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Electric Stunt => Gettin all AMP'ed up! => Topic started by: RC Storick on September 27, 2013, 07:53:29 AM

Title: MAH question
Post by: RC Storick on September 27, 2013, 07:53:29 AM
I am currently using the TP 5S 2700 25C MAH battery. I have noticed I am only using 945 MA from the battery. Should or could I use a smaller battery? Also is there one that's smaller and lighter?
Title: Re: MAH question
Post by: Doug Moon on September 27, 2013, 08:13:47 AM
Thats the average over how many flights?

How long is your timer set for?

Title: Re: MAH question
Post by: Crist Rigotti on September 27, 2013, 08:20:06 AM
I am currently using the TP 5S 2700 25C MAH battery. I have noticed I am only using 945 MA from the battery. Should or could I use a smaller battery? Also is there one that's smaller and lighter?

I'm sure you are using more than 945mah for a full flight.  Recheck how you got to the 945mah number.
Title: Re: MAH question
Post by: RC Storick on September 27, 2013, 08:25:14 AM
That's what I am putting back into the battery

5min 30 seconds flight time and this is the average over the life of the plane.

65% left after each flight
Title: Re: MAH question
Post by: Dean Pappas on September 27, 2013, 08:33:19 AM
Hi Sparky,
I kinda doubt that's all you are consuming as well, but if this is really the case, you could have much better performance up top and in turbulence by finding enough prop to use maybe 60% of your battery.
That would mean either more diameter, more blade width or 3 or 4 blades.
Can you borrow a different charger for comparison purposes?

Dean
Title: Re: MAH question
Post by: Larry Renger on September 27, 2013, 08:36:12 AM
Either you have discovered better than 100% efficiency, have a defective charger, or are flying a 1/2A size model.

My 1/2As use about 750 mAh, the .15 size P-51 about 1900 mAh. Their batteries are 850 mAh and 2200 mAh respectively.

I suggest some troubleshooting of your measurements.
Title: Re: MAH question
Post by: RC Storick on September 27, 2013, 10:57:48 AM
Hi Sparky,
I kinda doubt that's all you are consuming as well, but if this is really the case, you could have much better performance up top and in turbulence by finding enough prop to use maybe 60% of your battery.
That would mean either more diameter, more blade width or 3 or 4 blades.
Can you borrow a different charger for comparison purposes?

Dean

I am reading it with my battery meter and then the charger and they both agree.
Title: Re: MAH question
Post by: James_Mynes on September 27, 2013, 11:04:13 AM
5s, 18 volts. Maybe he is getting flights with low amp draw.
Title: Re: MAH question
Post by: Dan Bregar on September 27, 2013, 11:15:49 AM
1945 mah would be more like it !  ;D
Title: Re: MAH question
Post by: John Cralley on September 27, 2013, 11:33:26 AM
If that is REALLY all you are  using, than there is plenty of room to switch to a smaller battery.

However, like the other "Doubting Thomases" that posted above, I find it hard to believe that 945 mah is all you are using!!! That figure would mean that you are ONLY pulling about 10+ amps using your setup!!!

Do recheck with a different charger. A quick and dirty check would be to put a watt meter (or an appropriate amp meter) between your battery and the ESC and read the static amp value you pull. You can then divide the amps by .06 and multiply by 5.5 to get the static drain for your flight time.
Title: Re: MAH question
Post by: Tim Wescott on September 27, 2013, 12:23:43 PM
5s, 18 volts. Maybe he is getting flights with low amp draw.

If he's flying one of the planes he's written about, it's in the 50-ish ounce range.  That ought to work out to more than 20 amps.

A quick and dirty check would be to put a watt meter (or an appropriate amp meter) between your battery and the ESC and read the static amp value you pull. You can then divide the amps by .06 and multiply by 5.5 to get the static drain for your flight time.

A real quick and dirty check would be to try flying on a 5S 1200 mAh pack -- if you can find one, and if you dare stunting.

John's method will cough up the maximum expected power draw, not the power draw during normal flight.  But it should get you in the ballpark.
Title: Re: MAH question
Post by: Howard Rush on September 27, 2013, 01:51:34 PM
What prop are you using?  
Title: Re: MAH question
Post by: Dan Bregar on October 06, 2013, 01:56:07 PM
So Robert, what did you find out about your MAH usage  querry ?  Some of us would like to know what your secret formula is for ultra low battery consumption ?  ;)