Which Battery to Buy?

[yash101]

Originally Posted by Al Skierkiewicz

Yash,
Those first two things are some of the reasons we don't want them on FRC robots. Our batteries get dropped a lot during competition.

I am not sure what you mean by SLA battery maintenance. These are sealed batteries and there is nothing you can do for maintenance except to charge. While they likely will not tolerate no use for a year or more, a few months is not a problem.
I recommend you check out the Battery University site for some really good info on batteries.

It is not that difficult for these batteries to be used "Properly". Typically, they have much higher ratings than lead acid batteries, yielding a much harder to reach "danger zone". Some Lithium Polymer (LiCoO2 gelled) batteries can handle currents as high as 250 amps/hour. Most of these batteries are only dangerous when subjected to mechanical parts that can poke or puncture the packets.
Lithium Polymer/Ion batteries can be used quite safely if just a couple guidelines are met. Some of the ones I can think of at the top of my head include:
-Use a hard case (so the cells are isolated from sharp parts)
-Use good safety measures. A properly-rated fuse, built into the battery (for ICOE), an external fuse for excessively high currents that don't reach the battery's limit and then, all the current FRC safety measures should suffice!
-USE THE RIGHT CHARGER

I really think that the cons of Lithium-based batteries are quite sparse as compared to the pros.
I really believe that FRC is not making the move to renovate the battery technology because GelCel Lead Sulfuric Acid batteries have proven their existence to be reliable. After all, they are the oldest technology for rechargeable batteries. This is the reason why we cannot blame the experts for their decision. However, as long as the safety specifications are met, the newer technologies are extremely safe.
It is EXTREMELY uncommon to have our telephones explode when we drop it or keep it plugged in overnight. Arguably, one could say that the batteries are smaller. Yet, they contain similar (or even the same) chemistry and reactions and are equally as succeptible to these failures. I guess that a cell phone battery explosion is not as spectacular as a Lithium car battery substiture, but they are equally as dangerous.

In short, Lithium-based battery technologies are not as dangerous as feared to be. An integrated charge controller can be used to maintain charging safety. A thermal resistor can be used to shut down the battery in case of an approaching thermal runaway. A fuse/breaker can be used to ensure that the battery maximum ratings are never reached.

Not to mention, How light are Lithium batteries. I would not have to be as scared to drop a lithium battery (as long as the casing is strong) on my foot as a lead sulfuric acid battery.

Mr. Skierkiewicz,
you were speaking about lead acid maintenance. Gel-cel batteries are not meant to be maintained. They are not supposed to require hydration. The main caveat to this sealed design is sulfation. You cannot do much to prevent this process from happening, especially at the juice we pull out of these cells. Thankfully, newer Lithium-based designs do not experience as many lost chemicals due to a similar process!