Ask MetaFilter questions tagged with batteries

Lithium battery capacity derating: C-rates

Green With You — Wed, 02 Dec 2009 21:39:15 -0800

Asking for someone else: is it possible to calculate or estimate the capacity derating of a lithium polymer battery when discharged at high C-rates? Or can this information only be obtained empirically or from manufacturer data? Does the capacity derating follow some sort of known relationship with respect to the C-rate?

Please help me build a motor scooter!

banished — Wed, 09 Sep 2009 15:32:13 -0800

Can you help me build an electric motor scooter? I have a bunch of old bike parts in a garage, so I should be able to put something together. I found a simple explanation here, but what I am looking for are specifics on where to get each of the materials (especially the motor, the batteries) and how the batteries should be wired to the motor and details on any power regulating circuit that needs to be built.

This is intended for a little kid, so whatever I build needs to be safe, and not TOO powerful.

recycling a degraded rechargeable battery

randomstriker — Mon, 10 Aug 2009 11:23:01 -0800

Laptop battery recycling: no nearby location will accept mine so far because it's degraded and puffed up. What are my options? I am in Vancouver BC. I have an Electrovaya Powerpad that has been sitting around for a few years, and over time I guess it has degraded and produced hydrogen gas that has inflated the casing.

I've been to all the nearby shops that recycle rechargeable batteries, and understandably they freak out when they see this. What are my options for responsibly disposing of this?

How is incoming charge distributed amongst multiple batteries wired in parallel?

gribbly — Mon, 27 Jul 2009 16:03:53 -0800

Say I have a three batteries (all 12V SLA of the same Ah capacity) wired in parallel to form a bank. I connect a dumb charging source (let's say 12V, 5A). How will the incoming charge be distributed amongst the three batteries, and what does it depend on? I'm keen to understand the principlesat work here. I've built several battery banks (largest was eight deep cycle marine batts), so I've done a fair bit of just plain trying it out. I'm not trying to enhance my theoretical understanding, so I can figure out what will happen in a simple situation like:

Battery 1: 100% charged
Battery 2: 50% charged

...Battery 2 will receive more of the incoming current. But how much more? Will it receive 100% of the current, with Battery 1 receiving 0%? That's my guess - and in fact I'm guessing that Battery 1 will be charging Battery2 in this situation, and they'll end up equalizing then charging in parallel.

If I'm right about that, how do I generalize to:

B1: 100% charged
B2: 75%
B3: 50%

...I'm guessing B1 and B2 will charge B3 until B2 and B3 equalize, then B1 will charge B2and B3 until all three equalize?

What are the key factors at play here? State of charge of the batteries has to be the main one, but... well any help appreciated. I've googled for info, and read the basic battery faqs, but none have helped me understand this.

Can I power my keyboard in 2019?

Brennus — Mon, 15 Jun 2009 05:32:19 -0800

Do batteries lose charge? I am thinking about buying a larger lot of CR2032 and AA batteries off ebay. I am probably going to need many years to go through them. Batteries usually have expiration dates, do they really hold most of their charge until then or do they practically become useless before that? Also, does anybody have experiences with buying batteries off ebay?

WAH!

Neonshock — Sat, 11 Apr 2009 02:38:31 -0800

My HP Pavillion dv6000 laptop works fine...except for one little battery related thing. You know the battery icon on the screen? On the bottom left - yeah that one.... It always shows at being 5% remaining, plugged in and charging (which it is, and has been for about...the last two months) but I never the less, ever gains any battery power. Sometimes when I startup its at full, but then when everything starts up properly it falls immediately down to 5 percent again. Its annoying because now im scared to remove it from the power....

My google has failed me. Any ideas Mefis?

I'm getting sick of no point and click!

Kid Charlemagne — Thu, 12 Mar 2009 15:23:14 -0800

My ~~Your~~ digital camera ~~favorite band~~ sucks down the batteries! Is this fixable or would I be better off getting something else? So I've got a Fuji Finepix pseudo-SLR that's a few years old. It's autofocus is iffy, but most of the time (or if I resort to manual focus) it produces some really nice images. The problem is, it will decide it's done with four AA's after about three pictures, even if the backlight and flash are off. A volt meter will still show the "dead" batteries at better than 1.5 volts, which leaves me pretty displeased (but if you ever need to power about 30 small flashlights, I've got your back).

