Results tagged “ESC” from The GPSy EV Project

My Piaggio hit the dust a few weeks ago. I went to school with no problems and was on my way back when I heard a loud pop, lost power, and an acrid smoke started pouring out of the ESC/electronics components.

I finally got around to taking the electronics out this weekend. It looked like the Phoenix HV-110A hit the dust.

I was using 2S Pb (SLA) and my max watts were under 100A the entire time (according to my wattmeter). The HV-110 burst into flames when the moped was being driven under relatively light load. This is despite it being force cooled and the ambient temp here relatively cool. Also, the system was under a 90A circuit breaker which didn't trip.

I've contacted Castle Creations and hopefully they'll let me know what happened in more detail and perhaps help me towards a (beefier?) replacement.

My replacement servo-tester finally came in yesterday. I immediately tore it apart and replaced the potentiometer in it with a cable so that it could plug into my Magura throttle. The design of this replacement looks very simple. All discrete components: a 555 timer IC, rectifier, and some caps. I think I'll try to reverse engineer it so that I can just build it myself next time.

While I was waiting for the replacement to arrive (two weeks!), I took my Boxer almost entirely apart and placed the ESC and other electronics in the compartment where the old gas tank used to be. I also made a pannier for the batteries on the side. The result is a pretty clean ride:

The bike is very stock looking, which was one of my key goals. From the outside, the only indication that it perhaps isn't gasoline powered are the two SLA batteries in the panniers. The only real work that needs to be done is to clean up the remaining wiring for the servo-tester / throttle.

This is a neighborhood kid who helped me make the battery carrier. He insisted on being in the photo.

I'd like to revise the battery carrier to be a little more stealth. This first version was just a hack-up to get the things mounted.

Right now I only have batteries mounted on the right side. Two SLAs (2 x 12V = 24V @ 18 Ah) give me a top speed of 30 kph (20mph) which is just fine for the type of intracity commuting that I made this bike for. The bike has such good starting torque that it's low max speed isn't that noticeable.

I originally planned to mount a third battery or perhaps fourth on the left side. However, two batteries are giving me the speed that I want so I might put a regular pannier on the left so that I can carry groceries.

The following are some screen shots of the CycleAnalyst after my first test ride in this new configuration.

My range was 6.5 km on almost fully recharged batteries. This surprised me. I only pulled out just over 7.5 Ah before the batteries died. The batteries are rated at 18 Ah (20 hr) nominal and around 12Ah (1 hr). I was sucking juice out of them pretty fast, still I expected a little more capacity.

The Wh/km of this bike is excellent as it's very light and not all that fast.

The speed here is given in km/h. So that would be around 20 mph max and 15 mph average.

The batteries were seemingly dead at the end of the test run. As you can see, Vmin was 15 volts (this includes voltage sag/drop from power use) which was causing my CycleAnalyst to reboot sporadically and the ESC to cut in and out. Very bad.

Yet when I hooked the SLAs back up to my smart charger, it said that they were 42% full. Which is about right as I pulled 7.5 Ah out of an 18 Ah battery. Still, there was really no juice left in them. Maybe if I had let them rest a little bit, I could've gone a few more kilometers.

I'm trying to figure out what to do. The max speed is fine but the current range is a bit lower than what I had wanted. I wanted a range of around 12 km so that I could go to work and back without recharging. Some people mentioned that AGM SLAs take a while to "break in" so I guess I'll try to see if that's true and if performance gets better as time goes along.

p.s. Just a side note, Amax was 129 amps @ 24 volts = 3000 watts or 4 electric horsepower! This was just starting torque, when I was cruising it was sipping around 300 watts to keep me going.

Some miscellaneous notes that are bouncing around my head.

• The Phoenix HV-110 has a listed max volts of 50 volts, which I thought would mean I could use 40 NiMH cells, with a nominal voltage of 48 Volts. However, you are limited to 36 cells NiCd/NiMH which gives a max nominal voltage of 43.2V. This is a little bit of a bummer since I had planned on doing 5S packs of 9.6V which would have given me 48V. I think this is because although the nominal voltage is 48V in that case, the peak voltage (fresh off the charger) can be in excess of 60V and the FETs most probably aren't rated that high.

• It turns out that I could've bought the 180 kV motor instead of the 130 kV motor. As it stands, I'll either have to get a smaller V-belt or a larger front pulley if I want a max speed of 45 kph (30 mph). No worries.

• I'm wondering what the best way to charge my NiMHs is. They don't sell many 38.4 V chargers, so I may just stick with 2 x 19.2 volt chargers and charge 2 packs at a time. I may want to get even more chargers so I can do the entire megapack at the same time.
  

My replacement ESC from Castle Creations (the Phoenix HV-110A) finally arrived today, along with a Castle Creations USB programmer for it. The Phoenix HV-110A is considerably beefier than the ELF controller that I burned out. I reprogrammed the Phoenix using the very nice USB programmer (notably: BRAKING off) and installed it onto my Piaggio.

If you have the right QuickTime codec installed, you can watch a very boring video of my biking revving up to speed.

Yes, that is indeed duct tape holding the motor wires and everything else together. My anderson powerpoles will arrive on Monday....

On the road, the moped ran just great, with a maximum speed of 20 kph (15 mph) as predicted by the voltage * kV (24V * 130 kV) of the motor. I also very quickly tripped the 30 amp fuse that was protecting the batteries. Luckily I had bought a whole pack of 30A fuses and had them in my pocket. I decided to go to a higher voltage as that would increase my top speed as well as lower the max amps drawn at the same speed.

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I wanted a bit more speed so I wired up the RC racing NiMH packs that I had gotten into a single pack: 9.6V 3800 mAH packs * 4 == 38.4V 3800 mAh megapack and plugged that into the system.

