patricke

HEY cyclists! Im looking to build my first, of hopefully many ebikes. I have a hard-tail, schwinn frontier, and am looking to buy a motor kit and battery for an easy conversion for my first bike. My main limitations are in cost, im not trying to spend more then 800usd but can if its vital. I'd like some free advice into what type of motor and battery i should go for, i dont need to exceed 25 mph, for in my state thats the limit on ebikes but little attention is payed to them by the piggers, and im looking for at least a 20mile range. I live in a very hilly area and am quite used to peddling up steep embankments but id still like a motor with some oomph. Thanks everyone!

turbo1889

I think the first decision you need to make (or at least closely study and consider your options) for your needs and the bike you wish to convert is which of the three main ways you want to go for your motor:

1 ~ Direct Drive Hub Motor (rear mount strongly preferred)
----- Can be the most reliable and trouble free with the least maintenance issues
----- Provided you get a 800+ watt version will climb most hills for most people on most bikes
----- Considerable efficiency losses while climbing hills, efficiency while hill climbing often is 50% or less (eats up battery power fast when climbing hills).
----- Best efficiency at near, but slightly less then, top end speed on flat ground.
----- Noticeable "drag" while pedaling only without running the motor due to the direct drive set-up (if the wheel is turning the motor is turning so if you are pedaling only then you have to put out a little more effort because your turning the motor as well).
----- If of decent quality and not abused can have the longest working life.

2 ~ Internally Geared Hub Motor
----- All but a select few of these motors use plastic gears in their internal gears inside the hub and those plastic gears can break and wear out especially in colder weather which makes the plastic more brittle.
----- Lower power levels then direct drives with most available units being about 250 watts with a few more powerful versions that go up to 500 watts.
----- Provided you get a more powerful 500 watt version will climb most hills for most people on most bikes, the less powerful 250 watt versions will bog down and stall unless you keep pedaling very strongly while climbing hills.
----- Not as bad of efficiency losses while climbing hills as a direct drive hub motor.
----- Have a wider efficiency range then a direct drive but still have a best efficiency speed which varies depending on the particular motor and the voltage and controller setting that it is run at.
----- No noticeable "drag" while pedaling only without running the motor because there is an internal free-wheel inside the motor gearing inside the hub that disengages the motor except when it is being used.
----- If you must mount your motor in the front fork of your bike, using one of the smaller 250 watt size internally geared hub motors is the safest option and the least likely to damage your front fork.
----- The lower power sizes of these motors are among the cheapest e-bike motors available but often don't last as long as a direct drive hub motor.

3 ~ Mid-drive or Crank-drive Motor
----- A mid-drive or crank-drive motor hooks up to your bikes main drive chain or pedal crank and works through your bikes gears right along with you pedaling. Most kits use some kind of freewheel arrangement so that the motor won't turn the pedals but a few set-ups will turn the bikes pedals when the motor turns so you must always pedal whenever the motor is used. Some people actually like it that way because it makes sure they have to pedal in order to use the electric motor and they can't get lazy, but there is a safety issue and you can end up getting your legs and feet smacked by spinning pedals just like on a tandem bike if the captain and the stoker don't play nice together.
----- The most efficient type of drive with an efficiency range that is as wide as the gear range on your bike, the power and efficiency zones of the electric motor should be matched to your pedaling speed so as long as you change gears up or down to keep your pedaling speed in a normal comfortable zone the motor will also be in its optimal zone as well.
----- Will climb any hill that you could climb by gearing down under pedal power alone plus some and do it without losses in efficiency that suck down the battery pack juice.
----- Since the motor drives through your bikes chain and gears with higher power mid-drive set-ups this can result in those components wearing out faster then they normally would, this is especially true for high power mid-drives that are over up to or over 700 watts. Chains will stretch out faster and need to be replaced more often and although increased sprocket and chain-ring wear is less noticable and doesn't need to be replaced as often as chains it will increase as well unless you are running a low power mid-drive in the 150 to 350 watt range. Good thing is that bike chains are fairly easy and cheap to replace and chain stretch is where most of the extra wear occurs.
----- A good mid-drive will have no noticeable "drag" while pedaling only without running the motor because there is free-wheel on the motor output sprocket. Some mid-drives use an extra chain loop that goes to the motor so you may be spinning a little more chain then you would on a pedal only bike but that makes very little difference when it comes to pedaling the bike without the motor running and the weight of the batteries will be what you notice when pedaling only. Depending on how the extra chain loop is routed you may need to be extra careful about strapping down your shoe laces.




