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Battery "Memory"


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#1 Marty Hamrick

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Posted 21 May 2007 - 03:55 PM

I was just wondering if with all the technological advancements with batteries and chargers if it was still advisable to fully drain a brick battery (we use Anton Bauer Propacks) all the way down before you charge it.It's always been standard procedure wherever I worked in a shop with a fleet of cameras and bricks.I was always told that if you used one for say,only 15 minutes before recharging,the battery would develop a "memory" and only be good for 15 minutes the next time it was used.Is this still the case or are we following an outdated and unnecessary procedure?
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#2 Brad Grimmett

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Posted 21 May 2007 - 05:04 PM

I use the discharge/charge feature I have on my charger. I don't use Anton Bauer's though. I use custom batteries with a PAG charger. I think AB chargers may do the discharging/charging for you. Or maybe it's only the newer versions? I know that Nickel Metal Hydride and Nickel Cadmium have more memory than Lithium Ion's. I believe the NiCad's are the worst (which is what I have).
Which batteries are you using Marty?
I think in general the newer the battery the less memory problems you will have. But that may just be optimism on my part....
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#3 Marty Hamrick

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Posted 22 May 2007 - 09:35 AM

I use the discharge/charge feature I have on my charger. I don't use Anton Bauer's though. I use custom batteries with a PAG charger. I think AB chargers may do the discharging/charging for you. Or maybe it's only the newer versions? I know that Nickel Metal Hydride and Nickel Cadmium have more memory than Lithium Ion's. I believe the NiCad's are the worst (which is what I have).
Which batteries are you using Marty?
I think in general the newer the battery the less memory problems you will have. But that may just be optimism on my part....



I'm using the Logic Series Nicads.The chargers don't have a drain feature.What we do generally is drain them by leaving the camera and on camera light on until it drains.
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#4 Brad Grimmett

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Posted 22 May 2007 - 03:39 PM

I'm using the Logic Series Nicads.The chargers don't have a drain feature.What we do generally is drain them by leaving the camera and on camera light on until it drains.

That seems like a good plan. My understanding is that it's better to drain the battery quickly than it is to drain it slowly. This method is probably giving the batteries some extra life.
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#5 Daniel Sheehy

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Posted 22 May 2007 - 04:30 PM

My understanding is that the memory effect was more a feature of the older NiCd batteries.
This is supposed to have been eliminated with the Li Ion batteries, hence the removal of the drain feature from the chargers.

I use Sony Li Ion packs for a Betacam, and while I make every effort to use each battery dry, most of the time the batteries go onto the charger with a little juice left in them. I have yet to see any harm done to them by this.
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#6 Rob van Gelder

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Posted 23 May 2007 - 02:53 AM

Guys, the memory effect is still there, the basics of the chemistry is not that different from a few years ago, but our working practices and demands are.
That has lead to using higher voltage battery packs, like 13.2 and 14.4 volts and these packs work much better in battery operated equipment.

The reason is that most of the electronic equipment has a cut-off voltage around 10.5-11 volts. If you use a 10 cell NiCd pack of 12 volts, it means that you have not drained the pack completely (or more than say 70%) when the equipment stops operating. Then recharging means that the batteries "empty-level" will rise and you can charge only that amount that you took out.
Effectively and certainly after some cycles of small discharge and full charge you'll find that the usable capacity is lower that the original rating.

This is the memory effect.

Now with the newer 13.2 and 14.4 batteries, you will (normally) always discharge the cells fully to approx 0.9 -1.0 volts before your equipment gives a battery warning, that is the best situation . You can still abuse and introduce memory effect in higher voltage NiCd packs if you discharge only 20% and charge fully, several times.

NiMH and Li-ion have according to the manufacturers much less or no memory effect, but have also other drawbacks.
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#7 Michael Collier

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Posted 23 May 2007 - 04:02 AM

case in point that even newer batteries suffer from memory, I have seen just recently a NiMH battery (a 140 watt-hour anton bauer unit...quality pack) go bad in less than 5 months. I couldn't believe that it could happen so quickly. The photog responsible only shot a story or two a day, and after every shoot they would put the battery on the charger (I assume this is what happened, I cannot see how it could be otherwise.)

A cheap (though low quality) discharger can be built by putting 2-3 diodes in series along with either a high watt resistor of lower ohm value, or a lower wattage unit of high ohm value. The resistor limits the ability of the current to flow, and the diodes cut off the battery before it gets to drained (it takes .7v to bias the average diode, so three would cut off the discharge at about 2.1. a zener diode could also be used, with the reverse voltage being the cutoff) cost: about 3 bucks at radio shack, $.08 in wholesale. Add another resistor and an LED and you have a status indicator. Be careful of the ohm value of the resistor though, discharging too quickly can also damage the battery.
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#8 Alessandro Machi

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Posted 23 May 2007 - 05:46 PM

case in point that even newer batteries suffer from memory, I have seen just recently a NiMH battery (a 140 watt-hour anton bauer unit...quality pack) go bad in less than 5 months. I couldn't believe that it could happen so quickly. The photog responsible only shot a story or two a day, and after every shoot they would put the battery on the charger (I assume this is what happened, I cannot see how it could be otherwise.)


Don AB's have fuses somewhere on them, maybe the fuse has gone bad. Sounds like the battery would still be
under warranty, no?

It takes just one bad recharge to ruin a battery so I would not recommend doing unsupervised quick charges if you won't be around when the charger should be finishing it's charge.
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#9 Brad Grimmett

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Posted 24 May 2007 - 05:04 AM

Don AB's have fuses somewhere on them, maybe the fuse has gone bad. Sounds like the battery would still be
under warranty, no?

The fuses are right there on the back of AB's and are quick and easy to replace. I'm sure they'd know it if it was a bad fuse since the battery woulnd't work at all.
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#10 Alessandro Machi

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Posted 24 May 2007 - 02:30 PM

The fuses are right there on the back of AB's and are quick and easy to replace. I'm sure they'd know it if it was a bad fuse since the battery woulnd't work at all.


What about the Anton Bauers that have two fuses? Could the battery still work (but at a limited capacity) if only one of the fuses goes bad?
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