Using the resources of this site and it's links I have been able to find that NiMeH AA batteries have a rated like of 1200-1400 mAmp-hrs and "extended life" NiCads are 1000 mAmp-Hrs, but I have not been able to find similar ratings of plain old disposable alkaline batteries. I have recently bought a Toshiba PDR-M1 and I am trying to figure out which batteries will last the longest.

Does anyone have info on alkaline batteries? Are some brands better than others or are thyey all pretty much alike?

-- Bob Huffman (huffmun@msn.com), March 14, 1999

Answers

The problem with Alkalines is that the ratings are deceptive for use in extremely high drain applications like digital cameras. Because Alkalines have a high internal resistivity that gives them their long life in MOST applications, they cannot deliver the short bursts of very high current that are required by applications like digital cameras and electronic flash. In trying to deliver the high current drains that Digicams and Flashes require, the Alkalines will overheat after very little useage and this will degrade the performance. As a result, the alkalines will be often become unuseable for Digital Cameras or Flashes after only around 10-20% of their rated capacity is consumed.

-- Doug Green (dougjgreen@yahoo.com), March 14, 1999.

Doug, thanks for the useful information but please give me the bottom line -- which batteries will last longer in my PDR-M1, alkaline or NiMeH, or long life NiCad?

PS I know a Doug Green who is an attorney in DC - are you him?

-- Bob Huffman (huffmun@msn.com), March 14, 1999.

BTW, I'm not a lawyer, not in DC. I'm a Marketing Director for a high tech company in San Diego with lots of experience in Multimedia Graphics and Digital Video ICs.

As far as Batteries go: the longest life, but also the most expensive solution, will be to use Lithium batteries. The best tradeoff between cost and long life will be from using NiMH batteries. If your demands are not too heavy, NiCads will also work OK. Alkalines are the worst.

FYI, in my DC260 with my personal low use of the LCD: NiMH batteries can usually last for 2-3 full 48 MB flash cards (200-300 pictures in Best mode), shot within a couple of weeks, on one charge. Heavy Duty NiCads can last for at least 1 full 48 MB card (around 100 shots) per charge. Alkalines tend to crap out after 40-50 shots, and of course, unlike the others, are not rechargeable. Lithiums will last longer than one NIMH charge, but they are also not rechargeable.

-- Doug Green (dougjgree@yahoo.com), March 14, 1999.

It so happens that I also have a PDR-M1. After the second set of alkaline batteries died way too quickly for my taste I did the same looking around that you're doing. I read Tinhuat Oh's pages and followed the links on this website and others and ended up buying two sets(8) of NiMH AA batteries by Nexcell from Thomas Distributing. I thought that would just be the beginning of my search and that I'd even want an external battery pack, but the Nexcells really changed my mind. I've never used more than one fully charged set at a time -often finding one FULLY charged set to easily be sufficient for WELL over 200 images at hi-res with flash and the LCD turned on the entire time. If you read Tinhuat's pages it's pretty obvious that a PDR-M1 would greatly outperform the Nikon 900 he uses in terms of battery life, probably because of the power consumption of the electric zoom on the Nikon, and he gets better than 200 shots on many trials.

A word to the wise. Unless the situation has changed, don't buy the cheap($10) Maha charger. I did, and found that it put out a much lower than advertised charging current. I modified mine by installing a few lower value resistors to up the charging current, but still find it a cumbersome and lacking solution. The modified unit does pretty well topping-off and keeping a set of batteries trickle charged once you've given them a thorough charge with a good charger. From reading Tinhuat Oh's pages it would seem safe to recommend the better GP or Maha chargers that Thomas Distributing sells.

The links for the distributor and the King of All Battery Testers, and a very nice guy, Mr. Oh:

Thomas Distributing: www.thomas-distributing.com/batteries.htm Tinhuat Oh: http://members.xoom.com/cp900/

Just for information's own sake, I've found that my Nexcells usually end up with a terminal voltage of about 1.414 Vdc per cell when fully charged and topped off, as measured with a Fluke multimeter. I use a Radio Shack #23-406 NiCD/NiMH fast charger set for the lower NiCD rate and then top off with the Maha trickle charger. This works because the Radio Shack charger is strictly a timed charger and I don't recharge them unless they're thoroughly discharged. I prefer the lower rate of charge as it leads to less battery heating and should allow the batteries to be cycled a greater number of times. Beware that most NiCD chargers are not suitable for charging NiMH's because of differing battery chemistries and methods of maximum charge determination. A typical NiCD charger could overcharge a set of NiMH's by not turning off the charging current or not switching to a trickle current at the proper time. This could lead to cell rupture and a mess, to say the least. Good luck.

-- Gerald Payne (gmp@francorp.francomm.com), March 14, 1999.

Thanks to Doug and Gerald for all the good information.

Question for Doug: You said that the lithium batteries are not rechargeable. There is a type of battery called "lithium ion" which is rechargeable. I assume you were not referring to this kind. Do you (or anyone else) know if rechargeable lithium ion batteries are made in AA size? (The Sony Mavika we have at work has a rechargeable lithiun ion battery.)

-- Bob Huffman (huffmun@msn.com), March 16, 1999.

I don't think you'll find Li-Ion AA's any time soon. As I understand it the Li-Ion's cell chemistry is such that each individual cell of a Li-Ion battery produces 3.6Vdc and an AA of practically any type only produces about 1.5Vdc. You'll love the NiMH AA's in a PDR-M1, but if you really need to power the thing forever and a day there are some rechargeable gel-cell lead acid battery packs available via the web and possibly in some camera stores by now. But considering how long the PDR-M1 will operate on a set of well charged Nexcells and how bulky and how many more times expensive the commercial gel-cell packs are it's probably overkill. If you do buy a gel-cell beware that the DC adapter jack on the PDR-M1 is labeled 5Vdc not 6Vdc and might not like the 6 to 6.6 Vdc that most gel cells put out so be sure that the gel-cell pack is designed to work with the PDR-M1(while I'm pretty sure the PDR-M1's internal battery compartment is probably regulated to about 5Vdc, that doesn't mean the adaptor jack is.) On the other hand, if you do buy one that doesn't smoke your camera let the rest of us know... :-)

So far I'm too chicken/happy with the Nexcells to try it -and I have an unused 6V gel cell sitting in my shop. I would say that you could hang a simple linear 5V regulator off a 6V gel cell, but it's not really completely practical in high drain applications since most of the higher amperage regulators need about 1.25 Volts of headroom over the 5V output you'd like. It'd work for a bit, but you'd probably only get half the gel-cell's useful power output before the regulated voltage dropped below a useful level. Good luck.

-- Gerald Payne (gmp@francorp.francomm.com), March 17, 1999.

Thank you for the information

-- William Jones (rlt1@gateway.net), April 04, 2001.