For a direct drive rear hub motor here is one in your price range you could look at:

https://www.electric-bikekit.com/387-...eeks-delivery/

I haven't personally used that specific motor but a lot of people on this forum have done so with some good results. Here is a long thread with one main posters experience with them and a few other users of that motor chiming in as well:

https://www.bikeforums.net/showthread...onversion-kits




I don't have any specific suggestions for an internally geared hub motor, there are a lot of them out there from a whole lot of sources that are within your price range for the smaller 250watt size of those motors. The big 500 watt versions are considerably more expensive and with your budget wouldn't leave you enough money for a decent battery pack set-up after you paid for the motor kit. I suggest just doing some web-searches and searches on this forum, there is plenty of information on those motors out there and in the smaller size they are very common.



For a mid-drive set-up this is the best deal I know of for a decent quality kit (I'm ASSuming your in North America):

https://www.sickbikeparts.com/catalog...roducts_id=170

That's a "Cyclone" brand name 650 watt external controller mid-drive kit or a very close clone of one. I don't own that specific product (Yet !!!), unfortunately a deal like that wasn't available at the time I purchased a Cyclone mid-drive kit and I had to buy from Taiwan direct where they are made and payed over twice as much for a lower powered 360 watt internal controller kit that I eventually had to convert to use an external controller because I kept burning out the internal controller units. The external controller models of the Cyclone motors are known to be reliable products (their smaller sized motors with internal controllers are known to burn out internal controllers a problem their bigger models with external controllers don't have), they aren't the most efficient, best looking, quietest, or smoothest mid-drives on the market but they are built strong with metal gears for a much cheaper price then fancier mid-drive kits out there.

Another popular and cheap mid-drive out there is the GNG mid-drive kits (google "GNG electric bike kit") of which I can only recommend their two newer and more efficient brush-less versions with a caution that the more powerful of the two, the on that uses a toothed rubber belt in its reduction eats belts out of the box and you will need to keep up a supply of spare belts for it. I do own one of those but I've modified mine to run at lower power outputs then it was designed for to keep it from eating belts and to make it run quieter and smoother.






As for batteries, expect to spend half or more of your budget on your battery pack set-up (or in other words for your budget the absolute most you can spend on the motor kit and everything else but the batteries needs to $400 or less, preferably less without sacrificing quality and getting a junk motor kit that isn't going to be reasonably reliable and last a while.). There are very few e-bike applications where using the old cheap and heavy lead acid batteries make practical sense. There are, also, very few applications were using Ni-MH batteries which are the next step up make practical sense.

Your going to want some kind of Lithium (Li) battery technology. They are not cheap but they pack a whole lot of power into a small and light weight package that is ideal for most e-bike applications. Since your budget is limited I will limit the discussion to the two ways I know of where you can get the most Li batteries for the lowest cost:

1 ~ Use RC type Li-Poly battery packs, a bunch of them all wired together.
----- The idea is to find which big 4+ cell pack with high mAh capacity gives you the most juice for the lowest price per watt storage capacity.
----- The "go to" place for doing this is usually hobbyking.com although you can sometimes find a little better price somewhere else.
----- You figure out which pack is your best deal that you can wire them together in series and parallel to give you the right voltage to work with your motor kit and provide the greatest capacity for how much money you have to spend.
----- You can either wire them together permanent as a pack and then use a non-balancing, low current, over-nigh slow charge, e-bike charger to charge them together as a big pack permanently wired together. This is not an ideal situation and will wear out the packs prematurely but it has been done with reasonable success by some people.
----- Or you can buy a hobby type balancing charger designed to charge those packs individually. This means you will have to make a wiring harness out of plugs so you can dis-attach the individual packs from each other and charge them as RC packs. This will give you the longest battery life and good safe charging but you will need as many chargers as you have packs to charge them all at once or will have to take the packs and charge them in steps for each re-charge session swapping out packs on the charger every couple hours (also known as a PITA). You can get more power and lighter weight size this way then in the #2 option below but you will eventually end up spending more money to get enough hobby chargers to charge all the packs at once with a charger for each pack that together make up a big pack with the wiring harness to power the bike.

