Mikrokopter MK bends over backwards to be helpful - yet again .... NOT!

[MombasaFlash]

Following my posts around here aiming to get a handle on the FW 0.86 update BL-Ctrl temperature issues, hot battery cables, whether to use 4S or 5S cells, and a definitive stance on the value of capacitors, I thought I would also ask the manufacturer.


Here is the email that I sent:
I am finding that the BL Ctrl temperatures are very high when carrying a Canon 5D mk2 - up to 95°C. I am wondering if it would be better to use 5S LiPo's instead of the 4S. Firstly, will the FC, BL-Ctrl's and AXI motors handle the increased voltage and secondly, must I change the BL-Ctrl Elkos for a higher value/voltage?

Also, there are four Elko spaces labelled C1-C4, should I also instal Elkos there and if so, what value?

The configuration is FC v2.1 ME (FW v0.86e), BL-Ctrl v2.0, AXI 2814/22 motors and APC 12"/3.8 props on an Octo XL.


Here is the answer:
"Unfortunately we dont't know how the AXI Motors affect the BLs in the temperature. We recommend the MK3638 Motors."

 

[DennyR]

You should have replied "So it's true, you do like crap."

 

[BorisS]

Something like this makes me rage !!! I always ask myself how much these guys not only MK but other FC producers DW PH etc. make. If they are all to greedy to get one or two dedicated support people and to get some manuals going with their products. If i look at the website of PH they are not even capable of completing it since beginning of 2011. What use is a parts check list for the CX frame from DW were the list is not checked off.

Than sometimes you get the answer from the producers that the reseller has to give support, knowing everything about the product he needs to know. Sorry BS and not to discredit any of the dealers but having things on their plate like having to know MK WMK maybe even hoverfly, PH DW CS frames, giving support, building RTF components or Copters, marketing themselves keeping up to date and most of the time getting new components at the same time as the customer. How should they know more about a product than the customers or be able to give support at these stages. Most of the time I am pretty sure (only difference probably faster communication channels) they have just as little info as the customer. Someone in this chain sooner or later has to setup some real support.

Just compare it to the CS Gimbal. 5 videos in youtube to demonstrate what the product is about and how it is used and i bet a lot of customers are happy including me.

Most of these products are not perfect or have a short life span but at least give the customers a clean and easy introduction to the product and dont show the attitude of I dont give a .... figure it out yourself and after 1 year of not getting a AV 200 straight (because it is not possible to get is jitter wobble flex free) buy an upgrade kit for another 100 $, that dosent even touch the matter, but tries to get you closer perfect leveling gimbal which will never exist with hobby servos.

Like mentioned before in a thread its up to use to ask for more than is offered at the moment. Someone on the lines is making money either the producer, the resellers or both. But one of them has to digg in at some point and get some support going. Although i am more than happy with the support from my reseller Krleas but i think he will also struggle to provide the same level to someone who buys less, again because the time and material is not given. I guess it would have to be the producers to lower their prices to the resellers that they have the budget to hire dedicated support or even the producers demanding it from the resellers, given a fair price is offered to them, similar to other industries.

Gotta think about it these knowledge bases/forums MK, this one, RCgroups are all filled mostly by the additional time spend by the customer figuring their just bought product out or helping other customers that don't know were to get help from.

Ah whatever just my 1000 euros spent again or how do you say it just my 5 cents ?

Boris

 

[Macsgrafs]

Hi Boris, but I bet MK would soon be on your back if you use thier setups for commercial gain
Its not just MK, have you had any dealings with hobbyking? I bought an eagletree air expander but it was short on the pitot tube...in other words there wasnt a tube in the plastic bag! So I contacted HK & they said they would send another. Now let me explain what the part costs etc direct from eagletree.

1 x pitot tube $9.99
Rec orded post to UK $40
TOTAL: $49.99

Hobbyking has over 30 in stock so i asked that they take a tube from current stock & send me, but they refused. I opened a paypal dispute & they offered me $2.99 for a new pitot tube...now paypal is telling me to send back the WHOLE order for a full refund...but it wioll cost me $30 to return it

I will put this one down to experience & nEVER will I be honest with hobbykign again, just wish I had an email address for the owner so that I could remind him how I paid $500 after a dispute which went in my favour...2 months later the police bring me my original order so I paid hobbyking back $500 even though I didnt have to

Ross

 

[MombasaFlash]

I paid extra for a HobbyKing order to be shipped by 'Three Day EMS'. That order was made and paid for on 12 December. We now have 20 December and still no sign. Can't wait to make another order with them!


