Is there a common method of preventing batteries from leaking out and destroying the device? Why does this happen in the first place? I have laid another head lamp to waste because it was sitting in my truck unused for several months. Could it be because of the lack of use? In that case, should the batteries be taken out in anticipation of less use?
Acid cell and Alkaline Batteries function by a process of controlled corrosion of two different elements which creates a voltage potential and a current if the circuit is completed.
This process is in continuous motion from the day of manufacture, while it sits on the shelf in its packaging, while installed in the equipment during off/idle periods. It accelerates with higher discharge rate during use, and continues after the cell is unable to produce useful power to run the device
Alkaline batteries have a sealed container that serves as one of the electrodes. While it undergoes a lot slower corrosion than the case on the old Acid cells, it still corrodes. It is part of the process that allows the battery to function. You don't prevent it.
- Dead batteries should never be left in equipment, their process is nearly complete and the shell is close to breach.
- Live batteries have a date on them for a reason. Chemical reaction occurs even if the battery is live and able to run the equipment. Often with today's LED technology, for example, the batteries will corrode through and start leaking long before they become too weak to run the flashlight.
- Prevention is worth a pound of cure. Remove batteries from the device when not in use for extended periods of time. If it is part of a crash kit where you need batteries with the device at all times for emergency use, store them in a separate ziplock bag and check their dates periodically as well as for leakage.
- Don't mix different cells in a device which takes more then one cell. Alkaline cells tend to leak when a potential voltage is applied, i.e. when you try to charge them. This can happen in devices with more than one cell in series if some of the cells have less capacity than others. This is why one should never mix cells by type, brand or age in devices where the cells are connected in series (which is virtually all devices that take cells in the same compartment).
Yes on battery removal. I've had better luck with name brand batteries.
Before you pitch the lamp, try some vinegar, scraping off the scale ( I used a cotton swab soaked in vinegar) then neutralize with baking soda and finally rinse with water. I just resurrected a kitchen timer this way.
I think ( but don't know), that the battery chemistry is more likely to leak after a use that fully depletes them, or heats them thru a hard use.
It is generally always recommended that the batteries be removed from devices that are not in use. Even the device manufacturers recommend this.
I'm not sure what actually leads to batteries leaking other than a failed seal. It is possible that a device exposed to wide temperature excursions may make the battery seals more prone to failure.
There is more information at this link as to what kinds of things can lead to battery seals failing. Like all things on the internet there may be some points made there that are not fully valid ... but the electrical engineer in me tends to agree with these points:
Do not mix batteries of different sizes, brands, remaining charge level and age.
Be aware that a sharp drop or case deformation (denting) of the battery could lead to degradation or failure of the battery seals.
Use common sense and check condition of the batteries in a device fairly often. If a device is to remain idle for an unknown time then play it safe and simply remove the batteries. You can put them in a zipper lock plastic bag so in case they leak you can keep the caustic chemicals contained in a safe place.
A few more thoughts:
While alkies may leak, the crud they exude is alkiline, not especially damaging to the device and isn't too hard to clear away. Old-style/cheap (zinc-carbon?) Batterues use an acidic electrolyte, which is more destructive if it escapes.
Batteries can go bad before their nominal date I have a package that should have another year on it but that has started leaking.
NiNH is indeed aomewhat less likely to leak, partly because the chemistry is a bit scary (especially when fast-charging)