hightekbikes.com motor kit review. Electric bike kit.

[HighTekBikes]

That is some great data Dogman. I will repair or replace your motor for free if and when it craps out. I want to know what the limits are also. I'm going to have to send you a watt meter, I want to get some current readings. I did another test and verified the controller is limiting to 20A and will allow a brief peak to 22A. Did you check the temp of the controller by any chance? I have one apart and plan on increasing the current limit.

 

[RTLSHIP]

Dogman, what you seem to prove is that the Aotema hub motor has no way to vent its' heat build up. Also, you show that this is true of hub motors generally. Your old ice cube idea may have to suffice.

 

[dogman dan]

No I haven't had any issues with controller temps, so I have just ignored it. I do mount the controller so it can get a lot of good ventilation. No rain issues here! In late summer, when it gets rainy, I tend to ride home before the afternoon showers pop. I just carry baggies to put over the whole battery and controller if I get caught, and another to cover the trottle.

WOW Terry! that is some offer, to replace my motor if I smoke it! Even without that offer, I plan to beat it hard. If I plan to ride bikes in this town, I need to know where that point of no return is. But I am thinking It won't melt down as easy as the brushed one did. I am though, real interested in knowing what the effects of different riding styles are. Yesterday I learned that full throttle no pedaling sure can heat a motor up. :lol: Like we didn't know that already. Today I'll ride it normal for me, full throttle, lower gear, pedaling hard at about 15 mph. And tomorrow, half trottle and very low gear. It will be great to have a wattmeter too, so that'd be great. Simulators and calculating averages is fine, but nothing beats real world data.

Back to controller temps, 10 bucks will put another thermometer inside the case, but I have an infared that I can get cover temps with. Which would you like, and if inside, tell me where you want it measured. the heat sink? Moffsets?

Just to show that you can never think this stuff through too much, overnight I realized that measuring the winding temps like I am doing may not matter so much. As long as the magnets are under 150 F, the epoxy won't melt off the hub. Since the brushless hub has it's magnets on the outside of the hub, on the spinning part, they should be able to cool themselves much better. On the brushed hub I melted last summer, the mags are deep inside, with no good way to cool off. So they got hot and stay that way longer. The windings can take quite a bit of heat I think. I saw no damage to the windings on the hub I melted at all. All the problems I had were on the non rotating, inner part.

So , I am starting to think, just monitoring the outer temp of the brushless motor should be fine. A cheap infared thermometer can do that without taking the hub apart.

I didn't ride the bike down the hill yesterday JinbaIttai, I need the car at work some, so I often carry the bike on monday morning, and leave the car there all week. The temps will be much lower this morning, so that will be interesting to see too. Any off throttle time seems to keep heat rising slower for sure.

Rtlship, No doubt about it , why there is no cooling fins on the hub is a mystery to me. Just more ribs paralell with the flange that holds the spokes would help a lot. In my mind the design is fine for rides with sla's, usually about 10 miles. And under 95 F, I don't think there is any problem at all at 36v. After that, using a big ol lifepo4 pack, is where we are pushing the motor into new territory. My case, living 15 uphill miles from home, in the desert, is not much different than someone going cross country. Justin had no problems, but he did it about 1500 miles further north than where I live, 40 miles from the mexican drug wars. The info I want to know, is what throttle setting is sustainable in my climate in the summer. Then I could just use the speedo to hit a target speed that won't put me in the danger zone to melt the motor when it's 110 out there. Another option, is just knowing whether a stop to cool off, and how long to make it, makes a difference at the top of the big hill.

 

[davespicer]

Your old ice cube idea may have to suffice.

Maybe there'd be a way to use evaporative cooling?

Canvas water bags used to be hung on the outside of vehicles driven in dry climates - they were porous enough that some of the water evaporated and cooled the rest. (There's a thread about them at http://www.exploroz.com/Forum/Topic/19537/canvas_water_bag.aspx) Adapting this concept to a hub motor would look, um, weird, but...

