MM Xl rating questions - RC-Monster Forums

lincpimp · **MM Xl rating questions -** 02.03.2011, 03:03 PM

So I am wondering how the XL compares to the Hydra line. I have a 2028 and want to run it in an 18-20lb rc on 10s... I have a hydra 180 hv, and will run mech brakes.

Also wondering if I should run a closed system for water cooling. Make a small radiator out of al tubing and run glycol in it. No pump, but the radiator to cool it and the heat will transfer out of the esc. No idea how hot this setup will be, but seeing the data log info from the XL on 8s, ny system should pull less amps on 10s.

Any thoughts?

What's_nitro? · 02.03.2011, 03:12 PM

What's the burst rating on the Hydra? I thought boat ESCs were like plane ESCs in that there wasn't much headroom there. I don't think you will need 180A continuous (will you?) but burst rating is important.

Your cooling idea sounds good. How long would the tubes be between the ESC and the radiator? If you're not using a pump they can't be too long... You might be better off trying to fit a regular air-cooled HS onto it somehow.

lincpimp · 02.03.2011, 04:37 PM

Quote:

Originally Posted by What's_nitro?

What's the burst rating on the Hydra? I thought boat ESCs were like plane ESCs in that there wasn't much headroom there. I don't think you will need 180A continuous (will you?) but burst rating is important.

Your cooling idea sounds good. How long would the tubes be between the ESC and the radiator? If you're not using a pump they can't be too long... You might be better off trying to fit a regular air-cooled HS onto it somehow.

Yeah, I was thinking that too. Depends what I do with it. If it goes on top "of a baja tranny I could just make the tubes and "radiator all in one and place it right above the esc in the air stream. Maybe I should just sell it and get an XL? Only issue is that i want to run 10s as I have alot of 5s packs.

BrianG · 02.03.2011, 05:02 PM

What about heat pipes? They work well for today's ~90w+ CPUs...

http://en.wikipedia.org/wiki/Heat_pipe

RC-Monster Mike · 02.03.2011, 05:30 PM

I used an HV180 on my baja last year - it barely got warm. Boats see huge spikes when they come out of the water at full wood and then drop back into the drink. The Boat ESCs don't have the smooth startup that a car esc has(or brakes), but they are plenty durable.

lincpimp · 02.03.2011, 05:31 PM

Quote:

Originally Posted by BrianG

What about heat pipes? They work well for today's ~90w+ CPUs...

http://en.wikipedia.org/wiki/Heat_pipe

Something like this, minus the fan?

http://cgi.ebay.com/Scythe-SCKTN-300...item4152518a72

Guessing I could just mount it to the top of the esc? My only issue with the hydra hv is that is has a stacked board design with multple water cooled heatsinks sandwiched in there. So just trying to cool one of them would be a waste of time. If I could do a heat pipe off each channel (2 per board) that could be an option.

I was just thinking that a closed system filled with something conductive would transfer the heat . Somewhat like a thermosiphon. But the heat pipe looks like a better idea.

The wiki page mentions making a heat pipe by just boiling the liquid in the pipe then capping it off. I am guessing you just want the liquid to start to boil when capping it off, so when it cools it will pull a vacumm? They mention that the liquid volume will be much less than the total volume inside of the pipe, 10% maybe? Or less?

Interesting idea. My idea and placement would allow for gravity to cycle the fluid back to the heat source, and airflow for cooling would not be an issue while moving.

lincpimp · 02.03.2011, 05:32 PM

Quote:

Originally Posted by RC-Monster Mike

I used an HV180 on my baja last year - it barely got warm. Boats see huge spikes when they come out of the water at full wood and then drop back into the drink. The Boat ESCs don't have the smooth startup that a car esc has(or brakes), but they are plenty durable.

Good to know, as I think I have that exact esc. Got it from Ben (bb16) in a trade. Could you tell me what brand and spec the bec is? What voltage did you run?

Thanks Mike.

RC-Monster Mike · 02.03.2011, 05:39 PM

Sounds like you have the very ESC I used, as I gave it to Ben a couple months ago. I used 7s, 8s and 10s on the ESC. The BEC is rated to 40volts and 5 amps and outputs 6volts to the servos - made by Koolflight.

BrianG · 02.03.2011, 05:42 PM

Quote:

Originally Posted by lincpimp

Something like this, minus the fan?

http://cgi.ebay.com/Scythe-SCKTN-300...item4152518a72

Guessing I could just mount it to the top of the esc? My only issue with the hydra hv is that is has a stacked board design with multple water cooled heatsinks sandwiched in there. So just trying to cool one of them would be a waste of time. If I could do a heat pipe off each channel (2 per board) that could be an option.

