Need opinions.Putting together my first ebike from scratch.

[Supertux1]

Hi Forum! This is my first post but I have been reading and researching for several weeks.

I'm going to be building my first ebike over the summer, the intention is to commute to work and back on nice days, but I would also like to have a little recreational fun with it too. (Not racing or difficult single track trails etc...)

My route is 12 miles each way and contains a little bit of everything, bike paths, city roads with and without bike lanes (25mph), and paved country roads (45mph) with narrow paved shoulders, there are one or two hills and they aren't very steep, but long.

On my morning commute, I spend almost an hour in traffic and spend about $4 in gas a day. It would be nice to not have to do that anymore with the option of working to get healthier. I weigh about 185 pounds height 6' (not fat) and I have strong skier legs although my cardio fitness isn't that great. I'm very lazy.

I will be able to charge at work if I can take the battery inside, but my bike would be locked to a rack where I can't supervise it all day.
I don't necessarily care about it being 20mph/750W legal as long as it looks more like a bike than anything else.

This is a very popular bike city with bike lanes, dumb bike cops and smart bike thieves, so I have to be careful with how things look.

Tinkering Background:

I have an extensive background with mechanical and electrical things. In my man cave I build 5KW tesla coils and large electric/nitro RC helicopters. I'm not as familiar with bikes. I could put one together but I don't know how to lace a wheel, repair chain links or install/uninstall a freewheel. (I could learn, but I want to keep my first project very basic.)

Here are my requirements:

o Able to go at least 12 miles in aforementioned conditions in under an hour with no pedaling. Less is better. (It takes me 45 minutes to drive.)
o It has to look like a bike. Nothing in the frame triangle. No explosive device looking things with wires out. No questions from cops.
o Expensive parts (battery/controller) easily removable and/or lockable.
o Full suspension.
o Disc brakes.
o Safe Lithium Battery

I looked at some of the pre-assembled retail ebikes and didn't like the way they looked (not like a bike), price/power wasn't optimal and they look difficult to repair or upgrade. I took a look at the BionX kits, and they look they have the performance but seem proprietary, which means expensive and difficult to repair or upgrade, and also not a big fan of the LiMn battery chemistry.

So with all that in mind I have decided on the following components as potential candidates, I want this to last me a long time so I am being conservative with ratings.

I'd like to run it by the forum for a sanity check before I pull the trigger and buy it all:

Battery: 48V LiFePO4 Ping Battery, either the 15Ah or the 20Ah:

http://www.pingbattery.com/servlet/the-12/48V-15AH-V2.5-LiFePO4/Detail
http://www.pingbattery.com/servlet/the-2/lifepo4-lithium-ion-phosphate/Detail

The 15Ah says rated at 15A, continuous 30A, cutoff 40A. 720W,1440W,1920W
The 20Ah says rated at 20A, continuous 40A, cutoff 50A. 960W,1920W,2400W

Never had a LiFePO4 battery before, only the LiPo sausage exploding fireball kind in RC.
What's the lifespan difference in running a Ping LiFePO4 battery at its 1C rated vs. 2C continuous discharge rate?

eBike Kit: I think I'd like get the 48V e-bikekit.com rear direct drive kit: http://www.e-bikekit.com/shop/index.php?p=product&id=136&parent=4

I am curious as to which brand of controller and motor hub this kit uses. Is it the same as the suspicious Chinese ones on eBay?

The specs from e-bikekit.com list this controller as 20A @ 48V which would be 960W.
Is this a continuous rating or one of those Chinese maximum theoretical we dare you to try for more than a minute eBay numbers?
What's the real deal here?

If it's a continuous rating, then should I pick the 20Ah Ping battery, or if a max rating, then the 15Ah Ping battery?
(Remember, I want to be able to ride the whole 12 miles in under an hour, without pedaling, faster is better.)

This kit comes with special brake pulls, is that for regenerative braking or just simply to cut the power to the motor?
If not for regen, is the motor compatible with regen if I want to upgrade the controller later? (I am fine with soldering etc...)

Bike and Bike Accessories: This is the area I'm most clueless, so most questions.