Suppose discs of canvas were glued to each motor cover, and a fine spray rigged to dampen them. An occasional shot of spray would keep 'em wet, and the breeze from the bike's motion would evaporate (and hence cool) 'em - and hopefully the motor covers beneath.

There must be better evaporative surfaces than canvas these days, but that'd be a start, especially in hot, dry climates. Lessee... who do we know who lives in one of them?? I know he's posted here at least once or twice

 

[HighTekBikes]

Two ideas come to mind. Forced air cooling with two fans mounted on the fork. And water-sealed openinging in the case that can be removed. So drill 1" holes in the case and fit with removable plugs. This lets hot air out and cool air in.

 

[dogman dan]

I do have hub covers with holes in em, from the bd 36. They may be identical enough to try it. One think I didn't try last summer was one of those neck cooler things. They have a gel inside that would stay wet for a few hours. The main thing I did last summer was put the bike on the bus about halfway home. Then in september I put a bike rack on the car, and started parking it at the kmart at the bottom of the big hill. That left me with a 9 mile ride to the car.

This year, I just want to know if, and I suspect it's very true, the brushless hub runs cool enough to forget about it and just ride, with maybe a few minor modifications to the usual full throttle till it melts style I prefer.

A few tidbits from todays ride. In the morning, in about 40 F weather, arrived at work 14.5 miles later with a temp inside the hub at 135F, and cover was about 50 F less. 40 or 50 F less for cover temp seems to be a trend. Coasting down the big hill, took a few minuites, but only cooled the hub inside by about 1 degree. Clearly the hub, cranking away making energy at 25 mph, still makes heat. Another kinda knew that thing, but interesting that 40 F morning wouldn't cool the motor much unless you stop. Once stopped the hub will start to cool off immediately, dropping a good 5 degrees in 5 minuites or less. So imagine that, turn off the little heater inside and it cools off.

Coming back I combined two things, a middle of town, stop signs every 1/4 mile type route that I know makes the hub run hotter, and use more battery simply because you keep stopping. Very soon I was at 140 F inside the hub. Trying to measure the controller temp was a bust, using the infared thermometer just gave me pretty close to ambient temp readings every time I did it. I guess the heat sink on that is adequate for 36v. BTW it was about 75F for the weather.

About a mile from the big hill I began to ride at about 3/4 throttle or less, enough to go about 16 mph. By the bottom of the hill the hub cooled inside by about 3 degrees, so again, turn down the little heater inside and it runs lots cooler, Duuh. Sorry if some of this seems childishly obvious, but it isn't allways so easy for noobs to know this. The windings in the motor have resistance, so in a way, they are like a weak stove element. On the pre hill, about a 3/4 mile that climbs 200 vertical feet through sams club and then kmarts parking lots the 3/4 throttle trick kept the temp climb down to a tolerable level, and I began the 10% grade mile at 140 F. A few minuites of brisk pedaling at 3/4 throttle got me to the top at a speed of about 10-12 mph. Not bad, yesterday the full throttle no pedaling got me 30 degrees more, and this approach only added 10.

After topping the hill, I have 5 miles to home, all uphill, but not much slope, maybe 30' per mile at most. Back to full throttle, and taking the scenic route, added about 6 more miles to my route home, for a total ride of 20 miles. At the very end of the ride I finally got the temp up to the thermometers maximum, at 158 F. At that point the hub measured 95 F on the outside. I have heard about windings being good to 100c, so 212 F. Based on what I was seeing with the thermometer, I would guess that full throttle rides of at least 30 miles could safely be done in 75 F weather. Short cooling breaks or just intervals of lower throttle settings could extend that even further. Clearly soon I'll be overtemping the thermometer I have inside the hub long before I get home, but I think I can gather enough data to get a basic Idea of what the winding temps are by measuring the cover of the hub. As I kinda already knew, rides that completely drain a 20 ah battery are not a problem if the weather is under 95F

 

[RTLSHIP]

I bet it will take the hub longer to cool in summer time. m i think most Aotema owners should be fine as they likely are not going to use it to such an extreme. Does top speed change when already running hot for a half hour or more ? If top speed changes, then maybe the motor is stressed by prolonged heat.

