Really hot controller

[jasonf150]

Today after my ride home I felt my controller and it was REALLY hot. Is that normal? It's zip tied to my rear rack, so it's not inside a bag or anything. The temp today was only about 90, so it wasn't crazy hot outside. I felt the battery and it felt just slightly warm. It's a cell man 52v 9ah tri battery. The controller is rated for 36v - 72v. And the controller is an unmodded 25A model. So I'm not sure if it was just normal, or if I was pushing it too hard. I was riding close to WOT most of the way home. 12 miles. I was keeping at about 25mph most of the way, then about 31-ish for about the last 2 miles. Any thoughts or advice?

Jason

[neptronix]

You are running it at or around 25A constant, non-stop. Of course it is going to get hot. Your motor wants more amps than it can supply as well. I am sure that thing accelerates extremely slowly.

You really need a 12FET!

http://ebikes.ca/simulator/

Want to see what i'm talking about? put your motor info into the bikes.ca simulator above.

[jasonf150]

Well I've only had this setup for a few weeks. I can't justify to my wife already upgrading stuff. I definitely don't need to go faster, specially since I already am using close to my allotted aH in just 12 miles. And >30mph is already pretty scary without any real protection. Note to self, need to get some knee/elbow pads and maybe start wearing my motorcycle helmet. Anyway, I charge at work, but according to the simulator, I only have about 9 miles at wot. Anyway, I guess I just need to slow down and not push it so hard.

BTW, would the 40A mod be good enough to keep it from overheating, or would that make it worse? I have ebikes.ca's 6xIRFB4110 25A model now, and I hear you can up it to 40A pretty easily. I just don't want this thing to blow on me. And in 3-4 months, i'll be riding home in >110° weather.

[neptronix]

I would not trust a 6FET on 4011's to do much more continuous power. It's getting hot because of the 25 amps. Adding more will not help you.

You picked the wrong controller for the job and it is cheaper to sell yours, then buy a more suitable one than blow yours up and have to buy a more suitable one

9 miles is a pretty reasonable expectation for that setup, if you are going full throttle the entire time and not pedaling.

BTW, lycra folks do 25-30mph and they wear no protection. If you feel that is unsafe on a bike, maybe your bike is the problem. It's not all that fast.

[el_walto]

25amp controller should be fine pulling 25amps if open to the air. I would not worry about it and too much and just go with it, is it hotter than 100celcious?

[Lebowski]

I would think your hall sensors / phase winding combination is wrong. With certain combination the motor
will run but use a lot of current and get crazy hot. Measure the current from the battery when you let the
wheel spin unloaded, it should be really low...

[amberwolf]

Assuming the phase/hall combo is correct (1-2A no-load current, wheel-off ground full throttle), then the controller is probably just getting hot because of the power pulled thru it.

Being hot may be perfectly normal for that controller under your loads--I don't know.

Sometimes there is a lot less air circulation behind the rider than in front, so if it is possible to move the controller to somewhere under the downtube, it might stay cooler. But it might not make much difference. It does make a difference on CrazyBike2--when I had the 12FET in the front triangle, it stayed quite a bit cooler than it does in the center frame between my knees (and the motor stayed cooler in front than it does in teh rear, too, but that is because of my big cargo boxes surrounding it, I think).


Oh, and if it is already getting unbearably hot at 25A, running it at 40A will probably damage it.



FWIW, taking the end covers off the controller will likely cool it a lot, but would expose it to rain/etc. (like that mini-hurricane-winds/rain we had Wed evening that blew me off the road!).

[wesnewell]

90 degree day. Black controller in direct sunlight will get hot as hell. Even an unpainted one will get pretty hot to the touch. Are you overlooking the obvious?

[veloman]

90 degree day. Black controller in direct sunlight will get hot as hell. Even an unpainted one will get pretty hot to the touch. Are you overlooking the obvious?

Agreed. All this talk about motor and controllers being able to sustain a certain power and rarely do I ever see the very important variable of ambient temperature mentioned. My controller gets pretty warm in 90 degree heat too, especially if I'm doing a lot of stops and hills. It would not get warm at all if it were 60 outside.