With 38.4V, my top speed increased to 30 kph (20 mph) and -- more importantly -- I could get to this top speed with popping the 30 amp battery fuse. However, if I tried to go up a steep hill, I would pop the fuse. I need to wire two 30 amps in parallel to get 60 amps -- or put in a 60 ~ 90 amp circuit breaker.

The ESC definitely got warm, in the high 30C range (90-120F). I think I will use active cooling for it. I have some CPU fans that I got at clearance that should do the trick. The motor barely broke a sweat, I do not think I will need to do much in the way of cooling it.

The moped was definitely a lot of fun zipping around the neighborhood with it.

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It got dark so testing was over for today. I spent the night rewiring the ESC into the test-box for my low-voltage systems and put a big CPU fan on all of it.

All in all, very very exciting. All that remains is to get some more NiMH packs and wire them in a 3P 4S configuration to get a 38.4 V 11.4 Ah pack. This should be enough to get me to work with a comfortable margin to spare.

The ELF 100 ESC (electronic speed controller) arrived today and I installed it in my Piaggio Boxer. The install was a cinch and everything seemed to be going very smoothly.

I did some test runs with the rear wheel elevated using my 24V SLA batteries. Here is my data table:

I ended the no-load test at dial position 7 on the servo tester as I didn't have a secure way of securing the moped on the center stand and if it came off the center stand during the test, the kinetic energy would rocket it off my back deck.

I tried some partial loads and the amps consumed quickly jumped to 30A as the ESC tried to maintain motor speed.

The motor sounded very good and heated up only a very small amount (to 38 centigrade). So everything looked good for a road test. I took it to my front yard and dialed the servo up to 4.

The moped took off and I dialed it to 5 and went down my street at about 15-20 mph. At the end of the street, there is a slight down incline and in order to come to a stop, I dialed the servo back to 0.

The rear wheel skidded to a halt and the ESC beeped menacingly at me then shut up. I tried to dial speed back up again and nothing happened.

I tried resetting the system and it didn't work. That's when I noticed the ESC was getting VERY HOT. I now have a blister on my index finger. I yanked my main system power and pushed the unit back home. I'm just glad it chose to blow near my house and not 5 miles out!

I let the ESC cool down and then plugged it back in again. It quickly started heating up again, drawing 10 A off the battery (240 watts) and not making any sounds (it normally will "sing" to you to let you know it's OK).

Although I didn't see where it went, I have the feeling that I let the magic smoke out of my $30 ebay special ESC. I've since yanked it off the bike and will likely go and buy a "real" ESC (like a Phoenix HV100).

Until then, I'll try to conduct an autopsy on my ESC. I've got the protective shrink wrap off and the chip that seems to be the one getting super hot is marked 78M05 and it has three leads coming off of it. I'm hoping that if I post some good autopsy pix, maybe Fechter on E-S can help me diagnose it.

In any case, the moral of the story is that the HXT outrunner will work, but it really really really needs a good ESC. And you should make sure your ESC settings are correct before taking it for a test drive. In the back of my mind, I'm wondering if the ESC was set to brake at throttle 0, which would have been disastrous.

p.s. A quick google reveals that a 78M05 is a voltage regulator chip. Makes sense that that would what blew. My guess is that when the ESC told the motor to brake, the motor said "sure, here's A GAZILLIO AMPS in back current to ya!" and that blew out a chip on the ESC.

The servo tester that I ordered last week arrived by mail today. Still no sign of the ESC from Hong Kong so I can't wire everything up, but it's a start.

I go the E-Sky EK2-0907 servo tester from Hobby Lobby. With shipping, it was $13.69 although you can get it for a few less dollars if you shop around. I just wanted a basic model and it fit the bill. Most of the units that I see on ebay are identical to this.

You really can't get much simpler. It has inputs for battery power (5-6V) and two server outputs. There were no instructions enclosed but except for wiring it up wrongly, I can't see what the instructions would've said.

On an RC model, you would hook the servo motors to the servo tester to make sure that they were operating correctly (i.e., moving through their full range) in order to diagnose whether your servos were sticking or your RC receiver wasn't sending the right signals.

I'll be using it as my throttle control. I'll be plugging the motor ESC (electronic speed control) into the servo teste. The ESC looks like a servo to the unit and so if you dial in 0, the motor should be at a low RPM or stop; and 10 would be full speed.

I took the servo tester apart and it looks like the main knob is a standard 5K potentiometer. That means that once my testing is finished, I can replace it with a Magura 5K pot throttle that is standard for many e-motorcycles. For now, I'll leave it be.

The main controller chip is most likely something like a 555 timer chip. Basically a servo tester sends out 10-20msec pulses every 60 msec and the servo throw depends on the length of the pulse (10 msec for minimal throw; 20 for max). This is an efficient design and one that's very resistant to RF noise and signal loss. Which means I can make the controller wire pretty long (and unshielded) without too many problems.

The other thing that arrived was a Venon Smart Temp. I was about to buy a cheap BBQ or auto indoor/outdoor thermometer so that I could monitor my engine temperature when I noticed the Venom was just a few dollars more. The neat thing about it is that it will also monitor my BEC/servo voltage too. And if the motor temp exceeds a pre-programmed limit, it can limit the throttle to a pre-programmed limit. So I can set it, for example, that if the motor gets over 60C, then the max throttle is reduced to 60% to protect the motor.

Hopefully my ESC will come tomorrow or Wednesday. My house is filling up with parts that I can't use! I should also be working on the motor mount as well as get some of the servo wiring and BEC placement done in preparation. I could also use some more Dean's connectors....