DescentBB

Pulling out a old metal detector I removed the 9 volts battery as it was corroded where it looked like it leaked out the bottom. The battery had been plugged in to the detector for over 15 years. I replaced the battery with a Duracell with a experation date of Mar 2004 but was still new in the plastic wrap.
The metal detector wouldn't work. Checked the voltage on the battery and it read 5 volts. Tried another no name 9v battery and that didn't work either. Went to the trash and fished out the old discarded Eveready and yup, it made the detector operational. So who would like to 'splain this one?

you put the batteries in the wrong way?

They mated for life?

Unix wrote:They mated for life?

LAFFIN!

Bad contacts?

Get a battery that isnt past its expiration date?

Zuruck wrote:you put the batteries in the wrong way?

Yeah right. 9 volt bat. only connect one way

Avder wrote:Bad contacts?

Skim reader. Old bat. works just fine.

Vindicator wrote:Get a battery that isnt past its expiration date?

Another skim reader! The bat. that works is about 15 years beyond its expiration date.

So again, why is the REAL OLD bat. powering up the detector and the new ones aren't?

um... You need to find a new place to buy batteries

its a great left wing conspiracy woody

I must be in a hall of mirrors. All the replys look like Mobius.

woodchip wrote:I must be in a hall of mirrors. All the replys look like Mobius.

No need for insults bud!

woodchip wrote:I must be in a hall of mirrors. All the replys look like Mobius.

rofl.. now that is a good 1 Woody
and I have no figgin clue why that would do that other then what Clutch said

Because the new battery is an alkiline and the older one is a old style battery (forget technical term) and was (surprisingly) able to hold a charge?

Ironically, the answer is in the subject eh?

Battery technology evolved over the last decade or two towards higher capacities. So over time the chemical makeup changed. This may have caused a higher internal resistance of todays 9V blocks, ie. todays 9V batts can't deliver the (milli) amps that your device needs to operate. Also I'd guess that those changes in the chemistry will cause a much shorter "half live".

Just wild guesses tho

Don't all batteries deliver about 450 mA? Or am I sorely mistaken?

Heh, a fun thing to do with 9V batteries: on a cold day, one of my friends connected two 9V batteries directly to each other. Well, it got so hot that my friend dumped the scorching batteries in a garbage can in Grand Central Station. Oops.

Grendal is close

Over the years, battery technology has changed, for two reasons.

1) Better performance (I will come back to this, so settle down woody)

2) Various environmental issues, and/or material cost and avialability.

Ok, back to performance.
Old battery technology was pretty simple by todays standards. Under load (in use) they didn't have that long of a life compared to current batteries. They tended bleed down in a pretty linear fashion.
i.e. as you used them (in this case) it would slowly decrease from 9v to 8v to 7v to 6volts and so on. In the case of your device, over the years the case broke down and leaked some acid. Yet the battery must have been in pretty good shape when you left if 15 years ago, and the device likely doesn't draw much current, and can operate with less than a perfect battery. This is why the old one worked.

New batteries (when compared to old technology) will out last the the old ones under load.
i.e. if you loaded both at 200mA (both starting new/fresh) the new one would continue to output the 9 volts for a longer period(but not by any amazing amount- maybe 20%)

The big difference in the way they act is the power/voltage curve as they decay.
As decribed above the old carbon acid would decay in a linear fashion.
Most battery technologies today tend to hold the max voltage output longer, but when they start to fail, they are not linear, they tend to fall off a cliff.


(bad graphic coming)

OLD STYLE Decay

9v------
8v......|-----
7v............|------
6v...................|------
and so on

NEW STYLE

9v-------------------
8v...................|-
7v.....................|-
6v.......................|---

As far as why a duracell that was only 8 months out of date. It should have worked, likely it was either defective or had been stored in very poor conditions such as high heat

Good reply Kev.

Old acid leaking eveready measures 8v

Duracell March expire date measures 4.5v. Has been stored in kitchen drawer so I don't know about high heat being an issue.

No name measured 6v. Also stored in kitchen drawer.

As you explain it Sickone, I understand why they put expiration dates on batteries nowadays. The old eveready doesn't have a expiration date.

Good one Woodster.

I was going to say "It's all a RIGHT wing conspiracy..."

Another fun thing to do is to get about 100 9-volt batteries and connect them to each other in series. connect the ends of each line to a heavy duty copper wire, then spark the wires together and watch the lightning bolt jump inches thru space!

Lobber wrote:Another fun thing to do is to get about 100 9-volt batteries and connect them to each other in series. connect the ends of each line to a heavy duty copper wire, then spark the wires together and watch the lightning bolt jump inches thru space!

And right after you do that, try the classic 9v battery test, lick the two wires. Comeon, whats the worst that could happen? It's *only* 900 volts...

This sort of ties into the "video game made me do it" thread.

I see lawsuits in your future