2 ~ Use the smallest size of Prismatic LiFePO4 cells that are generally used for solar power storage.
----- The idea is to use the smallest sizes of Prismatic LiFePO4 cells that are usually used for storage on small portable solar power stations and use those to build an e-bike battery because they are such good high quality cells at such a reasonable price.
----- The cells can be purchase individually and wired together to make a pack of the right voltage to work with your motor kit or purchased in already wired together groups to form a complete battery pack. The most common such arrangement is four cells wired together in series to make a 12.8V battery. Obviously those can be easily wired together to make the right voltages to match up with the most common e-bike kit voltages of 24V, 36V, and 48V.
----- Usually buying the four cell 12.8V batteries is the cheapest option and also is makes for easy charging options (more on that below) so it is a simple matter of finding the best deal for those batteries that you can wire them together in series and parallel to give you the right voltage to work with your motor kit and provide the greatest capacity for how much money you have to spend.
----- You can either wire them together permanent as a pack and then use a non-balancing, low current, over-nigh slow charge, e-bike charger to charge them together as a big pack permanently wired together. This is not an ideal situation and will wear out the packs prematurely but it has been done with reasonable success by some people and it is safer and less damaging to the batteries to do this with the prismatic LiFePO4 batteries then the Li-Poly RC hobby battery packs.
----- Or you can wire the 12.8V battery packs together with removable plug wire harness that puts them in series to multiply the voltage to power the e-bike and then make a second charging wire harness that hooks them together in parallel for balanced charging at 12V. You can use a regular 12V car battery to charge them when set-up this way and provided you use a low Amp setting on the charger and charge them slowly overnight it won't hurt them to do this and is a very cheap solution for charging without hurting the batteries. Or you can purchase a 12.8V four cell LiFePO4 charger which will allow quicker charging at higher charge levels then can be safely done using a cheap and dumb car battery charger since it is specifically designed for charging that type of battery and you may get slightly longer battery life as well.


I personally mainly use and am partial to the second option of the prismatic LiFePO4 batteries, specifically using the four cell 12.8V batteries that are already assembled from the individual cells and using a removable plug wiring harness to run them in series to provide multiplied voltages of 24V, 36V, or 48V to run the e-bikes and then charging them in parallel with a charging wire harness at 12V. I have a dedicated LiFePO4 computer controlled 12.8V expensive charger in my shop at home that I use to charge them that way but when I have to charge anywhere else I just use a regular 12V car battery charger set on its low charge setting including the one in the shop where I'm employed and have even on occasion charged my e-bike batteries directly off of a car using jumper cables with no problems.

This is what I have found for myself is the best buy for this type of battery set-up for my needs:

https://www.batteryspace.com/LiFePO4-...thout-PCM.aspx

----- Two of those wired together in 2s1p arrangement make a 25.6V 20Ah battery
----- ----- (410 usable 80% duty cycle watt hours for 24V e-bike kit)
----- Three of those wired together in 3s1p arrangement make a 38.4V 20Ah battery
----- ----- (614 usable 80% duty cycle watt hours for 36V e-bike kit)
----- Four of those wired together in 2s2p arrangement make a 25.6V 40Ah battery
----- ----- (819 usable 80% duty cycle watt hours for 24V e-bike kit)
----- Four of those wired together in 4s1p arrangement make a 51.2V 20Ah battery
----- ----- (819 usable 80% duty cycle watt hours for 48V e-bike kit)
----- Six of those wired together in 2s3p arrangement make a 25.6V 60Ah battery
----- ----- (1,229 usable 80% duty cycle watt hours for 24V e-bike kit)
----- Six of those wired together in 3s2p arrangement make a 38.4V 40Ah battery
----- ----- (1,229 usable 80% duty cycle watt hours for 36V e-bike kit)

