Ping 36v 20 ah, 5000 mile review.

[dogman]

Aww crap, maybe take a pic and post a new thread about the battery connections in the tech or battery section. These dang things are pretty vulnerable where the wires attach. Even the way I have mine set up, I'm suprised I haven't had a disconnect just from vibrations bending the wires where they solder on.


The bd36 is a good motor, I got 2000 miles out of mine, and it's still got half the brushes left. I have heard others say 5000 miles is the brush lifespan. Heat in the summer is my problem with mine, combined with a 15 mile uphill ride home. In the winter, my ah capacity drops, and I was barely making it home most days, but it's still a great motor as long as you are not trying for long range, or cross country riding. Even riding a bd36 in phoenix would be fine for 10 miles. Not that many ebikers ride more than 10 miles at a time, though it's common enough for us sphere people. We are kinda special.

A few things I do like better about my aotema brushless, is it has a better starting torque than the bd. So I don't have to pedal till I''m going faster, and can leave it in my ridiculously high top gear. The aotema is a sensorless system, so it lacks the halls and thier 5 chances for a bad connection. It runs lots cooler than the brushed, but we'll see if I get to ride this summer or ride the bus when it's 105.

[RTLSHIP]

Is it hot in New Mex yet? My 11 mile trip w/ 48v 15ah was a success except for the torn off soldering on the skinny charging cables. Took about 2 1/2 hours to fully recharge ( with tape holding skinny wires on).
I don't think I have any bad cells. What I felt inside the pach was likely insulation, not pouches.
11 miles in 40 minutes is pushing it on a new pack. But it's close to broken in.
Only 2 BMS shut downs as my thumb is getting better. 3 places where amp current rises most: 1) hard/sudden accelartion; 2) hills/incline; 3) headwind. This is well documented, also.

[needWheels]

dogman haven't they changed the BL model a few times now?
I know the BD was changed once. It used to be insanely fast (like 29 on 36v?) but not take hills.
They they "beefed it up" and it got slower.

But they seem to tinker with the BL model every year. BD is discontinued this year though, right?
Oh wait no, here it is, but look the controller is downgraded by 5 amps?
http://www.werelectrified.com/ProductDetails.asp?ProductCode=BD36+Kit
At least they redid that ugly website!

[dogman]

hmm, I thought the bd was gone too. At least as a kit, it dissapeared for awhile, but new summer, new shipment I guess. I had the 2008 model bd 36's . One went 29 mph on 48v, the other about 27.

It is getting warm here, 99 the other day, but now back to about 95. After labor day is when we usually get two weeks of 105-115. Hope it's only 105 this year. We have .08 inches of rain this YEAR. Today the humidity is 3%. At a certian point, that "its a dry heat " thing backfires, and you start to turn into living jerky.

[RTLSHIP]

My BD36 with 36v will do around 24 or 25 mph with no wind. Typically I usually do not hit that top speed. With 48v SLA about
28 mph with no wind. With lifepo4 48v 30 mph.
Add or subtract a little to factor in wind. It's nice to read that the brushes go about 5,000 miles with normal wear. My hub has approx 2200 miles. One question: will a lower amp controller on the BD36 prevent BMS cutouts? I would imagine that
torque, acceleration and energy consumption would drop. Top speed might still be reached.

[dogman]

I'm not sure about the cutouts, it's the motor that wants to pull the amps when you get cutouts, so maybe not. I would think a higher amp controller would solve the controller cut outs, and replace them with bms cutouts The bd 36 has a harder time starting than the brushless motor for some reason, so when you stall it a bit, it cuts out. Less throttle, was my solution, and more pedaling on the start.

[needWheels]

I finally saw 28mph today but the headwind was getting a bit extreme.

I doubt I'll ever see 29 because my wheel isn't true enough and I don't ride with full 65psi, more like 50.

When I got back I borrowed a neighbors temp probe and the inside of the motor between the spokes was 123 !!!

That can't be good for it eh?

[dogman]

The magnets glue starts getting soft around 170-180 I'm told. Where you measured is where the coils are, and they can go a bit hotter than the magnets.

[OneWayTraffic]

Have you considered painting the motor black to aid radiative cooling?

[RTLSHIP]

Black color attracts sunlight. White repells it. If you own a black car in the summer, you will know what I'm thinking.
Step on the asphalt, with barefeet, in July.

[dogman]

I'm not sure of the physics of that black to radiate thing, but in the sun, black gains more heat for sure. I was going to paint my battery box white, but found when riding, the metal cools ok from the wind. We need cooling fins on motor hubs. I'm going to try a wet cloth wrapped around the hub when it gets hotter. Water definitely helps, a splash on my hub now, is instantly seen on the thermometer, dropping about 4 degrees.

[needWheels]

dogman do you think I should take the case off my controller and just let it sit naked in the small bag under my seat?

I forget what the conclusion was, if the cutoff after the rolling hills was because of my motor overheating or the controller?

Was it the motor overheating and therefore making the controller work impossibly hard, and dropping the 35A cutoff to a lower number? So cooling the controller would not help because the source of the problem is the motor?

Sorry I guess I sorta hijacked this thread (and your BD36 sale thread).
I guess we could use a dedicated BD36 thread like visforvoltage has a dedicated WE sub-forum.

[needWheels]

I don't like those black motors lol, I almost bought a golden motor but decided against it because I didn't like the black.

Too bad they didn't design it with vents and little fins to draw in air at speed.

