Your needs for the motor are easy as pie. But there is a bewildering variety of ways to do what you want.

Since the ride is only 5 miles, I will digress from my standard recommend of a larger more powerful direct drive hubmotor.

I'd say a small gearmotor kit, but not the tiny 250w version, with a 36v 10 ah battery from a reputable source will do you just fine. Typical performance for those at 36v is 20 mph. You may live where the speed and watt limits are much lower though.

The short list of very good vendors for me is...

Grin Cyclery--Canada
EM3ev--China
E-BikeKit--USA

But once you tell us where you are, we may narrow that down. There are some very good other vendors in California, one pretty OK one in Texas. One very inexpensive vendor in California, Etc.

Where you live may also affect which kit is best for you. For example, I just road tested a new version kit from one of the above vendors that is remarkably water resistant.

d8veh said:

You need to fill in your profile of where you live so that we an advise what laws apply. Then we need to know your weight, how hilly your rides are, and what bike you want to fit the kit to. Only then will you get meaningful answers.

Click to expand...

i weigh around 165lbs. i live in idaho and already know the laws regarding ebikes. idaho has pretty loose laws regarding most vehicles. i have a 26in mountain bike i am thinking of using. the ride is entirely flat, may a very slight decline or incline here or there.

dogman said:

Your needs for the motor are easy as pie. But there is a bewildering variety of ways to do what you want.

Since the ride is only 5 miles, I will digress from my standard recommend of a larger more powerful direct drive hubmotor.

I'd say a small gearmotor kit, but not the tiny 250w version, with a 36v 10 ah battery from a reputable source will do you just fine. Typical performance for those at 36v is 20 mph. You may live where the speed and watt limits are much lower though.

The short list of very good vendors for me is...

Grin Cyclery--Canada
EM3ev--China
E-BikeKit--USA

But once you tell us where you are, we may narrow that down. There are some very good other vendors in California, one pretty OK one in Texas. One very inexpensive vendor in California, Etc.

Where you live may also affect which kit is best for you. For example, I just road tested a new version kit from one of the above vendors that is remarkably water resistant.

Click to expand...

thanks for the list of vendors. i life in idaho in the middle of nowhere so im pretty used to always having to go online to get anything. there is almost never a local place for special stuff.

one question though. will that advice still hold up for a ten mile ride? my commute is only 5 miles but it is 10 miles both ways and am planning on only charging it on a round trip.

Yes, with the smaller gearmotors, that have 15 amps controllers, you can easily do it on 36v 10 ah of battery.

With the larger gearmotors, or direct drive motors with 20-25 amps controllers, I recommend 15 ah battery. You'd still make the distance on only 10 ah, but the motor could strain the battery too much later on when it gets older.

However, for the short duration of your ride, your weight, and your lack of big hills, 10 ah would work for quite some time even with the larger motors. If you went with that route, I'd say it would last longer if you charged at work and at home.

If you want the most versatile possible set up for longer rides, then a larger 500-1000w motor kit, and a 15 ah battery gives you more range, and more ability for the battery to tolerate hill climbs up to 10% grade. It's not unusual for a new ebiker to get very happy, and start wanting to take the long cut, at least on the way home from work.

Backtracking, for just the ride to work and back, you really only need the much lighter gearmotor, and 36v 10 ah battery. You'd have between 12 and 20 miles of range depending on the speed you ride.

Back to Vendors, you are really close to the best kit vendor worldwide, Grin. If you have the budget, his Ezee kit is very good.

Drunkskunk said:

Welcome to the forum.

What you want is easily attained. Any of the various 500 watt kits can exceed your need for speed and performance. The one critical factor is the battery. A good battery makes a good ebike. A bad battery makes you walk. The battery is the single most important part of an ebike. And as such, it's going to be the most expensive part.

Generaly, you need a battery sized to provide 36 watts per mile at 20mph. Thats more than you'll actualy use in normal riding, but includes a reserve for things like head winds, unexpected hills, carrying more weight, and the normal loss of capacity over time. A quality built battery sized at 36 watts per mile will still be usefull 3 years from now, and probably longer than that.

