Mikrokopter BL Ctrl operating temperature limits

[MombasaFlash]

I recently faced down assembling the Bluetooth data link. After a whole lot of fiddleass soldering and cussing I was somewhat relieved (and surprised) to discover they actually worked. Not only that, they worked out at the field too. I have not yet tested their distance limit (claimed to be 1 km) but 50-60 metres was sufficient to at least get some basic data back whilst airborne.

I was keen to know the in-flight BL Ctrl temperatures, particularly with the Canon 5D on board. Without the 5D the range of temperatures for the eight BL's was 61 - 81°C. With the Canon 5D the range was 68-95°C.

95°C !! Ye Gods. Is that normal?

And this is with the 16 heat sinks, the PDB sitting high on 20mm stand-offs AND the canopy sitting on 10mm stand-offs and a not-particularly-hot-day at 16°C.

For all the blah about the AD-8 HLE being aimed at carrying the Canon 5D I was completely unimpressed by the miserable six minute flight time. As Droidworx and AltiGator unwittingly conspired to screw up my 'brand new' AD-8 HLE order and sent me the 'old' model with 410mm booms I do not have the option of installing bigger props to create more lift. Of course, that may just increase the motor load and make the BL's run even hotter and wear out the batteries even faster.

The basic question here is what is a healthy/safe operating temperature for the BL v2.0?

 

[Droider]

What firmware are you running?
What motors ans battery have you on board?
Whats your take off weight?

DroidWorx/ AltiGator should have sent you replacement booms if you bought your ADX recentley

Are the longer ones on the way? When did you buy your AD8HL?
The new boom lengths is quite new.. Announced on 18/10/2011

They will not help with BL temps. BL soft shutdown starts at 100ºc - 95 is hot but I have the same issue. There is a whole load on MK.DE about this as it seems to have occured after the latest 0.86 firmware upgrade

Dave

 

[MombasaFlash]

Firmware: FC v0.86 / NC v0.26
Motors: AXI 2814/22
Battery: 6600mah Vislero LiPo
T/O weight: circa 5500g with 5D (3750g without)

Droidworx did offer to replace the booms after I contacted them to moan about AltiGator's restocking fee based on purchasing incompatible props because the DW spec sheet gave misleading/incorrect information. However, by then I had already plumbed in the motors and there was a question over whether the motor wires, which had been shortened by about 50mm to fit the 410 mm booms, would be long enough for the 430 mm booms. So I declined and left it as it was.

That is interesting about the v0.86 firmware being a possible cause of high BL temps. If there is that much of a furore going on I guess we can expect another release soon.

I should have taken a screenshot of the BL temp display because the difference in temperature between individual BL's was always consistent. For example, the lowest temperature was always BL #5 and the highest was always BL #1 or #3.

What sort of temp. range do you get?

Gray

 

[Droider]

My all up flying weight with 2 x 5000mah batteries is about 3.8kg.. flying time 12 mins with 550D 18 mins with Nex5

Motor AXI2814/22
Props Xoar Carbon's 13x6.5

With the 550D I have to land at about 8 mins in because BL's are up at 117ºc!

With the Nex5 I am up in the high eighties.. I have never before with previous firmware seen these temps I am usually between 45ºc and 65ºc on 0.84

Dave

 

[MombasaFlash]

Hmm, maybe I will revert to 0.84, since 0.86 doesn't offer anything crucial that I would miss.

I have a NEX 5N on order, should be here by Wednesday, and I reckon there is little doubt that the image quality will be indistinguishable from the 5D for web content.

The DW AD-8 was purchased specifically to carry the 5D, but with high temperatures and limited flight times I might find that the original insect ... sorry ... MK Octo with the NEX will become the main rig with its soft flight characteristics, light weight and decent flight times. That one was also updated to 0.86 but there is no way of knowing what the BL temps are.

 

[Stuminator]

Hey Guy's have you thought of moving away from a distribution board & mounting the BL's out on the arms under the prop wash ?. Also you could go to 5S batteries and run a BEC to power the FC & stack and another BEC to run the Gimbal servo's. Doing that will see you drawing less current however you may need to think about lower KV motors as well. My new MegaHexa is already undergoing these mods to reduce the BL temps and to increase reliability. In the end however we need Holger to offer a higher rated BL for heavy lifters and I'm sure it won't be long.

Cheers


Stu

 

[Droider]

Hey Guy's have you thought of moving away from a distribution board & mounting the BL's out on the arms under the prop wash ?. Also you could go to 5S batteries and run a BEC to power the FC & stack and another BEC to run the Gimbal servo's. Doing that will see you drawing less current however you may need to think about lower KV motors as well. My new MegaHexa is already undergoing these mods to reduce the BL temps and to increase reliability. In the end however we need Holger to offer a higher rated BL for heavy lifters and I'm sure it won't be long.

