On 03/20/2014 12:34 PM, David Platt wrote:
In article ,
William Sommerwerck wrote:

I've been using alkaline batteries for decades (including nicads and NiMHs,
which are also alkaline), and have not had these sorts of problems. Yes, I
have had leakage. But it's been uncommon, and in only one case was the contact
badly damaged.

I have a Sony TFM-117WB with four Duracell C cells in it. They've been there
over a year. I checked them the other day, and they were fine.

I have never seen a 9V battery, of any chemistry, from any manufacturer, leak.

Alas, I've seen leakage from pretty much every size of alkaline.

One thing I have read, is that alkalines are quite unlikely to leak if
they haven't yet been used... but that discharging them triggers an
electrochemical process that starts the leakage syndrome (swelling
and/or corrosion).

So, if you have a device which is mostly kept around as a standby
(e.g. an emergency flashlight or radio), and isn't actually being
used, then the batteries will probably be OK up through their
published shelf-life date. However, once you use the device and start
drawing the batteries down, it's best to replace them relatively soon
after the first-discharge date (e.g. a year or so).

The devices I've had which have been crudded up or damaged by alkaline
leakage all seem to be of the "light or occasional use" variety, where
the batteries are neither left in an "unused, on the shelf" state,
*or* used up and thus replaced within a couple of months.



For some history - back around 2004/5 I was selling some New Old Stock
Williams brand pinball and video games that had been sealed in their
factory boxes since 1980. In about 50% of the cases one or more of the
three AA alkaline batteries had leaked enough to damage the battery
holder and in a couple of cases enough to damage the logic board
slightly. These were EverReady or DuraCell batteries (both used by the
same game manufacturers).

Later I had a few more of these games (still sealed) that I sold around
2010 and 2011 - again the batteries either had or had not leaked, and
again the damage was minimal.

In a few cases the 3 batteries still held full charge - 1.56VDC!

I think the reason batteries leak is because of current flow through the
battery, in other words is the battery is sitting on a shelf it is less
likely to leak than if it is a circuit where a tiny bit of current may
flow. If batteries are damp that can lead to self conduction and leakage
too.

I have these old still charged batteries still (somewhere buried in my
shop) in a plastic bag to see how long they will last...

John :-#)#

--
(Please post followups or tech inquiries to the newsgroup)
John's Jukes Ltd. 2343 Main St., Vancouver, BC, Canada V5T 3C9
(604)872-5757 or Fax 872-2010 (Pinballs, Jukes, Video Games)
www.flippers.com
"Old pinballers never die, they just flip out."