Help choosing first Ebike!

[Sierratim]

I have a 750 watt hub motor with 48 volts 17 amp hr bat. I have to go up very steep hills in my neighborhood. I am 6ft 200 lbs. This bike screams going up hills. You should never have to walk your EBike unless your battery is dead.

Mine is a 250W mid-drive rated for 90Nm peak torque. I've documented several rides on this forum up the steepest local road; 31% (17°) grade as posted by the local road dept. We've driven out to measure this grade and confirmed the signage.

Note that the 250W rating is often for Euro compliance and as I understand it is the max power the motor can continuously deliver under max operating temps without thermal overload. My ebike has torque sensing that reports rider and motor torque. Up steep grades the motor can develop a full 1hp (~750W). It has never cut out due to thermal overload, even on grades that went on for several miles.

For the record, I'm in my 70s and have 1 artificial knee and 1 'bad' knee. Haven't found a hill I've had to walk yet.

The bike has a 600Wh/17Ah rated battery, which is more a measure of how far I can ride, rather then motor capability.

 

[pjt729]

If you're talking about Surface 604 Shred, it has Bafang G360 motor which is rated at 500W.

But Surface 604 installed 25A 12MOSFET controller, which makes it 1200W max. (or precisely speaking 1365W @ full charge) at least in theory.

So yes, it has pretty good hill climbing power. Also the G360 has 12:1 reduction ratio, and they advertise their internal gears able to withstand 100nm of torque.

So on their website (and the website on the bike shop that sells them) they say it peaks at 750 watts. Do you think that's just so that they're advertised as "legal" even though they're capable of more power? This is what their website says

CONTROLLER​

SURFACE604 Designed 12 MOS 48V 500W 17Ah, Smart

I have no idea what any of that means. I know volts times amps is the peak watts that can be provided but I don't know what that 17 ah means. If that's amps, then it would peak at a little more than 800 watts.

 

[Sierratim]

If you're talking about Surface 604 Shred, it has Bafang G360 motor which is rated at 500W.

But Surface 604 installed 25A 12MOSFET controller, which makes it 1200W max. (or precisely speaking 1365W @ full charge) at least in theory.

So yes, it has pretty good hill climbing power. Also the G360 has 12:1 reduction ratio, and they advertise their internal gears able to withstand 100nm of torque.

The controller capability (1365W) is of course different than the motor capability (500W). I would expect the controller to be comfortably rated above the motor spec. A 1365W controller for a 500W motor seems like a good match.

 

[indianajo]

Thank you for all the replies! Based on what you guys are saying, should I just eliminate the hub motor bikes I was looking at or is there a possibility I could get up hills with them?

I ride a hub motor bike, on the front. A mac12. Very torquey, can start me & 80 lb groceries in the middle of a 15% grade. 330 lb gross. It doesn't sound as if your terrain would overheat a mac12. They can't run slowly up grade at full throttle for more than ~20 minutes. I ride mine on 77 hills over 27 miles, and it is fine if my knee is acting up that day.
OTOH, what I like about geared hub motor is I can pedal it myself without drag 80% of the time. Then when the wind picks up to 25 mph in my face, and my ride home would take 6 hours, I use the motor. You with your knee problem, the drag of a mid drive unpowered would not be an issue. Main down side there is frequent chain replacement and sometimes parts of the motor. My chains last 5000 miles and when I wore out a hub motor @ 4500 miles, I had a new one on in 2 afternoons. Would have been one afternoon if I hadn't of had to make a new mount for the controller because the wires on the new one were too short. Other down side to mid drive, all the pedaling has my heart "has nothing wrong with it" at age 70. You don't get that aerobic exercise with a mid drive. Keep up a YMCA membership and use the pool for lap swimming 4 times a week for heart maintenance.
That controller that quotes 17 ah, big lie. Controllers don't store much energy, and that is what AH is. AH is the rating of batteries. Controllers will put out a certain number of amps, which is current, not energy. My first controller would put out 30 amp. This controller with the MAC is less amps, but I can't measure it without installing a shunt, which is too much trouble.

 

[Sierratim]

I ride a hub motor bike, on the front. A mac12. Very torquey, can start me & 80 lb groceries in the middle of a 15% grade. 330 lb gross. It doesn't sound as if your terrain would overheat a mac12. They can't run slowly up grade at full throttle for more than ~20 minutes. I ride mine on 77 hills over 27 miles, and it is fine if my knee is acting up that day.
OTOH, what I like about geared hub motor is I can pedal it myself without drag 80% of the time. Then when the wind picks up to 25 mph in my face, and my ride home would take 6 hours, I use the motor. You with your knee problem, the drag of a mid drive unpowered would not be an issue. Main down side there is frequent chain replacement and sometimes parts of the motor. My chains last 5000 miles and when I wore out a hub motor @ 4500 miles, I had a new one on in 2 afternoons. Would have been one afternoon if I hadn't of had to make a new mount for the controller because the wires on the new one were too short. Other down side to mid drive, all the pedaling has my heart "has nothing wrong with it" at age 70. You don't get that aerobic exercise with a mid drive. Keep up a YMCA membership and use the pool for lap swimming 4 times a week for heart maintenance.
That controller that quotes 17 ah, big lie. Controllers don't store much energy, and that is what AH is. AH is the rating of batteries. Controllers will put out a certain number of amps, which is current, not energy. My first controller would put out 30 amp. This controller with the MAC is less amps, but I can't measure it without installing a shunt, which is too much trouble.

My mid-drive Brose motor does not display any drag when pedaling without assist.

 

[Sierratim]

So on their website (and the website on the bike shop that sells them) they say it peaks at 750 watts. Do you think that's just so that they're advertised as "legal" even though they're capable of more power? This is what their website says



I have no idea what any of that means. I know volts times amps is the peak watts that can be provided but I don't know what that 17 ah means. If that's amps, then it would peak at a little more than 800 watts..

