A123 versus NIMH on receiver and servos?

[CHammond]

I am building a 25% yak with a 26cc engine and can't decide what to go with for batteries on the receiver. I am going with NIMH on the ignition. What are the pros and cons between the A123 and NIMH packs, and 4.8 or 6.0 volt for the nimh?

Any help is appreciated to help me decide. Thanks.

Chuck.

[RTK]

Go for the A123's for both, if your ignition will handle it. Currently Nimh has no advantage I can see. A123's charge in a fraction of the time so you can go with a lighter battery reducing overall weight. You can also draw a higher amp load with them, but I doubt that would be an issue in that sized plane.

[dick hanson]

Wall Mart has -VPXpacks here, for 12 bucks
these are 1100 ma A123
one of these packs is plenty for any 25%model and weighs under 3 ozs
I am doing sets now for my 31% Bucker and 27% Cap
one set per radio and one per ignition. recharge? 5-10 mins
no regs - no special nuttin -just A123 and a Spektrum rx
How times have changed --
My larger 2300 cells all go now to powerpacks for electric motor powered models .
glow engines - gone ---RIP

[buildflycrash]

12 bucks at WM or pay a couple bucks more and get them already all made up from Trouy Built.

http://troybuiltmodels.com/newsite/p...phate/tbm.html

Well worth it to me.

[andyjayh]

Are the Li-Phos cells the same as A123? I thought they were similar but slightly diferent in some way? Higher capacity at 2400 rather then 2300mha.

[Zeeb]

	Quote: Originally Posted by andyjayh
	Are the Li-Phos cells the same as A123? I thought they were similar but slightly diferent in some way? Higher capacity at 2400 rather then 2300mha.

No they are not the same...

Some vendors are trying to pass of the Li-FE04 as the same battery, but it's not. They are both Lithium Iron Phosphate, but the A123 uses a Nano-Phosphate which is how they can get the tremendous power delivery; lots of Lithium and very little Iron Phosphate. The process is patented so the only way you get A123 performance, is to buy A123 batteries. While that pack you mention is a higher mah rating, that doesn't mean much when you look at the continous and burst discharge ratings, you'll quickly see the difference between the two batteries.

Take a look at Fromeco's website and you'll see both types clearly identified. Some vendors are not so forthcoming.

For the OP; the only issue for you would be any restrictions of the input voltage for the engine ignition. Some won't take the 6.6 volt output of the A123's, which is actually almost identical to a five cell NiMH fresh off a charge. So if you're ignition will accept a 5 cell NiMH, it should be fine. Some with ignitions which won't take the voltage are using either regulators or placing a couple of diodes (which will cut the voltage a bit) in the power feed line for the ignition module. There's no reason not to run 6 volts for the flight pack.

[Hammbone]

Yes, these are different batteries, and the A123's have higher current ratings, but either one is plenty for rx or ignition applications.

Jim

[tonyc9075]

I just switched from NIMH to A123. Built my own packs from Black & Decker VPX packs. I still have a NIMH on the motor but the servo's are powered by A123. After one flight I am convinced that I need to replace all NIMH receiver packs with the A123's.

[CHammond]

OK, now who sells actual A123 battery packs already made. A friend was buying some from an ebay name (hopmeup) at $28.00, but they were only for a limited time. They have since gone up to $38.00 I believe.

[Boogie]

www.fromeco.org

[CHammond]

Does anyone fly these particular batteries on the receiver, and how well do they perform?http://troybuiltmodels.com/newsite/p...ges/ah2400.jpg

[bodywerks]

www.sincityjets.com has them the cheapest that I know of.