A DIY A123 receiver battery-pack

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A DIY A123 receiver battery-pack

Postby RCModelReviews » Fri Dec 31, 2010 8:28 pm

Project video is at: http://www.youtube.com/watch?v=BN9_3nMTvc0

Please feel free to place your comments and questions in this thread and I'll be happy to answer or elaborate for you.
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Re: A DIY A123 receiver battery-pack

Postby Startazz » Fri Dec 31, 2010 9:54 pm

I've just seen the video Bruce and thought it was good but what i wanted to know is could we knock some of these batteries up for our main flight batteries?? like say a 1800mah 11.1v or am i way off the mark?? i only ask because i'm still learning about all these different batteries as you might be able to tell ;)
IT'S BETTER TO DIE A TIGER THAN TO DIE AS A PUSSY!
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Re: A DIY A123 receiver battery-pack

Postby radialarm » Wed Jan 05, 2011 6:20 am

I was watching your video, and noticed the voltage of the pack. All my Rx's state max. 6V, and two of these cells are 7.4V. Am I correct? I could be wrong as I'm not too knowledgeable about the A123 cells. My question is, is it safe to use this voltage with my Rx's. I know that under load the voltage will be lower.
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Re: A DIY A123 receiver battery-pack

Postby TG72 » Wed Jan 05, 2011 2:10 pm

IMO, your best how to (101) video to date. These are excellent Bruce, and hope there are many more to come. Thanks!
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Re: A DIY A123 receiver battery-pack

Postby SansHeli » Sun Jan 23, 2011 1:56 am

radialarm wrote:I was watching your video, and noticed the voltage of the pack. All my Rx's state max. 6V, and two of these cells are 7.4V. Am I correct? I could be wrong as I'm not too knowledgeable about the A123 cells. My question is, is it safe to use this voltage with my Rx's. I know that under load the voltage will be lower.


I had the same concerns re. the voltage at full charge so I would like to hear if we are risking inducing some of the "magic smoke" (as Bruce so eloquently puts it).

BTW, Bruce, thanks for all your effort in putting the YouTube vids and web site articles together - much appreciate the "honesty and non-advertising biased" opinions. Keep up the good work!!
"It's not just that helicopters crash. They crash, then in many cases continue to beat themselves to death." - RH

Raptor 50 V2 & SE, T-REX 450 SE, (and a number of gas and elec. planes), JR12X, JR XP9303/Spektrum 2.4GHz
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Re: A DIY A123 receiver battery-pack

Postby RCModelReviews » Sun Jan 23, 2011 5:56 am

Two lithium-ion or lipo cells will deliver 7.2V but A123 cells use a different chemistry (LiFePO4) so they have a nominal voltage of 3.3V per cell (6.6V per 2-cell pack).

Experience has shown that, apart from some 9g and smaller servos, or a few used on helicopter tail-rotors, all other RC servos (rated for 6V) work just fine on the 6.6V that such a pack puts out. The same goes for the receivers. All receivers have a voltage regulator that drops the voltage down to (in the case of 2.4GHz stuff) 3.3V or less anyway.
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Re: A DIY A123 receiver battery-pack

Postby lowglow » Mon Jan 24, 2011 7:44 am

All receivers have a voltage regulator that drops the voltage down to (in the case of 2.4GHz stuff) 3.3V or less anyway.


Bruce does this apply to the Assan recievers? I am sick of unreliable Nicad packs and I'm keen to give the A123 packs a go.
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Re: A DIY A123 receiver battery-pack

Postby RCModelReviews » Tue Jan 25, 2011 3:17 am

Yes, this applies to Assan.
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Re: A DIY A123 receiver battery-pack

Postby lowglow » Tue Jan 25, 2011 5:56 am

Great, guess I betta place an order with HK then :D
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Re: A DIY A123 receiver battery-pack

Postby Kamu » Sun Jan 30, 2011 3:49 pm

While watching this you were so careful not to short the battery leads. But you didn't mention a warning when you were checking the receiver plug with the multimeter. It is so easy to cross those two while metering them!
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