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Battery Storage

Published : 24th April 2004


I know I've seen this information printed in either the Focal or the Samuelson books...but I cannot find it at the moment.

Question : In between shoots, what is the best condition to store your camera batteries?

I seem to remember that Ni-Cads want to be in a state of discharge whilst LA gel-cells like full charge...or is it vice-versa? And, the term 'storage' doesn't mean long periods...maybe a few weeks or a month at most...or, for such a short period, does it not matter?

Anyone?

Cheers,


Jeff Barklage, s.o.c.
US based DP
www.barklage.com
view reel  :  www.reelsondemand.com



Leave 'em charged. Dead batteries eventually go really dead, for good.

With NiCads, what you are trying to avoid is the dreaded "Memory Effect". That happens when you constantly re-charge partially used batteries. Eventually, the battery "remembers" the partial discharge as a full discharge. Reason : [I think] the battery grows large crystals in a partial charge, which are harder to "melt" to create electricity [if I remember correctly.]

The fix : Try to use the battery until its discharged before changing it. Or : discharge the battery before recharging it.

Lew Comenetz



>With NiCads, what you are trying to avoid is the dreaded "Memory Effect"

There are a few companies that make Ni-Cad DEMEMORIZERS and they can do wonders to bring back a battery or even a cell that was thought to be gone for good. Its a somewhat expensive investment but in a pinch it can save a shoot if conditions cause you to wind up with a dead Ni-Cad or two.

Jeffery Haas
Freelance editor, camera operator
Dallas



As far as I know nicads are lasting longer if they are left at full charge. To accomplish this we used to build special chargers that supplied a very small amount of current, nominally C/100, where C is the shell's nominal capacity in Ah and the outcome is in Amperes. So for a 12V/7Ah battery the current for long term storage would be 12V/70mA.

As far as know most modern battery systems and chargers accomplish this automatically. So if you just charge your nicads and leave them on your charger you will have the optimum storage condition. Of course you should check with the manual first.

Regards

Argyris Theos
DoP
Athens Greece



>With NiCads, what you are trying to avoid is the dreaded "Memory Effect"

>Its a somewhat expensive investment but in a pinch it can save a shoot >if conditions cause you to wind up with a dead Ni-Cad


We used to drain the Ni-Cads with an automotive light bulb. In some cases, several bulbs in series. Rejuvenating PDQ, very cheap.

Robert Rouveroy csc
The Hague, Holland

I plan to live forever. So far, so good.



Robert Rouveroy wrote:

>We used to drain the Ni-Cads with an automotive light bulb. In some >cases, several bulbs in series. Rejuvenating PDQ, very cheap.

This topic has been covered before. Discharging is not the same as "draining".

If you completely drain a NiCad you stand a good chance of damaging it.

Discharging means only discharging to about 1 volt per cell or thereabouts (depending on a lot of factors, if in doubt, consult your suppliers).

I know there are battery manufacturers/suppliers who subscribe to this list.

Maybe they could comment?

Andy Taylor
Camera Engineer
Arri Media
3 Highbridge
Oxford Road
Uxbridge
Middlesex UB8 1LX
UK
www.arrimedia.com
www.arri.com



>We used to drain the Ni-Cads with an automotive light bulb. In some >cases, several bulbs in series. Rejuvenating PDQ, very cheap.

Andy, you're absolutely right. We used to discharge until the light bulb went dim. Otherwise the polarity 'might' reverse. Unfortunately, there were no new-fangled gismo's to (expensively) drain the Ni-Cads at the time I'm talking about. Anyway, replacing shot batteries were relatively cheap. We managed.

This is what I meant by bringing up old stories, "at best irrelevant but harmless, just distracting" . To acquaint newbie’ s among us to appreciate that in a pinch, they CAN fix things in the field. To bring up a hashed over subject of a month ago : I feel that any person in training for AC or DP, should be able to solder up a connection between a camera and a battery. The advice to BUY a cable was wrong.

Robert Rouveroy csc
The Hague, Holland

I plan to live forever. So far, so good.



Andy Taylor writes :

>This topic has been covered before. Discharging is not the same as >"draining".
>If you completely drain a NiCad you stand a good chance of damaging >it. Discharging means only discharging to about 1 volt per cell or >thereabouts.


Gospel.

To learn about rechargeable batteries, battery chemistry, and charging/ reconditioning methods go to  www.cadex.com

To learn more than you probably want to know about the above, buy Isadore Buchman's book at the same site.

Brian Heller
IA 600 DP