Minimun amp rating of and esc for 2s & CMS7700

[Gee]

To match up an inexpensive esc with the cms7700 motor on 2s. What would be the min amp rating of the esc to look for?

[Mister-T]

This one suck current like russian drink vodka. Mamba max is the cheapest solution out there. If you don't like it try Speed passion GT or Tekin R1pro

[Gee]

Thanks. I still would like to know what the minimun amp for an esc could be. What's BrianG been doing lately?

This should be on his calculator web page under the heading 'All the crap that Gee doesn't know how to figure out his self." That would not be a small page either.

I'm sure BrianG page has all the information I need to get my answer. Just don't know how to.

[mriccucci]

The amp draw depends on the load placed on the motor by what you've got it in. So you cant really know unless you put a meter on the system and find out.

[BrianG]

Originally Posted by mriccucci

The amp draw depends on the load placed on the motor by what you've got it in. So you cant really know unless you put a meter on the system and find out.

Exactly. The best you can do is figure out the minimum possible current (0A when off ), and the maximum possible current (very high current at stall). The running current will be somewhere in between.

Not trying to sound sarcastic, it just depends greatly on weight, gearing, etc.

I'm not sure, but I do know the 7700 is a hog. The MM esc will get quite warm while pushing any 1/10th off-road with the 7700 motor. 1/10th on-road might be ok. I'd guess you'll be in just under the 100A range pretty easily if it's in a decent sized vehicle, but that's a wild guess.

Like mriccucci said, it depends a lot on the application and load on the motor. Perhaps if someone is running a similar setup as you will be running and is using the same running gear you can get some input from them. We'll need to know what your plans are though.

J.

[What's_nitro?]

Sounds like a job for the MGM 8012!

[Gee]

Okay, I guess I will have to give it up. I know there's better setups and the villian isn't stable at higher speeds and all the kinds of different motors that would be better. But I am not asking of those questions. Just so I don't get bombarded with post telling me which boat would be better or what not. I think you know what I getting at there. Just looking for what min amp esc to run in this configuration.

Here is what I am working with because it sitting here not being used. 2 - CMS7700 motors. Villian IV and 2s batteries. I was searching for 2 inexpensive esc to run in the villian. I came across these esc and I liked the features and water cooling built in. The prices are not that bad either. I would be getting water cooled jackets for the cms7700's and keep the villians gear boxes to adjust the setup with different size pinions. Ofcourse I was hoping a 25amp esc would get by in the setup.

http://www.himodel.com/electric/Seak...ng_system.html

They also have a 35amp and a 60amp esc.

So with the setup what do you think about the amps.?

Aha, and now we get to the point! Discussion could have been much more accurate if you had mentioned you were running this setup in a villain to start with. There can still be no definitive answer as to what amps you'll be pulling, but a 60-70A ESC might very well be OK, if it's decent quality. Cooling won't be so much of an issue, and load should be relatively low compared to 1/10th off-road.

J.

[Gee]

My bad. I'll will be more up front in my questions from now on. I just didn't want to get all the responses telling me the othe motors I should use, or scrap the whole thought and get the SB27. But then again this is RCM. That don't happen here. No matter how whacked out our projects can get. We're all supportive. Family, gotta love em. Thanks for the help.

So it sounds like a 60amp would be a minimum to try. Any thoughts on the type of esc I linked to?

[lincpimp]

Originally Posted by 83gt

Cooling won't be so much of an issue, and load should be relatively low compared to 1/10th off-road.

J.

I have to disagree, boat have very high amp requirements, as the speed goes up, so does the load. I would not be suprised for a 7700 on 2s in that boat to pull 80amps or more, each. I have a supervee, and a few other boats. The sv27 can produce almost 700watts, so on 14v (4s lipo under load) that is 50amps. Of couse, motors running half the voltage will have to pull twice the amps... The only way boats get by is due to water cooling, even a feigao will run cool in a boat with a decent water cooling system. It will still not be effecient, but will run cool.