turbo1889

I just ran a google image search for "schwinn frontier" to get an idea of the geometry of the bike you want to turn into an e-bike. You don't have a whole lot of room to play with on that bike. Something with a little longer wheel base would be better especially for battery mounting. Its going to be hard to keep the battery weight down low with that bike. Your options for battery mounting pretty much look like an over the wheel rear rack. Trying to mount them lower on the rear isn't going to happen without running into heal strike issues with any kind of rear pannier bags or baskets to get the weight down close to the axle height on the rear. If you use RC hobby Li-Poly battery packs you would probably be able to mount the batteries in the center frame triangle with thin sheathing on each side leaving the narrow slot in-between formed by the thickness of the frame tubes as a battery storage compartment but that will only work with the smaller thinner RC hobby Li-Poly packs it won't work with the prismatic LiFePO4 batteries which although only slightly heavier are larger physical size and bulkier and won't fit in a thin frame triangle pocket formed by just sheathing both sides of a regular bikes center frame triangle.

Your only options for mounting of a mid-drive motor are forward of the BB/Crank attached to the bottom of the lower frame tube, forward and above the BB/Crank attached to the top of the lower frame tube, or directly above the BB/Crank tube mounted to the seat down tube (not a recommended mounting position unless you have a very narrow motor drive system). Due to how tightly the rear wheel is tucked up against the BB/Crank the options of mounting a mid-drive motor behind the BB/Crank either in the lower or upper position above or below the chain-stays is not possible on that bike in addition a high rear mount behind the seat-tube is also out as well. So your mounting options for a mid-drive are more limited with that bike then some other bikes but not too badly. Obviously no mounting issues with hub-motors (there rarely is on any bike).

My personal favorite mounting positions for battery and motor are to put the weight of the batteries balanced on both sides of the rear wheel as low as possible down near the height of the rear axle and mount a mid-drive motor behind the bottom bracket either above or below the chain-stays. That is possible with bikes with a longer wheel base with the rear wheel not tucked in as tightly behind the BB/Crank. Obviously long-tail cargo bikes fit that description but also a lot of road touring bikes designed to handle rear pannier bags without heal strike issues and mountain bikes with a rear suspension system that necessitates a few extra inches of room behind the BB/Crank for the suspension linkage can often be made to work with that kind of mounting arrangement as well.

turbo1889

Also, if you decide to go with using RC hobby type Li-Poly battery packs, you should bear in mind that if your going to balance charge the packs using an RC hobby type balance charger (what those packs were designed to be charged with) all the cheaper chargers can usually only charge a pack with a maximum of 6 cells packs and the chargers get much more expensive to charge packs with 7 or more cells. Some 24V e-bike kits can be made to run off of 6 cell Li-Poly packs wired in 1s#p arrangement. For 36V e-bike kits you buy 5 cell packs and use a 2s#p wiring arrangement. Some 48V e-bike kits will run off of 6 cell Li-Poly packs wired in a 2s#p arrangement but most won't unless you use a controller where you can adjust the low battery shut-off down a little, same goes for the 24V systems but they tend to be a little more forgiving for a little under voltage then the 48V systems.

Just forgot to mention that fact when working with the RC hobby Li-Poly packs that the price of the charges goes up exponentially once you start using packs with more then 6 cells to a pack if you want to balance charge the individual packs with hobby chargers (highly recommended for longest service life).

chas58

Here is a list of of what to expect with different motor/battery types.

Click on picture:




Unless you are a pretty hard core tinkerer with electronics, you are not going to want to get Lipo (that is definitely not plug and play). Lithium ION, or better yet LiFePO is a lot safer and easier to work with for most people.

I'm not sure why anyone (other than the electronics tinkerers) would get LiPo unless they want a very large pack and don't mind the complexity of wiring things in parallel and series, tracking the status of each battery individually, and the safety/fire issues. That is a lot of caveats. They are great for the hard core guys who like that kind of thing.


