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Electric Stunt => Gettin all AMP'ed up! => Topic started by: Larry Wong on August 13, 2007, 08:55:58 AM

Title: 123 Batteries
Post by: Larry Wong on August 13, 2007, 08:55:58 AM

read in the news paper that G M will be using 123 technology there might be hope for better batteries as
more studying for our future. like the 123 in power tools. #^  #^  #^

Title: Re: 123 Batteries
Post by: Kim Doherty on August 14, 2007, 07:23:31 AM

Larry,

Lot's of people are using A123 batteries for modelling applications right now. They are very tough! You can charge them at very high rates (turn the charger to max amps and walk away) and run them down till the motor stops turning. You won't hurt them. The down side is that they are only 3.4 volts per cell and are heavier than an equivalent Lipo. They are however fairly cheap. (around $10 per cell on Ebay).

I am currently running a 4S pack of A123's in one of my helicopters and they work quite well.

Kim.

Title: Re: 123 Batteries
Post by: phil c on August 14, 2007, 02:35:29 PM

Kim, can you figure your power to weight ratio of the A123's compared to a Lipo?  Most people are only using 75-80% of the LiPo capacity, so the cell weight is kind of deceiving.   Also, have you found the advertised discharge curve(nearly dead flat with a very steep drop right at the end) to be true?  i.e. after a short intial power burst the motor runs at a steady rpm until just  before it suddenly runs down completely?

Title: Re: 123 Batteries
Post by: Igor Burger on August 14, 2007, 04:39:10 PM

A123 has 70g (2.5oz) per cell, discharge voltage 3.3V (nominal) and capacity 2.3Ah

Title: Re: 123 Batteries
Post by: Igor Burger on August 14, 2007, 04:41:08 PM

we already spoke about A123 here:

http://stunthanger.com/smf/index.php?topic=4625.0

(includes some weight calculation)