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-   -   ESC thresholds! (https://www.rcuniverse.com/forum/clubhouse-190/11679044-esc-thresholds.html)

Dr.Ew 05-26-2020 04:41 PM

ESC thresholds!
 
So I can’t seem to find a proper answer to see if a 70amp ESC and 4000kv brushless setup can handle a 3000mah 50c 3s Lipo battery. Doing the math it seems that the max amps for the battery would be 150amps. Obviously that’s more than the ESC’s 70amps but it’s also not a continuous amp load either. The ESC says it can take a 290amp max burst. So am I safe to run the 3s? Or do I need to purchase a different battery? I also know that gearing has something to do with it as well but the manual for the truck says it can handle up to 3s Lipo batteries. Assuming that the drivetrain and differentials will be fine I want to know if the Brushless system will handle it. I don’t want to buy something I’m just gonna fry in minutes when I could just get something that has more amp rating. In the same sense I don’t want to undershoot the ESC because I heard doing that will kill my batteries. Any help would be appreciated for a Newbie! Thanks!

Truckdriver198831 06-07-2020 01:50 PM

All you can do is try it out and see what happens, im running a 3s max esc with 3s max motor, and i run them both on 4s and it runs great, just watch temps , i would look into getting a temp gun, if the motor or esc is getting 160f fairly quickly 3s would be too much as its on its way to 200f , hope that helps

Dr.Ew 06-08-2020 07:26 AM

ESC Reply
 
Thanks for the advice. I actually got the 70a ESC and 4000kv brushless setup made by Onyx which is really Horizon Hobby. It worked great and never heated up for the four minutes I drove it. But unfortunately the setup was faulty out of the box. I only realized that it didn’t beep or light up from the moment I plugged it in until after it died. But Horizon Hobby stands by their product and is gonna send me a new ESC and motor. Also their not asking for the old one back so I get to keep the old motor which is still good. Only problem is, is that the part is on back order and won’t be in until the end of June. Honestly I’m under the belief that I’m cursed for buying a cheap RC Truck. I’ve basically changed almost every part except the chassis the A-arms and dogbones. Also the receiver and transmitter is the only electrical part that is stock. What’s really sad is that I bought the truck exactly 1 month ago! Anyway I’ve learned my lesson and will stay away from that certain brand of RC forever! Thanks again for your advice!

Truckdriver198831 06-08-2020 08:12 AM

I find the old saying you buy cheap you buy twice, still holds some what true, also trying to run high powered brushless systems in older machines is also a struggle and leads to broken transmission parts and down time lol,

rgburrill 06-08-2020 08:13 AM

It starts with the motor rating. And I'm not talking about the 4000kV. I'm talking about max volts and max current or power ratings of the motor. You select your battery and ESC based on those numbers. All kV tells you is how fast the motor turns per volt. And the higher the number the less power it has - yes less. 4000kV is something a quadcopter would have, not a decent truck. For power you need big wires and that usually means lower kV. So look at the max voltage and current/power rating on your motor. If it will take more than 12 volts then your 3S is ok. It not your battery is too big. And while putting 14 volts into an 11 volt motor may work for a while soon you will let the smoke out.


Dr.Ew 06-19-2020 07:18 AM

Reply the and truck driver
 
Thanks guys. I’ve definitely learned a lot since then and your both right! Like truckdriver says “you buy cheap you buy twice!” Also I now know that the higher Kev means higher top speed lower torque. However if the motor can’t take it then it’s hopeless to try and keep experimenting with ESCs and such. I finally decided on getting an Arrma Granite blx brushless 4x4. Was looking at the rustler but an extra $100 for the possibility that I could kill the spur gear instantly doesn’t outweigh the Arrma has set mesh points depending on the pinion gear you use. Yes that means I can only use what they provide but I haven’t been able to use an RC car/truck for more than 10 minutes, without something breaking, since I started this hobby! Super frustrating! I will one day get the Rustler 4x4 VXL but not before I try the Granite BLX.

The one thing I am concerned about is the transmitter and receiver reviews that aren’t the greatest. They say it has slow response time and doesn’t work without delays. Any advice on the subject?

Truckdriver198831 06-19-2020 12:07 PM

Good choice! I think you would of truly been happy with either because rc itself is just wonderful :) , that DX2 radio that comes with the arrma is seriously no good, thats where the traxxas is superior in my opinion , i had the DX2 in a little jet boat i made and it was so laggy and delayed it actually caused impellar parts to break ( long story ) you'll want to switch that out first thing, im surprised they haven't fixed this problem


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