The math is simple. Volts times amps equils watts. And it just so happens that at 36 volts, you need 1 amp per mile. So a 36 volt 10 amp battery will give you a reliable 10 mile range at 20mph, and probably a good deal further in normal riding.

There are a lot of choices for motor and battery combos. many of them depend on personal taste. The simplest solution is a 305 RPM 500w direct drive motor coupled with a 6 FET controller and a 36 V 10AH battery is good for 22mph peak and at least 10 miles range. You can upgrade any part of that, and indeed most people eventualy wish they had, But those basics arwe a good starting point.

Check out EM3ev. they are known for good quality batteries and excilent customer service. There are other vendors as well, but this is a good starting point.
http://www.emissions-free.com/store/

Click to expand...

yes, the battery was my biggest concern. if i get lifepos4 batteries, what would be a good average to expect in terms capacity loss over time? i dont want to get a battery that will last me exactly 10 miles and then once it can only hold 80% of its original capacity, have to pedal the rest of the way.

also, i little clarification: you say i good 36v with 10 amps will go about 10 miles. i only see batteries rated in amp hours. since you say amp hours later on is that what you mean? also, what difference in performance would i get with a 24v 15ah battery vs a 36v 10ah battery since they both give me 360w?

Take your pick, depending on how fast you want to go. Not much cost difference from smallest to biggest so I'd suggest the 48V 1000W kit.
http://www.ebay.com/itm/Rear-Wheel-Electric-Bicycle-Conversion-Kit-24V-36V-48V-250W-500W-700W-800W-1000W-/290754592384
For such a short range, battery choices are many. Just make sure it will support 30A. Personally, I use nothing but rc lipo, but you might want something like this.
http://www.bmsbattery.com/packs/559-48v-10ah-38120-lifepo4-battery-16-cells-ebike-battery-pack.html
Select 30-60A bms. This will give you at least 20 mile range at 20mph,and 10+ at max speed of ~30mph
More info on motor kit.
http://endless-sphere.com/forums/viewtopic.php?f=3&t=49638

bobbintb said:

...the battery was my biggest concern. if i get lifepos4 batteries, what would be a good average to expect in terms capacity loss over time? i dont want to get a battery that will last me exactly 10 miles and then once it can only hold 80% of its original capacity, have to pedal the rest of the way.

also, i little clarification: you say i good 36v with 10 amps will go about 10 miles. i only see batteries rated in amp hours. since you say amp hours later on is that what you mean? also, what difference in performance would i get with a 24v 15ah battery vs a 36v 10ah battery since they both give me 360w?

Click to expand...

Many folks loosely interchange the terms Amps and Amp-hours, which leads to confusion. The two figures of interest are your consumption in Wh/mi and the battery capacity in Wh.

A pretty reliable range approximation is straightforward: determine your average Wh/mi consumption then apply that to the available Wh your battery can provide.

• Usable Battery Wh rating = (Ah) x (mean voltage across the discharge curve) x (Depth of Discharge)

Different chemistries can tolerate different DOD figures which should be considered to de-rate the baseline battery capacity. DOD=80% is a general rule of thumb for LiFePO. For example, considering a 36v 10Ah battery at 80% DOD:

A '36v battery' most likely has 12 cells which at a mean cell voltage of 3.2v gives a mean battery voltage of about 38.4v, so:

• 38.4v x 10Ah x (0.80) = 307Wh

If you are using 25Wh/mi (not a bad guesstimate - pedal more and this could drop a lot - get lots of headwind and it can increase) gives you a range of:

307Wh / 25Wh/mi = 12.3mi

Here is a couple of snaps from a range spreadsheet for both 10Ah and 15Ah batteries that may help you guesstimate your range according for different battery and consumption rates:



At the end of the day, the particular battery voltage and Ah combination to arrive at a Wh value doesn't matter as long as you have a motor/controller that matches the battery - you can trade volts for Ah. There are ways to over-volt and get better range, but keeping things matched is easiest for a basic build.