About the only thing I know for sure is that an aluminum framed bike needs reinforcement in the dropout/forks to prevent torque stripping.
(I have RC helicopter experience and fun stories of how torque loves to modify weak aluminum/plastic parts.)
I am familiar with DoctorBass' torque arms and might get some if they are still available. Or make my own.

I have this bike in mind because it has the most good ratings on Amazon and meets my requirements of disc brakes and full suspension: http://www.amazon.com/GMC-Topkick-D...4W2C/ref=sr_1_1?ie=UTF8&qid=1332192244&sr=8-1

The only fault the reviewers say consistently has is that it weighs a ton, but they say it's a good value.
Since it will be electric powered, weight is not a huge deal.

It's also a 700c bike, so I am interested in what the going opinion is on 700c vs 26" in ebikes?

Also any thoughts about mounting a battery on the back of a full suspension bike?
Are there any good seatpost racks that are up to this task?
(I have the machining skills to make or modify a mounting platform.)

Sorry for the long post. I want to make sure I do this right.

 

[LegendLength]

o Able to go at least 12 miles in aforementioned conditions in under an hour with no pedaling. Less is better. (It takes me 45 minutes to drive.)

For that you'll need about 350 Wh or the equivalent of a 48V 7Ah pack. Personally I'd steer towards getting a pack double that size to avoid charging at work.

o It has to look like a bike. Nothing in the frame triangle. No explosive device looking things with wires out. No questions from cops.

This is always a difficult part of the build. Sounds like the only option is a bag on the handlebars or hanging off the seat post. Then you would take the bag with you when you go into work.

If you do go that route ensure you have a hard shell around the batteries to allow for worst case scenario (i.e. crashing).

o Expensive parts (battery/controller) easily removable and/or lockable.

Could try putting the controller in the bag too but they really need airflow. You don't want it heating up the batteries either. But if you want stealth there aren't many options (controllers look pretty ugly in the open). Perhaps you could compartmentalize your bag so the controller is in one part that has air cooling and the batteries are separated by some type of thermal insulation.

The 15Ah says rated at 15A, continuous 30A, cutoff 40A. 720W,1440W,1920W

You won't get much more than 1.5 kW continuous out of that motor so I think the 15Ah would be fine. But might be best to wait for advice from someone who has used that chemistry (there are many on this forum who have).

This kit comes with special brake pulls, is that for regenerative braking or just simply to cut the power to the motor?

They'll almost definitely be regen. Note that regen on these types of controllers is pretty much an on-off affair. i.e. the regen is not proportional to how far you pull the level in.

I am familiar with DoctorBass' torque arms and might get some if they are still available. Or make my own.

That kit comes with a universal torque arm which would be fine for 1.5 kW rear wheel setup. Ensure your main axle nuts are very tight though. Testing on the forums have shown this is the most important thing.

I have this bike in mind because it has the most good ratings on Amazon and meets my requirements of disc brakes and full suspension: http://www.amazon.com/GMC-Topkick-D...4W2C/ref=sr_1_1?ie=UTF8&qid=1332192244&sr=8-1

Unfortunately it's going to be a piece of shite if it's $300 . It's sad but just the way things are with full suspension bikes. I'd strongly recommend buying a good 2nd hand FS frame for $150 from pinkbike.com or somewhere similar, then adding the accessories yourself. These are frames from bikes that were $1000 - $2500 5 years ago.

For simple commuting like you're doing it doesn't really matter that much. But I still like the idea of buying a very good quality, strong, well reviewed frame for any type of e-bike build. The main reason is you are putting a lot more stress on the frame due to the additional weight.

I'd also consider buying a high quality rim + spokes and getting it laced (expensive though). The dead weight of the wheel (16 lbs or so) is immense for a normal rim.

It's also a 700c bike, so I am interested in what the going opinion is on 700c vs 26" in ebikes?

I think it's fine either way although you'll have more luck buying tyres etc. for 26 inchers. Especially wide downhill style rims (e.g. 36 mm).

Also any thoughts about mounting a battery on the back of a full suspension bike?

