Sony Digital Camera Forums

Digital Photography Technique => Digital Darkroom => Topic started by: Clive on September 30, 2005, 05:43:02 PM

Title: NP 400 battery
Post by: Clive on September 30, 2005, 05:43:02 PM
I understood with older Li-ion batts that they should be discharged fully before recharging or else they get "memory" and only partially recharge afterward. Now I read somewhere NOT to fully discharge the batts.

My question: Is it okay to recharge a half-drained NP 400 Li-ion battery?

Some days (tomorrow) I want to head out with a full batt and yet am scared to charge it if only partly drained. (I only own one NP 400 and should have two...I do have vert grip with LiMH rechargeables, so am covered .. still.)


Title: NP 400 battery
Post by: digital master on September 30, 2005, 09:33:05 PM
As far as I have been led to believe by our techies at work the Li-ion battery has never suffered from the memory effect, hence their use in mobile phones.

The original Ni-Cad used to suffer badly and to a lesser extent the Ni-Mh.

Hope this puts your mind at rest Clive
Title: NP 400 battery
Post by: ISO3200 on September 30, 2005, 11:46:56 PM
You just charge them as you wish, I top them up before going out, no harm done. Takes a few minutes, not 2 hours; the charger must sense when they're done.
Title: Thanks!
Post by: Clive on October 01, 2005, 02:41:32 AM
Thanks for the info. Much appreciated. Now I feel better. It's in the charger.

As noted, I am off to "teach" my outdoor photog class tomorrow and we will be shooting (and talking and showing) for 6 hours outdoors. The students expect me to take pix so I wanted a fresh batt. We have a review meeting in 12 days so I have to hold up my end of  the deal ... basically answering the question: Under the same circumstances as us, can the teach actually take pictures? :)

It will be a a fun day.

Title: NP 400 battery
Post by: Akshay Jamwal on October 01, 2005, 06:32:38 AM
I've read that it's actually better for the batteries if you recharge them often. Apparently they live longer if you recharge them regularly and don't let 'em discharge completely, whereas NiMH works the opposite way.
Title: NP 400 battery
Post by: Stäck on October 07, 2005, 10:05:43 PM
Lithium-Ion (and Lithium-Polymer) do not have the same kind of memory effect as Nickel-Cadmium had. They do, however, have something of the opposite. Every time a LiIon is fully discharged, it loses a little bit of it's maximum capacity. The general advice for them is "charge early, charge often".
LiIon cells degrade over time (less if they're stored discharged in a cool place), so use them while they're fresh.
Title: NP 400 battery
Post by: ISO3200 on October 07, 2005, 10:53:13 PM
The guys in white coats are working on 'Hydrogen' batteries these days, someone I know is involved in making them commercially viable. They say 10-hour laptop use, not 2 hours. Maybe they'll be in cameras ten years from now?
Title: NP 400 battery
Post by: Stäck on October 09, 2005, 01:31:58 AM
We will probably see new battery types show up every few years. Battery technology has made quite big advances in the last few years, and will probably continue on for a while.
Camera batteries today aren't very much of a problem, generally. You can take a couple of hundred pictures, and it's practically possible to have a couple of spares. Any new battery technology will probably first show up in applications like laptops and cars, and then possibly things like cameras and mobile phones. From what I heard of hydrogen cells, they may not be very suitable for small, low-power applications (like cameras). But who knows what will be invented in a couple of years...