 

[ekingsting]

Thanks for all the interesting data on temps Dogman. I read somewhere that motors cool internally by moisture in the air. Do you know anything about this? If so what is the humidity when you test? I live in the mountains about 10 mi. from the coast with more humidity than you. so I am just wondering since i run at 48v.

 

[dogman dan]

Another data point, this morning, riding to work in about 50 F, the internal thermometer reached 128 F after 15 miles of riding. This is about the temp reached by 10 miles in the 70 F afternoon. Drove the car back home, so no data on the ride home.

Right now humidity is around 5% and will be till monsoon season when the summer thunderstorms come in July. After that, humidity can be 15% or 95% depending on if it rained the day before. But most of the year here, we have very low humidity. The lack of humidity really affects air cooling. It's the reason all the engine covers got cut away from baja bugs, and all us desert motorcyclists know not to ride too hard in June, the month with the highest temps and the lowest humidity. I used to carry a squirt bottle in my bug, and hop out and add some humidity to fix vapor lock. As soon as the engine sputtered, I knew it was time to get out and squirt down the engine.

Last summer, before the first bd36 went up in smoke, I would feel a definite voltage sag when the motor got real hot. That was the hot windings getting increased resistance with heating. But the windings never failed, it was the magnets coming off that stopped me. The heat also weakened the magnets, which made the motor run hotter, and slower. Eventually It would only go 5 mph, and after about a half mile, smoke poured out.

So if your are riding along, and suddenly the motor is slow when your battery is fine, feel the hub. When it's hot enough to affect the windings, it will be hard to hold your hand on the cover. 90% of the USA doesn't need to worry about this too much. But parts of California, Nevada, Arizona, and West Texas are plenty hot and dry enough for this to be something we need to find out about. Last year on the second motor, I just stopped riding more than 10 miles if it was over 95F, and that motor went the majority of the summer just fine.

 

[stevero2001]

Dogman,

When you are climbing your hill, have you checked to see how warm your controller is getting? This would be good to know also.

Thanks,
Steve

 

[dogman dan]

The heat sink must work good, I just get readings off the controller cover that equal ambient temperature. So the infared thermometer is not getting that data. At some point Ill have to put the thermocouple inside the case for the remote thermometer. It's not doing me a lot of good inside the hub. Not enough high temperature range. I never had any problems last summer with the brushed controller other than over amp cut outs. It would start cutting out when the windings got too hot and drew more amps. That controller is live and kicking in the ev globlal.

Today I rode both ways, temp inside the hub was 133 F when I got to work, and the covers were about 80F. Riding home, in 75F, I got to the bottom of the hill at 145F, and the covers were 92 F. About half way up the hill, the internal termometer went off the scale at 167 F I knew I was ok, it's only 75 out so I kept riding. Arriving home, the covers were at about 100 F, and in about five minuites the internal temp cooled enough to show on the readout. So I guess I never got too far above 170. Interesting how hot it gets even in nice weather. But we know as long as you can stand to hold your hand on the motor it's ok.

That's it for this week, tomorrow I'm riding the ICE scooter.

 

[HighTekBikes]

According to the manufacturer, the max temp for the magnet glue is 200 degC (392 degF).

 

[dogman dan]

That is pretty interesting, I'm far from the only one who melted magnets off a motor last summer. Many of the cases I recall were on bd36 kits, so maybe it was just a qc problem. I'm not planning to back off any riding this motor this summer. I want to know one way or another whether this model motor and controller combination can take it or not. I suspect it can. The brushed hub was making heat with about 20 % more of the energy used. But the main thing may be the obvious higher quality of the brushless hub, compared to the cheap construction of the brushed hub. On the brushed hub, there is a lot of space between each magnet, so if the epoxy got soft they could move around a lot. On the brushless, the mags are very tightlly fitted so they shouldn't start squirming around. This should help the epoxy hold at higher temps.