So MK replied after I emailed them thank you but you did not actually answer any of the questions:
"... if you use a bigger LiPo, the BLs get more energy and will get even hotter.
We could not confirm, that the temperature of the BLs get higher with the new software.
For using 5S LiPos the capacitors C55 on the FC and C1(only on red NaviCtrl) have to be 25V Types."


Wonderful. That goes entirely against the advice I am getting here regarding changing to 5S packs and 35v capacitors so now I don't know WHAT to do about the temperature problem !! Even worse I have just ordered an AV200 (heavier and therefore even more heat generating) and double battery tray in preparation for changing over from flat 4S Vislero's (of which I have twelve [a good 2000.- euro's worth]) to 5S bricks.

My patience may just expire at which point I shall return full-time to my tried and tested, understandable, mechanical, manly helicopters.

 

[Macsgrafs]

You need to log into hobbyking & do a live chat, ask when they are dispatching your order & it will ship within 24 hours. I found this to be so common, that every order so far this year I have had to live chat support & kick some butt!!!

I dont use BL's because I know they were 1) Far too expensive & 2)not man enough to handle 50A. So I went the I2C-PWM route.

It does sound like no matter what you do its going to build up more heat...have you changed your firmware back to an older working version? I am running 0.86D, but as I said no BL's.

Ross

 

[*****]

why don't you ask your supplier?
ofcourse MK recomends their own stuff , would be the same if you buy a benz and ask benz i have bought lorinzer wheels but the car doesn't track right.

answer: buy original wheels.

lets look at your setup:

we also build rtf machines and they DO carry heavy cameras..

what is your camera weight true weight not theoretic weight
what battery are you using?
size of your cables going to the PB
you had a hle8 right?
what power board V8? (with the side frames?)
active coolers?
standoffs to raise the dome?
holes in the dome?
extra stuff we need to know about?
traco,s on FC? 24165 and 24150?

soldering of the bl,s are they spot on the PB pcb? flat? no space between them?
what adhesive used for the coolers? (it needs to be a conductive glue Arctic Silver)
how big are the coolers?
do you get different temps on the bls? or are they all about the same?
wich props?

 

[DucktileMedia]

Dear MK:

Do you know where Jeff from Xaircraft is? I am eagerly trying to buy one of their products. Can you help me put a DJI system on it? Also, is it ok if I send you money for your commercial license to use with my Xaircraft? Thanks


P.S. I have 1000 motors I would like to return for a full refund. they say T-motor but You can peel off the sticker and put your own sticker on it.

 

[MombasaFlash]

why don't you ask your supplier?...

Precisely my own conclusion. MK makes the FC, the BL-Ctrls, yep ... why not give them a call?

Anyway, thanks for looking to help. The AD-8 HLE in question is currently semi-dismantled as I wait (seemingly forever) for bleeding HobbyKing's package, but to answer your points ...

what is your camera weight true weight not theoretic weight
Canon 5D with standard 24-105 lens @ 1633g
what battery are you using?
Two Vislero 6600 mah LiPo's @ 708g each (6227g total take-off weight inc. LiPo's and camera)
size of your cables going to the PB
single 12AWG cables (with a splitter for two packs using Deans connectors)
you had a hle8 right?
AD-8 HLE
what power board V8? (with the side frames?)
MK OctoDistributionBoard V8b with side frames (see photo below)
active coolers?
finned heatsinks
standoffs to raise the dome?
20mm stand-offs
holes in the dome?
DW high airflow dome
extra stuff we need to know about?
traco,s on FC? 24165 and 24150?
2x standard 5v Recoms on FC
soldering of the bl,s are they spot on the PB pcb? flat? no space between them?
No. They sit lower to gain access to the i2C without modifying the PDB (see photo below)
what adhesive used for the coolers? (it needs to be a conductive glue Arctic Silver)
Have no idea what the adhesive is. It was supplied in the Cooler Kit
how big are the coolers?
full length of FET's
do you get different temps on the bls? or are they all about the same?
No. Wildly different with a Bl temp range spanning 48 - 93°C. The hottest BL's are at the front i.e. 1&2 then 3&8 then 4&7, and the coolest 5&6
which props?
APC 12"/3.8 nylon

Once the heavier 12AWG double battery cables are installed (and possibly the battery connectors will be changed for 6mm bullets) I will make no further changes before flying (without camera) to ascertain distribution of temperatures. If the front BL's are still running significantly hotter I will load the back of the frame to see if this reduces the current to the front motors in case it is a balance problem - although the frame is currently perfectly balanced as far as I can tell. Why should it not be? It is a symmetrical design with identical components around the structure balancing each other out.

