Dead NP-F960
 

Well one of the two NP-F960 batteries I bought in September 2001 seems to have died. When I put it on the camera and plug in the charger I get a hollow battery icon and no time is calculated. The other battery charges as expected, and my PDX-10 batteries also charge fine with the same Sony charger.

I haven't actually used my VX-2000 under battery power for quite some time now, and this battery was fine the last time I tried. Now I always assumed that there was no problem leaving the charger plugged into the camera for extended periods, thinking the battery would shop charging when full. But could this be the problem? I really have not used these batteries all that heavily, and use the VX-2000 primarily as a deck these days.

Whether you can leave them plugged into the charger really depends on the charger. I have some chargers that get the batteries warm and keep them that way. Others that charge to full and then shut off.

In one of my manuals, I don't know which one, they recommend not leaving the battery on the charger for more than a few hours after reaching full charge.

I just searched the VX2100 manual and all it says is to stop charging after the battery is fully charged but it doesn't say anything about why.

I never leave batteries on more than a couple of hours beyond full charge except in those chargers I know shut completely off.

Just looked in the VX-2000 manual and it also says to disconnect the charger after the battery is full, no reason. I'm using the original Sony charger that came with the camera. But it doesn't seem too likely that this is the problem as I have left the charger connected to the camera for months at a time during the past 2 and a half years without problem. All things considered though, guess I'll leave it unplugged after charging from now on...

I have found that most chargers keep trickling a charge after they appear to have shut down the main charging cycle.
For me, this has led to reduced battery life, both immediately and longterm. I always pop the batteries off as soon as the main charge is finished and they perform better. It would appear that trying to ram more charge into a battery after its main cycle is finished, is counter-productive and actually reduces its capacity. In-camera chargers keep laboring away for a long time, to put those extra few minutes on the running-time meter. I think it's best to take them out when they've reached near their top capacity and the increase slows to a crawl.

I use several old Ni-Cad and NiMH batteries and one Li-Ion to power my powerful, dual bike lights. This gives a good measure of how long a charge lasts on a steady and continuous draw. When I have left them on their chargers too long, they don't last as well. This is a handy way to extend the usefulness of old camcorder batteries. They have lost enough voltage capacity to quickly drop them below a camcorder's auto shut-off level, but have plenty left to run lights in a reduced voltage range.

Steve McDonald

Even on the most automatic charger made by Sony, they state that it takes an additional hour to reach maximum capacity after the battery is charged fully (GO FIGURE THAT ONE OUT). I have a 3rd party charger with instructions that say the same thing.

Problem is, none of them indicate when the additional hour has elapsed.

Mine always come off the charger when the indication mechanism say's, 'Charged.'

I have LiOn batteries I purchased nearly 10 years ago with a Hi-8 camcorder that are still going strong.

Boyd, I have another thought about that NP-F960. On an older Sony digital camcorder, I'd sometimes use a battery down to its last bit of power. When I put it back in the camera later, plugged in the AC adaptor and left the camera off, as you do to perform an in-camera charging, I'd notice this: The battery, being fully-drained, had to sit in this charge cycle for 7 or 8 minutes, before anything showed in the empty battery icon or any number appeared in the time-remaining counter. You may have to leave a battery in the charge mode for this long, to see any results, if it's fully discharged.

I recall that I once had a tempermental stock charger, that came with a camera. If a battery had been discharged down to even 1/4-volt below the camera's shutoff level, this charger wouldn't start charging it. I got an after-market charger and it worked no matter what the battery's discharge level was. A Sima SPM-13 charger is my way of getting all my Sony NP-F batteries quickly and dependably charged and saves having to use the camera.
http://www.simacorp.com

Interesting, but I think it's really dead since I left it on the camera for days and it wouldn't charge. But I also have an external charger (somewhere!). I'll dig it out and see if that will charge it, but really don't have a lot of hope at this point. Thanks for the suggestion though, it's worth a try!

Some batteries can build up after a long period of inactivity and/or deep discharge a kind of microscopic internal isolation barrier which can be broken down by applying on the battery a sufficient overvoltage (current limitted) during some time . What I suggest for the 960 is to put it for a couple of minutes on a 12v DC source with a serial resitance ( like a 5W 12v bulb) for current limitting. Or like I do, if you have a stabilized DC power supply with adjustable current limitter you can put the battery for a while on 12 to 24 V and set a 100mA limit.

Ha, ha, that reminds me of my dad, who passed away several years ago. He was an engineer who was rather eccentric and he loved to tinker with things. One of his scary gadgets was a HUGE capacitor that he would charge up, connect to dead NiCAD batteries and then zap them with the high current discharge to break down the barrier you describe. He rigged some sort of shield just in case they exploded. But don't try this at home kids! ;-) I thought this effect was limited to NiCAD batteries though, while the Sony's are L-ION?

Well known for Nicads indeed, but all conductive materials when sticked together (like in dry batteries) and passed by a small current under a low voltage get barrier effects (exception is gold/gold). This has nothong to do with the electrochemical behavior of the battery. So if the battery seems lost there is nothing wrong to advise your "kids" to try the condensor or overvoltage suggestion before throwing it away. Although I only wanted to suggest what to do with a dead batt, there is maybe more to say on Lithium-ion batteries and some posts in this thread: LI-ion batts are very critical w.r.t. of end of charge voltage and if you want them ruined in a very short time you only have to keep them for a few days on a 10mV overvoltage! That's why it's so unpredictable wheter you can keep them charging all the time...cheap charger output voltage which reach the 10mV overvoltage tolerance. Some other (depending on the internal control chip) keep current controlled overvoltage pulses as a trickle charge. The latter chargers tend to save "dead batteries" because of the overvoltage braking down the barriers but these are not advised to keep the battery on all the time.

When I worked on the repair bench for Tektronix, we 'fixed' bad nicads by briefly connecting them across a 12 volt car battery. This was done with the bare end of a wire that we flicked across the battery terminal. This worked about 50% of the time.

The capacitor would be a better choice. I'm not certain it has to be something like a 1000 farad capacitor to do the job, though.