I've looked at some of the previous ask-mefis on this subject, tried some of the advice and gotten a wall wart power supply for the thing, but that's not really that useful when I'm camping or bike riding. Is there some amazing trick that has recently come to light (like a firmware upgrade or capacitor replacement or the like) that might fix this or am I better off getting somethng new?

If get something new is the answer, can anyone recomend a good medium to medium-low end digital camera that will let me take a reasonable number of pictures on a single change of batteries? As long as I'm asking for a pony, how about a dependable autofocus.

Public Display of Deafness

still_wears_a_hat — Sat, 07 Mar 2009 14:45:08 -0800

A question of etiquette: Can I change my hearing aid batteries in public? Or do I have to duck into the bathroom? I'm thinking about both things like work meetings, or social gatherings in bars. My batteries give me some amount of warning (beeping every 20 minutes) when they're ready to go, but I'd usually rather change them right away than wait until I'm by myself (and I don't always get the 2 - 3 hours of warning that I'm supposed to). It's a lot easier to change the batteries on a table than in my hand or my lap, and I'd rather not juggle my purse, battery package, hearing aid and 2 batteries on a bathroom counter if I don't have to.

So, can I just change them in public, or is that not OK behavior? Will people be freaked out by my pulling something out of my ear and messing with it?

Can an Xbox recharge rechargeable batteries?

AlbatrossJones — Fri, 27 Feb 2009 13:20:06 -0800

If I put rechargeable batteries (batteries, not a battery pack) in an Xbox 360 controller, and plug in the charge wire that is typically used for their battery packs, what will happen to my rechargeable batteries? Will they actually recharge? Will nothing happen? Am I toying with fate, here?

Appropriate power adapter for a Roland A-33 midi controller?

larsks — Sun, 01 Feb 2009 17:20:42 -0800

Help me find a power adapter for my Roland A-33 keyboard. I've tried what seemed obvious and haven't made much progress. I recently purchased a Roland A-33 midi controller. Works great on batteries, but I would like to stop feeding it batteries and instead connect it to the wall. The power connector on the keyboard is a labelled "DC in 9v 80mA", with negative on the pin and positive on the outside. It also says, "Use ACA Adapter Only".

I picked up a 9v power adapter at Radio Shack (output: 9V DC 1.5A) and an "Adaptaplug" size "Q" that seems to fit. If I plug everything in I get bupkis.

So, can I make this adapter work for me? Or do I need to find some sort of custom power adapter? Help me, Hive Mind!

How should someone in London dispose of a printer?

marmaduke_yaverland — Mon, 26 Jan 2009 14:12:37 -0800

Trying to get rid of a printer, some battery packs and an old PDA, without simply throwing them in the black bag. How does one recycle electronics ethically in London? Previous answers to this question seem to deal with USA only, and I live in London. The options I have found apply only to businesses and industry junking stuff in bulk. I can't find advice on my council website (Kensington and Chelsea). I know they take little batteries, but not the power pack kind. I would rather not spend money if possible because I am but a poor graduate living with me Mam.

The printer is broken and much hated, the PDA is ancient. I don't know if anyone would take these as donations.

I think the law says you can take electronics back to the shop that sold them to you now? The printer is from 2003, I can't remember where my Mum bought it from and I don't have a receipt. These things are starting to clutter my life and I wish to be rid of them, please help me!

Batteries were included!!!

TeachTheDead — Sun, 21 Sep 2008 12:34:56 -0800

This should be a simple question, but I cannot find exactly what I need. I found a year old camera the other day in a box that had been left with batteries in it. There is some corrosion from the period of time the batteries had been in there. The camera is still pretty new, but I need to know how to remove the corrosion so that I can still use it. Any ideas!? No bonus point for anything since bonus points wont (and never do here) really do you any good. Thanks in advance friends...

Where to find a battery USB charger?

tomble — Mon, 07 Apr 2008 04:22:02 -0800

Help me keep my mp3 player charged while I'm travelling! I'm travelling in a couple of months, and taking my mp3 player with me of course. However, with a couple of long flights ahead of me I'm worried that my mp3 player won't last the duration, and that I won't be able to charge it while flying.

What I'm seeking is essentially a battery pack with a USB socket in it, so I can load it up with fresh batteries and then charge from that. I would have thought it was easier to find such a device than it has been, but perhaps my search terms are all wrong.