First thing to help would be to make sure the sun isn't hitting it. (I may make a shade for my black Mac motor too). But really, a 6 fet isn't the best for riding at 1200watts constant. Get an EB312 from cellman with a programming cable and lower your amps for the summer. I may do this as well to be on the safe side. Maybe strap and ice pack to your controller?

[veloman]

You are running it at or around 25A constant, non-stop. Of course it is going to get hot. Your motor wants more amps than it can supply as well. I am sure that thing accelerates extremely slowly.

You really need a 12FET!

http://ebikes.ca/simulator/

Want to see what i'm talking about? put your motor info into the bikes.ca simulator above.

Come on now Nep, 52v 25amps is not a "slow" bike. Compared to the 'motorcycles' on this forum, maybe. But it's in general a decent power setup. (That's what I run on my Mac and can rip 28-30mph on moderate hills with some heavy pedaling.)

[neptronix]

I'm saying it's slow relative to what the motor can put out. He is running such low amps that a headwind would slow him down considerably. A high speed winding needs adequate amps to maintain speed and peak efficiency. This is more important on a DD than our MAC motors.

I believe the problem to be a combination of running the controller at it's maximum power constantly and ambient temperatures. Combine the two and you got a hot potato

And there's nothing wrong with a slow motorcycle

[Kin]

BTW, lycra folks do 25-30mph and they wear no protection. If you feel that is unsafe on a bike, maybe your bike is the problem. It's not all that fast.

while this is totally true, I also think that it's close to an exaggeration. In short races, yeah, they're in the 25-30 range, but in general long practice it's more like 23-26mph. Now that's insanely picky for me to point this out, but 30mph is 44% more kinetic energy than 25mph. And, when my brother (the lyrca boy in the family) crashed in practice once, he sheered his thigh raw such that it took two days to scab the massive wound and the first night his clothes fused in a bit when he finally fell asleep. Retrospectively, it's pretty stupid he wasn't medically treated for that business, and maybe we ended up taking him somewhere (it was half a dozen years ago, I forget).

What I think you duly point out is that if Jason feels unsafe, and it isn't just because of calculating things in your head to be unsafe, then could be a problem in riding experience/comfort or bike saftey. Because the unsafeness is kind of a reality, but not one you should 'feel' if you're in control.

With regards to the controller, I think everyone else has more experience but the motor is a pretty powerful motor for the controller. Neptronix has it on the simulator, it's not at peak efficiency for the motor or controller.

[veloman]

There shouldn't be any unsafe feeling at 25-30mph on a decent road with such a speed limit, and not cluttered with moving objects/people/animals. The only time I know I need to take caution is cornering, especially if it's wet. Buzzing by parked cars at 30mph in the door zone in heavy urban traffic is unsafe, but if you ride smart, most roads should feel safe at that speed. If I'm on a wide street with no blind corners, 25mph feels quite slow. I do spend a lot of time below 20mph for efficiency, since I have so many stops.I hear lots of people on here claim that their bicycle feels unsafe at 25-35mph. IMO, it's either due to not being experienced, or a poorly maintained/constructed bike. I always wear a helmet though. Just in case, and because it's so easy to take on and off and I barely notice it's there when riding. Usually always wear gloves too.

[Kin]

Yesh, sorry, again I was being nitpickity.

You should not *feel* unsafe. But, realistically, if you were to crash, it would hurt. Frankly any situation in which you *feel* unsafe is probably one you're not in good control of, and so it's unsafe. But if you're just thinking "I need protection just incase because analytically I know it's not 100% safe" then it's not that wrong.

[jasonf150]

...on a decent road with such a speed limit, and not cluttered with moving objects/people/animals...

On nicely paved roads with noone or nothing around, yes I feel safe. It's mostly the roads. Lots of little bumps and potholes. I'm used to looking for cars from my past riding motorcycles so that doesn't really bother me. I've done 145mph on the freeway on my sportbike, so the speed doesn't bother me either. It's mainly the road itself. There are a few spots on my commute where the cracks in the road are pretty bad. So bad that sometimes I ride on the wrong side of the road, which really pisses the lycra's off. So yes, I was just thinking that some knee and elbow pads would serve me good justincase I went down. I do wear (albeit fingerless) gloves. And being a programmer I should probably wear full gloves to protect my fingers.