Cheers


Stu

Hi Stu and welcome to MRF. I hear what you are saying but I NEVER had temps like this.. I am hoping to do a down grade test at the weekend I also have a IR camera booked for work next week which will make for interesting tests

Dave

 

[Pjtyros]

Hi I have been following this thread with interest as I am about to mount a Canon 5D (weight 1.2Kg with wide lens). So today I have just done some tests. I have a standard Hexa XL with the MK3538 motors and 12" apc props, 6600 lipo. After 6mins flight I am getting a max temp reading of 50c with the average about 48c. I added weight to simulate the camera so the all up weight was 4KG. I was a little surprised as this seems low compared to what you guys are getting so I landed and checked the temps shown in the MK tools with my laser temp gun and found them to be exactly the same. Outside temp about 12c today.

Paul

 

[MombasaFlash]

I down-graded to FW 0.84a and did two flights this morning for a comparison with FW 0.86d BL temperature readings. This time I took screen-shots to show the consistent lower temperatures of BL's 3,4 & 5, both with and without camera. As the 6600 LiPo + 5D flight time with FW 0.84 was pretty much the same as the FW 0.86 data, the 'high temperature' is not affecting battery life and raises the question that FW0.86 is simply giving out false, elevated readings?

2x 5000 mah, no camera : 16'30" @ 37-72°C
1x 6600 mah, Canon 5D : 06'46" @ 55-83°C

to save scrolling back up this page the data with FW 0.86d was:

1x 6600 mah, no camera : 11'20" @ 61-81°C
1x 6600 mah, Canon 5D : 06'38" @ 68-95°C

As there was nothing much to do but wait for the low battery alarm I looked at some other stuff. The '3D' display shows the centre of gravity to be way off - and this was the no camera flight. Don't know how this is possible with such a symmetrical assembly.

 

[Droider]

Holgar has just posted this on the MK forum

http://forum.mikrokopter.de/topic-post347156.html#post347156

Dave

 

[Droider]

Hi I have been following this thread with interest as I am about to mount a Canon 5D (weight 1.2Kg with wide lens). So today I have just done some tests. I have a standard Hexa XL with the MK3538 motors and 12" apc props, 6600 lipo. After 6mins flight I am getting a max temp reading of 50c with the average about 48c. I added weight to simulate the camera so the all up weight was 4KG. I was a little surprised as this seems low compared to what you guys are getting so I landed and checked the temps shown in the MK tools with my laser temp gun and found them to be exactly the same. Outside temp about 12c today.

Paul

What firmware are you running?

Dave

 

[Stuminator]

Hmmm interesting maybe I need to look at other props as I'm running the APC 13 x 6.5. I aslo live in the tropics where the ambient temp is around 33 degrees Celsius which doesn't help.


Cheers



Stu

 

[Pjtyros]

I am running the latest firmware 86d. I did these tests with my top cover removed as I new I would be near the weight limit. After
my post I repeated the tests with my plastic dome in place and I was amazed to see the temps shoot up to around 80c for the same flight. I then off loaded the 1.2 Kg load and put my 300g camera on board my temps were 45-50c with no top cover and 75-80 with. So
cooling seems to be more important than I had previously thought. I will look to making some kind of open frame to protect the
electronics. Reading the post from Holger would suggest that there are better props than the 12in apc, what are your thoughts?

Paul

 

[MombasaFlash]

Here is some good ole boring geeky stuff ....

Just came back from four flights to try and get a handle on this FW 0.86 temperature business.
Using FW0.86e the User setting #7 is on a Tx switch, U7OFF = motor smoothing Off (value=256), U7ON = motor smoothing ON (value=0)
The dome cover is the heavy-duty, ventilated one with a ring of holes and it sits on 10mm standoffs i.e. there is a 10mm gap all around the bottom between the dome cover and the top plate.

The Canon 5D is with the 24-105 standard zoom and weighs in at 1600g. the mount is an MK HiSight SLR2 (281g)

• 1. with dome, hover, U7OFF BL range: 41-63°

• 1. with dome, hover, U7ON BL range: 50-88°, ... flight time: 11:03 6600 mah LiPo

• 2. +Canon 5D, with dome, hover, U7OFF, BL range: 53-95° ... flight time: 07:07 6600 mah LiPo

• 3. +Canon 5D, no dome, hover, U7OFF, BL range: 41-67° ... flight time: 06:40 6600 mah LiPo

• 4. no dome, hover U7OFF, BL range:40-63°

• 4. no dome, flight, U7OFF, Bl range: 34-49° ... flight time: 11:12 6600 mah LiPo

So the "motor smoothing OFF" option appears to make little difference with the camera on board. Temps still reached 95°C for one BL. Removing the Dome sees the most significant reductions in heat build up - even the fancy perforated option with 10mm stand-offs - and including some forward flight reduces it even further.

