Batteries Heat and Load

[flysolo]

Align 450dfc combo stock with pulse 3s 2250mah 45c compared to Align 550dfc combo stock with pulse 4500 6s 45c.

On the 450 after a flight the motor is stone cold. The esc is a little warmish but not much. The battery is hot and if I use older batteries of other brands they puff up and get even hotter.

On the 550 the battery is cold after a flight but the esc is hot and the motor is extremely hot.

Is it gearing, head speed, amp ratings, battery quality or what is it that makes them behave so differrently?

What to prefer, hot battery or hot components? Or is there a sweet spot where everything is balanced?

 

[pvolcko]

Bigger the heli the hotter the motor and ESC are going to get since they are handling more power. Extremely hot means you probably need to making some timing adjustments or something to the ESC to get the ESC or motor temps down. But, remember motor temp will jump after you shut the heli down since the air flow through the motor stops and it just dumps all the heat to the outside can. Batteries should not be getting hot under any circumstances or puffing that bad. A little puff/sponginess that goes away after they cool or charge up can be expected, just as long as they don't get hot to the touch. If they're getting hot then you need to either increase capacity (2500 or larger if it will fit/balance) or increase discharge rating (45C to 55-60C).

 

[Tony]

On the 450, the battery is going ot get warm. Remember, the older the battery, the more IR (internal resistance) each cell is going to have and the hotter the pack is going to get. This is where quality batteries like Gens Ace or Pulse come in to play.

As for the 550, you might want to look at your gear ratio. It may be a bit too high. Dropping one tooth on the pinion will cool that motor and ESC down, as well as keep a better head speed since you are putting more torque through to the head.

 

[flysolo]

The older 3s batteries are turnigy and wellpower 30c and the difference with the 45c pulse are very noticable. Going to try the 65c pulse but they are almost 50% more expensive. Is the motor and esc on the 450 going to get warmer and battery colder with a higher c-rated battery?

Don't know if it's a problem but the motor on the 550 got so hot that it burnt a wire to the rpm sensor off. I have a temp sensor but it's mounted to read battery temp at the moment and it never gets warmer than 30°c so I'm about to move it.

 

[Tony]

Burning a wire is a HUGE issue. I'm thinking you are either WAY over geared or you have a locked up bearing somewhere.

There is no need to run a 65C battery on a 450. I'm running 30c 2200mah 3s batteries and they get warm, but not hot. And no, your motor will not get warmer with a larger c rated battery. Remember, the motor PULLS the power, the battery doesn't PUSH it. And the ESC just regulates the power from the battery to the motor.

 

[flysolo]

Gonna get this for the 550 and try it out:
10t helical pinion

I use the gov in the Esc and the max rpm i can get is 2250 at 94% power. With the 10t i would get 2050 at 94% power. But with more torque? How does that translate when flying?

 

[Tony]

before you change anything, turn off the gov and fly at a flat 85%. If the motor is cooler, then your gov is hunting putting a LOT of heat into the motor.

 

[flysolo]

Ok, I will try that. What kind of head rpm speed is "normal" for a 550 with 520mm blades do you think?

- - - Updated - - -

I think before I strted using the gov I had around 1850 with 85% throttle. I'm thinking maybe I should have a lower rpm set in the gov and then it would be easier on the esc and motor to keep that head speed. Is that what you call hunting? Trying to keep the speed?

 

[Tony]

Smack 3d you want about 2500 or so. For mild 3D, something around 2200. For just sport flying to save your battery and give longer flight times, run 2000. If you only had 1850 at 85%, then you are not over geared, and I can almost assure you that getting rid of that gov will cool that thing down. I will bet it's hunting it's butt off causing power surges and heating it up.

 

[flysolo]

I only had time to reprogram the esc yesterday but I did 3 packs just now after work. I think you were right Tony, with flat 85% throttle the motor is much cooler.

With a full pack the head speed was around 2200 and in the end at 21.9v it was around 1900 both when hovering(inverted

 

[Tony]

You can try kicking it up to 100 100 90 100 100 and see what that does. This will give you an idea of what your absolute max head speed is and how the motor feels after the flight.

 

[flysolo]

Yeah, I tried at 95% throttle and it was 2500! It felt more like the 450 in the air. I like the high rpm but i guess that would drop pretty rapidly?

 

[Tony]

It will drop, but maybe not as much as you might think. However, running a high head speed is really only needed for smack. IMO, I would stick with the 2100-2200 HS for flight longevity.

 

[flysolo]

I think around 2100 would work nicely for me, gonna try some more settings. The soft start does not play well when not in gov-mode so I might give that a try agin to. I found a setting for gov gain that maybe should be lower.

I've got a high current sensor coming in the mail http://www.horizonhobby.com/products/SPMA9590. It's rated to 150A but i realized now it uses EC3. Am I missing something? I thought EC3 couldn't handle that much.

 

[flysolo]

I'm doing a complete rebuild of my 550 now and going to fit the amp sensor but I have to remove the soldered EC3's. My soldering pen could not handle it so I had to go to the shop and get a soldering station. Nothing fancy but with display and good temp range it should be a piece of cake right.. Lol, i suck at soldering so I will probably ruin the sensor.

Anyhow, with the sensor soldered directly to the esc cables it should be capable of 150A continous

 

[coolgabsi]

Not to thread jack but I have been using the soldering station hobbyking sells (it's a weller copy) for about 8-9 months now and it is AWESOME! Just bought a pack of tips from eBay and it is awesome

Just FYI .

 

[flysolo]

After using mine today I can't believe I didn't get it earlier. It's like 10 second to do a perfect solder joint compared to 5 minutes and really ugly work with my old one.

This is my amp sensor re-soldered and fitted, really happy with it

 

[Tony]

It's amazing what a good soldering iron will do. I use the Hakko 936 and I LOVE IT! It's what HK copied off of. I have been using this soldering iron for over a decade and the only thing that went wrong was when I pressed way too hard and broke the handle lol. Otherwise, perfect!

That looks good too by the way. Very nice job!

 

[flysolo]

Not so sure that you would say that if you looked under the shrink wrap lol, but I'm pleased with not destroying the sensor.

It looks a little messy now with all the wires but I'm gonna hide some of them. I intentionally put all telemtry on the outside of the frame.. Now I'm going to update the esc and then the 3gx, perfect for saturday evening

 

[pvolcko]

Wow, you get that thing totally kitted out with sensors. g-force sensor? altimeter? Too bad you can't really look at the data read out while flying.