Where do I get a waterproof battery case?

strangecargo — Wed, 30 Jan 2008 17:22:36 -0800

Where can I get compact, water(proof|resistant) and somewhat sturdy battery case? Gearfilter: I've recently decided to stop using disposable batteries unless absolutely necessary, so I've started using low self-discharge rechargeable NiMH batteries to power the headlamp that I take with me on climbing trips. I usually keep an extra set of batteries in my pack because it would be Really Bad to be without light while wandering along a cliffside looking for a walkoff in the dark. I used to use a normal retail battery package with the cardboard bits torn off, but now that my spare batteries aren't single-use, I'd like to keep them in something sturdier. What I want is a compact case for at least 3 AAA batteries that will keep them dry and protect them from jostling around in a pack full of hard metal objects.

I apparently fail at Google on this one. I can't seem to find anything made for this purpose. Has anybody seen anything that would work?

NiMH AA and AAA batteries are 1.2V?

knave — Fri, 11 Jan 2008 12:50:48 -0800

What's the deal with NiMH AA and AAA batteries being 1.2V? I'm frustrated that I bought into these things without knowing they put out a lower voltage than alkaline batteries. Two of my intended uses of the batteries are my LED flashlights and my LED bicycle headlight. Neither of these will power on when I use NiMH batteries (both Rayovac and Sanyo Eneloop).

How is it ok for these batteries to masquerade as AA or AAA, when they are not drop-in replacements for a standard AA or AAA battery? Is there any hope for future rechargeables actually being 1.5V? At this point, I have a dozen battery-shaped objects that are pretty much useless to me.

Battery pack for SAD lightbox (Apollo Health P1)

selfmedicating — Thu, 10 Jan 2008 14:54:15 -0800

Where in northern Virginia can I get a battery pack for my SAD lightbox? It's the P1 from Apollo Health, and I'm hoping for a battery pack before a trip this weekend. Thanks for any help!

Effective/interesting domestic uses of solar power?

vizsla — Fri, 28 Dec 2007 19:51:17 -0800

What domestic devices can be operated effectively on solar power these days? Know any interesting alternative uses? Wide open question.

Convenient, extra power for my phone?

illek — Tue, 06 Nov 2007 20:44:51 -0800

Do those "battery powered emergency phone chargers" work? I was actually looking for an extended life battery for my cell phone and came across the emergency chargers, the kind that run on AA batteries. Do you have any experience with them? They are pretty inexpensive and I'm thinking it would be a handy little thing to have in my bag...if they work. Thanks!

What happens to the energy in a rechargable battery?

smithygreg — Mon, 29 Oct 2007 08:37:01 -0800

What happens to the energy that is lost from rechargeable batteries when they self discharge? What happens to the energy that is stored in a rechargeable battery as it sits on the shelf and is not used and self-discharges? Is it just stored inside the battery in a different form?

Drunk-friendly camera (with AA batteries)?

knapah — Thu, 13 Sep 2007 07:40:37 -0800

Waterproof, shockproof camera which takes AA batteries? I am looking to buy a camera for use with a drinking society where chances are the camera will be passed around, dropped on the floor, into pints of ale etc. So I need something durable.

I've seen other threads on this topic such as this one http://ask.metafilter.com/60311/A-shockingly-wet-digital-camera and I was all set to purchase an Olympus 725SW from ebay.

However, I suddenly realised that it doesn't take AA batteries, something which would be distinctly useful for a variety of reasons.

Any ideas?

I'd prefer AAs over buying a spare Lithium battery, but if it comes to that I will

Where can I get a battery-powered LED clock?

ManInSuit — Mon, 06 Aug 2007 14:53:45 -0800

Where can I get a battery-powered LED clock? I'm looking for a cheap LED clock, ideally with a big bright display, that I can use for an outdoor sign I'll be putting up for a one-time project.

I’ve looked around and found lots of LED clocks w. battery backups, but from what I’ve been able to discern, the battery backup just keeps the clock running, it doesn’t actually keep the numbers lit.

