Skaldiddog's "Progress"

[SkaldidDog]

Originally Posted by rob_b

I was thinking a little more minimalist... as previously posted in Erik's berg thread Dlux Berg Build - Page 60 - RCCrawler. Someday, maybe.

The cupped leading edge scares me a little. Very elegant look however.

[rob_b]

Hey, I never said it was functional

[Frankenwheely]

Originally Posted by SkaldidDog

Nope. But how about some crispy hot wings!?!

Yea, yea Chicken and skids...What about RIBS

[SkaldidDog]

Holy Ribiliciousness them's was tasty. Looking forward to doing them with ya'll again. Thanks for posting up. I had leftovers last night while doing this.



Way Cool Experiment: HH Minis

If you recall some time back I noticed that HHM's warmed up to ~150F when plugged in and sitting still. There was much debate as to how to solve the problem or if it was even a problem. It's not a problem but any electrical engineer will tell you that cooler electronics run better. Several pages back I noted that at a fixed throttle input (after warmed up) my set of minis jumped in speed probably 25% when I hit them with a compressed air hose. That convinced me that HHM's, like all other electronics, would perform better if cooled. Enter one aluminum skid. If I was not convinced before, I am now.

For the record I have had my rear ESC (bottom) at +4 on subtrim so that it keeps up with the front (top) ESC once everything is warmed up and I'm driving. This is because it was sandwiched between a delrin (poor heat conductor) skid and another hot ESC, both wrapped in plastic. The rear ESC is always warmer so it needs a bump of +4 to keep up with the cooler front ESC. Note in my pics from yesterday that the lower (rear) ESC is glued to the skid at the cap and along the entire rear margin of the lower board. So I started driving yesterday. After a few minutes my rig acted odd. I picked it up and feathered the throttle. The rear ESC was way faster than the front and the entire skid and TVP bases were warm. This was the smoking gun. The cool, lower, rear ESC dumped a huge amount of heat into the skid and was much faster and more responsive than the front. I had to go -5 on the rear subtrim to reel it in to mirror the front ESC speed and, very importantly, the initiation of wheel spin. The rear axle spun way before the front too. So, I stopped running (1.5 packs) and went home. The rig was undriveable.

So I'm now going the road of unsmashed, unwrapped, vertically mounted ESC's. First version is the easy one, no soldering required. I'll drive this tonight and then separate another set of HHM's and spread them out on the skid, position them vertically with FETs out and likely attach them to the skid with my own custom micro heat sinks that will be attached to the FETs.

Yesterday's starting configuration.



Today's starting configuration.







Yeah COG blahblahblah. Dial your rear ESC up +9 vs your front and tell me the performance loss is outweighed by lower COG. Compared to BRSL's the vertical minis are still lower COG even with my receiver cool and high on the cross brace. The scary thing about the differential heat thing is that it's constantly variable. After you've done a hard dig or bound it up the ESCs have to recover. If the ESCs have been differentially heated (or cooled) they will be doing their own mixing of your wheel speeds even if your mixing is at zero on your radio.

It just may be the best aspect of an aluminum skid plate is it can double as a very efficient heat sink for any ESC. This aspect alone outweighs any performance enhancement due to reduced coefficient of friction or any performance loss due to increased weight or COG. Time to drive, get soldering and crank out some micro heat sink/esc mounts. They'll weigh a gramish each but man I can't wait to see what these HHM's can do when chilling out.

J

[Jslick]

???LOVESAC???

[SkaldidDog]

Originally Posted by Jslick

???LOVESAC???

Got 2 of them. That's the small one.

Love Sack Babaaaay!

[danbillyboo]

I like your idea about your Skin ! Nice !
Do you know if HH know about this high temp ?


Sent from my iPhone using Tapatalk

[SkaldidDog]

Originally Posted by danbillyboo

I like your idea about your Skin ! Nice !
Do you know if HH know about this high temp ?

Thanks.

HH are well aware. Many hundreds of pairs of HHM's are on the rocks without issue. I'm just trying to claw back a little more power by helping the ESCs shed heat.

J

[chevotafun]

Yes I have noticed what you are talking about.
Not that my HHM get smoking hot but I do notice that after running about 3/4 to a full battery

that near the end of that battery I need to turn down the rear as the wheels are now going faster than the front.

I have mine on a rowdy plate

[SkaldidDog]

Originally Posted by chevotafun

Yes I have noticed what you are talking about.
Not that my HHM get smoking hot but I do notice that after running about 3/4 to a full battery

that near the end of that battery I need to turn down the rear as the wheels are now going faster than the front.