RE: the controller. I'll have to try the test at wot with the wheel off the ground and see what A it's pulling. I think it's probably a combo of direct sunlight and no air passing by it. I've been playing with various locations since I built the bike and I actually want to get rid of the rack anyway, so I'll move it and see if that helps. It's pretty much in direct sunlight now since the sun is above but also behind me on the way home. I wish I had a temp gun to check it, but I don't. We do have one at work, so I can test it in the morning, but that's not really the time when it's hot.

Meanwhile today, I CA-limited it to 20A and still get +29mph, so I'll run it like that and see if it helps with the heat. I also have an email in to ebikes.ca to see if i can pay the difference + shipping to upgrade to the 12fet one.

[neptronix]

There are different factors that lead to safety being less or more of an issue.

Do motorcyclists, scooter riders, and mo-ped-ers feel unsafe over 30mph? probably not... why? they have decent brakes.. they have suspension.. fat tires.. all the stuff that can handle higher speeds with ease.

On my race bike, 30-40mph is no problem, but that feels real squirrely on my MAC bike. I have strong regen and a fat tire on the rear, and a 203mm disc on the front. I can effortlessly stop as fast as a car can. I no longer worry about potholes or braking.

If 30mph is scary on your bike, you need to think about how your bike handles the speed. My first build with a 250w motor was scary because it had cantilever brakes all around and thin tires.

[spinningmagnets]

One option is to add more fan-cooling to the controller (the stock fan is small, and might not even be working). Mainframe computers and servers sometimes have fans that run off of 48V directly. I searched google for "computer fan 48V" and found this $10 fan, 80mm square (3-inch), ball bearings
http://www.ebay.com/itm/80mm-25mm-New-Case-Fan-48V-52CFM-PC-CPU-Computer-Ball-Brg-4-Screws-584a-/180769444422#ht_948wt_952

[jasonf150]

That fan has a voltage range of 24-48. Does that mean my 52v nominal is too much? Or is it close enough?

[spinningmagnets]

Yes, even at 60V it should be fine...

[Kin]

I was going to comment the same. Chances are it's good until 63v. There's actually a chance it's only good to 54v. As far as I'm aware, computer fans are also brushless motors but they usually don't have 3 phase wires because the motor controller is integrated underneath the center part. So, I guess, it depends on what that controller can handle, and 63v and to a lesser extend 54v are common capacitor maxes.

[jasonf150]

I've been in contact with justin at ebikes.ca in regards to upgrading to the 40A 12fet model, but for now, I've added some shade to my controller. If this works I'll make it nicer looking. I also have plans to move it to the seat post.

[jasonf150]

Finally got around to moving my controller. I have arranged with ebikes.ca (once again, great customer service from Justin) to swap this one out for a 40A 12fet. This controller was also having issues with the throttle. When I would turn it on, it would sense too much voltage coming from the throttle (5.06v) and would stop responding to it. So I had to unplug it and plug it back in almost everytime I started riding. He said it was probably a diode or resistor. Honestly I don't really understand those precise electronics. Anyway, we're still working out the process.

On the rear rack, it was getting direct sunlight for my entire ride home. Here, it should get none. Also, I'm hoping that the wind passes it more efficiently. So I moved the controller to the seat post. This also managed to clean up the wires quite a bit. I made the "plate" big enough for the 40A controller, which is why it seems so big. It's just mdf right now, which I know isn't a permanent solution. I'd like to use ¼" aluminum. I can get it 2" wide of-the-shelf at Home Depot. That should be wide enough. We'll see when I get the new one.....or if this one breaks . To mount the plate, I used a RAM mount I had for my phone. Then I used a ball point pen body for the standoffs. Just cut little sections out so the controller would clear the screw heads. Can't really see this in the pictures. These are also not strong enough, so I'll use something else in the final version.

I removed the rear rack and put the taillights on the seat post. I don't really like rear racks. I carry a water-backpack everyday so I just put stuff in it that I need to carry.

[veloman]

Your legs don't hit that wood/controller? Make sure there is 1/4" or so between the wood and controller for air flow.

[jasonf150]

No they don't actually. I rarely pedal. My leg does touch the top of it when I have one leg straight down. It's nbd though.

I do have little standoffs in there. I put them there because there are screwheads under the controller.