Lithium Rechargeables, how stable when being bounced around on bike?

[socalrunner]

I am looking at using 2 - P3D flashlights for use on my road bike for night riding.. I was considering using rcr123's. I have been reading that great care must be used with Lithium rechargeables.. Will the constant movement and bouncing around cause me some concern when using these..

I am also looking at 2 other lights than use 18650 batteries.. I am better off just using 2 - L2D's with AA Nimh batteries?

Any input greatly appreciated..

 

[DM51]

You would only have a problem if the batteries were rattling and banging around loose in a container, as there might be some physical damage to the protection circuit. If they are fitted in a light, and don't rattle, they will be OK.

The safety issues are to do with over-discharging them (don't let them go below 3.0v) and the need to take care when charging (don't try to charge over-discharged cells, don't let them overheat, don't overcharge them, etc etc).

 

[socalrunner]

Since I am going to use for extended periods of time, I was going to only use protected cells so the over-discharge would not be an issue..

Heat will not be a problem because they will be air cooled while riding my bike.

 

[Martin]

As long as you don't overcharge them, short them out, cook them or puncture them, Lithiums don't give you a problem. Eventually, they have been safely used in all sorts of mobile applications for a long time, now. I bet, some folks are even using them in weapon lights.

 

[DM51]

Since I am going to use for extended periods of time, I was going to only use protected cells so the over-discharge would not be an issue..

Heat will not be a problem because they will be air cooled while riding my bike.

The protection circuit should be looked on as an additional safety device, rather than as a substitute for sensible practice. In other words - don't rely on it 100%. Pull the cell when the charge gets low, don't let it run right down.

Reasonable heat is not a problem, but the one REAL danger sign with Li-Ions is if a cell heats up during charging. This is an indication that the cell is dying or dead, and could explode if you continue charging it.

 

[SilverFox]

Hello Socalrunner,

I am not sure how good your suspension is, but these cells seem to survive in RC helicopters, airplanes, boats, and cars.

I would consider using some foam for a cushion, provided the draw is low enough that the batteries don't overheat.

Tom

 

[xiorcal]

If you're using them in LED lights, check with AW about how high the current needs to be to kick the protection circuit in.
Any direct-drive application of LEDs on Li-Ion can be dangerous.
The current drops significantly, in correspondence to the voltage drop in the batteries during discharge, and that results in less load on the battery.
A draw too low on the batteries can overdischarge them before the protection kicks in, as it is designed to cut off at a lower than ideal voltage. Under greater loads, the battery sags below this voltage, cuts off, and recovers to safe voltage on resting.

-Xiorcal

 

[bagman]

I run a pair of AW's protected 18500's in a PILA G3 as my main bike light and have never had any problems.

 

[LuxLuthor]

Many of the stories you hear about trauma related problems with Lithiums are the RC soft Lithium Poly cells which are not encased in a metal shell like these cells. I think it would be fine to use for your purposes as long as you don't slam into things where there will be trauma that may deform the case and possibly break the protection circuit. As someone else said, put some foam cushion around them, and they should be fine.