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View Full Version : OT: Rechargable Batteries (Godfather?)



~~~~~ s y ~~~~~
13-06-2004, 05:16 PM
Hey all,

Since buying my digital camera it's been eating up my rechargable batteries faster than me finishing a meal. At the moment I use 1.2V 500mAh batteries. I do know that I have to buy one with 1600 or so +mAH. However, I still cannot find 1.5V rechargable batteries. Do they exist? Where?

Cheers, :)

Growly
13-06-2004, 05:21 PM
You mean AA rechargables or other 1.5 v batteries?

AA are available at DSE, unless I read the question wrong again (sorry in advance, Godfather).

godfather
13-06-2004, 05:24 PM
500 mAh batteries (1.2v) are far to low in capacity for cameras. But you know that! New cells are now available at 2300 mAh, over 4 times the capacity of yours. As cells age, their capacity drops so your 500 mAh are probably only 200 mAh by now anyway?

All NiCad and NiMh rechargeables are 1.2v, thats simply a limitation of the technology. Most cameras should be very happy with 1.2v batteries though (they are about 1.4v when fully charged actually).


There are 1.5v Rechargeable Alkaline Manganese (RAM) AA batteries available but these are NOT suitable for cameras. They require a special charger as well, a standard charger will kill them on the first charge.

The RAM batteries are suited to low discharge applications, and would die quickly in camera use. They do not self-discharge like NiMh batteries and will stay charged on the shelf for years.

Why do you feel you need 1.5v cells?

~~~~~ s y ~~~~~
13-06-2004, 05:32 PM
> Why do you feel you need 1.5v cells?

I was wanting to get the longest lasting available on the market :D In this case, I will just go get some bigger mAh rechargables soon....

Many thanks for your response, much appreciated

godfather
13-06-2004, 07:08 PM
> I was wanting to get the longest lasting available on
> the market

The cell voltage is not an indication of how long they last.

The capacity in mAh is.

Growly
13-06-2004, 08:24 PM
The 1.25Vs available at DSE may not be the greatest, but they work, and they're rechargable.

PaulD
14-06-2004, 08:24 AM
"The cell voltage is not an indication of how long they last. "

That's all the camera uses to decide when to stop using the batteries.
Some cameras tend to stop before fully exploiting rechargables.

godfather
14-06-2004, 09:01 AM
If the camera is designed to use rechargeables, then the terminal voltage will unlikely to be a singular defining event in the camera's ability to fully utilise the charge, more the delta (dV/dT) change of the voltage will be.

Most modern electronic devices appear to look more for the delta change as an indicator (both of fully charged and terminal discharge points) than just the voltage.

One camera I used to use would stop using 1.5v Alkaline batteries even though they had reasonable power left in them, on the basis that the voltage drop (dV/dT) was telling the camera the battery was flat when it was just the expected sag that alkaline 1.5v batteries give on high load.

With 1.2v rechargeables that drop is usually only seen when the battery really is flat, due to their flatter voltage vs charge remaining characteristics and lower impedance.

andy
14-06-2004, 09:30 AM
I got some (4) 1600 mAhr nimh cells complete with a charger from DSE recently ($39). They seem to last a lot longer in the camera than the Alkalines I was using (I've got a Canon A75). They seem to work fine but they don't "taper off" like a normal cell, they just suddenly stop. You can get larger capacity cells but at a larger capacity price. The ones I got suggest 1000 recharges as a life cycle so that works out at around 0.4 cents per charge, less if you take out the cost of the charger. I purchased a second set of cells as well for $25. The charger takes 16 hours to fully charge and then goes on a trickle cycle so you can safely leave the cells in the charger until you need them and they wont over charge or lose their charge. The nickel metal hydride cells don't have the "memory" problem of the nickel cadmium cells so you can recharge them before they get flat.

Davesdad
14-06-2004, 10:25 AM
Eveready produce 1850 mAh Nimh. I got mine last year so they may even produce higher capacity cells by now.

godfather
14-06-2004, 11:25 AM
Eveready (and other brands) NiMh are available at 2300 mAh. In fact some are now 2400 mAh, but not yet seen here.