Keep it as sprung weight (i.e. on the frame not on the swingarm). If you mount it on a pole that extends from the swingarm you will need to brace it hard otherwise it will flop around a fair bit.

Sorry for the long post. I want to make sure I do this right.

I commend that and recommend you continue with that style of build. I think most on this forum have spent a lot of money on things they didn't really want due to lack of prior research (including myself). I've probably wasted $1000 on crap I didn't need due to postage, small items, change of design direction etc.. Your requirements are probably the easiest you can get so you are lucky there (except for the stealth requirement). So I wouldn't expect too many issues.

One thing though while I remember is be careful of the rear deraileur. Most kits come with 7 speed at most and mountain bikes usually have 9 speed deraileurs. These do not mix well due to indexing. You may need to buy a new 7 speed deraileur. They are usually terrible quality and limited for choice unfortunately.

 

[Supertux1]

o Able to go at least 12 miles in aforementioned conditions in under an hour with no pedaling. Less is better. (It takes me 45 minutes to drive.)

For that you'll need about 350 Wh or the equivalent of a 48V 7Ah pack. Personally I'd steer towards getting a pack double that size to avoid charging at work.

Charging at work isn't a problem, I sit at a desk and can watch it all day. I figure I'll be taking the pack in anyway for security reasons. My main concern is deep discharging and ruining the battery, so lots of overhead.

The more that I think about this, once I'm at work I may want to run errands in the city at lunch time, so a little bit extra would be nice too.

o It has to look like a bike. Nothing in the frame triangle. No explosive device looking things with wires out. No questions from cops.

This is always a difficult part of the build. Sounds like the only option is a bag on the handlebars or hanging off the seat post. Then you would take the bag with you when you go into work.

If you do go that route ensure you have a hard shell around the batteries to allow for worst case scenario (i.e. crashing).

I think I am leaning towards hanging off the seat post to keep it sprung weight and reduce road shocks that could damage the cells.
It is not uncommon around here to see people with pannier bags on either side and rear bags, so I think this will be okay as long as the wire connections out of it are discreet.

I found quite a few paddle rear rack kits that can support up to 20 pounds: http://www.amazon.com/dp/B000FIATVC
Maybe rig something up so that the rear of the rack is connected to the frame with something like this on each side to eliminate rack bouncing: http://www.amazon.com/Monroe-901403..._2?s=automotive&ie=UTF8&qid=1332214222&sr=1-2

There are also weather resistant bags with a compatible rail latching system that are large enough to hold the Ping 15Ah (16lb) battery with room to spare: http://www.amazon.com/Topeak-Trunk-...sporting-goods&ie=UTF8&qid=1332213139&sr=1-14

Plan is to build a reinforced vented box out of 1/4" plywood for the battery and line it with foam rubber to absorb micro vibrations. (Just a bigger version of what I do for RC planes and Helis.)
The only issue then would be heat dissipation if I tried to put the controller in, so maybe that goes outside on the top/side of the bag, anodized black or a coating of some kind of black paint that doesn't interfere too much with the thermal dissipation properties. It would be great if this was also weather resistant but not a requirement. It doesn't matter how complicated the design gets as long as everything looks like hardware that's supposed to be there.

(If you can't already tell, I love Amazon. I get free two day shipping on most things, including bikes.)

o Expensive parts (battery/controller) easily removable and/or lockable.

Could try putting the controller in the bag too but they really need airflow. You don't want it heating up the batteries either. But if you want stealth there aren't many options (controllers look pretty ugly in the open). Perhaps you could compartmentalize your bag so the controller is in one part that has air cooling and the batteries are separated by some type of thermal insulation.

One of the reasons why I want to be conservative and over-engineer things when it comes to the power ratings of components. 1.5kW is a lot of power, how efficient are these controllers?
I could cut some holes in the sides of the bag and sew in some mesh panels where they won't easily be seen. Maybe just mount the whole thing to a massive block of aluminum and drop it in the bag and call it done.
Ideally I'd like to be able to park my bike, disconnect one or two electrical cables, then pull the bag off and walk away.
What would even be cooler is to make it modular to go on another bike this way.
(This is what initially attracted me to the BionX system.)

