50 miles on first build . . . think I need advice on second

[Anthony King]

After doing a couple of short shakedown rides I took the half-fat e-dummy on a couple long, hilly rides today.

I was very curious how much juice it would take to get both kids back from my sister in law's, a 17 mile route with 1,134 ft. of elevation gain. The battery (36V 20Ah Ping) went through 18.46Ah and the voltage at the end of the ride was 39.7. I pedaled quite a bit, but didn't kill myself.

Here are the happy passengers:

I'm fairly satisfied so far. Since it appears the bike will make bicycle errand trips with the kids in town possible (12 miles, relatively flat but one big hill coming home) it would be nice if the whole family could come. So I'd like build a bike for my wife.

I think the eZee I currently have on the Big Dummy would work well for her. So I could either get another for her or . . .

I could give her mine if it makes sense to upgrade the motor on the Big Dummy.

The eZee worked pretty well, but with the kids on the bike and no other cargo the motor seemed to bog down when the grades got over 4%. I'd like to be able to carry the kids and extra cargo when running errands and get up the big hill coming back home a little easier.

Any general advice welcomed, but I have a few specific questions.

1) What difference can I expect if I reduce the wheel size on the cargo bike? I have used 24" wheels on it in the past and could significantly reduce the diameter of the front wheel (18% redcution) by going with a 24 inch rim and more modest tire. The ultra-fat front tire does make for a smooth ride, but if climbing will be significantly improved by reducing the diameter I'll relace the wheel and give it a go.

2) Since in use the bike is very heavy and speed isn't much of a concern would a powerful direct drive motor make any sense since I could extend the battery with regen in hilly New England?

3) If so, what DD motors should I look at recommend?

4) Am I correctly diagnosing the "boggy" or "jerky-jerky" motor sensation on the steepest sections of road as lack of motor power? On these sections I seemed to be able to back off the throttle a little and find a sweet spot where the motor felt smooth.

If I should leave well enough alone and jus build my wife a bike, don't be afraid to tell me. I have a feeling I won't get that advice around here. Keep in mind speed isn't my concern. It would be nice to stay around 10mph on the steep hills (while pedalling moderately). My concern is being able to get a vehicle that could top out at over 400lbs. up hills.

Also open to cases for non-hub drivetrains if you think that would improve the bike.

Thanks as always.

 

[e-beach]

IMHO, like all things e-bike it is a combination of things. I have a 36v front hub yescomusa 800w motor and a Headway 15ah pack and I don't go up the hills around here fast either.

I think that you need at least a 48 volt 1000w motor and maybe a 60v or even a 72v pack. That of course means a controller, wires switches, etc that can handle a pack like that. I can tell you from experience that the C rating of my Headway LiFePo4s under load don't match the advertized C rating. In fact my old SLA's got me up the hills better then my Headways. I have read that the Ping C ratings are similar to Headways, about half or what is advertized.

I would say if you are going to make changes or do another bike go 48 volt motor and over volt it.

As for lacing smaller rims onto your motor, you will get some more torque out of them. I don't know how much. I would be cheaper then building a new bike or getting an new motor for a bit more pull up the hills.

I you want another motor, consider a yescomusa 48v motor with a overvolted controller and pack. Those of us around here who run on yescomusa motors find them very robust for the price.

 

[dogman dan]

One obvious solution would be double motors, using just one except on the hill.

What speed are you looking for? I found my longtail worked pretty good with a 10 turn 28mm direct drive motor. That's the 9 continent type, in a slow winding. It would only go 15 mph tops, on a 36v ping, but be able to haul the weight, stopping and starting with less waste heat. Then for the hills, you'd also engage the Ezee.

The flaw with this plan, is that you'd need a second battery for the Ezee.

A decent approach could be to get a 10t rear motor kit, they sell them at EM3ev, and put that on the longtail. Then make the second bike a normal bike, using the Ezee. Just going to the dd motor would likely get you enough improvement. 4% should not be much of a problem for the dd motor, and it's a VERY efficient motor for the rest of the ride.

