Discharging batteries

[sixtycyclehum]

I usually take about 3 Anton Bauer bricks with me at the beginning of the day...they charge up to about 16.2 and when I'm done shooting I usually leave my camera and frezzi (powered by the brick) on and let them discharge all the way before putting them on a charger.

Talking to another photog today, I discovered I'm the only one in my shop that does it. I always thought that the battery's memory is affected if you just stick it on the charger at half charge. Did I hear wrong?

Keep in mind, I'm coming up on 1 year shooting news...

[PhotogFromFL]

It all depends. I sometimes put mine on w/a half charge and they seem to work fine. I've heard in the long run(2-3 yrs) is when you really might start seeing them drain quickly if you don't run them all the way down.

[2000lux]

Do you have one of those chargers that will discharge the batteries completely before it charges them? Check the charger, manual, or with the manufacturer. It may not be necessary for you to do the draining.

[WHIZkid]

If you're still shooting with old school Ni-Cads, you're do'n the right thing.... Those things did develop crazy memory.
But,,, with today's new and impoved elaments, and "smart chargers", this shouldn't be a problem.

[Tazof99]

I shoot with Anton Bauers. Every so often they "Auto Callibrate" themselves to (I assume) reset the memory. There is also a reset button on the battery.

I've never waited for them to drain entirely. I've had them for about 3 years now, and I am JUST starting to see 'signs of age.'

[canuckcam]

Over-discharging the cells to less than 1v per cell would probably damage the battery more than having a bit of memory, then putting it on a conditioning cycle to make it 'forget.'

[Shaky & Blue]

Originally posted by sixtycyclehum:
... when I'm done shooting I usually leave my camera and frezzi (powered by the brick) on and let them discharge all the way before putting them on a charger. DO NOT DO THAT. YOU WILL VERY LIKELY DAMAGE THE BATTERY.

What you're doing is called overdischarging the battery. A battery has to maintain a certain voltage level in order to be able to accept a charge. Thus, a discharged battery actually can still provide power. The problem is that if you go below the discharged state, the battery begins pulling the power out of its own materials to produce the charge, effectively destroying itself and reducing its ability to hold a charge in the future. That is overdischarging.

Most modern camera batteries are considered discharged somewhere around 10v or 11v. Your camera will therefore shut off at, or just before, the battery reaches a fully discharged state. A light, however, has no shutoff point and will continue to pull power out of the battery while it eats itself, until the resistance of the filament is greater than the current and discontinues the circuit. That's a very, very low level. If you do this frequently, you WILL destroy the battery's ability to hold a charge.

The reason people usually believe they should discharge a battery is because of "memory." If a battery is consistently discharged to the same level (above the fully discharged voltage), the battery's power curve can change so that it drops off drastically when the battery reaches that level of discharge. But in order to develop a memory, you have to consistently discharge it to the exact same level, which is very unlikely the way we use them. Further, the electronics in the Anton Bauer chargers maintain the batteries such that memory is not an issue.

The chargers will also rejuvenate an overdischarged battery, but they can only help so much. You may notice that your batteries take a lot longer to charge than everyone else's. If so, that's because your charger is trying to fix the damage you've done to the battery before it starts the charge cycle. Eventually it will just get stuck in rejuvenation mode, and the battery won't charge at all.

Anton Bauer recommends NOT discharging the batteries, but simply putting them back on the charger and leaving them there when not in use. They say you CAN discharge them periodically for "diagnostic purposes," such as when a battery starts having trouble holding a charge and you want to force the charger to go into diagnostic mode to optimize the battery's performance. But even then, they say not to discharge it more often than once every six to eight weeks, and they say NOT to use a light to overdischarge it.

So stop it.

[Deaf and Blind]

AB batteries are the only battery on the market with a three year warrenty.
As far as I am concerned you put the battery on the charger irrispective of how much charge is in it, even if the fuel gauge says full as AB recommend you leave them on the charger unless actually using them.
They do have a microprocessor which regulates each cell, keeps a history and should you go get the software you can plug the charger in to your computer and download the whole life of the battery it's serial number and construction date!
I just chringe when watching some cammos and how they treat what is a superb piece of battery engineering.
But like most people if your not buying the equipment then it's cost is of no concern until such a time as said unit meets an untimely death and your told sorry mate no budget to replace those this year.