 

[*****]

Precisely my own conclusion. MK makes the FC, the BL-Ctrls, yep ... why not give them a call?

Anyway, thanks for looking to help. The AD-8 HLE in question is currently semi-dismantled as I wait (seemingly forever) for bleeding HobbyKing's package, but to answer your points ...

what is your camera weight true weight not theoretic weight
Canon 5D with standard 24-105 lens @ 1633g
what battery are you using?
Two Vislero 6600 mah LiPo's @ 708g each (6227g total take-off weight inc. LiPo's and camera)
size of your cables going to the PB
single 12AWG cables (with a splitter for two packs using Deans connectors)
you had a hle8 right?
AD-8 HLE
what power board V8? (with the side frames?)
MK OctoDistributionBoard V8b with side frames (see photo below)
active coolers?
finned heatsinks
standoffs to raise the dome?
20mm stand-offs
holes in the dome?
DW high airflow dome
extra stuff we need to know about?
traco,s on FC? 24165 and 24150?
2x standard 5v Recoms on FC
soldering of the bl,s are they spot on the PB pcb? flat? no space between them?
No. They sit lower to gain access to the i2C without modifying the PDB (see photo below)
what adhesive used for the coolers? (it needs to be a conductive glue Arctic Silver)
Have no idea what the adhesive is. It was supplied in the Cooler Kit
how big are the coolers?
full length of FET's
do you get different temps on the bls? or are they all about the same?
No. Wildly different with a Bl temp range spanning 48 - 93°C. The hottest BL's are at the front i.e. 1&2 then 3&8 then 4&7, and the coolest 5&6
which props?
APC 12"/3.8 nylon

Once the heavier 12AWG double battery cables are installed (and possibly the battery connectors will be changed for 6mm bullets) I will make no further changes before flying (without camera) to ascertain distribution of temperatures. If the front BL's are still running significantly hotter I will load the back of the frame to see if this reduces the current to the front motors in case it is a balance problem - although the frame is currently perfectly balanced as far as I can tell. Why should it not be? It is a symmetrical design with identical components around the structure balancing each other out.

can you remove the dome and show me as much of the PB structure?
my biggest concern is you PB and the bl controlers with the glue
as you said its in balance so why do the others run hot?
that we need to find out.
anyway i would also suggest in using a single lipo 8000mah in 4S
this saves you about 500 grams of weight , less weight is longer flightime , but less amps will set you back in flightime.\
my guess is that the flightime wit the single battery will give you the same time as you have now only 5000 grams less to Drag around.

 

[*****]

Precisely my own conclusion. MK makes the FC, the BL-Ctrls, yep ... why not give them a call?

Anyway, thanks for looking to help. The AD-8 HLE in question is currently semi-dismantled as I wait (seemingly forever) for bleeding HobbyKing's package, but to answer your points ...

what is your camera weight true weight not theoretic weight
Canon 5D with standard 24-105 lens @ 1633g
what battery are you using?
Two Vislero 6600 mah LiPo's @ 708g each (6227g total take-off weight inc. LiPo's and camera)
size of your cables going to the PB
single 12AWG cables (with a splitter for two packs using Deans connectors)
you had a hle8 right?
AD-8 HLE
what power board V8? (with the side frames?)
MK OctoDistributionBoard V8b with side frames (see photo below)
active coolers?
finned heatsinks
standoffs to raise the dome?
20mm stand-offs
holes in the dome?
DW high airflow dome
extra stuff we need to know about?
traco,s on FC? 24165 and 24150?
2x standard 5v Recoms on FC
soldering of the bl,s are they spot on the PB pcb? flat? no space between them?
No. They sit lower to gain access to the i2C without modifying the PDB (see photo below)
what adhesive used for the coolers? (it needs to be a conductive glue Arctic Silver)
Have no idea what the adhesive is. It was supplied in the Cooler Kit
how big are the coolers?
full length of FET's
do you get different temps on the bls? or are they all about the same?
No. Wildly different with a Bl temp range spanning 48 - 93°C. The hottest BL's are at the front i.e. 1&2 then 3&8 then 4&7, and the coolest 5&6
which props?
APC 12"/3.8 nylon

Once the heavier 12AWG double battery cables are installed (and possibly the battery connectors will be changed for 6mm bullets) I will make no further changes before flying (without camera) to ascertain distribution of temperatures. If the front BL's are still running significantly hotter I will load the back of the frame to see if this reduces the current to the front motors in case it is a balance problem - although the frame is currently perfectly balanced as far as I can tell. Why should it not be? It is a symmetrical design with identical components around the structure balancing each other out.

btw hobbykings delay are normal its the customs fault not hobbyking.
we always wait for about 3-4 weeks to get stuff.

