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Old Nov 20, 2004, 6:11 PM   #1
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I'm thinking about buying a canon a75 (4 batteries) and i wonder if you could give me some tips:


1 -which batteries + recharger should i buy?

2 - what do you think about these ones?:


Energizer, 1850 mAh batteries, Model No. CH30MNCP4, 27.83 DolarsS




&

Digital, 2200 mAh batteries, Model No. CH-4900, 18.74 Dolars




3 - a friend of mine will buyitfor me and he said that he can only buy from these stores (cause they're in his city). So, if u can look at some of these sites below and indicate a recharger + batteries, i'd be glad


Walmart

Office depot

Office max

Radio Shack

4 - one last question: how lonf does the battery last, before having to recharge it?

thanks for helping


Rafael[/quote]
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Old Nov 20, 2004, 7:36 PM   #2
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First thing about batteries... The mAh is how much power they hold, the bigger the number there, the longer they will last.

Second, the amount of time that they will last in you camera is dependent upon several things, how long you use the lcd display, how many shots use the flash.
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Old Nov 20, 2004, 7:40 PM   #3
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rob_strain wrote:
Quote:
First thing about batteries... The mAh is how much power they hold, the bigger the number there, the longer they will last.

Second, the amount of time that they will last in you camera is dependent upon several things, how long you use the lcd display, how many shots use the flash.
i just wanna know your opnion about the charger and batteries that i put in my post... are they good?
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Old Nov 20, 2004, 7:48 PM   #4
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Personally, I dont know if I trust a brand called Digital, but you never know. I can tell you that the Energizers are really good, but are a little lacking on the amount of power they hold. I dont know if the Digital ones will withstand a long life of charging and discharging. I dont see anything wrong with them and havent heard anything bad about them.
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Old Nov 22, 2004, 7:24 PM   #5
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I personally would stay away from these ultra fast chargers that charge faster than 1 hour. There are chargers that can charge as fast as 15 minutes but they use special cells. I'm a bit sceptical about these as well. I'd pick a good 1-2hour charger instead. I've tried several of them and settled on Lenmar Mach1 gamma. This is the only charger I've used that charges NiMH cells fast (60-80 min.) while keeping the cells cool.Other chargers that charge that fast heat the cells far too much. This harms the life of your cells badly. I've seen people who used NiMH cells with typical 1 hour "smart" chargers using -dV control that had their cells failing after as little as 50 cycles or so. Often the cells get too hot to touch after 1 hour charge. This means that the surface of the cells is heated to above 60 degrees Celsius. The maximum temperature at the end of charge recommended by most manufacturers is 50-55 C. Everything above that harms the cells significantly. The Lenmar peaks at about 40C half way in the charge cycle and by the end of charge the cells are just a bit over room temperature. i don't know exactly how they did it, patented technology... the usual hype but it works. I hear the Lightning Pack 4000N also keeps the cells cool during charging, but I haven't tried it 'cos it's not available here in Europe. It has the advantage of being more portable (no separate power supply) and does not have the internal fan, which means that it runs 100% quiet. On the negative side it charges only cells in pairs (2+2) and is slower.
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Old Nov 30, 2004, 10:57 PM   #6
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rob_strain wrote:
Quote:
First thing about batteries... The mAh is how much power they hold, the bigger the number there, the longer they will last.

Second, the amount of time that they will last in you camera is dependent upon several things, how long you use the lcd display, how many shots use the flash.
That's not necessarily true.....

The ratings on batteries are misleading....

For example,Alkalines have a rating of around 2600mAh.... so why do they die quickly in a digital camera??

It has to do with the discharge curve. An alkaline battery is 1.5V, but is optimized for low current, slow discharge. As it discharges the voltage drops steadily, so for example when it is half discharged its voltage may be around 1V. If you use them in a digital camera (say 4 batteries) with a nominal cut off of, say, 4V, they will start at 6V and will drop to 4V when they are about half discharged, at which point the camera will stop working.
On the other hand NiMH batteries have a nominal voltage of 1.2V, but they hold their voltage better. e.g. When they are half discharged, the voltage can still be around 1.1V. They might then drop to 1V when they are 90% discharged.

What does that mean??
You have an alkaline of 2600mAh and a NiMH of 2200mAh. When your digital camera stops working, the battery's "effective rating" might be 1300mAh for the Alkaline and almost 2000mAh for the NiMH.

If you use either type in an quartz analog wall clock, the Alkaline will last longer than a NiMH.

BTW, if you've used an alkaline battery in a digital camera and it died, DON'T throw it out. It will have at least half of its capacity left!!!! Use it in a lower current device, and it will work quite happily for months!



The first pack says it can charge NiMH but they may be rechargable Alkalines. I can't see what the second pack is.... it could be rechargable Alkalines again, for example. Make sure you buy NiMH batteries
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Old Nov 30, 2004, 11:16 PM   #7
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Thanks for the info, I didnt know that. You learn something new every day.
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Old Nov 30, 2004, 11:31 PM   #8
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I purchased 4 Energizer 2500 mAh NIMH for $19.26 including shipping and 4 free battery storage boxes from Thomas Distributing. I ordered on Saturday morning and received today. I just charged them and am running the discharge mode of my camera to condition them.
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Old Dec 9, 2004, 3:17 AM   #9
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It's interesting to hear so many people complain that fast chargers get the batteries too hot. Am I missing something, or can this problem not be solved by using a device as simple as a fan?
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Old Dec 12, 2004, 10:54 PM   #10
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Internal temparature will still be very high, even if you use a fan.
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