Sure.

A123 systems built a cell based on a chemical compound called Lithium Ion Nano Phosphate (LiFePo4). These cells (I have used them in my real robots and in my vapours already) have certain major advantages over the Nicad and NiMh packs. Since A123 systems were the first to use these cells we have called them A123 cells even though there are other manufacturers out there.

For starters, a Nimh cell is between 60 and 70 grams. So is a A123. A nicad cell is about 85 grams. So where is the advantage? Well a single nimh or nicad cell is 1.2V to 1.4V, so you need 30 to make 36V. A single A123 cell is 3.3V to 3.6V and only needs 10 to make 33-36V. That is the difference between 2.1kg per pack or 700 grams per pack. That is a significant weight loss.

I run Hannibalito 3, my real life feather on 4 cells, so 350 grams of battery.

This does come at a price though, you need to keep the temperature of the cells down, otherwise they degrade very rapidly. That means you shouldnt try to run 2 lem 130s on a single pack, or 2, or 3. As a rule of thumb, the maximum output of these packs is 70A. So if you have a motor thats consumes 300A, divide that number by 70 and you will know how many packs you need in parralel.

In comparison, Nicads over 3000mAh are capable just shy of 100A, nimh 50A maximum. so that makes the division as such:

2 brand X motors draw 500A max at 36V. to power them its would require:

A123 500/70= 7.15 packs rounded off 8 packs.
Nicad 500/100=5 packs
Nimh 500/60=8.33 rounded off 9 packs

In weight that would be:

A123: 8* 700g= 5.6kg
Nicad: 5* 2.55kg = 12.7kg
NiMh: 9 * 1.95kg = 17.55kg

So even though you would need more packs than with NiCads, the packs themselves are much lighter therefore still saving weight. The packs are much smaller too so they are easier to fit. mind you these numbers are a guideline so dont treat them as gospel, in fact they are even on the light side. However this is what i would consider the bare minimum for battery usage.

Added bonus although for vapours not really applicable, you can charge them really fast. as long as the packs are balanced it is no problem shoving a 10A charge per cell in there. Another bonus is that as opposed to LiPo or NiCad there is no danger of fire.

That ok Shane?

(Message edited by leorcc on June 24, 200