The 10t really perks up with 48v, so when you purchase a battery, get a 48v 20 ah for the longtail, then still use the 36v with the lighter bike and ezee.

Or, if you can find one, get a 5304 crystalyte, or similar huge motor for the longtail. The problem with this approach is you will go from about 20-25 wh/mi to 30-40 wh/mi. But with a large motor, you can blast up those steep hills at 3000w of power. This is what I did with my longtail. I can still ride slow and efficient, but having the power, it's hard to hold back and not ride 30 mph. As a result, I could not keep using the pingbattery for that motor. I had to go to more powerful and hazardous lico to run that monster motor, and carry more capacity for anything more than a 10 mile ride.

 

[Drunkskunk]

Looks like a great bike. I don't think any Direct Drive motor is going to give you enough torque to compete with the Ezee unless you go for a much bigger motor, and even then, it would need a large amount of power to climb.

The Ezee is geared pretty high, and a fat tire on a 26" rim has a diameter close to a 29er, so the Ezee is going to be struggling on a steep hill anyway. I would suspect you would be better off with a couple of 10 or 12 turn MACs, one front, one rear. Run the at 48 volts for the best results. The Ezee is a great motor, but it doesn't have the options for the higher wound, slower but better climbing motors.

Going down to a 24" wheel would be similar to shifting down a couple gears on your pedals. you would pick up more torque and generate less heat, but at a lower top speed, and you would feel the bumps more. From a motor's standpoint, the smalest wheel is best. But from a rider's perspective, well, you've already experianced how great that fat front tire is. The motor is there to serve you, so giving up some ride quality to save on battery may or may not be something you want to consider.

 

[999zip999]

The ezee for the wife at 36v and 48v a must on the longtail. I love a dd slower wind not the slowest. They have a sweat spot at speed and wh/m goes down. Or the mac 10t. Or have the kids go on a diet. That's a good pic. The weight adds up, kids heavy bike and you. Plus you have to bring something.

 

[bowlofsalad]

I don't know if you put helmets on those children, but that was the least you could have done. I can imagine the little boy hitting the back of the little girls head really hard coming to an abrupt stop. I imagine if the bike landing on it's side would break bones in a leg in both of those children as well. And if the bike rolled at all while hitting the ground, the children would have more then broken legs, probably ribs or worse with that bar in place crushing into them like a giant baseball bat.

My advice is to find a different way to transport people on a bike, I recommend considering a recumbent posture with a brace that the children keep their feet on. I think I'd carry a child on a bike is either on trailer, or separate recumbent type seats, all while wearing helmets.

 

[d8veh]

You can get better hill-climbing by using more current. What current are you presently running? I've seen 20 and 25 amp Ezee controllers. If you want more, you can use a standard Chinese one, which are not very expensive, but you have to change the hall and phase wire connectors. My favourite is the 30 amp KU123 from BMSBattery. You might even get an increase in efficiency because it'll climb faster, so you might find that you use less battery for the same journey.

 

[Anthony King]

Thanks, lots of ideas.

My biggest concern is that I will damage the motor, though it doesn't seem to get hot at all. It just sounds like it is straaaaaining. But I assume if it were being overworked it would get hot, no?

As long as I'm not doing anything to damage the motor my main concern is now range. Yesterday's trip made me realize I didn't research the grade of the rail-trail enough. We are on that for about nine miles into town. One way into town we went 14 miles and only used 3.7Ah, but on the way back (with the 50lb bag of pig feed added to the bike) we chewed through about an amp hour per mile on the rail trail, and were near 14Ah before we climbed the big hill home. The rail trail is steeper than I thought.

