First DIY Build - input needed (I read the FAQ!)

enforcersu

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Hi All -

I've got a Stromer ST1-X that I'm using for my commute, but since biking is my hobby, and n+1 reasons, I want to build my own e-bike that I can switch off for my commute (and my wife could use as well if so desired).

I was thinking of using either a Specialized Crosstrail or Trek DS1 for the build, and I think I want to get a rear hub conversion. I'm a bit lost in terms of battery or power.

Ideally the bike would be able to keep up to my Stromer (28mph max speed). I like pealing, but I just use the e-bike to extend the range I'm able to go.

I have a 30 mile commute (each way) in the SF Bay Area. It's quite hilly, and can be windy. I'm 6'4 ~180lbs, and can do this commute on my regular road bike, but am just looking for an ebike so that I can do the return trip without dying 4x/week :)

Would be open to any suggestions in terms of:
Which rear hub would work best?
What battery size should I get (I could charge at my work if necessary, but it would be great if I could get something that'd do 60-70 miles of relatively hilly terrain).
Ideally I'd get regenerative braking.

I think I hit all the questions in the FAQ. Appreciate any help!

Thanks
 
Welcome!

You may not know this, but you are asking for a big battery. With the hills and wind and cold of the bay area, you will need something like 27 watt hours per mile. So that would be something like 70 miles x 27 watts = 1890 watts divided by say a 48v motor = 39.37 ah battery. That is big. Now you could charge at work and then cut it down to a 20ah battery provided you can get a full charge during your time at work. I personally heavily advocate for putting the batteries in the triangle of the frame for best balance and handling of the bike, but a 20ah battery would probably not fit. The option would be to get panniers and split the battery in two halves.

Another option is to get a smaller battery and pedal more then most of us do when we ride.

I wouldn't consider anything less then 48v and 1000w DD setup for SF hills. However that makes for a heavy bike with a 20ah battery. Have you looked into Bottom Bracket motors?

:D
 
Sounds like you are an already fit cyclist and that you like riding a bike - electric assist or not. I think you should seriously consider a smaller geared hub motor because that will be a lot easier to pedal without the electric assist. It will feel more like a regular bike.

You will lose regen, but the the consensus on this forum seems to be that regen is more useful for saving brake wear than it is for extending range. If your trip has a lot of up and down over hills, then just use motor power going up and coast and pedal and/or use light power on the downhills. That saves battery power too.

The safe rule of thumb for commuting battery use is about 25 WH per mile. I can easily average in the 15 WH per mile range if I'm willing to ride at a typical cruising speed of about 20 mph and pedal assist. But increasing my speed to a typical speed of 25 mph and especially going up hills, I can easily exceed 25 WH mile. My longest trip has been 58 miles on a little more than 1000 WH of battery (28.5 amps x 36 volts) consuming a bit more than 17.5 WH/mi. But my typical speed was a fairly leisurly 20 mph or so for the majority of the trip.

Your real world needs will be determined by things like how fast you want to go and how hard you are willing to pedal. Given the 30 mile one way trip, I'm assuming you'd like to average closer to 25 mph than 20 mph. So 25 WH per mile might actually be an underestimate. OTOH, if you are seriously going to ride major chunks of the commute on your own power, then you'll need less battery. But if we assume 25 WH/mi that means you need 750 WH of battery or about 16 amps at 48v. But that also means you may be fully charging and depleting that battery twice a day which means it won't last as long as would a larger battery with more capacity. So if you are an average rider, you need about 1000 WH and have to charge at work. But if you are a stronger rider, you could probably get by with 750 WH or less capacity. A smaller battery's lower weight will keep things feeling more like a regular bike.
 
Read need Advice link in sig.
 
20 ah, and a 500w rated geared hub kit. (but run at 48v, for 1000w of hill climbing power) Coasting down the hills will be much faster than cranking out regen, and the motor will handle hills better, up to their 300 pound total weight limits. Lighter wheel will help, since that battery will be pretty heavy. Charge at work for sure, so get two chargers.

IMO, a bit long a ride for a practical bike commute, but since you already do it, no need to point out the time, need for more frequent bike maintenance, etc. You should be able to shave some time off the commute now, you'll be going up the hills faster now. You should be able to climb pretty steep hills at 15 mph, with medium hard pedaling.

But expect to cruise the flat closer to 25 mph, because as it empties the battery the voltage drops, slowing the max speed.

Re the bike, the longer ride I do, the more I want to do it on a longtail. Partly this is to effectively carry 2000wh, but its also for the comfort. Get the ass off the front wheel, and the ride is much more comfortable. Instead of riding the pogo stick, its the rocking chair.

