Has anyone tried this? I thought it would be a nice upgrade, im not into sport flying, i enjoy hovering and flying around a field so the lower voltage is fine for me. 4 1125MAH A123 cells is 6.8 oz, a stock eflite 1800mah battery is 6.6 oz so im thinking the weight wouldnt be an issue. I like the idea that you dont have to baby them, and charge them at a very fast rate (10-15 minutes). Has anyone tried this on a 450 size heli?

You also need a charger that can charge them and a balancer for the A123 batteries. Are you talking about this battery http://www.battlepack.com/LFP18650P.pdf ? I have heard those aren't true A123 batteries, but they are the same chemistry. A123 batteries only come in a 1100mAh and a 2300mAh cell. You probably need to solder them end to end. Are you planning on assembling them yourself or are you planning on buying them pre-built? If you want them pre-built I can give you a link for a company the builds packs of A123 cells. Then you need a hot soldering iron. There are plenty of people who have used them on T-Rex 450's on Helifreak and RCGroups. Are you planning on discharging them 100%? I am guessing the B400 will use 180mAh/minute so you would only get 6.25 minute flights at 100% discharge.

Nick

I usually keep my head speed low, i plan on buying them assembled. I was going to buy the cellpro 4s for my lipos, and that has a a123 cell capability with it too. Im assuming it can balance a123 cells too up to 4 cells? i plan on buying another ESC and yes discharging them 100%

thanks for the info....