I had brought my charger so we were able to stop, eat pizza, and the battery got a full charge before we were finished. So now my questions are:

Battery Questions:
1) Any recommendations for a good portable charger? I have the 5A from Ping. It isn't portable and with the loud fan I wouldn't want to plug it in just anywhere. If I have a portable charger, though, it would be easy to get a full charge while doing errands in Keene (where the grocery store is) and that should be good to get me back home.

2) I'd lean toward getting a second battery over a charger, can I mix battery voltages? For instance, my 36V has plenty of juice to into Keene and back to the center of Troy. Could I carry a 48V 10Ah for the final ascent home (with the kids and pig feed this hill took 6.9Ah yesterday). Except for this hill I'm happy with the 36V as my main battery, since I'm carrying the kids most of the time I have my CA speed limit at 14mph. Maybe that will make bowlofsalad feel better.

Controller Question:
1)Is there any problem using a 35A Infineon w/ my eZee? Playing around w/ the simulator is looks like this would give me a little more power on the hills.

Bowlofsalad: I have some unique needs for my bike and I don't know a ton about recumbents. We ride into town off-road so that we aren't near any high-speed car traffic but the trail we take only has room for a single track vehicle, so trikes are out. It is also sandy in sections, which is why we have the huge front tire to make sure we don't wash out in the sand and crash. If there's a recumbent that can fit at least 2.5 inch tires and carry everything I need (me, two kids, up to 100 pounds of cargo) I'd love to know about it. I'm not being sarcastic, that would be neat.

 

[amberwolf]

My biggest concern is that I will damage the motor, though it doesn't seem to get hot at all. It just sounds like it

is straaaaaining. But I assume if it were being overworked it would get hot, no?

Yes--usually too hot to touch, after 10-20 minutes of severe overwork, probably hot enough to cause any hall sensors in it to

work erratically if at all (this has happened to my Fusin geared motor a couple times).

I would guess that the type of overload you are seeing, with "stuttering" of the motor, is either the current limit of the

controller or the BMS of teh battery, trying to roll back the power being delivered. Most likely the controller.

A bigger (higher current) controller would fix that in that case, but it could also allow you to fry the motor. Most

likely the existing motor will be fine even with what you're experiencing, as long as you can tell it's not getting hot. So

for your "controller question", I would say--don't use the bigger controller unless you have or install a temperature monitor

inside the motor to warn you of possible damaging heat, so you can stop and let it cool off--remember that the heavier your

loads, the worse that problem will be on hills.



I would personally go with the two-motor approach, because even two small motors would do what you want easily enough, if the

one small motor almost does it. I use two motors on CrazyBike2 now, and they are MUCH better at moving the bike together

than either one is separately, for acceleration from a stop (same problem as a hill presents, only the hill is continuous and

the startup from a stop is not).


One caveat: If you use a rear motor, it's going to have to take a lot more abuse as a wheel than your front does. So make

sure it is built to take that--out of the box, it may not (neither of the ones I've had could take much at all, until I

rebuilt the second one with better spokes in a different pattern). The regular bike wheel can do better at taking the loads

because it's spokes are longer and probably thinner, and it rpobably has a better rim, too, as well as better spokes than

what come with most hubmotors (thicker is not usually better in this case).






For range: as long as your controller supports a higher voltage battery, then yes, you could stop and unplug the first empty

one and then plug in the fresh one. But the higher voltage battery will spin the motor faster for the same throttle

settings, so each time you change packs you have to "relearn" using the throttle to get the speed you're after. It's also

possible you'll heat up the motor faster with the higher voltage, because it will also be able to use up more power (watts),

given the same current limit of the controller, depending on how you handle the throttle.






As for recumbent bikes that do what you want, mine does (CrazyBike2), but you'd have to build one yourself if you wanted one.

It won't change the issue for the kids' riding positions that Bowlofsalad is concerned with, however--you'd have to

install seats for them, too, with foot pegs or similar for each one, to do that. And that you could do with your existing

cargo deck, as bolt-on items.