 

[RTLSHIP]

Any comments on the spokes. My Aotema came with professionally trued spokes and a tool. I just had my BD-36 trued at
2,000 miles. The bike shop tech told me to watch out for bumps etc. Maybe steel suspension forks can help? That's what I see on dogman's Mountain bike. I've owned several regular bikes and never had a spokes issue before. It's a different
ball of wax with ebikes because there is more speed and often more weight.

 

[dogman dan]

On both my aotema hubs, I never broke a spoke, or had one go much out of round once it got settled in. The spokes seem pretty strong. The suspension helps I think, but the real strains seem to be on rear wheels. On the trike in particular I have had a hard time with those rear wheel spokes breaking and the rim is always bending. The trike was super rear heavy, with a pile of lead in the tray. The trike became the beach cruiser, and I am looking at making the rear carriage into a trailer.

 

[dogman dan]

640 miles on the motor as of today. I did a long ride today, 28 miles in one discharge from my ping. Going slower, hypermiling, I never saw a temp reading above 130 F. It was cool though, in the 50's. Clearly one solutiong to motor heating is to slow down. At speeds of 15 mph or so, I'm getting 1.4 miles per amp hour of non sla battery. I also did some riding at around 12 mph with a 24v nicad pack, getting 12 miles out of an 8 ah nicad. 1.5 miles per ah on that one. It barely runs on 24v, but once I got the hang of it, it did ok. You just had to pedal your starts, and then kick in throttle at about 8 mph, or from a dead stop, you could get going, but you had to feather the trottle very light. I couldn't belive that I didn't hit a controller low voltage cutoff, but this controller was fine down to around 24v, with the pack starting out at 28v.

I have another nicad pack coming, and with it and my ping I should have up to 50 miles of range, and 40 miles even in the hills. I am planning to ride across New Mexico south to north. Not in one go, but one section of about 40 miles at a time. I can catch a ride to the center of the state from a truck that goes to albquerque often, and ride home from there to start out with. Today I rode the fisrt section, from the southern state line, to my house. I saw Justins talk and got all in a tizzy. It will be about 400 miles from Texas to Colorado.

 

[RTLSHIP]

I was surprised when my Aotema would not shut off either. Well below 31 volts the bike still ran until it was like the rabbit
on the drums w/ little juice. Dogman, you were right about those lockwashers. I had only 1 and the axel did a 180 degree flip several times. I recently received extra washers. This is important because a loose axel can pinch thr green, yellow and blue wires

 

[stevero2001]

Dogman,

There is a neat tool that lets you map out your ride, including elevation. You can even download the data into excel, and calculate slope on sections of the route in smaller increments. This lets you see what the worst slopes are at any given point. Here is an example route that I took near my home in San Diego with a lot of steep hills.

http://www.mapmyride.com/route/us/ca/sandiego/857123842756243531

Click on elevation box in the upper right corner. Once you click that, it will show the slopes by color code. You can map your own route and save it anonymously, and then post the http like I did here. If you don't want to give away your location, just map to a nearby cross street. It would be interesting to see how others routes look, so we can have a better idea what the real performance of differnt motor/controller/battery setups are.

Just note, the longer the route, the more it averages out the slope, so it appears less overall. There are short sections on my route that are over 20%, but they are mixed into an average 8% section.

 

[dogman dan]

That is cool. I got a bit dorky and couldn't seem to get it together to save the map, but it is pretty good. On my hill, it shows the dips , flat spots, etc pretty darn accurately. I measured elevation with an altimiter, and then distance with an odometer and came up with 10% grade. But I was wrong, measuring the road distance, which is longer measured along the slope rather than across the horizontal plane.

I realized this just yesterday when I was looking at various routes I may ride on a national geographic TOPO program. Right away I saw how off my 10% was, more like an average of 5% . When I just looked at it on the other program, it showed a 6% section and at the top, a 7% section. The whole route climbs 800 feet, but there are enough rollers along the way to call it 1000 feet total. It does seem to not see a few of the steep, short hills. Since I couldn't quite figure out how to save the map, if you want to look at my route go there yourself and look at this route. In Las Cruces NM, starting at my work, in Mesilla Park on Conway street. This is near Main and University streets in the south end of town. go up university street to I 25, north alongside 25 to HWY 70, then east on 70 to Holman- Dunn exit. You can see the interchange out my front window.