I have mine on a rowdy plate

Is your rear ESC the one directly touching the slick ass Rowdy plate? The front ESC has slowed in relation.
J

[chevotafun]

Originally Posted by SkaldidDog

Is your rear ESC the one directly touching the slick ass Rowdy plate? The front ESC has slowed in relation.
J

Yes I do believe that is correct and yes

I'm very interested in your next test to see if putting them on there side will make a difference

in theory it should

Things will be changing
With me changing to the bully2 diffs
I have NCD slotted CF plate to put electronics on

Be intesting to see if the CF will be any different,
I think your on the right track to the best solution

[TSK]

Have you considered running a small fan for the esc? I;m sure the added cooling would far outweigh the added weight?

And are those just shoe goo'd into the skid? Maybe some thermally conductive (non-electrically conductive) goop can be used to take more advantage of the AL skid's heatsink properties.

[SkaldidDog]

Originally Posted by chevotafun

Yes I do believe that is correct and yes

I'm very interested in your next test to see if putting them on there side will make a difference

in theory it should

Things will be changing
With me changing to the bully2 diffs
I have NCD slotted CF plate to put electronics on

Be intesting to see if the CF will be any different,
I think your on the right track to the best solution

My thought behind mounting them vertically was ease of V2 testing, not ripping anything off of the board when I remove them and more importantly getting the board to touch the skid for better heat transfer. This can only happen on the edge of the board. Feel how warm the edge of the board is after a few packs. As JRH has said many times, these low mass ESC's have no where for heat to go. Larger wires may help (e- flow and heat sink) but my battery wires are only 1" long. Regardless these babies warm up dead still so I think improved e- flow is not the best solution. We'll see but I do believe a performance improvement is eminent.

Originally Posted by TheSCorpionKing

Have you considered running a small fan for the esc? I;m sure the added cooling would far outweigh the added weight?

And are those just shoe goo'd into the skid? Maybe some thermally conductive (non-electrically conductive) goop can be used to take more advantage of the AL skid's heatsink properties.

No on the fan. Yes they are gooped. A tiny thin layer of goop between the ESC and skid allows for very effecient heat transfer based on the finger test. Maybe there is a better adhesive out there. Please chime in if you find one. And goop hangs on to Al like mad.

I hope to finish the heat sinks tonight. I've not driven the V2 setup yet due to life and may not. I might end up jumping straight to V3. Won't be the first time.

J

[chevotafun]

Originally Posted by SkaldidDog

Is your rear ESC the one directly touching the slick ass Rowdy plate? The front ESC has slowed in relation.
J

After looking at them last night
It is actually the front esc on the plate and not the rear.

[Jslick]

Originally Posted by chevotafun

After looking at them last night
It is actually the front esc on the plate and not the rear.

How do you have yours wired up?? That also might be a common factor.

[WAM]

Originally Posted by SkaldidDog

No on the fan. Yes they are gooped. A tiny thin layer of goop between the ESC and skid allows for very effecient heat transfer based on the finger test. Maybe there is a better adhesive out there. Please chime in if you find one. And goop hangs on to Al like mad.

Here you go.

Amazon.com: Arctic Silver Thermal Epoxy: Computers & Accessories

Since heat generally travels up better than down, I wonder if the skid heat sink is such a big deal. Just having the two plates vertical and a little separated might do wonders since the air can easily escape upwards.


BTW, that silver filled epoxy is somewhat electrical conductive too. Keep it off active traces.

[chevotafun]

Originally Posted by Jslick

How do you have yours wired up?? That also might be a common factor.

Chris the battery man wired the esc's
I just put them to the motors

[Jslick]

Originally Posted by chevotafun

Chris the battery man wired the esc's
I just put them to the motors

I mean what is your BEC powering? is it powering everything or just the servo?

I have the BEC just powering just the servo and dropped one of the red wires on the smashed brmini to the RX.

[ROWDY RACING]

Originally Posted by SkaldidDog

Here you go Rowdy. The gap eats small bits of sand from time to time but I've never had any binding etc.



J

What's the weight on this setup Joel?

[chevotafun]

Originally Posted by Jslick

I mean what is your BEC powering? is it powering everything or just the servo?

I have the BEC just powering just the servo and dropped one of the red wires on the smashed brmini to the RX.

it's powering everything
Hmm interesting might have to try it that way and see
Thanks for the input