Charging a charged battery

[Ryan Piggott]

I had 3 batteries for my D70s at the very beginning, then 1 quickly died and wouldn't charge or give off any energy at all. Just recently my second battery did this as well, but it will last a whopping 1 minute unlike the other completely dead one.
Now i am down to one battery. Sometimes before going on a trip i will pop it on the charger knowing that i used the camera a little bit, and i didn't want the battery to die on the trip.
Is it bad to top off a battery if it isn't dead, or if it still has 3 bars?

 

[KmH]

There are several different kinds, and brands, of batteries.

What kind and brand a do you have? Lithium-Ion, Nikon? or aftermarket?

 

[Ryan Piggott]

well the two batteries that both quite, are cheapo's (emagine that). The batteries are unlabeled as to what brand they are. The one that never worked is a 3.7v (not much, maybe thats why) 1900mah Li-ion, and the one that just recently quite is a 7.4v 1900mah Li-ion.
The one that still works is a Nikon battery, i assume the one that came with the camera, it is a 7.4v 1400mAH Li-ion

 

[battletone]

Generally for a brand new battery you want to charge it full and drain it fully 3 times to condition it. After that you should be good to go.

But cheap batteries are cheap. Walgreens might re-brand other batteries, and that is fine if you use them and you like them...but for a camera battery where you don't usually have the ability to test out many batteries and the company is generally not know, its best to stick with something from a reputable source.

 

[Ryan Piggott]

yeah, i will only by nikon batteries when i get a chance to pick up a new spare.
But is it bad to stick a fairly charged battery, back on the charger to top it off?

 

[gpimages]

I have been shooting Nikon for about 3 years now. I have (2) batteries for my D70s and (4) for my D200 and D300. I always put them on the charger every time I get home no matter how much they were used. I have not had any failures.
Glynn

 

[battletone]

yeah, i will only by nikon batteries when i get a chance to pick up a new spare.
But is it bad to stick a fairly charged battery, back on the charger to top it off?

No. Condition the batter when you get it, then use as needed.

 

[icassell]

It was my understanding that NiMH batteries need conditioning but Li Ion batteries normally do not. Am I mistaken?

 

[Ryan Piggott]

Awesome, thanks

 

[musicaleCA]

It was my understanding that NiMH batteries need conditioning but Li Ion batteries normally do not. Am I mistaken?

No, you aren't.

Li-Ion batteries don't require much conditioning. You can use them as needed. The downside of Li-Ion batteries is higher resistance than NiMH (making them less suitable for flash units), and slightly lower capacities for the amount of space used (again, making them slightly less suitable for flash units). Neither of these downsides are problematic when using them in a camera body. The only time you need to do anything special with Li-Ion batteries is when storing them or not using them. It's important to keep current flowing through the battery occasionally; once a month as a general rule. So if you don't use the Li-Ion battery at all, it should be fully discharged and recharged once a month (meaning, roughly, it's good to use the battery for one complete cycle each month). If you don't do this, the battery's capacity will drop faster than normal.

Something else to understand about charging Li-Ion batteries is the voltage of the battery depending on how much of it's capacity is used. From 100-80%, the voltage provided is roughly equivalent to it's rated voltage (so, 7V for a 7V battery). As the overall charge drops, the voltage provided drops as well, roughly logarithmically. This means that as it nears 0% charge, the voltage provided drops dramatically. On the flip side, when charging, you can go from 0-80% very quickly, but to finish the charge will take roughly the same amount of time that it took to get from 0-80%. That just has to do with the physics of the whole deal; I'm not gonna get into that. You probably didn't need to know all this anyway.

The reason NiCad batteries need this "conditioning" is that after some time, if they are not fully discharged/cycled, they develop crystals inside the cells and the overall capacity drops. This is easily solved by cycling the battery completely every so often. So, for flash batteries (which should be NiMH if you're shmart ; Sanyo Enloops are among these), you shouldn't take them out and top them up all the time. Just carry spares and be sure to discharge them completely every once and a while.

Speaking of which, I have a few sets that really need a good discharge. Shoot.

 

[Garbz]

To go further, LiIon batteries require very sophisticated chargers. The type of battery chargers with cameras have all sorts of intelligent technology to prevent overcharging. Chances are if you put a full battery on a charger then it will do very little to it except trickle a tiny little amount into it.

Also the crystal problem isn't to do with NiMH batteries. These will also exhibit sudden death like LiIon batteries do, the crystals form in NiCad batteries. These can be sort of part reconditioned by fully discharging and fully recharging them. Or my fav trick, hit the battery with an arc welder, or connect the battery where the tube in a camera flash goes and put a gazillion jules though it :evil:

 

[musicaleCA]

To go further, LiIon batteries require very sophisticated chargers. The type of battery chargers with cameras have all sorts of intelligent technology to prevent overcharging. Chances are if you put a full battery on a charger then it will do very little to it except trickle a tiny little amount into it.

Also the crystal problem isn't to do with NiMH batteries. These will also exhibit sudden death like LiIon batteries do, the crystals form in NiCad batteries. These can be sort of part reconditioned by fully discharging and fully recharging them. Or my fav trick, hit the battery with an arc welder, or connect the battery where the tube in a camera flash goes and put a gazillion jules though it :evil:

BAH! Thank you Garbz for catching my NiCad/NiMH mixup. I'll change that. >.<

And yup indeed. As the charge in the battery goes up, the charger reduces the current going through the battery. Good thing too, since overcharging can result in explodey-ness. >.>