OK, we have LiPo, Lion, and now LiFe batteries.
Wazza difference? Is one safer than the other? Longer life? More amps?
What gives?
Wazza difference, you say?
More money for about the same thing as Nihm, with less the hassles.
My opine only, not the general public’s.
First, the energy density of lithium batteries is much higher than NiMh, therefore you need fewer cells to get the same voltage. In RC flying this is important because it saves weight. In model RRing it means a smaller battery pack to fit into a loco.
LiPo- used a lot in RC, foil case, sensitive to over discharge or over charge-I wouldn’t use them in model RRing - model RR esc’s don’t have low voltage cutoff(LVC) so they can be easily over discharged (this is dangerous)
LiIon & LiFe- metal case, many come with an LVC board on each cell or on a pack, they tolerate abuse more than LiPo,
All lithium batteries need chargers that are specifically designed to charge lithium packs.
Hope this helps,
Dave
(lots of info available on the battery forum of RCGroups.com)
Lithium Polymer is usually in a flexible case, sometimes like a little pouch. A little more easy to damage.
Lithium Ion normally in cylindrical cells, but often in prismatic (rectangular)… both the above pretty comparable in energy density.
Lithium metal batteries (as in Lithium Iron, or Li Fe) will have even more density, but more expensive right now.
What’s safer? Really all about same, you have to have a good charger to keep from damage, etc.
I think you will find that LiIon will be most cost effective and “sturdy” right now. LiPo too easy to damage, LiFe too expensive to justify extra density.
Regards, Greg
Greg brings up some good points, but lithium-polymer cells are not flexible. What’s moving are the welds between cells, I don’t recommend flexing any lithium battery-pack.
Actually lithium metal and iron cells are much cheaper then ion, but when supply and demand increases the price will decrease.
In the next couple of weeks we will be offering a higher milliamp cell for the same price as the 2600mah, and we’re passing the savings on to you.
But as Greg stated, that lithium-ion cylinder cells are studier then lithium-polymers, due to the shape and thickness of the nickel plating.
Rick Isard
Cordless Renovations, LLC
Actually li-po cells are flexible, and can come in bags. They can also be housed in rigid cases. My statement was possibly inaccurate when I said “usually” in a flexible case.
But the basic cell construction allows them to be made in flexible “containers”. They are often used inside equipment where the battery is not replaceable.
Read a few articles like: http://en.wikipedia.org/wiki/Lithium-ion_polymer_battery
Read the part on technology:
“Cells sold today as polymer batteries are pouch cells. Unlike lithium-ion cylindrical cells, which have a rigid metal case, pouch cells have a flexible, foil-type (polymer laminate) case.”
I was trying to highlight the differences as Steve asked. In designing electronic devices, this is usually the determining factor. By the way I HAVE designed hand held computers/pda’s and other consumer devices with the li-po’s in “pouches”.
Greg
Dave Ottney said:This will be changing soon. :)
... model RR esc's don't have low voltage cutoff(LVC) so they can be easily over discharged (this is dangerous)...
Yep, I’d rather have it in the ESC and allow me the freedom to choose the batteries I want from loose parts.
I know that kinda goes against pre-made packs, but not all locos can take a standard sized brick.
Regards, Greg