In any case, my hill is not really so exceptional, but where it comes on the ride does make sure the motor is nice and hot when I start up it. Since the steepest part is 7%, I see why the motor pulls up it so easy.

 

[stevero2001]

At top left there is map new ride, to start. Once you get in route near top left of map window there is save route button. Just click box for save anonymous, and then cut and paste the http link that comes up. I'll check out your route later when I get home. Have fun.



Also can use this to start fresh route:

http://www.mapmyride.com/create_new

 

[dogman dan]

I'm just too dumb to figure out how to put the url in the post. If it won't drag and drop, I'm clueless. I did figure out how to save it to favorites, so I can look at it later. A few things are just a bit misleading on it though, it doesn't see smaller hills, and on my route, the bike trail goes up and down some short, and sometimes steep hills while the adjacent road is graded to one elevation. So a few hills get left out, and also a few dips for underpasses built since the google earth shots were taken. All told, my odometer tells me the google map route misses about a mile of distance caused by the hills. But it's a really cool tool, maybe you should do a thread to point it out to everybody, not buried in this thead. I'm having fun with it, looking at some tougher areas on a ride across the state I'm going to do. One funny thing, it won't let me map a route that uses the interstate. I'll have to get on the I 25 for about two miles at one spot, or go around, 20 miles. The program knows the shortcut is illegal. :lol:

 

[stevero2001]

If you open it with your favorites, you can highlight the http address in the address line, type CTRL-C (copy) then in the reply window, type CTRL-V, and it will paste it. I did look at your route and guessed at some of your intersections. Here's what I came up with:

http://www.mapmyride.com/route/us/nm/lascruces/ 862123846208785201

The line is too long, so you need to remove the space before the 8... to get it to work.


One thing I found is, if you do a shorter route, it has more resolution and you can see the shorter grade changes. I try starting a thread later on this.

 

[dogman dan]

That is close enough for govt work. My actual route stays on the left side of I 25 following a bike path between the frontage road and the freeway. That is where all the little hills are that don't show. If you map just the steep part, where it shows 4%, you get some 6% and a flat spot in the profile. So yeah, the longer the route, the more it averages things. But also, this town has grown, and the route I actually ride doesn't show on the google map. So it shows grades for the road, but not the adjacent bike path which still has the hills . Now that I'm riding with a thermometer, I'm seeing that it isn't just the big hill that heats up the motor, but the length of the ride, and the fact that little hills get the motor nice and warm before I start the hill. We do have a good hill nearby, check out Organ Pass, 7 miles further west on Hwy 70. I can't belive I was ever young enough to ride that one for fun. It was fun to come down of course.

Boy, the scale you look at does make a difference! I was just looking at a ride my wife didn't like much from a few weeks ago. Looking at 2 miles of it, it shows a 4% section. Look at the same area and map just a half mile, and it shows that it really has up to 11% in spots. Verrry interesting. So to really see your route, you need to look at it in very small chunks.

Heh heh, looking at my hill smaller and smaller, It just keeps getting steeper. 4% averaged over a longer distance, it has some short sections of it that are 8% and one spot is 13% for a hundred yards or so. No wonder that flat spot in the middle of the climb feels like a lot of relief! Interestingly, I thought the steepest part was at the top, but actually it's at the bottom. This is a very fun tool!

 

[dogman dan]

I just got my hands on 48v, an 8 ah nicad pack from ebikes-ca. At full throttle, no pedaling, the aotema will go 27 mph on my bike. This is no areo position, especially now that I put a front basket on it the other day. The 48v pack carries in the basket. slightly higher speed is surely possible, in a tuck, or a recumbent.

 

[RTLSHIP]

Mr Dogman, you said that you charge your Ping 36v pack with an SLA Charger. Does a WE charger without modification work? This is intersting because most people with an Aotema or WE already have a 36 v charger.
If the Lithium charger ever busts, justs pull out the SLA charger. This is a good reason to buy 36 v LifePO instead of 48v.