 

[MombasaFlash]

Phew! This is going to take up a lot of space.

AD-8 is all disassembled anyway waiting on the 10AWG cable. So here is a bunch of close-up pics of the PBD showing top, bottom and i2C isolator.

One positive and one negative auxiliary pad have been enlarged by scraping away the black paint to create a larger soldering surface and to permit one battery cable to go left and the other right. Hopefully this will also address the issue that Jess raised regarding distances from power supply to BL.

The board with rows of pins under the i2C is for distributing 12v (switched and unswitched) and 5v to LED's, video, i2C isolator, HDMI converter, 5v LED's (eventually) with feeds coming either from Extension PCB or via a Traco mounted directly on the PDB (not shown). The i2C previously took its power from the FC.



A 4S/8000mah LiPo saves approximately 164g over 2x 4S/5000 (856g vs. 1020g). This equates roughly to a 18% weight saving. But the 10000 mah of the 2x 5000 equates to a 25% increase in mAh - theoretically !! So 'in theory' the 2x 5000 should offer a slightly better overall deal. The two eCalc screenshots at the end show how the theoretical performance compares between the two.

One thing that I remember, and which might be highly significant, is that each time the IMU levelling was performed the copter had a tendency to fly forwards and to the left. No matter how carefully the horizontal was checked and re-checked it would always be the same ... forwards and left. Eventually I left it there and adjusted Elevator and Aileron trims on the Tx to achieve stationary hover.

This could mean that the front and left motors are constantly working slightly harder to keep everything level, and ... they would work proportionately harder as payload is added. Could possibly have a bearing on the imbalance of BL temperature readings.

Hallelujah! The HobbyKing package just arrived.

 

[*****]

oki
so you glued the coolers yourself i guess.
the purpose is that the coolers actualy touch the fest and are not "floating" on the glue?
for example i use 2 drops (like a top of the matchstick)
to do ALL controllers , the less glue the more cooling
could it be the glue is to thick?
aldo i dont like that the boards are lifted to get rid of the i2c connections.
the purpose of the board also is to get rid of the temps.
and also shorten all cables to the motors , less conenctions is less heat.
\sohrter the cables the less magnetic problems

 

[MombasaFlash]

I do not really like the 'floating' boards much myself but at the time I wanted to avoid irreversibly damaging the PDB by cutting i2C traces. Although everything is fairly wobbly when unattached it all seems solid enough once the BL's are bolted down to the chassis stand-offs. The pieces of gel are to prevent the 'useless' PDB tongues from flapping.

As for the main PDB dissipating heat, the BL boards are normally only attached to the PDB by the legs of the capacitors and pins for the i2C circuit. Therefore, how can the main board ever be effective as a heatsink? Of course it would certainly be structurally more sound than having the PDB 'floating' as it is now but I do not see how heat from the FET's can effectively be dissipated with the BL and PDB simply sort of touching in a few places.

For the adhesive, yes, it is entirely possible that more adhesive was applied than is necessary but then again, significant pressure was applied for a full 24 hours whilst it set in order to squeeze out excess and to hold them all in place. It was not a quick setting glue. I did not question the type of adhesive supplied with the heatsink kit. I had to trust that the dealer (FlashRC, France) had sent me a bona-fide kit that included a proper heat conductive adhesive.

The first MK Octo has motor wires soldered directly to the BL's. This I specifically wanted to avoid with the DW AD-8 because post build work is seriously hampered with everything permanently fixed by solder. On the AD-8 the motor cables are barely longer than if they had been soldered direct, in fact I cut three inches off each cable to avoid an untidy and unwieldy excess. But they do of course each have a 3mm bullet connector. They are good quality EC3's and certainly tight. I much prefer the serviceability they provide so it will just have to live with them because that ain't gonna change.

BTW, is it not normal to fine-tune the hover with Elevator and/or Aileron trim on the Tx after writing the 'level' position to EPROM (throttle up & right)? If the Tx trims MUST be at zero the only alternative would be shimming the FC, since it is currently set as level as about five spirit levels can manage.


The 10 and 8AWG cable has finally arrived so I will solder on two battery hook-ups and pray for a sunny day to test it all. All changes will be made one at a time.

 

[*****]

I do not really like the 'floating' boards much myself but at the time I wanted to avoid irreversibly damaging the PDB by cutting i2C traces. Although everything is fairly wobbly when unattached it all seems solid enough once the BL's are bolted down to the chassis stand-offs. The pieces of gel are to prevent the 'useless' PDB tongues from flapping.