Of course, temperatures will not be so extreme with a lighter weight. i.e. lighter camera.

No surprises really ! Except that the User setting 7 option doesn't seem to make a huge difference either way.

 

[Droider]

This thread has posted more useful information than the MK one! Sound testing there MF.. If you have the time and the inclanation it would be good to see your results with either the 0.82 or 0.84 firmware.. I am working as I type and things are manic right now so I dont have time to test all the options out but getting fed up with the MK smoke and mirrors game. Just took a break and flew 2 packs with my WMK quad in the sunset no mither no problems just good smooth reliable quality flight time..

Dave

 

[MombasaFlash]

After initially seeing that 95°C temperature (the first time I have had access to this sort of in-flight data because I had just assembled the bluetooth link) and then reading all that stuff on the MK forum I did in fact go back to FW 0.84a from 0.86d. I noted data for just two flights. I was also finding out how long two 5000 packs lasted. So the temperature/battery data from the two flights on 9th Nov. with FW 0.84a was ...

• 1. 2x 5000 mah, hover, no camera, normal dome (with no holes) BL range: 37-72°, flight time: 16:30

• 2. 1x 6600 mah, hover, Canon 5D, normal dome, BL range: 55-83°, flight time: 06:46

I deliberately leave it in an extended hover as that is going to make the motors and their controllers work the hardest. Although a larger difference between low and high temps was displayed with the no camera flight, overall displayed BL temperatures were certainly less than with either version of FW 0.86. However, I did miss the dynamic GPS (GPS had to be turned off and then turned on again once the new position had been reached otherwise the MR went back to where it started from) and was keen to reinstall 0.86 hoping that version 'e' would clear up the high temperature business.

Unfortunately, I do not believe it has.

 

[Droider]

So E has been released?.. not checked MK yet but will now..Not sure what you mean about the GPS thingy.. it sounds like you got it in come home on all the time.

Dave

 

[MombasaFlash]

The link to download the FW 0.86e is on that MK forum link that you posted here three days ago.

Here is the firmware link:

http://mikrocontroller.com/files/Flight-Ctrl_MEGA1284p_V0_86e_MotorSmooth_UserParameter7.hex


On the subject of the GPS with FW 0.84a, if the GPS hold was activated and then the MR was moved to a new position it would go back to where it started the move once the sticks were released. I had to switch GPS Hold off, move to the new position and then turn it back on. FW 0.86 features 'dynamic GPS Hold' that allows the MR to move (whilst in GPS Position Hold) and then, when the sticks are released, accepts the new coordinates as the new Hold Position. At least that is how I have understood it and that is how it now behaves.

BTW, the criminal UK postage rates for that double-buzzer low battery alarm prompted an eBay search. Two buzzers inc. post from Hong Kong for less than the price of just one buzzer in the UK.

I am finding that I actually prefer the MK Octo to the AD-8. The Octo is just no fuss and it is VERY stable. The DW has had all the love, attention and the fancy stuff, but it is not nearly as steady and tends to hunt a bit in the air. It also has a problem maintaining a constant altitude over an extended period. It tends to very gradually sink. The Octo stays almost perfectly motionless until you bring it down.

I was very annoyed to discover that the Sony NEX-5 does not have an a/v output. What a stupid way to spoil an otherwise rather impressive little camera. I will be getting around the problem with an HDMI to composite converter. It is an ungainly solution but should work. I have not been able to find a comparable camera from another brand that does not include a live audio and composite video output, either via a mini jack or USB socket. Sony alone puts just an HDMI output. Divots.

 

[Bartman]

has anyone seen a decrease in BL temps with the .88 firmware release? i'm not running a data link so i'm in the dark with regards to this.

just pulled a BL with no temp reading....didn't realize the temp was a necessary element for the BL to work. would have guessed it would be fine to go without it but, as Dave mentioned that it's a control parameter when the temp limit is exceeded, it sorta makes sense.

thanks,
bart

 

[MombasaFlash]

has anyone seen a decrease in BL temps with the .88 firmware release? i'm not running a data link so i'm in the dark with regards to this.

just pulled a BL with no temp reading....didn't realize the temp was a necessary element for the BL to work. would have guessed it would be fine to go without it but, as Dave mentioned that it's a control parameter when the temp limit is exceeded, it sorta makes sense.

thanks,
bart

I discarded the plexy cover a while back so the whole thing is open to the air to avoid cooling issues. A recent in-flight data check showed my BL temps to be all around 45-60° (according to the MKTool OSD).

I am wondering whether that USER 8 option is still active in v0.88 (Motor smoothing or something) that was introduced by Holger in response to the v0.86 over-heating comments. I also wonder whether it ever did anything useful !