You could modify the bike you already have to be semirecumbent, but I don't know that you'd get much benefit from all the

work, and unless you moved the pedals up over the front wheel you'd wind up having to put the seat back where the cargo deck

is now, losing cargo space and changing the way the bike handles.

 

[Anthony King]

I was more curious if bowlofsalad had in mind a production frameset I wasn't aware of--just out of curiousity. Despite bowl's vivid imagination I'm hardly convinced the bike is a kinder-deathtrap.

I would guess that the type of overload you are seeing, with "stuttering" of the motor, is either the current limit of the controller or the BMS of teh battery, trying to roll back the power being delivered. Most likely the controller.

OK, this makes sense. The simulator says I could pop in a 35A controller and not overheat fully loaded (440lbs) on short grades of 8%. I only have very short stretches of road with those grades, and the sim says I'd have 11 minutes before overheating so I'd have a lot of room for error. Average grade of the hill to my home is 4%.

I've gotta do something w/ cruise control and/or move the throttle to my left hand. I already have problems with my right hand from building wheels constantly and the twist throttle on long rides is making it worse.

 

[amberwolf]

I've gotta do something w/ cruise control and/or move the throttle to my left hand. I already have problems with my right hand from building wheels constantly and the twist throttle on long rides is making it worse.

Have you tried a thumb throttle? I have problems with twist for similar reasons, and because they can cause "incidents" if grabbed while trying to keep the bike from falling over/etc. :lol: Thumb works much better for me.


However, on long rides it's still easier with a cruise control. Some controllers have it built in, htough it might not be enabled, requireing either soldering across a pair of pads, or changing a setting in it's programming. There's a number of good threads about that for a lot of controllers, but it takes some searching to find. Some are linked in the wiki (and you are welcome to add more links to the wiki article if you find them, or even write a cruise-control article).


I'm going to be making a pushbutton cruise control for CrazyBike2, but it'll be a while, till I can get thru my house fire leftovers and find the parts. I have three common speeds I use for cruisable distances: 10MPH, 15MPH, and 20MPH (technically 19.999999MPH ), so each button will just latch that voltage on the throttle, then if I engage the thumb throttle it'll unlatch. I'm not sure exactly how I'll do it yet, but it can't be that hard.

Alternately the thumb throttle will just "merge" with the output of the buttons, so if the throttle voltage is higher it'll override them, then when I let go it goes back to the cruise. Naturally the controller will shut off if I hit hte ebrake lever (or it will go into regen, if it's set to). Then I just press the button that's already depressed (or toggle the switch's lever) to mechanically disengage the cruise. that's the simpler way to build it, but takes more thinkiing to operate in a hurry under traffic conditions.

 

[Anthony King]

Have you tried a thumb throttle? I have problems with twist for similar reasons, and because they can cause "incidents" if grabbed while trying to keep the bike from falling over/etc. Thumb works much better for me.


However, on long rides it's still easier with a cruise control. Some controllers have it built in, htough it might not be enabled, requireing either soldering across a pair of pads, or changing a setting in it's programming. There's a number of good threads about that for a lot of controllers, but it takes some searching to find. Some are linked in the wiki (and you are welcome to add more links to the wiki article if you find them, or even write a cruise-control article).

My right thumb is what gives me the most problems, the way the wire exits the thumb throttle makes it look like a left hand installation would be awkward.

The cruise control mod looks fairly straight forward even though I've never done anything like that. Jumper wire soldered btwn. the "CR" pad and any ground pad. What gauge is jumper wire?

I'll likely go thumb/left hand and add the cruise function. The only stops on my ride into town are to lift my bike over an oak that has fallen across the rail trail.

 

[e-beach]

I've gotta do something w/ cruise control and/or move the throttle to my left hand. I already have problems with my right hand from building wheels constantly and the twist throttle on long rides is making it worse.

You can also take some pressure off you hand and wrist with a Motorcycle Throttle Assist. They are really cheap on eBay.

