Rechargeable AA batteries suddenly can't hold charge? EDIT 2: Is it the camera?

[Modelworks]

Charging rates are measured in C/unit of charge. If the battery is a 2000mah then the options for charging rates are:
C/10 = charge at 200mah for 10 hours
C/3.3 = charge a .6Ah for 5 hours
C/1 = charge at 2A for 1.5 hours

Anything less than a 1.5 hour charge time for a cell is destroying the battery. The reason for the 1.5 hour charge time for C/1 is because nimh are only 66% efficient, for every 100 units you put into it, you get 66 back.

A good charger will discharge the battery before charging it. Even better chargers will use pulses to charge where the battery is charged for a second, discharged for 1/10th second then charged for a second, cycle repeats until battery is finished. The 1/10th second discharge cycle lets the battery recoup the hydrogen lost in the charging process.

I tried the retail chargers and most sucked. Batteries charged but never had their stated capacity. I got sick of it and built my own and even the cheaper nimh batteries now have good run times.

 

[Modelworks]

My dad says that also works with car batteries. If the car battery doesn't take a charge, hit the charger's 100A boost for a second then try.

That is very risky. There are two way lead acid batteries fail, a short develops between the cells due to build up of sulfur deposits or the plates themselves fail.
If the failure is due to a short from sulfur deposits then a large current could burn out the short or cause a plate failure. If it is a plate failure a large current will only make the short worse . The proper way to do it is with high frequency pulses over a long period of time. The pulses cause the plates to vibrate and over time knock the sulfur crystals loose.

 

[ShawnD1]

Charging rates are measured in C/unit of charge. If the battery is a 2000mah then the options for charging rates are:
C/10 = charge at 200mah for 10 hours
C/3.3 = charge a .6Ah for 5 hours
C/1 = charge at 2A for 1.5 hours

Anything less than a 1.5 hour charge time for a cell is destroying the battery. The reason for the 1.5 hour charge time for C/1 is because nimh are only 66% efficient, for every 100 units you put into it, you get 66 back.

I have a little chart of battery stuff on my cubicle wall. It says quick charge time for a NiCad battery is 1 hour. NiMH is 2-4 hours. Lead batteries 8-16 hours. Lithium batteries quick charge in less than an hour.

Overcharge tolerance:
NiCad = moderate
NiMH = low (do not overcharge them)
Lead = high (overcharge as long as you want)
Lithium = extremely low; overcharge and trickle charge both cause damage

The overcharge thing is why you don't want to have a cheap charger for NiMH. You can do that with NiCad batteries and it's fine, but overcharging damages NiMH batteries a lot more.

 

[KingstonU]

Ok now I am thinking it must be the camera (shitty Canon A560 from work that is like ~5-6 years old). Any batteries I put in it die within 5 minutes. New Alkalines, charged NiMH, whatever, they die almost right away. Is this possible? I tried scrapping the battery contacts and still same... So do I need a new camera?

 

[ShawnD1]

It's possible the camera has a very narrow voltage range that works. Instead of running down to 1.0V, it runs to 1.2 then stops? New camera.

 

[KingstonU]

I am just surprised that that this seems to have happened suddenly. Maybe the camera suddenly developed a short somewhere that drains the batteries or it got accidentally knocked around? Sigh now I have to go camera shopping...