The 15Ah says rated at 15A, continuous 30A, cutoff 40A. 720W,1440W,1920W

You won't get much more than 1.5 kW continuous out of that motor so I think the 15Ah would be fine. But might be best to wait for advice from someone who has used that chemistry (there are many on this forum who have).

This kit comes with special brake pulls, is that for regenerative braking or just simply to cut the power to the motor?

They'll almost definitely be regen. Note that regen on these types of controllers is pretty much an on-off affair. i.e. the regen is not proportional to how far you pull the level in.

Yeah someone will have to verify that e-bikekit.com kit does something with regen. That'd be awesome if it did, but I'm not too concerned if it isn't. I'd just have to make the dropout more bomber.
Regen can't possibly extend the range that much because there's not a whole lot of kinetic energy to convert into power and the efficiency must be low. (Unlike a car.)
(Future idea: car stereo power capacitors & diode in parallel with battery. http://web.ing.puc.cl/~power/paperspdf/dixon/42a.pdf)
It'd only be useful for brake assist with the heavier bike/battery/wheel, but I'll have disc brakes so it's not a real requirement.

I am familiar with DoctorBass' torque arms and might get some if they are still available. Or make my own.

That kit comes with a universal torque arm which would be fine for 1.5 kW rear wheel setup. Ensure your main axle nuts are very tight though. Testing on the forums have shown this is the most important thing.

I have a pretty good idea of where the weak points are in most mechanical things. Cheap aluminum part breaks? Replace with stainless steel. Rinse. Repeat.
I would use blue loctite on everything that is attached to something that moves.

I have this bike in mind because it has the most good ratings on Amazon and meets my requirements of disc brakes and full suspension: http://www.amazon.com/GMC-Topkick-D...4W2C/ref=sr_1_1?ie=UTF8&qid=1332192244&sr=8-1

Unfortunately it's going to be a piece of shite if it's $300 . It's sad but just the way things are with full suspension bikes. I'd strongly recommend buying a good 2nd hand FS frame for $150 from pinkbike.com or somewhere similar, then adding the accessories yourself. These are frames from bikes that were $1000 - $2500 5 years ago.

For simple commuting like you're doing it doesn't really matter that much. But I still like the idea of buying a very good quality, strong, well reviewed frame for any type of e-bike build. The main reason is you are putting a lot more stress on the frame due to the additional weight.

I'd also consider buying a high quality rim + spokes and getting it laced (expensive though). The dead weight of the wheel (16 lbs or so) is immense for a normal rim.

Yeah I'm not having any high expectations for the bike itself. This one seems to be the best 'cheap' one I could find.
I do have an old (15+ years) 700c Trek bike with no suspension and V brakes and a few other department store type bikes lying around, but I feel they would fare no better.

I'm sort of relying on e-bikekit.com to know what they're doing when it comes to rim building. Someone will have to comment on the quality of that.
As I learn more, I'm starting to think that maybe a geared motor would be better for my requirements.
(Smaller, lighter, more stealth, longer range at the expense of gear wear and top speed.)

It's also a 700c bike, so I am interested in what the going opinion is on 700c vs 26" in ebikes?

I think it's fine either way although you'll have more luck buying tyres etc. for 26 inchers. Especially wide downhill style rims (e.g. 36 mm).

That's what I hear. 700c is sort of new and less adopted / less 'standard' in certain areas right?

Also any thoughts about mounting a battery on the back of a full suspension bike?

Keep it as sprung weight (i.e. on the frame not on the swingarm). If you mount it on a pole that extends from the swingarm you will need to brace it hard otherwise it will flop around a fair bit.

I found some rack kits that are made exclusively for rear suspension bikes that involve the usually connection at the dropout and then another further up on the diagonal arm.
It would be mounted lower than a seat rack, and could take side bags, but it looks like it would interfere with the disc brakes and other unwanted things aside from the shocks it would take.

Sorry for the long post. I want to make sure I do this right.

I commend that and recommend you continue with that style of build. I think most on this forum have spent a lot of money on things they didn't really want due to lack of prior research (including myself). I've probably wasted $1000 on crap I didn't need due to postage, small items, change of design direction etc.. Your requirements are probably the easiest you can get so you are lucky there (except for the stealth requirement). So I wouldn't expect too many issues.