 

[amberwolf]

My right thumb is what gives me the most problems, the way the wire exits the thumb throttle makes it look like a left hand installation would be awkward.

Depends. I prefer having the thumb tab *below* (well "inside" on my CrazyBike2) the handlebars, which seems to be backwards from how the ones I've had are made to be used. So for me they'd actually mount better on the left side, htough I prefer the right. Presently I have one on each side, though, one for each motor. Later I will merge them so either one controls both motors, so I can use either hand for whatever reason I have at the time.

But the wires don't get in the way for me no matter which way I have them installed.

The cruise control mod looks fairly straight forward even though I've never done anything like that. Jumper wire soldered btwn. the "CR" pad and any ground pad. What gauge is jumper wire?

Doesn't matter, cuz it's just a no-current bridge. Can just use a solder blob if the pads are next to each other, if you have to.



I'll likely go thumb/left hand and add the cruise function. The only stops on my ride into town are to lift my bike over an oak that has fallen across the rail trail.[/quote]
Sounds like time to bring along a hand saw or an axe on your cargo deck, stop and do a little cutting each time you go by. A few rides later you don't have a block to the path anymore.

 

[Anthony King]

Sounds like time to bring along a hand saw or an axe on your cargo deck, stop and do a little cutting each time you go by. A few rides later you don't have a block to the path anymore.

Not patient enough for that. My Husqvarna and gear fit nicely on my Dummy. Cutting firewood is its second job.

 

[D A Snyder]

You have asked a lot of good questions and presented your story well. I live near San Francisco so I can relate very well to the problems your trying to overcome. As to the jerky behavior i have experienced the same thing on my 1000 watt Sierra Climber (5:1 geared hub). When your pulling a steep hill, even though you are using a heavy duty fork, in your case the Surly, the torque from the motor will start a harmonic response to ever so little flexing in the fork. Like you, I back off the throttle and it quiets right down.
Now, for the rest of the story. I paid a visit to Xtracycle back in the spring and had a great discussion with their development people about their latest iteration of electric cargo bikes and how they settled on the current design, the "Edgerunner". They use a 26" wheel in front, non powered, and put an eZee 20" geared hub wheel in the back. The 20 " wheel gives much better torque to the road and at the same time, allows the motor to spin at a higher RPM where it is most efficient. Now another element to this package that makes it successful is the battery. When it comes to heavy loads and steep climbs, you have to have a battery that is capable of delivering continuous high amperage rates for a long period of time. A battery of 1C rating just will not do the job. You should have at least a 5C rated battery or higher if you want trouble free service. To me another key element would be to add a cycle analyst and let it control your maximum continuous amperage based on the capability of your controller. I use the Lyen model 3077 9 FET controller and set the amps at 40.
See http://california-ebike.com/product/sierra-climber-high-torque-geared-motor-kit/
Good luck to you.

 

[Anthony King]

Thanks, DA
Amberwolf helped me figure out the problem in another thread. I hadn't set the shunt resistance in my CA y, so the CA was interpreting my amps as much higher than they actually were. When the faulty amp reading went over 50 (the max A setting in my CA) the CA would regulate the amperage, and the controller would then try to increase the amperage again. The cycle would repeat, causing the herky-jerky.

Now that the shunt resistance is correct everything is running smoothly.

And I seem to have plenty of power. I've only visited SF once, but I remember extreme grades. The hills where I live are not that steep--at least the road grades aren't. They are very long and challenging sometimes, but there isn't anything on my usual routes over 10%--and the sections over 8% are very short.

Granted, I pedal quite a bit, but now that the set up is correct I'm blown away by how powerful the hub is--even in my huge front wheel. I had a solo run today and took the speed limit off my CA. Hitting 30mph on the flat was not very hard, and I steamrolled up the two mile hill home.

The Edgerunner does look nice. I'd like to eventually get one my wife.