Ideally, what I’m looking for would be something like this:

- Cheap (Say, less than $25)
- Big display would be great (over, say 2” high), though I guess not totally critical.
- Bright and visible in the evening (so, I guess: LED not LCD)
- Ideally, can run easily on standard batteries, but if it requires super-minimal hardware hacking, (assembling an external battery pack, cutting a wire or two) that might be okay, too.
- Battery life isn’t a super-big deal I don’t think. The sign will only be up for 12 hours or so. It’s not the end of the world if we have to change the batteries once or even twice during that time.
- I’m in Canada, so- bonus points for naming a supplier who happens to be here, and special Canadian sadness if you name a supplier who won’t ship here.

(For background – I’m doing a series of performance events for Nuit Blanche, an all-night city-wide art event here in Toronto. I want to be able to make a sign that says “next performance at 9:20 [or whatever] with a clock built into the sign, so people can know exactly how long till the next performance. It’ll be nighttime, so I’m imagining an LED clock is the best way to go. But If anyone has other ingenious ideas, I welcome them…)

Stubborn powerbook battery won't charge

Rumple — Mon, 30 Jul 2007 10:49:25 -0800

The battery in my G4 Powerbook won't charge, and I am a long way from any technical help! I have a Powerbook G4 15 inch 1.67. The battery is about a year old and is not one of the recalled ones. I left my computer in hibernate mode while away for a week and when I came back the battery was drained, which is not uncommon. However, now the battery will not take a charge at all. Some relevant symptoms:
- menubar indicator shows 0%,"calculating until full", which never changes
- the lights on the battery do not blink
- depressing the battery button produces the flickering green "battery empty" signal
- the computer will only boot if the PMU is reset, but will soft reboot without that step
- it runs fine with the battery in or out, but of course dies immediately the power cord is pulled out

I have googled around and done the PMU reset and also tried:
command-option-p-r (reset PRAM) (whatever that is) and
command-option-o-f; reset-nvram; set-default; reset-all

One potential confound is I am using an aftermarket power adapter which apparently only puts out 50 watts not the 65 of the stock model. This is preventing me from updating the firmware - it demands 65 watt adapter. However, I have never had a problem with this adapter and it shows as charging.

Sytem profiler:

Battery Information:

Battery Installed: Yes
First low level warning: No
Full Charge Capacity (mAh): 3421
Remaining Capacity (mAh): 0
Amperage (mA): 0
Voltage (mV): 9831
Cycle Count: 293

AC Charger Information:

AC Charger (Watts): 50
Connected: Yes
Charging: No

So, any ideas, hive mind? Software, hardware, battery itself? I am in a town (pop. 800) with internet for one day, then back into the bush for three weeks, where I would like to have use of this battery!

How can I get my batteries to charge?

drezdn — Wed, 30 May 2007 13:58:31 -0800

Fixing problems with a 14.4 V cordless tool charger, or if that doesn't work, turning it into a "corded tool." I received a set of 14.4V durabuilt (target brand) power tools for my birthday roughly 2 years ago. The problem is both of the included battery packs are dead, and the charger won't even try to charge them.

(On the charger there's an on light, an off light and a set button, no matter how worn down the battery, the on light won't go on).

Is there something I can do to fix this (even if just tweaking the electronics)?

If not, would there be any reason why I shouldn't build a 14.4V XAmp power supply into one of the battery packs and make it so I can at least use the tools with a cord?

Looking for the best value AA battery available (or "Let's Have Some Truth in Battery Advertising")

zaebiz — Sun, 13 May 2007 00:08:56 -0800

So Energizer or Duracell? Or some other brand? I'm confused. Apparently they are both 5 times more powerful than the other. I'm looking for the best value-for-money AA battery on the market (i.e. battery hours per dollar). I understand it depends to some extent on the device. Let's say two devices - the TV remote control - and a digital camerra. Anyone have a link to the definitive report? (Oh and I heard of an excellent report on Which.co.uk but cannot purchase it because my credit card doesn't have a UK address. Anyone want to buy it and have me reimburse them by PayPal, and get to use the whole site for nothing for a few days?)

Help me find out what song this is

913 — Wed, 18 Apr 2007 00:49:05 -0800

Music video song filter: I believe the song/video was released in 1999. The music video consisted of people walking around with batteries strapped to their backs and I believe one of them was in the brain of a mini-robot. The song was on the charts the same time Britney Spears released, "Baby One More Time" but it was dramatically different than anything she would ever put out. I believe it was a male group.