I'll suggest that the 500W motor can deliver 750W peak but could go into thermal overload under the right conditions. This shouldn't cause permanent damage, but you'd need to wait for the motor to cool to continue using it.

I wouldn't say the motor can deliver more power, even though the controller is rated for higher output. This is just a safety factor to prevent the controller from being damaged by an errant motor surge, etc.

BTW - the spec 12 MOS 48V 500W 17Ah confuses me a bit as well;
12MOS : the count of power mosfets (a semiconductor) that are used to control the power to the motor. More is generally considered better, though quality parts are just as important IMO.
48V : operating voltage in volts. A high voltage rating is considered better. I'm concerned with this rating as the 48V battery actually charges to ~52V max. Perhaps they meant 48V nominal battery voltage?
500W : this is power handling capability. For a 500W motor that can peak at 750W this rating concerns me. An earlier post by Timpo suggests that the controller is rated higher?
17Ah : This is not normally a controller rating but a measure of how much current the battery can deliver over time, 17 amps for an hour in this case. Again, I'm a bit confused by the controller specs. Perhaps an email to the supplier could clarify these points.

 

[AHicks]

I agree. It looks like they've combined the controller, motor, and battery specs all together. From where I sit, this makes me suspicious regarding the competency of whoever put that add together, as well as the one that proof read it.

I have a 1000w hub drive, as well as an Ultra powered bike, which carries ratings all over the place (for good reason, not incompetency). Either bike will climb any paved hill I point them at with my oversized butt aboard.

I believe a REAL 750w Bafang hub would work well in this hill climbing scenario you describe - one that has 750 in the model number. The problem is many manf's are saving a couple bucks and rating smaller (350 and 500w) motors at 750. I'm not so sure about the ability of those motors to do what you want to do.

I will say that I believe the hub drives are easier to ride. The big reason being they generally do have a throttle, and they just don't give a darn what gear you are in when accelerating from a stop..... Mid drives, especially small ones, can be pretty picky.

And as relating to your knee, even if just cadence based the hub will work well for you. Keep the PAS level set to what you need/prefer, and go.....

 

[pjt729]

Okay guys. I just moved here in September and I've never really looked around town but school is out for winter break and my lesson plans are done so I took a little drive around in the snow today. Apparently if I head down around a half mile from that hill there is a path that leads to my complex. It seems steeper than the other one (Strava says it peaks at 35% but I don't think that's anywhere close to being right.) The difference is the hill is only a couple hundred feet long instead of a quarter mile (Google Maps says it's 216 feet to climb the hill) but the big difference is instead of having to start with basically no power, there is a 600 foot stretch of flat path that I can use to get some speed going into the hill. This should help make it fairly easy to climb, right?

Not great pictures but here's the path from the top of the hill and from the bottom right where the hill begins.

 

[BET]

This looks like the hill between my neighborhood and the main bike path. Steep but not long. Our 500 watt befang motors on our hub motor cadence sensing bikes have no problems with our hill. We have a Ride1 up 500 and a Espin Sport (500 w/ 750w peak).

 

[Kodak]

I think you underestimate the power of these bikes even the 500 and 350. No running start needed.

Just and old man riding a bike.

 

[indianajo]

If you hit a steep grade at 10 mph or faster, it heats the motor not very much. No slip, little heat. I do this a lot on my grades. Speed down one grade, hit the next at 20 mph or faster. But the Mac12 will start from zero on a 15% grade, my worst case, at 330 lb my worst load. 15% grade is 7/8" rise on a 6" level, if you want to measure your grade yourself. I used a level from K-mart and a ruler from some discount retailer.

 

[Kodak]

This should say it all.

Just an Old Man Riding a Bike

 

[pjt729]

Researching a little more and I think I might go with a mid drive. My concern was sending all the power through the chain and having the chain break but with gear sensors it's not as big of a concern and as long as you take care of the chain it shouldn't be much of a problem. I also found an even closer shop that sells electric bikes (though it appears only the 250 or 350 watt variety) that says they will work on any type of bike even if it wasn't bought from them so the concern about finding someone to work on it if needed isn't there any more.

 

[Sierratim]

Researching a little more and I think I might go with a mid drive. My concern was sending all the power through the chain and having the chain break but with gear sensors it's not as big of a concern and as long as you take care of the chain it shouldn't be much of a problem. I also found an even closer shop that sells electric bikes (though it appears only the 250 or 350 watt variety) that says they will work on any type of bike even if it wasn't bought from them so the concern about finding someone to work on it if needed isn't there any more.

Mid-drives are certainly worth serious consideration. I've had both; a DIY 1,000 hub drive and a mid-drive. I prefer the mid-drive mostly due to its sophisticated software, torque & cadence sensing, and better weight balance.

 

[2cartalkers]

It is not available yet but the new Sondors LX might fit the bill, it is a beast of a bike. Check it out!

 

[pjt729]

Anyone have any opinions on M2S? Not much here on their forum and I've read some reviews that their customer service isn't great but it also looks like it has some good power (even on the hub motors) and specs.

 

[AHicks]

Anyone have any opinions on M2S? Not much here on their forum and I've read some reviews that their customer service isn't great but it also looks like it has some good power (even on the hub motors) and specs.

I looked at those prior to the purchase of my Rize a couple months ago. I think they're a good bang for buck spent. Realize though, that service, beyond the most basic, matters little here. I do my own. Give me a bike that isn't defective some how on delivery, and I'll take it from there...

Point being, companies like M2S, with little in the way of track records when it comes to servicing customers, are not near as scary for me. That said, I didn't see anything too scary with their support.