Thanks t.nollet so many resources....

Originally posted by Dave Hederich
I'm not sure why development is still going on with Li-ion cells when LiPos appear to be superior in performance-to-weight, which is what is important to those of us who use them for e-flight.

But for most of the rest of the world, price matters. Li ion metal cased cells seem to be lasting longer and more reliably than LiPo. I think that's why most laptop makers have pretty much dropped LiPo. But for PDA's, thin LiPo are probably worth the price.

For some reason, we are able to get LiPo at a fraction of the cost the rest of the world is paying. Haven't figured out why E-Tec and Kokam's are so cheap but I'm not complaining.

Rick.

OK, I took a closer look at my ALBs - they are definitely NOT equivalent to E-techs. They are a bit thinner and some 15% "taller" (the biggest dimension). This weekend, we had an indoor aerobatic competition and after that I took the plane for some show flying. In that I used 2s 1200 E-techs and aleternatively 2s2p 720 ALBs. The ALBs choked fairly soon during hovering my "Bambula" (a plane to be soon featured on the RC Mania website maybe even with video). The motor takes some 6A during hovering, which is easily supplied by the E-techs.

The E-techs are superior to the ALBs, no doubt.

Excellent information, David. So far it doesn't sound as if the Toshiba ALBs will be top choices for e-flight. I hope that everyone will continue to compare the dimensions and performance of various LiPo cells against each other whenever they have a chance. It will be helpful to everyone if we learn who is actually producing which cells.

Reading the Toshiba press release it says the 'ALB' cells are wound electrode construction.

From what I've picked up the ETechs are wound construction also.

Kokam cells use stacked construction, which doesn't seem to perform as well with high discharge rates.

Jimmy

Jimmy,
You have to be careful about assuming that all of a LiPoly manufacturer's cells are all of one construction method or the other. For example, the Kokam 145 cells are "wound" construction. I know because I have a friend who took one appart in a innert laboratory environment almost a year ago. Also, some people in the industry maintain that high discharge capability can be obtained with either stacked or wound. I don't really know. But that's what I'm told.

Also, we don't want to assume that just because a few of a manufacturer's cells perform a certain way means that all their cells perform that way. E-Tec 250's, 700's, and 1200's are getting the reputation (rightly deserved) for being high discharge cells. However, their 130's don't perform nearly as well compared to their capacity as their larger siblings do.

I'm afraid we are finding that blanket statements about all of LiPoly manufacturer's cells can't be made. Each cell needs to be tested.

Gordon