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Rechargeable batteries


jacquesstar

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I have Ansmann 2800's for my lav transmitters. I re-charge them after use, but sometimes they sit in the box for a few days. The literature says that they should hold the charge for 3 years, but I am not sure about this, should I put the charged batteries back on the charger the day before the shoot if they have been sitting around for a while? Or, am I okay with using them a few days after they're charged?

Thanks!

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I use Ansmann Max-e batts and they hold their charge for a few days. Kind of Ansmann's ''eneloops''.

The other models don't hold their charge the same way. I'd top it too.

I ditched all my Ansmann 2850 batts for these 2500 that hold their charge exactly for that; they hold their charge. Now when I go out for a three day gig, I (most of the times) don't have to charge every night for the whole time; got quite a supply. ;)

PS: my guess about that litterature that says ''3 years'' is that it's 3 years of service... ie; you should be able to charge'em for three years and they'd be usable. But after 3 years of intense use like we do it (not for a light saber that'll go in the closet 3 weeks after christmas), my guess is that it won't be more than 700mAh 'ish after a charge.

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It depends... (thanks Senator) . Sanyo Enloops and Rayovac Hybrids do not 'self-discharge' like 'normal' rechargeable batts. Rayovac 'claims' less than 15% discharge after a year.. I have not checked this, but I'm skeptical... otherwise my Enloops and Hybrids can be charged weeks before use w/o any noticeable self-discharge issues.

I don't know about the Ansmann self-discharge rate.

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The current physics is that the higher the capacity, the less shelf life they have to hold charge. They all work *basically* the same.

Somebody explained it sorta like this: imagine taking a tortilla and covering it with peanut butter. The Tortilla is the insulation, the peanut butter is the materiel holding the charge. you coat the tortilla, then roll it up. That's what is inside a AA battery. That's why the high capacity AA batteries are actually bigger in diameter, they are pushing the specs of AA size. That said, the size of a AA is a fixed limit, so to fit more peanut butter, they use a thinner tortilla. The reduced insulation is why they don't have the ability to hold charge when on a shelf. That's why some of the eneloops can hold a charge for a year, but the 2700 or 2800 batteries will drop off in days.

There is enough competition for high power AA batteries that they are constantly getting better. My 2700 Powerex batteries lose power after a few days, but their newer Imedion series 2400mAh batteries claim a longer shelf charge (and come charged).

The black eneloop XX 2400 batteries are also a balance between capacity and shelf life.

These are the specs on the battery itself, so I don't know what the real world difference is in a Lectro SMQV between a battery labeled 2400mAh and 2750mAh. I should run some tests, but my 2700 Powerex's are at least a year old, so that could matter too.

BTW if you go all rechargable, I would invest in some about 2000mAh, like the white eneloop 200mAh ones. The bigger ones can get stuck, or are a tough fit in things like a 442, Ambient lockit, Denecke SB-3, Denecke slate battery holders. Those devices will still last way more than a work day on the lower capacity batteries. The sync boxes and slates will probably go a few days if you turn them off overnight.

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The tortilla/peanut butter analogy is nice, but flawed, the reason some batteries (eneloops etc) keep their charge longer is primarily because they use entirely different chemistry to 'normal' rechargeable cells, yes, the high capacity cells use thinner tortillas but that's as far as the analogy stretches.

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  • 1 year later...

Senator, thank you for the notice-it was a more definitive source on the diameter than the ansmann.de site itself.

 

Because this thread lost a bit of wind I thought I'd share this link http://cpc.farnell.com/batteries-rechargeable

 

You'll notice that battery choices can be filtered by diameter, capacity, size, voltage...and you can specify a functioning range to search within. Do appreciate that these measurements may not be as accurate nor precise as the ones volunteered on our forum, and that the site may not carry all manufacturers. So it's not really a database of measurements. But it is the only site that I found with product pages that cover physical size.

 

My conclusion for my SD302 after looking at a number of topics on our site here, is to get the Ansmann Max-e Slim Line 2500 mAh. 5035442 (but in the slim shape, which shaves .15mm off the diameter). I just don't know enough about the length dimension of varying equipment that I will need in the foreseeable future, so I solved things for now. Sound Devices specifies their battery tube at .6 inches with a .005" margin of error, which to me is better to think of expansion and contraction rather than a manufacturing error. I took this dimension and subtracted the range of change, and converted into millimeters. Then from out existing findings I concluded in mm's what I needed for an acceptable wiggle room. It's the swelling of the batteries that is the real concern here. I used this number as my maximum diameter when comparing results.

 

Even if I'm not reaching the highest ratings, I do like the idea of using the Max-e technology, even if it simply means that I can charge things at my convenience, rotating them out on the set, or getting a good night's sleep without ruminating whether I'll wake up to swap anything out in the middle of the night. I'm really echoing the opinion of another fellow on the boards here that came to this conclusion. And maybe they'll be good for the odd occasions when a friend is in a pinch that day, or a crew on the street that I'm familiar with says "hell ya we're stuck can you run back with your gear?" (That never happens to me. It's a fantasy).

 

The Maha Powerex 2700's were comparably slim at 14.4mm, for those simply chasing after maximum capacity and compatibility with the 302 and 442. And they throw in bundled packs along with nifty cases. I just liked my choice more after seeing how you guys measured it against the eneloop and punching in my own numbers.

 

It's really a different topic, but I'm okay with loosing the best capacity ratings currently if instead I can time with confidence when I'm swapping my batteries out. With my make-shift set up, I could conceivably have gotten varying capacity for different items, based on their drain,  shaved some money, and still plan to do a full swap-out at particular times of the day. That's in part what takes all this guesswork out of a proper distribution system. But my rag-tag gear doesn't warrant that kind of investment.

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  • 8 months later...

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