Lithium-Polymer Batts-Whats the deal? - Are Lithium-Polymer batts viable for sub

[anonymous]

Hi submarine guys...
I have been reading a little about the new Lithium-Polymer batteries for model planes and helos. They seem like the "wave of the future" for all types of models, and could be very applicable for our subs, but I have a couple of questions.
1. Can they be wired series/parallel, so we could end up with, say, about 12v@8ah, or more?
2.Is there off gassing of explosive gas, when they charge or discharge? Any other nasty chacteristics, like excessive heat?
3.What is their discharge curve like...is it pretty flat, like nicads or more like gell cells?
I know that there are some very savvy Electronic Engineer types out there who can educate the great unwashed masses,
so thanks for your help.

[petn7]

for micro helicopters they used

for micro helicopters they used 3 lithium cells to get the necessary voltage, so i guess that means they can be put together in series. as for parallel, i never heard of it done often as lithium cells often come with huge capacities already, but that doesn't mean they can't be put in parallel.

honestly, is there a need for lithium cells in submarines? i mean, nicads or other cells seem to work well enough and they can always be made bigger since most people often end up adding plenty of lead ballast anyways to make the sub heavier.

from what i hear, charging can get pretty dangerous as the lithium battery can give off smoke and gases creating a fire hazard.

as for their discharge curve, i'm not really sure what to say

[dietzer]

Go check out FMA Direct.

Go check out FMA Direct. They have a great FAQ on Li-Poly batteries, and they sell them, too. They also offer kits for making serial or parallel battery packs.

Carl

[anonymous]

Carl,
Thanks, will do.

Carl,
Thanks, will do.

[bigdave]

Although not Lithium-polymer, I am

Although not Lithium-polymer, I am expermenting with Lithium -ion batteries in my mini WTC's. They are a little more user friendly in model boats than the polymer are. They have a hard case on the outside, unlike the soft sided polymer. They still require a special charger, and need low voltage protection. The batteries are 3.7volts normaly and should not be discharged to under 3volts or battery death will result. They are not forgiving like nicads, they do not give you a second chance. The ones I am using are 1050 MA, and I have three in series for 11.1volts. I purchased them surplus, they were used for cell phones I believe. They do not take up a lot of room and fit fine inside my 1.75in ID WTC. With the low current draw of the mini Maxon motors I am using I should get a good long run time. Dave.