[SimonW]

I'm not sure of the other batteries, but doesn't the AB Dionic series protect itself from over discharge?

[svp]

I remember reading somewhere (it might have been our photog employee handbook) never to discharge the batteries completely. Never said anything about putting a battery on the charger at half charge though.

[Sportsguy]

I've always been under the impression that a battery's "memory" was caused not mainly from over-discharge, but damage from overheating on a charger. Am I wrong?

[Deaf and Blind]

The whole "battery Memory" thing is more a mis-match between the rating of a battery and the application to which it's applied.
Cheap arse manufacturers using batterys poorly rated for the application plus older battery technology has given raise to this myth.

Think of it this way...
Go take a perfectly good MP1 then flick the camera voltage over to say an Anton Bauer setting in the software. It will run for a short while then the camera will beep it's t!ts off saying low battery but you know the cell is good.
It's that sort of analogy.
Hope that makes sence?

cheers
D&B

[Shaky & Blue]

Originally posted by SimonW:
I'm not sure of the other batteries, but doesn't the AB Dionic series protect itself from over discharge? Yes, that's true. The electronics in the AB dionic batteries do protect from overdischarge. It's in the manual (http://www.antonbauer.com/downloads/MANUAL_DIONIC_90.pdf).

For that matter, Anton Bauer has all its manuals online (http://www.antonbauer.com/downloads.asp), so there's really no excuse for any of us not to have read the manuals for our camera batteries so that we know how to take care of them.

Originally posted by svp:
I remember reading somewhere (it might have been our photog employee handbook) never to discharge the batteries completely. Never said anything about putting a battery on the charger at half charge though. With the AB chargers, it shouldn't matter whether you put it on there without fully discharging it. Even the older, simpler chargers monitor the battery's health to some extent and charge or discharge them as necessary.

Originally posted by Sportsguy:
I've always been under the impression that a battery's "memory" was caused not mainly from over-discharge, but damage from overheating on a charger. Am I wrong? Memory doesn't have anything to do with either. Memory is caused by repeatedly and consistently discharging the battery to the same level, above its fully-discharged level, so that the battery begins to behave as though the memory point IS the discharge level. Since we rarely discharge a battery to the same level twice in our application, memory really isn't an issue for us.

Where is it an issue? Let's take D&B's scenario:

Originally posted by Deaf and Blind:
Go take a perfectly good MP1 then flick the camera voltage over to say an Anton Bauer setting in the software. It will run for a short while then the camera will beep it's t!ts off saying low battery but you know the cell is good.
The settings in the camera software for the different kinds of batteries have to do with the normal voltage levels of the batteris and their discharge levels. An NP-1 has a different discharge level from an Anton Bauer, so if the camera is set for the wrong kind of battery it may flash a warning or shut off before the battery actually reaches its discharge point. The camera could keep running, but it thinks it needs to shut down to protect the battery from overdischarge.

In that case, the camera will shut off at the same discharge level every time. If that's done repeatedly, the battery will develop a memory at that point, and the power below that level will be harder to get. Thus, in that situation, running down your batteries every day on the camera will actually create a memory, since you're forcing the camera to take the batteries to the memory point yourself.

If you just put them on the charger as they are instead, you're less likely to run them to the same point, and a memory problem is highly unlikely.

[sixtycyclehum]

Whoa! So I could actually be damaging the batteries...crud. I'm gonna stop doing that then. We all share the same batteries and chargers in my shop and I don't want to destroy anything.

By the time I get them on the charger they're usually at about 13.5 (I get a BATTERY END warning) so the batteries are never so drained that the camera turns off.

I've just noticed that sometimes I'll get a fresh battery that reads READY off the charger and it'll only have 14.5 on it. If I discharge the same battery (to about 13.5) and stick it back on the charger, the next day it'll have 16.2. SO I thought I was doing something right...better check out the manual. Thanks Shaky!

[canuckcam]

Interesting... well, for NiCad and NiMH batteries (ProPac/TrimPac/Hytrons) ... those cells should never be lower than 1v/cell. Thus at 1.2v/cell x 12 cells in a pack, the brick should never reach below 12v... ever. Set your low-battery warning accordingly (if you can.)