I was just thinking that a closed system filled with something conductive would transfer the heat . Somewhat like a thermosiphon. But the heat pipe looks like a better idea.

The wiki page mentions making a heat pipe by just boiling the liquid in the pipe then capping it off. I am guessing you just want the liquid to start to boil when capping it off, so when it cools it will pull a vacumm? They mention that the liquid volume will be much less than the total volume inside of the pipe, 10% maybe? Or less?

Interesting idea. My idea and placement would allow for gravity to cycle the fluid back to the heat source, and airflow for cooling would not be an issue while moving.

Yeah, pretty much any of today's air cooled CPU heatsinks use heatpipes now. The Wiki article mentioned that the heatpipe is actually more efficient than the same cross area of solid copper. Although, the liquid medium chosen should match the temperature you want to run the ESC at. But since ESCs are around 90% efficient (depending on throttle level), even 500w continuous is "only" 50W. Much above or below the liquid "tune" the heat is transferred mostly by the pipe itself (not the wick inside). Gotta be careful about what liquid you use depending on if you plan to run in the winter or not. Wouldn't be much use if the medium freezes, especially since it will happen sooner under a vacuum.

Most of the "movement" is not gravity fed, but done via the wick and thermal differences.

lincpimp · 02.03.2011, 05:43 PM

Ok, the koolflight bec, thanks. Think it will handle a 2028 cc motor on 10s in a baja geared for 50-60mph? Might go with a 4wd redcat 1/5, which will put more load on it...

It must be a good esc if it can handle a 180amp boat setup, as that is no laughing matter!

Jahay · 07:39 PM

Are hydra ESCs better to use over phoenix ice hv escs?
i want to run 9-10s...

My savage prob weighs in at around 16 fully loaded with lipos... so no where near as heavy as a redcat or a baja...

I was going to go with an ice hv 160 and use mech brakes... But are hydra systems better at handling the high current spikes ??? but would you definitely need some form of water cooling?

I was going to fab something up so the ICE HV would have one or two fans...

lincpimp · 02.10.2011, 11:35 PM

Well, you can use a regular car radio with a boat esc. So no need to fool with a pistix and the various issues tuning the radio.

Startup spikes on a boat must be more than a plane/heli, as water does not "slip" like air does...

Mike used this exact esc in a baja and it still works.

brian015 · 02.11.2011, 10:43 AM

Quote:

Originally Posted by Jahay

Are hydra ESCs better to use over phoenix ice hv escs?
i want to run 9-10s...

My savage prob weighs in at around 16 fully loaded with lipos... so no where near as heavy as a redcat or a baja...

I was going to go with an ice hv 160 and use mech brakes... But are hydra systems better at handling the high current spikes ??? but would you definitely need some form of water cooling?

I was going to fab something up so the ICE HV would have one or two fans...

I started with the hydra hv 180 in my truck and then switched to the ICE hv 160. I saw no performance difference and the advantage of the ICE is data-logging capablility. I haven't used a fan on the ICE and my temps have been fine.

Jahay · 02.11.2011, 01:34 PM

Brian, considering everyone always says and knows that Heli ESCs do not do well with high current spikes... Have you run into any problems at all?

And i know your extended LST is huge but how heavy is it roughly fully loaded with lipos???

And if you are having so much success with it, why dont more people tend to use them?
Also are you using a pistix so it recognises your TX?

THANKS BUD

brian015 · 02.11.2011, 03:05 PM

Quote:

Originally Posted by Jahay

Brian, considering everyone always says and knows that Heli ESCs do not do well with high current spikes... Have you run into any problems at all?

And i know your extended LST is huge but how heavy is it roughly fully loaded with lipos???

And if you are having so much success with it, why dont more people tend to use them?
Also are you using a pistix so it recognises your TX?

THANKS BUD

19lbs rtr. I use a pistix and have had no problems with it.

The highest current I've logged is 120 or so Amps - on 8s that's 3500 Watts. So I don't see how that should be a problem on the ICE hv 160.

Why don't more people use them? Maybe because not so many large scale conversions have been done, maybe because mechanical brakes are necessary - I'm not sure.

Others have used it. For example:
http://www.rc-monster.com/forum/show...ice#post372318

http://www.rc-monster.com/forum/show...highlight=baja