One thing though while I remember is be careful of the rear deraileur. Most kits come with 7 speed at most and mountain bikes usually have 9 speed deraileurs. These do not mix well due to indexing. You may need to buy a new 7 speed deraileur. They are usually terrible quality and limited for choice unfortunately.

[/quote]

That $300-crap GMC Topkick bike I linked comes with a 7 speed "Shimano RD-TZ30GS SIS" deraileur - I don't know if this is good but Shimano is good right? Also, the freewheel in the e-bikeskit.com kit is also a 7 speed.

Thanks for the help, I have learned in other hobbies how to waste money by buying the thing with the most clever marketing and finding out later that I didn't do a good enough engineering assessment of it.
Nowadays whenever I get into a new hobby or start a new project I tend to avoid the 'top of the line' marketing BS found by Google until I understand it more.
Sometimes I find the best solutions to tricky problems are actually homegrown by fellow hobbyists in their garage and that the commercial equivalents are just crap.
I like 'second best' or 'good enough' from smaller companies, many just start-ups, at a more reasonable price.

 

[999zip999]

You can get a used comly frame bike cheap that was 800usd. for 80 to 100usd. Older but with good compents Xl ect. Ping makes a split pack 48v20ah with longer wires.

 

[motomech]

QUOTE- "Charging at work isn't a problem, I sit at a desk and can watch it all day."- END OF QUOTE

Hey, I'm qualified to do that. Are they hiring?

 

[LegendLength]

Charging at work isn't a problem, I sit at a desk and can watch it all day. I figure I'll be taking the pack in anyway for security reasons.

I understand but I mean for the convenience factor of having to bring them in every day. One path to consider could be building a locked box for the batts?

The only issue then would be heat dissipation if I tried to put the controller in, so maybe that goes outside on the top/side of the bag, anodized black or a coating of some kind of black paint that doesn't interfere too much with the thermal dissipation properties.

Yeh I like that idea. I've thought about painting my controller black but have no idea if paint would ruin dissipation. Probably some mesh would be enough to block the outside view yet still allow airflow.

1.5kW is a lot of power, how efficient are these controllers?

I have the same motor but a lyen controller (very similar controller to the kit). The main thing that creates heat is running it at a bad rpm, like steep hills. Mine stays lukewarm at 1.5 - 2.0 kW on the road but going up steep hills off-road makes it sizzle! Even the power wires going to the motor get too hot to touch.

I currently have my controller 1 inch from my lipo in a fully enclosed aluminum case. I'm only riding on-road currently and haven't had any ill effects. So I think you'll be right with 1/2 inch separation and some foam.

Regen can't possibly extend the range that much because there's not a whole lot of kinetic energy to convert into power and the efficiency must be low. (Unlike a car.)

It's about 5% on my bike for 'average' riding. Great for saving brake pads though!

As I learn more, I'm starting to think that maybe a geared motor would be better for my requirements.

I think geared motor would be great for your requirements (100% city driving short trips). My only concern would be they are slightly louder than a direct drive hub. I've never heard one in real life though so I have no idea really. The big bonus is you can pedal easily without using power.

I found some rack kits that are made exclusively for rear suspension bikes that involve the usually connection at the dropout and then another further up on the diagonal arm.

Even though there's no off-road I would recommend against having the battery unsprung. It will defeat the purpose of having suspension IMO.

That $300-crap GMC Topkick bike I linked comes with a 7 speed "Shimano RD-TZ30GS SIS" deraileur - I don't know if this is good but Shimano is good right? Also, the freewheel in the e-bikeskit.com kit is also a 7 speed.

Same as mine I believe (or very close). They are rubbish but still function ok.

Note also the disc brake on those motors can be difficult to set up because of clearance issues for the caliper (the issues just keep coming don't they ).

 

[dogman dan]

Nothing wrong with the choice of a 48v 15 ah ping. Plenty of capacity, and it sounds like a typical 20-25 amp controller will provide you with all the amps you need. You don't mention any killer hills.