My best long distance bike ever was homemade. The small rear wheel improved its ability to climb, or tow. Finished cargo mixte..jpg
 
I haven't been at this as long as other posters, but I did a long term test on the ST1X and it's a great commuter. If you're set on a DD motor, you might consider a BionX conversion. Tested their 500 system and it's equally competent with a three -year all inclusive warranty.
 
Thanks all for the super helpful replies!

I was thinking about a Bionix conversion kit. I would be willing to charge at work (we have a pretty nice bike room with charge-ability, and that's what I do with my Stromer today.)

FWIW, with my Stromer ST1-x and the upgraded 814wh battery, I'm at almost exactly 50% by the end of my one-way commute daily. This works for me, because I charge at work to keep it topped off, but if something happened were I needed to go home early, or if I couldn't charge for whatever reason, I would make it mostly all the way home without needing another charge.

I don't necessarily want to do batteries in panniers, as I use this bike for commuting, so my stuff is in panniers (need the space!) Was hoping to put the battery in the triangle/trunk if necessary.

Would a Bionix kit be a good fit for me? I'm just a tad lost in terms of which kit to buy, and how to best pair a battery with that kit.

Appreciate the help everyone! Also - please let me know if you think a Crosstrail or DS1 isn't the best base for this build :).
 
enforcersu said:
FWIW, with my Stromer ST1-x and the upgraded 814wh battery, I'm at almost exactly 50% by the end of my one-way commute daily.

Assuming it actually has 814 *usable* wh, *and* the capacity display on the stromer accurately shows you wh usage (and not just pack voltage as a bar meter) then:
814wh / 50% = 407wh
407wh / 30 miles = 13.57wh/mile

So you have a very low power usage for your speed (assuming you ride at the Stromer's limit of 28MPH for as much of your ride as possible), meanng you are probably contributing quite a lot to the power used via pedalling.


If the stromer pack gets you the whole ride without recharging, then a 1kWh pack would easily do the whole ride, too, assuming the same ride conditions and bike power usage, and have some left over for detours, headwinds, pack aging, etc.


If you want to contribute less, it will take more of the battery's power to make up for that.

Or if you are presently not riding very quickly, but you'd like to change that, then it'll take more of the battery's power as well.

That means in both cases your wh/mile will go up, probably significantly, whihc means you need a bigger battery to go the same distance.



Would a Bionix kit be a good fit for me?
It might do what you want (other than perhaps the speed--I don't know what it's limits are), but like the STromer it is a closed system you can't easily modify if it doesn't do things the way you like them. ;) And not easily upgradeable if your requirements change. It's also much more expensive per unit of measure than it is to go with generic stuff and put it all together yourself.

But it doesn't require you to do any DIY to make it work, and there are dealers to help you with problems, a warranty for service, etc.

So there's pluses and minuses to everything.
 
@enforcersu, we are all a bit surprised at your range, so I have this question......does your bike have an eco mode and do you pedal all the way with it on?
Support Mode.JPG

:D
 
e-beach said:
@enforcersu, we are all a bit surprised at your range, so I have this question......does your bike have an eco mode and do you pedal all the way with it on?
Support Mode.JPG

:D

Yeah I generally keep it at "2" with custom settings for the stromer. I pedal the entire way, and use the boost to keep me at an average of ~23MPH for my trip. Don't mind pedaling, just like having the e-bike to make me a bit faster / take the intimidation out of the hills.
 
It's funny how surprised people are how much your pedaling is extending your range... actual pedaling def makes a big difference!

I would stay away from the Bionx system. They were way ahead of their time on quality when everything else was pretty low tech... but it's such a closed system, really hard to ever use an aftermarket battery, and you have to go to a shop with a Bionx dongle to plug into the system to get service done.

The Stromer is a nice smooth ride with the torque sensing, so you're going to want to make sure you like the pedaling characteristics of a new system before dropping big bucks. Sometimes its hard to go back to less smooth system.
 
So that explains the wonderment around here on your range. A lot of us around here don't pedal that much. That Stromer switch is a nice thing. It may have spoiled you a bit. With a kit you are going to have to do the same pedaling as you do now. If you want to have similar control of your watt usage, you should consider a Cycle Analyst from ebikes.ca. It will help you do the same thing. another option is a three speed switch which limits the return voltage from the e-bike throttle. You can flip that on the fly. Not all of us need that kind of stuff though.

