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-   -   30 amp for 10 amp ESC? (http://www.Wattflyer.com/forums/showthread.php?t=73289)

Stormrider51 03-05-2014 06:30 PM

30 amp for 10 amp ESC?
 
Probably a dumb question but I have a an E-flite P-40 Warhawk 300 ARF. The recommended equipment calls for an E-flite 10A Pro Brushless ESC (EFLA1010) and 430mAh 2S 7.4V battery pack. I have a 30 amp ESC from a now deceased Albatros. Is there a problem with using a 30 amp in place of the 10 amp? Also, are E-flite S60 6 gram sub-micro servos (EFLRS60) the same as used in the Albatros?

Thanks in advance,
John

Abuelo 03-05-2014 07:19 PM

John, using a larger ESC should not be a problem. 30%-50% higher capacity is often suggested as there is much less chance of overloading the ESC and damaging it plus it should run cooler under its reduced demand. In practice using the next size ESC up from the recommendation is common.

The only issues are the slight increased weight and possible plug incompatibility. If you have to buy new plugs and solder them you might consider applying the money to a new ESC closer to the recommended size and with compatible plugs. Save the 30A ESC for another plane. I'm a fan of Heads Up RC but there are other vendors.

Can't really comment on the servos but don't see a problem on these size planes.

dahawk 03-05-2014 07:26 PM

You're fine. Just do the normal reset routine. Plug battery in with full throttle, listen for the beeps, then bring it to zero throttle.

JetPlaneFlyer 03-05-2014 08:12 PM

Nope,
Going by the specs, it wont work. The 30A ESC out of the Albatros is for 3 cell to 6 cell batteries. The Warhawk on the other hand flies on a 2 cell battery, so unless the published specs are wrong the 30A ESC wont be compatible.

On top of that, even if it had been compatible, it's really a bit too big and heavy. The added weight would have a significant effect of flight performance. You can get a suitable 10-12A ESC for less than ten bucks, you might as well do the job right IMHO.

Abuelo 03-05-2014 09:40 PM

JPG, good points

Stormrider51 03-06-2014 12:54 AM

Thanks everyone for the replies and tips. I discovered that the connectors on the ESC are a different size than the ones on the motor. As Abuelo pointed out, by the time I buy new connectors and solder them on I might as well buy a new ESC. JPF says it wouldn't work because of differences in battery size. Looks like I'll be buying a 10 Amp ESC.

Also, it turns out that the servos are too large to fit the pocket in the wing. Gonna need servos too.

Thanks again. Obviously, what I don't know about electric planes would make a good manual.
John

mclarkson 03-06-2014 03:57 AM

In general, having too much ESC won't really hurt anything, whereas having too little is a significant problem. As stated above, many people like to go 20%-50% larger than called for, just to be on the safe side.

Stormrider51 03-06-2014 04:11 AM

Okay, so what about the problem of battery size that JetPlaneFlyer referred to?

mclarkson 03-06-2014 04:22 AM

He was talking about the input voltage. (Roughly speaking, the more cells, the higher the voltage.)

Some ESCs will handle, say, 3-cell or 4-cell batteries. Some will handle 2-cell batteries. Some will handle 2-cell or 3-cell batteries.

Putting the wrong number of cells on an ESC will give you an under-volt or over-volt situation.
So, too large an ESC isn't necessarily a problem (the first ARF I ever built is running a 30A ESC instead of the 12A it really needs), but it can be a problem if it can't handle whatever number of cells you're hooking it up to.

The 30A in my ARF is built for either 2- or 3-cell LiPos and I run 3-cells so I'm okay, although I am paying a weight penalty.

JetPlaneFlyer 03-06-2014 05:51 AM

Regarding the connectors on the ESC.
Almost any ESC that you buy will come with bare wires, so soldering on suitable connectors to match your motor and your battery is just something that you are going to have to accept.

The above comments about ESC size are generally correct in that having a ESC with a larger Amp rating than required isn't a problem, in itself. But what people forget is that ESC's have both Amp and Voltage rating and using an ESC with the wrong voltage rating most certainly is a problem. So you still have to check that the ESC that you plan to use is capable of operating on the voltage of the battery that your model uses.
In this case the 30A ESC cannot properly operate on the 7.4v that a 2 cell LiPo outputs, it needs higher voltage.

hayofstacks 03-06-2014 07:00 AM

I always use a much larger esc then required. there is generally less then $5 difference between a 30 amp and 45 amp esc. then you can always upgrade the motor without worrying about buying a new esc. my slow stick was only pulling 18 amps when I built my first one, and I ran a 40 amp esc. I'm now using the same esc on a 450watt setup I bought used and swapped out the 30 amper for my slowstick.

Weight will be an issue though, with the size of plane you have.


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