Battery is your biggest expense and is going to determine how fast you go (24 vs 36 vs 48 volts) how much you spend, and how much your rig weighs. As you can see, it is pretty hard to go over 20mph with 36volts. 24 volts is good for riding at slow speeds indoors (or maybe just for slow speed hill climbing).

turbo1889

The answer to that question is ~ $$$ ~ when it comes down to getting the most watt hours of battery for the lowest price the RC hobby Li-Poly packs (especially the Zippy cheap but acceptable quality brand name packs) are among the lowest priced option. They are, however, best suited to low powered light weight builds, especially 24V builds that will run okay at the slightly lower voltage level of 22.2V that the 6-cell packs put out. I've got some 3,700mAh 6-cell packs I picked up for $19.99 (special sale price) each along with a $59.99 charger (store brand but works good) that can charge four of them at the same time with four separate computer controlled balance circuits. With a simple wire harness that hooks four of those packs together in parallel that gives me a 22.2V 14.8Ah pack (263 watt hours at 80% duty cycle) pack for only $80 for the batteries. Yah, the charger cost me $60 and it cost me a few bucks to buy the plugs and wire to make the wire harness that hooks them together in parallel but with two $80 packs one on the charger on one on the bike it is a very economical option for a 24V system that will run fine off that slightly lower voltage and is very light weight.


I certainly agree that LiFePO4 batteries are a lot safer and have a longer service life and I certainly prefer them for any kind of high powered build especially with using the prismatic cells which are really good cells and if a single cell goes bad I can swap it out and do the repair myself and the whole pack isn't bad.

But the Li-Poly RC hobby packs can be used to good advantage as well in some builds and they are one of the two more economical options I know of so for someone working on a limited budget I'm going to mention the option that exists there. But it is certainly true that they have there disadvantages as well.

turbo1889

Also, @ OP

I suggest you look up the previous posts of above posting member, chas58, he has done more research and has more hands on experience with the geared hub motors then I do. My strong suit is mid-drive set-ups with a minor in direct drive hub-motors and my weakest area is what can be done with the geared hub-motors (or more correctly my direct experience with the smaller 200-350 watt power ones has been disappointing) so to get a good idea of your options from people with first hand experience in that area I would refer you to other posters; chas58 is one of them. I've heard good things about the 500+ watt bigger more powerful geared hubs but have yet to actually play with one myself and I've heard that if used correctly the little ones can work as well but apparently I haven't used them correctly (with the one exception of the hill climber assist drive I built using one of them but I'm not using it as a hub motor in that application).

chas58

I wonder if we lost patricke...

Lipo batteries are certainly worth considering. For the size, weight, and price, you can get Li-Ion batteries (if you include all of the extras besides battery price: alarms, voltage monitors, charger, etc); you really need to do your homework for Lipo. And, for those of us that have the time and passion they work great.

Li-Ion (or LiFePo) is plug and play. I got home late last night, plugged my battery in and went to sleep. Most people wouldn't sleep while a LiPo was charging (unless they really trusted their fire alarm).

Li-Ion is great for the casual user who wants plug and play.
LiPo for the hobbyist who is going to take the time and energy (and precautions) to make it work right.

I was leaning to Lipo for my next pack (small light weight pack for commuting), but I see no downsides to a small Li-Ion pack with quality Samsung cells. That and with the Li-Ion I can charge at work or at home while sleeping. If I'm using it every day, trouble free charging is a priority.

chas58

Here is a Lithium battery fire (RC guy?, E-bike guy? Lipo?) that burned a house yesterday.

Link to article:
Exploding battery leaves $150K damage bill

Maybe I'm just nervous, but Lipo does need respect.

turbo1889

Certainly does, and thanks for bringing that up (a fact I just took for granite and thus failed to mention). I personally charge my Li-Poly RC type packs in the shop on the concrete floor, and I don't use high Amp fast chargers but rather charge at a lower, slower, safer rate. Idea being the concrete floor makes a great heat sink to potentially prevent a problem from starting in the first place by keeping the packs cooler while charging and also if a fire does start that it where it is least likely to spread. In-fact I do that for all my non-LiFePO4 chemistry lithium batteries. LiFePO4 is very stable and almost idiot proof (nothing no matter how benign is ever completely idiot proof) so I don't even bother taking any precautions with them and charge them right on the hard-wood kitchen table and sleep peacefully doing so.

Jimi77

Some people charge inside a fireproof box - ie ammo can.

chas58

Yep, concrete floor or inside an outdoor grill are the top contenders for Lipo charging locations.

Just don't pick up a puffy pack that is charging and then go running to dad complaining you burnt your hands while the house is burning down. A 47 year old guy doing that does conjure up some odd stereotypes...