Originally Posted by Gee

My bad. I'll will be more up front in my questions from now on. I just didn't want to get all the responses telling me the othe motors I should use, or scrap the whole thought and get the SB27. But then again this is RCM. That don't happen here. No matter how whacked out our projects can get. We're all supportive. Family, gotta love em. Thanks for the help.

So it sounds like a 60amp would be a minimum to try. Any thoughts on the type of esc I linked to?

I would run a pair of 80 amp escs (water cooled) with the 7700 motors. And try to gear them down as much as possible smaller pinions) , as they will run quite a bit faster than the stock brushed motors. You should most likely step up the props a bit, but testing on the stock props should be fine. I have no idea how stable the hull is on the villian, 40mph may be all it can handle.

I got my sv27 up to 44mph, running stock motor and esc with a pair of 3600 12c 2s lipos in series. The batteries were limiting the boat. It was fun, the only thing in the water was half og the prop, and the last little bit of the trim tabs. We could see daylight under the hull...

[hemiblas]

I like playing around with crazy combinations like that atoo and think it would be a nice build, but people (Me included) have smoked many a speed controller doing stuff like this. I understand why you didnt post what you were trying to do originally. Every time someone with a villain get on the forums its always the same comments about limitation on the hull etc etc. Realistically if all you want is 35mph or under it makes a great boat in rough waters and then you get the extra speed to boot.



Ideally to make this work you would want to know the rpm of the titans and then regear so its up 10 or 20 percent if thats even at all possible. Even then an 80A speed control would still be a minimum I would use, with watercooling.

FYI I just bought a pair of the great planes 600 motors for my villain. It was either that or 2 brushless motors with speed controls. To keep things in perspective the supervee motors are like 1900 rpm/ volt and its a 45 amp speed control on that one.

[lincpimp]

Originally Posted by hemiblas

I like playing around with crazy combinations like that atoo and think it would be a nice build, but people (Me included) have smoked many a speed controller doing stuff like this. I understand why you didnt post what you were trying to do originally. Every time someone with a villain get on the forums its always the same comments about limitation on the hull etc etc. Realistically if all you want is 35mph or under it makes a great boat in rough waters and then you get the extra speed to boot.



Ideally to make this work you would want to know the rpm of the titans and then regear so its up 10 or 20 percent if thats even at all possible. Even then an 80A speed control would still be a minimum I would use, with watercooling.

FYI I just bought a pair of the great planes 600 motors for my villain. It was either that or 2 brushless motors with speed controls. To keep things in perspective the supervee motors are like 1900 rpm/ volt and its a 45 amp speed control on that one.

I bet a pir of sv27 motors and speed controls would really wake up a villian, on 4s. IIRC the octura m447 props work well on the villians, just havve to buy a normal and a counterrotating. Steven at OSE sells the whole thing as a kit, with the upgrade stub shafts to fit 3/16 props...

[Gee]

Didn't take is that way brian. I suppose using too low of and amp esc would just burn the esc up. If I remember correctly. Running at half throttle is actually worse on things then running at full thottle. So even thinking I would not need full throttle with that setup. Still doesn't get me in the cheaper seats.

How about....

It sounds like you guys feel the load would be lighter then a rustler for example. If I am running two motors and two esc to push this thing. Using a low gearing setup for each motor. That should help lighten the load that is put on each motor. Right.?.? I'm sure my math isn't going to work here. If each motor would be doing half the work. I could take the 70amp esc that I might get by with and divide that by two and run two 35amp esc. What are the odds the esc(s) would last until the LVC cut in for the lipos?

[tc3_racer_001]

id say just buy a sidewinder, add a fan, ubec and capacitor and call it a day... it MAY work great, but i dunno, seems to run the 5400 max... but with a ubec and capacitor it would take the load off, and you would have programming options :)

OR spend the money on the Mamba max esc and not worry about it blowing up, but that isnt cheap i know! (cheaper than buying a cheap esc for $50 then buying a mamba max when it blows up )