27 mph top speed on the E-BikeKit dd motor on 48v should be fast enough. The 45 mph roads with no shoulder will be a problem. Try to find an alternate route. Especially if you have miles of no shoulder and 55 mph cars. You'll have the range to ride a 17 mile route easily. But if you build a 45 mph bike, you'll get caught hooning around on the bike trails. You'll need to tone it down considerably on the multi use paths unless you ride them when they are empty.

The slightly sub 30 mph speed is a good compromise, faster on the skinny road, but tolerable to ride slower when you must.

But here is where it starts to get sticky. If you build this, it will handle like crap. Yeah, I have one, but really I don't ride it faster than 20 mph because of the poor handling. Rear motor and rear rack ping just doesn't cut it. This bike does ride ok if I go for short rides, with just 8 pounds of lipo in the box. Put the 16 pound ping back threre, and it rides too light on the front wheel.

One alternative for a bike for pavement is front hub. Personaly I like it a lot. But front hub installs on alloy suspension forks are particulary difficult to get right. Get it wrong, and you may be spitting teeth out. It's serious shit, and I cannot recomend it for a first build, unless you are using a really cheap bike with steel suspension forks. It helps the bike balance problem considerably, this is my favorite commuter, I have 7000 miles of commuting on this, or similar front hub full suspension bikes.View attachment 1

One thing to note, the front shocks bind and lock if the motor is powered up, so I only get shocks if I get off the throttle, and coast. One of the many probelmatic issues when using a motor on shock forks.

So what do you do? One option might be to choose a hardtail MTB. Get one with a larger triangle, and then you can fit the ping in a box in the triangle. Your ride is only 12 miles, so it should be just within the range of a triangle mount battery from emissions free. The last option would be lipo. But a 44v 12s 10 ah pack really would be cutting it fine.

For that long a trip, I don't really recomend a front hub on a no suspension bike. Suspension gets a bit important when going faster. A hardtail would be compromise enough imo.

For a ride that long, I also say go 26". It's a big enough wheel, and tire selection is so much better. You can go with balloons if you want, and get some cheap additional cush.

 

[Supertux1]

Thanks for all of the input guys!

I got to searching around and read some more based on the feedback given and I think I will be purchasing my items from ebikes.ca instead.

It seems that they have more options for the DIY'er type like myself and they inspect and modify cheap Chinese components and that's worth it to me.

I really like their kits with the Infineon controller, Cycle Analyst, and Crystalyte HS35 motors. So much more detail on each component from ebikes.ca, the simulator, and I like details.

(I don't mind paying the expensive shipping to the United States.)

So I think it's now very important that I find a good bike, throw some weights on it where I think I might want the battery and see how it feels balance wise.
Still sort of on the fence as to do a front mount or a rear mount (bike quality and balance are going to determine that), but definitely decided that I want a direct drive after watching some more youtube videos of geared motors.

I looked at Walmart yesterday, rode a few of the $250-$300 ones up and down the store aisles and wasn't really all that impressed.
All of the functionality I needed but with minimal adjustability and zero quality. Loose bolts and improperly adjusted components I can deal with, but some looked like they would just snap.

Oh I found a video on youtube from a place called 'high power cycles' or something like that, they used the exact same rack and bag I want to use!

Now I've been looking on bikesdirect.com and seeing a slightly higher quality bike there for about $400-$500 and up. Has anyone had any experience with bikes from this place?

Thanks again for your help!

 

[999zip999]

Look at pics on craigslist for used bikes. Unless you need a pretty bike. Mine I keep it low key.

 

[dogman dan]

I agree with that, hunt down a really good bike, but pay 500 for it used rather than get a 500 new bike that is only slightly better than the wallbikes.

I paid 300 for the giant in the pic above with the front hub. It's been a rock solid bike for 5000 miles.

In the 300-500 new ballpark, the best bikes for a first ebike are often the ones with just front suspension. Get a nice stiff steel frame with room for a battery, but have at least front shocks to smooth the ride some. Trek 820 is one example. Remember, the shifters can be fairly cheap, you won't be using them much at all.