Do batteries go weaker if not used ?

What is on the bomboneri? Its unlikly for a battery to go so flat even after

10 years.

ALL batteries will self discharge while sitting unused on the shelf. Depending upon the type of battery the rate of self discharge rate can be infinitesimally small, as in the case of silver oxide or camera/watch type batteries and Li-Ion for example, or quite high in the case of carbon-zinc (obsolescent), or the Ni-Cd and Ni-MH types in the rechargeables.

When it comes to the AA, AAA etc, (non-rechargeable) types then you should only buy alkaline cells of reputable brand name since these have a shelf life of at least three years from date of manufacture, and then only if they are of Japanese manufacture. Chinese made batteries (even with a well known Japanese brand name) are not as good as those made elsewhere. Their shelf life is quite poor in my experience.

Before buying bulk batteries which you intend to use next year you should make sure they are current technology alkaline and that they have a storage life date of 2009 or later. Good batteries don't usually come cheap and if the price appears to be too good to be true, then it probably is...

Chinese made

Make sure they're not "Buzz" brand. I bought some cheap 9V alkaline ones from Vorlac a long time ago. Every one of them leaked badly and caused significant damage to the gear they were installed in.

If you're going to store batteries for a long time, put them in a sealed container or bag in the fridge (not the freezer). I kept a Tandy D cell in the fridge for about 9 years then used it and it still had plenty of capacity.

Check around suppliers such as Jaycar, they sell 24 packs of AAA Alkalines for $12.95 with discounts for 10 & 20 boxes.

This is substantially cheaper than the supermarkets and they seem to work well. If you do find any duds, you will at least be able to return them for refund.

Dave

Hmmmm... one wonders whether keeping it in the fridge for 9 years has actually saved you money. ;)

Sure! Tandy gave it to me for free back in 1993 when they were running the Free Battery Club. :-) I never had a use for a single D cell, so it stayed in the fridge for all that time. I finally connected it to an LM3909 LED flasher, which it powered for a couple of years.

Hands up those who had more than one card? ;-)

Dave :)

you mean all those cards I have in my wallet are now no good?

BTW Do batteries go weaker if they are used? You just can't win!

d:)

--
Don McKenzie
E-Mail Contact Page:               http://www.dontronics.com/e-mail.html

Crystal clear, super bright OLED LCD (128x128) for your microcontroller.
Simple serial RX/TX interface. Many memory sizes.
http://www.dontronics-shop.com/product.php?productid=16460

Me! I had one per year for a few years.

Surely you wouldn't suspect any of the upstanding honest denizens of this esteemed newsgroup of cheating poor ol' Tandy into providing more than one battery per month...? ;)

Bob

I can tell you for sure that Energizer 2.5AH AA NiMH cells rapidly go weaker even if you don't use them. Their rate of self discharge is amazingly high compared to others I've used, especially in this warmer weather.

Bob

Good, it's nice to know I'm not going crazy. I use those for my camera flash unit, and if I charge them fully then leave them for a week they are virtually useless...

Exactly the same with me. Last week I fully charged a set of them & put them into my digital camera. When I went to take some photos 6 days later, the low battery warning immediately came on. I've got some old PowerBase 2AH cells which still have plenty of charge in the same camera even after a few weeks, so it's not the camera pulling a lot of current when turned off.

Rate of self-discharge of NIMH is quite fast but nothing like what you describe.

Your charger is probably overcharging the NiMHs. When this happens the cells vent gas and go dry internally. Then they hold even less charge.

I'm using a Lightning Pack 4000N charger which is well known for its multiple methods of preventing overcharge. That's why I bought it. It's only the Energizer 2.5Ah cells which are doing this. Duracell

2.65AH cells, Sony 2.1AH cells and PowerBase 2AH cells charged in it don't have this problem.

Everything else Eveready make is crap, so it's not that surprising their NiMH are no exception.

MrT.

I bought some NiMH batteries from the camera shop, 2500mAh powerbase AA's from my speedlite (flash) and they have been going strong for over a year now. These cells get abused too.

I bought my PowerBase 2AH cells in mid 2003 & they're still going great. Sanyo 2.1AH and Jaycar PowerTech(?) 2.3AH ones have come and gone while they've just kept going. As for the Energizers, I've got a few sets of them & it looks like it's only the 'oldest' (14 months) ones which have developed a very high self discharge rate.