I know my bike and routs well enough now that I ride on dead reckoning. I reckon I can get x amount of miles on x amounts of watt hours left on my battery unless I will need a charge along the way then I will bring a charger with me unless I don't have my charger with me and then I just ride slow and pedal. I don't even use a volt meter. I get caught 1 or 2 miles short of my house maybe 1 time per year. I have it down pretty well. But I hate it when it happens. :oops:

But 30 miles from home would be a long way to pedal a heavy e-bike. So the Cycle Analyst might be a better consideration then dead reckoning.

I, like WesNewel run on a yescomusa.com motor. I have, (compared to him) a paltry 12,000 miles on my motor. Generic Chinese e-bike motors can last a long time.

Other companies people like around here are
https://em3ev.com/
Luna Cycles

Also, check out the ebikes.ca simulator to get a clearer idea of your needs before you crack the wallet. I still think you should go with minimum, a 48v motor, perhaps over volted a little bit, a 20ah or more battery and a 40 amp controller to give you the help you need over the hills. Look at the motors the simulator has and learn what they are. The choose the kit and any accessories you want.

That's my 2¢.

:D
 
e-beach said:
So that explains the wonderment around here on your range. A lot of us around here don't pedal that much. That Stromer switch is a nice thing. It may have spoiled you a bit. With a kit you are going to have to do the same pedaling as you do now. If you want to have similar control of your watt usage, you should consider a Cycle Analyst from ebikes.ca.

Maybe. As I've been experimenting with longer rides, I've found that by staying in PAS level 2 or 1 (KT controller) it is pretty easy to to limit my power usage in a fairly predictable way. As a practical matter, that means I'm only going "fast" downhill, and I tolerate taking hills at a more moderate pace and with a higher effort. But averaging around 15 WH/mile is pretty straightforward if I do that.
 
wturber said:
..... (KT controller) .....

KT controller or KT computer?

:D
 
e-beach said:
wturber said:
..... (KT controller) .....

KT controller or KT computer?

:D

Controller and LCD display. I get the feeling I'm missing the joke.
 
No jokes, it is that the last thing I saw on my handlebars that looked even remotely like that was a bike computer. I haven't bothered to look at what can be done lately. I can't use them around here because they get stolen. The thief doesn't even know what he's got, just cuts the wires and snaps if off and goes down the road. It has happened to me with bicycle computers and that is no joke. Dead reckoning I say! Ride by the seat of ones pants!

:D
 
e-beach said:
No jokes, it is that the last thing I saw on my handlebars that looked even remotely like that was a bike computer. I haven't bothered to look at what can be done lately. I can't use them around here because they get stolen. The thief doesn't even know what he's got, just cuts the wires and snaps if off and goes down the road. It has happened to me with bicycle computers and that is no joke. Dead reckoning I say! Ride by the seat of ones pants!

:D

The KT controllers can work in conjunction with what are typically referred to as LDC displays. But yeah, they appear to actually be simple computers that control the motor controller and give system info/feedback. I've never considered that someone might steal the LCD display. Mines attached pretty securely. But considering how cheap they are, I should probably order a spare just in case. That and/or figure out how to reconfigure it so that the bike will operate without it.
 
wturber said:
That and/or figure out how to reconfigure it so that the bike will operate without it.
It'll power on and operate the motor without one as long as you short the battery-out and switched-battery-in pins together. Sometimes you also have to short the two data lines together.

But it might be stuck in it's lowest setting mode, whatever that is for that unit (or whatever it's been programmed for), without the LCD's buttons/comm to allow you to change it.
 
amberwolf said:
wturber said:
That and/or figure out how to reconfigure it so that the bike will operate without it.
It'll power on and operate the motor without one as long as you short the battery-out and switched-battery-in pins together. Sometimes you also have to short the two data lines together.

But it might be stuck in it's lowest setting mode, whatever that is for that unit (or whatever it's been programmed for), without the LCD's buttons/comm to allow you to change it.

Yeah. I should pin that stuff down for sure. The LCD wires are all connected with one small round connector. So getting to them means cutting into the cable. Also, default power is probably full power. I'm running at 80% so that the Voltage Booster can keep up. Overall, I like the spare LCD idea best. :^)
 
Don't know where you're located, but if you have a BionX dealer nearby, check them out. They are assembled in Canada, have a three-year all-inclusive warranty and are used on several OEM bikes. They're like most OEM companies in that they have proprietary parts. The other consideration, but a geared motor, that I've been impressed by is Maxon.
 
amberwolf said:
Maybe not wanna go with BionX now:
https://endless-sphere.com/forums/viewtopic.php?f=3&t=93078#p1361789

OTOH, there might be some smokin' deals on BionX stuff. :^)

That said, I've never been a fan of proprietary systems. I avoid them unless they offer some significant advantages or there are no or few alternatives.
 
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