For 12v NP-1's, there are 10 cells per bar, which means discharged at 10v. However, most cameras do a hard-shutoff at 10.5v or 10.7v. That means the NP-1 is not fully discharged but cannot power a camera. That's where the whole "memory" thing came into play - consistently running the bar only to say, 11v when the "low battery" warning triggers, the battery will eventually charge only to 11v.

Newer NiCad batteries should not be easily susceptible to memory problems at all. I have (personally) two Aspen NP-1's that are 14.4v and they've said it has no memory effect whatsoever. Powers my camera great, with my 70IS/BVV5 and no voltage readout, the unit is permanently configured for a 12v battery, so with the 14.4v discharge curve, once it hits the BVV5's "low battery" warning, I've got about 10 seconds of juice left. :(

[dinosaur]

I agree with "Shaky", depending on the brand and model of the camera, it should have a menu item to adjust the low battery "cut-off" level to 11.5v. Your low battery indicator should not be blinking on until the battery has reached a level between 11.5v to 11.9v. This prevents the camera from over discharging the battery. If your low battery indicator is blinking at 13.5 volts while drawing a normal wattage load, then your camera menu is the culprit, not the battery.

[Tim78]

sixtycyclehum,

Does this mean ALL of the cameras now have frezzi lights? I wish it was that way before I left!

[2000lux]

I've got an IDX i-400 charger and NP-1dx 12.2V 2.0Ah batteries. Is it ok to leave the batteries on the charger to trickle charge when I'm not using them, or should I keep them off most of the time? While I haven't been using them much I've been keeping them off the charger, and then discharging and recharging them once a month or so. I'll be using them more often soon and I'd like to be able to keep them ready to go. The manual is kind of unclear on this.

[sixtycyclehum]

Originally posted by Tim78:
sixtycyclehum,

Does this mean ALL of the cameras now have frezzi lights? I wish it was that way before I left! Hey Tim! No, just your's and scott's camera have frezzi's that connect to the battery plate...everyone else has to use those BP90's ;) . I just get the pick of the litter though cuz it's just me, Rameen, and Nevin on the weekends. How's Green Bay so far? Any progress on the tape ball?

[Run&Gun]

Run 'em down before you charge 'em. Even if you have a charger with a DDM that can auto calibrate them, it still charges it before it discharges and charges it again, so the damage is still being done. I shoot with Hytron 120's, and I have one(my first one) that I know I didn't run down all the way a lot before I charged it when I was in a hurry and now I'm having shorter run times(probably 45 min. to an hour less, at least) and sudden voltage drop-offs(It'll indicate 1:00 to 1:15 left and it'll die in 15 mins). It's about 2 1/2 years old, so I'm trying to see if A/B is gonna do anything.

A/B used to make a stand alone piece that would discharge batteries safely to the min. voltage point that wouldn't damage the battery.

[ May 11, 2005, 01:49 AM: Message edited by: Run&Gun ]

[Tim78]

Hey,

Is everyone using the BP90's to use the frezzis or are they still shooting interviews without light?

GB is going good.

No progress on the tape ball...I haven't brought it into work yet. How about the tape ball I left behind at the station? Are you guys working on that?

[skeyworth]

To anyone who wants one, I will send the Anton/Bauer Video battery Handbook. The is no charge for this.

Just call A/B at 800.422.3472 and ask for Scott.

It will basicaly expand on what "Shaky" has been saying

[Run&Gun]

The Video Battery Handbook can also be downloaded off of A/B's website.

[Tippster]

Originally posted by Tazof99:
I shoot with Anton Bauers...There is also a reset button on the battery.Really? Where?

I've never discharged my bricks. My coworker always does, despite the fact that the manufactureer says NOT TO DO SO (especially with the Logic chargers.)

He gets his batteries replaced more often than I do and gets yelled at by our engineer. Seems simple to me.

[McColl]

Originally posted by Tippster:
quote: Originally posted by Tazof99:
I shoot with Anton Bauers...There is also a reset button on the battery.Really? Where?

On older AB ProPac batteries, there's a very small yellow dot on the front of the case. The button is behind that dot, and can be pushed with a pin or paper clip.