Li-Ion Power Tool cells work great for RC!

Charging at 1300 watts probably wouldnt be to safe either

[MetalMan]

Originally Posted by BrianG

MetalMan, do you know what the Ah rating of those M1 cells are? I'm hoping for 3Ah (or more). They might be less since DeWalt says there's greater run time, but that might be simply because it's using 36v so the current doesn't need to be so high. I'd like to use a 5s1p arrangement for size/weight/simplicity, but have found nothing on the A123systems or DeWalt sites that says exactly what they are...

At this point I know as much about them as you (possibly less). To be honest, I'm not even going to get excited about them until Dewalt starts shipping the power tools.

Originally Posted by boss 302

Charging at 1300 watts probably wouldnt be to safe either

It would require a HUGE balancer too!

[cart213]

I just bought a V28 pack on ebay. I'm going to make two 2s1p packs and run them in series. I can't fit 4 cells flat on my MT2, so I have to split them up. Later on, I may try to buy a single cell off of someone to make two 2s2p packs, but for now I will have 3 leftover cells. Details will be forthcoming next week...

[MetalMan]

You may not get much power out of that pack. The helicopter guys say that these cells are good for about 45amps max, and after that their voltage drops off. That means that under acceleration your truck may be sluggish. This is the main reason for going 4s2p (or two 2s2p), since the pack would then be good for 90amps.

[cart213]

Yeah, I'll have to experiment and see how it runs with 4 cells. If it is sluggish, then I'll have to find another cell somewhere. I hate to buy a whole other V28 just to get one more cell and then go through the hassle of selling the other six. I hope that I can find a heli guy with an extra cell laying around. Or hopefully that vendor on rcgroups will be able to start selling individual cells soon.

[coolhandcountry]

I have seen these cells sold individually. I can't recall the site. If I find it or some one else does could post it up. I am not sure if they are the same or not either.

[MetalMan]

This is the guy that's selling individual cells:
http://www.rcgroups.com/forums/showthread.php?t=514378

cart, it may be worth it to wait a week and see if anything new develops with the single cells.

http://www.rcgroups.com/forums/showt...t=514378&pp=15

This is the only place I know of that is trying to get some for sales.

[cart213]

Yep, that's the guy I'll buy an eighth cell from if he get's his act together. I went ahead and bought the V28 pack because I'd like to take a look at the internals of the pack.

[BrianG]

Well, the DeWalt 36v systems using A123 Systems M1 cells are out now. No information about the individual cells though (like Ah rating). A little pricey, but not bad if they work well:

One 36v battery pack: $180
One 36v charger: $100

http://www.toolup.com/CategorySearch...exbx27851.html

I thought about getting a general purpose Li-Ion charger, but the DeWalt one isn't too bad and probably has balancer circuitry built-in. Since I plan on running 18v, I'd have to wait until both packs need charging and then charge them both in series on the stock charger.

So, does someone here have deep pockets and wouldn't mind picking up a pack to test? :)

[BrianG]

OK, I did a bit more research about the M1 cells and found this bit of information from here (scroll to about 2/3 the way down under the heading "A123 Systems - DeWalt 36v"):

nominal voltage                3.35v 
max voltage                    3.6v 
capacity                       2.2ah 
internal resistance            10-12mohm 
power density at 5 sec pulse   3500w/kg 
Continuous discharge           30, 189W, 2,700 W/kg 
Long pulse                     80, 240W, 3,480 W/kg 
Instant pulse                  100, 344W, 4,990 W/kg 
energy density                 110wh/kg 
weight                         70g/cell

Reading a little further, it seems these are the "EV" sized cells, whatever that means.

[squeeforever]

2200mah isnt bad for what they are although the voltage is less than lipos so you would have to add another cell or two to make up for the voltage loss. I wonder what the safest max discharge voltage would be?

[BrianG]

The voltage for these cells are comparable to LiPos (a little less), so I'd say a cutoff of 2.5-2.6v?

[squeeforever]

What kind of deminsions and design are they? Are they shaped like a LiPo cell or like a Li Ion?

[BrianG]

I would assume they are cylindical shaped, but the size? I dunno. There was a post further back that listed dimensions and weight, but the weight I found (above) was different than the weight posted earlier. Who knows? Like I said: someone want to buy a pack and get the info first hand?