As for the main PDB dissipating heat, the BL boards are normally only attached to the PDB by the legs of the capacitors and pins for the i2C circuit. Therefore, how can the main board ever be effective as a heatsink? Of course it would certainly be structurally more sound than having the PDB 'floating' as it is now but I do not see how heat from the FET's can effectively be dissipated with the BL and PDB simply sort of touching in a few places.

For the adhesive, yes, it is entirely possible that more adhesive was applied than is necessary but then again, significant pressure was applied for a full 24 hours whilst it set in order to squeeze out excess and to hold them all in place. It was not a quick setting glue. I did not question the type of adhesive supplied with the heatsink kit. I had to trust that the dealer (FlashRC, France) had sent me a bona-fide kit that included a proper heat conductive adhesive.

The first MK Octo has motor wires soldered directly to the BL's. This I specifically wanted to avoid with the DW AD-8 because post build work is seriously hampered with everything permanently fixed by solder. On the AD-8 the motor cables are barely longer than if they had been soldered direct, in fact I cut three inches off each cable to avoid an untidy and unwieldy excess. But they do of course each have a 3mm bullet connector. They are good quality EC3's and certainly tight. I much prefer the serviceability they provide so it will just have to live with them because that ain't gonna change.

BTW, is it not normal to fine-tune the hover with Elevator and/or Aileron trim on the Tx after writing the 'level' position to EPROM (throttle up & right)? If the Tx trims MUST be at zero the only alternative would be shimming the FC, since it is currently set as level as about five spirit levels can manage.


The 10 and 8AWG cable has finally arrived so I will solder on two battery hook-ups and pray for a sunny day to test it all. All changes will be made one at a time.

well it does help since the heat does go away , the purpose of the V8 boards was to get less heat and more power.
but if you float the bl boards you get the same as the old boards where lots of amps go thru a 0.4mm wire , wit placing the soldering pads onto each other , using a good 90watt soldering iron
the board will stick to each other.

u
all these small things will bring the temps down.

we always set the hle on the ground and level it with the calibration thats it.
you can NOT use the trimming function , in gps mode it will start to drift away , especially with the new 86 software in dynamic mode.
if your starts to float away in no wind its surely a balance problem , or motors not aligned.

as for sunny days forget it no chance find a large hall to fly in

 

[MombasaFlash]

Maybe. I take your point about the solder pads butting up against one another rather than current travelling down a capacitor leg. What I am most keen to address is the imbalance between BL temps. If they are now 45 - 90C (with the 5D and 2x 5000 4S) that averages out to 68 which I think is livable with - particularly if the dome is replaced by a Crash Cage which should reduce temps further.

I don't get why there could be either a balance issue or the motors are misaligned. Cannot see how either can happen. The MK Octo ALSO has trim to prevent sliding off level and on neither MRC has GPS hold ever seemed to be a problem. The MK Octo is particularly precise in GPS hold.

Anyway, 10AWG double LiPo cables with big fat 6mm bullet connectors are in so now I wait for an opportunity to fly - after ALL the LiPo Deans have been replaced with 6mm bullets. Crap!

 

[Bartman]

MBF,
i also shim the FC. I set it as close as possible then use small squares of playing-card stock to shim it to wherever it wants to be to fly without drift.

 

[DucktileMedia]

A little off subject but why do you have the case on your HDMI converter? that aluminum case weighs approx. 175 grams where the board inside weighs 25 +/- grams. As for gluing heatsinks, arent you supposed to use that special silver epoxy that transmits heat? if you did I wouldnt think it would matter so much that you had a little extra on it.

 

[MombasaFlash]

A little off subject but why do you have the case on your HDMI converter? that aluminum case weighs approx. 175 grams where the board inside weighs 25 +/- grams. As for gluing heatsinks, arent you supposed to use that special silver epoxy that transmits heat? if you did I wouldnt think it would matter so much that you had a little extra on it.

That was an early photo when the HDMI converter was being tried out. The case has since been removed.

I ordered the 'BL Cooling Kit' along with the AD-8 long before there was any hint that high temperatures might be an issue. It is the standard MK Octo kit with 16 heatsinks and two little vials of some sort of epoxy I guess and it came from an MK partnershop - AltiGator. One can do little else but assume that they are going to supply pukka gear. As such I did not question that the supplied two-part adhesive might be inappropriate. I assumed it was heat-conducting adhesive. What else can one assume? (Apart from ... to "ASSUME" is to make an *** out of U and ME).

Aaaahh, the bad language detector made a mess out of my philosophical doodad.

 

[Bartman]

sorry about that. i don't have much of a choice but to have some sort of filtering going on.