PDA

View Full Version : Lithium packs



AustinWolv
02-02-2005, 11:51 AM
Info here: http://neoairsoft.home.comcast.net/lithium.html

Briefly skimmed part of the article, and a couple technical parts didn't look right, but I don't have time currently to review it well.

Not very popular in Airsoft yet due to the charger requirement, but it has been done. Agrovale knows more about this than I do, so it'll be interesting to see his opinions further down the road.

Agrovale
02-02-2005, 12:41 PM
He has it right for the most part. But I'm going to have to disagree with him that voltage doesn't matter. In our application, it does. The motor will only pull the amperage that it needs, which shouldn't be the 20-30 amps that these are rated for. Therefore voltage will have impact, mainly on motor speed. If you are going to take the plunge make SURE you get packs that are rated for at LEAST 8C discharge.

I should also point out that the chemical brew inside these packs will spontaneously combust on contact with AIR. If you puncture the pack, you are supposed to put it in saltwater for a few hours, as saltwater will neutralize the chemicals inside.

AustinWolv
02-02-2005, 02:02 PM
I'd have to look again, but it looked like his charging guidelines were wrong as well.

Forge
02-08-2005, 09:08 AM
I remember speaking with a hobby store guy about these and he did mention the combustability factor as well, specifically that they may heat up extremely upon impact/ rupture. Something that disturbed me was that this may not immediately manifest itself in flames or heat but may slowly build, thereby inflicting damage on more equipment or persons (specifically referenced was the trunk of a car some guy threw his RC plane into after it crashed.)

Agrovale
02-08-2005, 09:45 AM
Yeah, that story was all over the RC plane forums with pics and all.

Here is the disclaimer from www.tanicpacks.com that you have to click through. (And if you like any of their products let me know becuase we are a tanic dealer ;) )

Safety Precautions for Lithium Polymer, NiMh and NiCD cells or battery packs offered by TanicPacks.com.

1. Never fast-charge any battery type unattended.

2. Never charge Li-Po cells/packs at any rate unattended.

3. Only charge Li-Po cells/packs with a charger designed specifically for lithium polymer chemistry. Example chargers include the Kokam USA, LIPO 402, LIPO 102 and LIPO 202; Bishop Power Products Apache S1215 and S1500; Great Planes Triton; and Schulze chargers with lithium charging capability.

4. Li-Po cells can ignite because of unmatched cell capacity or voltage, cell damage, charger failure, incorrect charger settings and other factors.

5. Always use the correct charging voltage. Li-Po cells or battery packs may ignite if connected to a charger supplying more than 6 volts per cell.

6. Always assure the charger is working properly.

7. Always charge Li-Po cells or battery packs where no harm can result, no matter what happens. We suggest a brick box or likeness. Have sand handy in a bucket for any need to extinguish any fire. NEVER use water on any cells or battery pack.

8. Never charge a cell/pack in a model. A hot pack may ignite wood, foam, plastic, etc.

9. Never charge a cell/pack inside a motor vehicle, or in a vehicle’s engine compartment.

10. Never charge a cell/pack on a wooden workbench, or on any flammable material.

11. If a cell/pack is involved in a crash:

a. Remove the cell or battery pack from the model.
b. Carefully inspect the cell or battery pack for shorts in the wiring or connections. If in doubt, cut all wires from the cell or battery pack.
c. Disassemble the pack.
d. Inspect cells for dents, cracks and splits. Dispose of damaged cells (see below).

12. Dispose of cells or battery packs as follows:

a. Discharge: with the cell or battery pack in a safe area, connect a moderate resistance across the terminals until the cell or battery pack is discharged. CAUTION: the cell or battery pack may be hot!
b. Discard:

- NiMH: place in regular trash.
- NiCd: recycle (cadmium is toxic).
- Li-Po: puncture plastic envelope, immerse in salt water for several hours and place in regular trash.


13. Handle all cells or battery packs with care, as they can deliver high currents if shorted. Shorting by a wedding ring, for example, will remove a finger.

14. Always store cells or battery packs in a secure location where they cannot be shorted or handled by children.

15. When constructing a pack, use only cells of the same capacity (mAh).