From the requirements that you've given, a 250w geared motor with a 9aH bottle battery will be more than enough. Total outlay would be about $500. Your bike would still be like a bicycle. It would be easy to pick up, and you could still enjoy pedalling if you wanted. Pedalling will be easy compared with how it is now. Speed would be about 15mph on the road. We have a lot of bikes like this in the UK because we're limited to 250w, the same as most of Europe and Australia. It's only when you're heavy (like 100kg +) and there's steep hills that this becomes inadequate. This low power is outside the frame of reference for most people on this forum because they're used to higher power, but I can assure you that 250w is adequate. I did more than 2000 happy miles on one before I upgraded to 500w. I upgraded because I have some very hilly terrain where I ride and I'm 100kg. I still like to go out on my 250w bikes occasionally. 250w bikes use about 10wh/mile or less, so you'd get a range of about 35 miles. You could use full power all the time, and still have plenty left over.

If you didn't want to pedal at all, a 500w motor would be better, but then you need a bigger, heavier and more powerful battery. Everything doubles in size, weight and cost, but that's the price if you want to be lazy and go a bit faster.

If you want more than that, there'll be plenty of advice on how to turn your bike into an electric moped.

ok, it has been a while since I have visited this. here are two kits i am looking at:

http://www.bmsbattery.com/ebike-kits/426-250w350w-q-85100sx-motor-e-bike-kit.html
http://www.bmsbattery.com/ebike-kits/371-250w350w-q-85100sx-motor-e-bike-kit.html

and the battery i am looking at:
http://www.bmsbattery.com/36v/571-bottle-ebike-battery.html

i just wanted to check with the forum to make sure these will meet my requirements. again i want a kit that will give me 10 miles round trip (minimal to no incline) and still be able to do so after the battery looses some capacity over the months or years. speed isn't important as long as it is at least 15-20mph. i'm not looking to go fast, just get there in time.

and another question. will i get more range with that battery choosing the 250w kit vs the 500w kit? what is the advantage of more watts? speed? torque?

Those two kits are look identical except for the display type. Either would do the trick for your needs. Price looks good, too. As for the bottle battery, there is a recent review of one of those on here by YPedal at http://endless-sphere.com/forums/viewtopic.php?f=4&t=54473

With the smaller geared motor and the bottle battery, it should be a clean and stealthy looking ebike.
Good luck with the build.

If you're going to be pedalling, you want at least an LED display. The LCD ones have more levels, so are better. If I were ordering the kit, I'd get the Q100C motor-wheel and the S06P controller. These motors at 36v will give you a max speed of about 28 km/H in a 26" wheel, and proportionally higher in a 700c. If you have nice brake levers or integrated levers/changers and cable brakes, you need a pair of the hidden wire brake sensors.

All the Chinese suppliers are now struggling to find a carrier that will send the battery by air, so check with BMSB before ordering. I think soon we'll all be using Hobbyking Lipos again.

man, that shipping cost is a killer.

bobbintb said:

man, that shipping cost is a killer.

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You have to look at the total cost, which is cheap.

If you have an mountainbike now or any other bike you can get a quick conversion kit from Clean Republic located in Seattle, wa

http://www.electric-bike-kit.com/hill-topper.aspx

there is a quick video on the entire conversion, takes 3 minutes, it took me 30 minutes cause I had to open up the dropouts for the thicker axle. I have 7 e-bikes of various forms, the Hill topper was my first, used sla batteries at first, then Lifepo3 and now Lipo. I use this bike setup for ny commute to work this year. A distance of 17 miles on flat Chicago roads, hauling my 250 pound body, takes me about 1.5 hours, top speed is a little over 20 mph, but I cruise at about 15mph. Motor is a gear hub, total weight of bike and batteries ...about 60 pounds, give and take.I also have a more poweful direct drive, which weighs about close to 100 pounds.
this motor drive the front wheel and I am using 8 6s batteries(48v 20a) for my commute, with plenty juice leftover. the motor is a 250watt unit at 24v, I over juice the motor to 48v and has been running over 2 years with no problem. The controller I think is 15a unit, but can take up to 50v.
since you are not looking for speed, a 36v 15a should be plenty and you dont have to charge at work.
the main drawback to this system is there is no throttle, just a button to give on and off, not drastic, you can get used to it pretty quick, they say most people use it either on or off most of the time. Next you will need to decide how you are going to run the wires, at least you don't have to mess with the gears in back. Just my 2 cents.

Jerry