[dogman]

With the bd controler, there is a heat sink on the back with some fins. I mounted mine so the fins faced into the wind so they could get cooler. Just don't put the controller in bag or box to waterproof and cut off air circulation to the heatsink.

When the motor gets hot, the resistance goes up in the windings, so then the motor draws more amps, working the controller so it gets hotter too. I could high amp cutoff my controller even when cold if I stalled the motor, so when it got hot, I could do it even easier. I just learned to feather the throttle.

I learned how to tell when the motor was too hot just by the way it climbed the hill. When the motor got too hot, it would get more and more sluggish. I found 10 mile rides would not ruin a bd36 even in 100 f weather. But in any weather, too long a hill can be a bad idea. The hottest I ever saw the motor I melted was on a 70 F morning, when I tried to ride the bike on the local single tracks in the mountains. 1/2 hour of steep climbing and I could smell melted epoxy.

[OneWayTraffic]

Black color attracts sunlight. White repells it. If you own a black car in the summer, you will know what I'm thinking.
Step on the asphalt, with barefeet, in July.

True, but if the motor is hotter than ambient, it should help on balance. It all depends on the balance between the suns radiation and it's own.

Anyway just a thought. I suspect most cooling is convective.

[needWheels]

It's kinda weird how they didn't design any venting for the motor at all
- it's not waterproof in the first place but yet they close it off anyway

dogman the heat levels you are reporting are with 36v or 48v ?

[davespicer]

When the motor gets hot, the resistance goes up in the windings, so then the motor draws more amps...

Think you might have meant "down", unless Ohm's Law changed while I wasn't looking (busy getting grey hair instead!)

[needWheels]

Heh I found that steveo did a mod like this to his motor...



Something a little less extreme might be useful though, even a small amount of airflow...

[OneWayTraffic]

When the motor gets hot, the resistance goes up in the windings, so then the motor draws more amps...

Think you might have meant "down", unless Ohm's Law changed while I wasn't looking (busy getting grey hair instead!)

LOL

Look at it like this. As the wire resistance goes up, then more of the work is converted into heat, which forces the controller to pump even more amps into the motor to maintain a set throttle speed.

[RTLSHIP]

I think these WE/Aotema hub motors do have some water resistance capabilities, but don't expect hub to withstand a monsoon. The inner heat is gradually attracted to the outer aluminum case and aluminum wicks away the heat gradually.
Of course, if your riding hard for a long time; the cooling process is probably delayed. I pretty for sure that aluminum cool much faster than steel.

[dogman]

Well, I'm usually full of crap when it comes to the electronic theory,,, But the hot motor does draw more amps, or turns more amps into heat than a cool motor, or something like that. You can feel it happen as you melt your motor. It's the same feeling as sagging sla's.

I'm running 36v on the commute home. I have heard air vents help, but by the time I tried it, the motor was toast, and the vents let the smoke out real good. I'm thinking of tying some cotton strips around the hub, inside the spoke flange, and keeping it soaked with water, but so far, I'm not seeing hub temps much over 160F measured inside, and cover temps at the same time are around 112. I think this brusheless aotema may be albe to take the heat at 36v. It should get hotter when its really blazing, but right now the hub seems to reach an equilibrium at around 165F. In colder weather, it reached the equilibrium at a lower temp.

[dnmun]

carry a little water gun, shoot a little spray on it when you stop, just enuff for it to evaporate, it would be hard and dangerous at speed, but a little water can go a long way in cooling if there is only enuff to evaporate, not running off, but resistance should go up as T*4, but the FETs carry current more easily as they get hot, which may be what you experience.

also you can run your nicads and lifepo4 in parallel too. the All-electronics.com place posted yesterday has the "battery combiners" parallel schottky diodes for cheap cheap. they had a new listing for the paired diodes in a 220T type package for $1.35. 25A60V.

get two and solder them through the tabs to the power cable going to the controller, and to the top of the two packs with the 2 pairs of legs coming out the bottom, to keep the series resistance to a minimum and get 50A surges without problems for $2.70.

[dogman]

When I stop at the base of the big hill, I get water at a fountain on the bike trail. If I splash some on the motor, the heat will drop about 5 degrees on the internal thermometer in about 30 seconds. The same drop without the water takes a five minuite wait. The water runs off too fast though, so I'm thinking about a tube sock tied around the hub or something like that to hold the water. Here, where we had 8 one hundredths of an inch of rain since January, air cooling won't work for doo doo till the summer rains come. 3% humidity yesterday, with no water molecules in the air, air cooling doesn't work. So far though, at 95F , I'm not seeing a heat level the motor can't tolerate yet. So most of the country has no worries, unless they climb more than 1000 vertical feet on a given ride.

[RTLSHIP]

last year there was some debate about whether WE brushed hubs get hotter than brushless. It's still not summer, but what's the answer. Of course we have to make some allowance for the fact that the magnets are fastened on better with the Aotema brushless.

[dnmun]

i think there is a thermal joint compound that sets up like epoxy. if it would hold onto the outside of your hub, you could make some small aluminum brackets that you could attach around the outside of the hub to dissipate more heat in the air. like little propellers, little heat sinks glued on with the thermal joint compound. maybe cut short, 1/2" long pieces of aluminum L stock, set up a jig where you had cut out a block of wood with the same radius as the hub, and then put the inside face of the bracket up and hammer it into a curve that would fit the outside of the hub. maybe use a piece of pipe on the inside to make the metal bend the same side to side, and hammer on the pipe on top of the sandwich. then epoxy them on.