Ask MetaFilter questions tagged with battery

iPhone battery charging questions

hokie409 — Tue, 22 Dec 2009 17:40:24 -0800

How does my iPhone battery charge? I'd like to understand how my iPhone and its battery work better. I have the 3G but it's jailbroken so I can see the battery percentage. I'm interested in some things I've noticed. I looked at some of the posts but I'm more interested in how it works than maximizing the battery life.

Queston- One does not appear to be able to simply plug in an iPhone with a dead battery. It must charge to around 5% before it'll turn on. Why is that?

Question- Can someone confirm that the iPhone charges less quickly when on vs. plugged in but off? For example, when you have a low battery and are leaving in 30 minutes does it make more sense to turn it off? Same question for leaving the iPhone on but turning off options like wifi, 3G, etc?
(Both of these questions are different from what I've noticed with laptop batteries for example. )

Question- Some phones have an option to not check email during certain hours. I don't believe there is that feature on the iPhone (exchange mail or gmail in my case). When I am not plugging in my phone overnight is there an option or app (jailbroken or not) that'll automatically stop checking mail or even turn off the phone to save battery and noise from like 1AM until 7 AM?

Thanks.

drain on Ford F150's new battery?

Elsa — Sat, 19 Dec 2009 11:27:29 -0800

Help us diagnose our Ford F150: what could be draining down the (new) battery overnight? We're suddenly seeing apparent battery drainage in our pickup truck, a 1994 Ford F150. Though the truck starts up fine, the dashboard battery gauge reads low immediately upon ignition, the windshield wipers are sluggish, and the dashboard lights are dim. We thought the old battery was likely dying, so we had it replaced with a new battery... but that hasn't solved the problem. (I'm posting this for my husband, who drives the truck. Here is the problem in his words.)

It's a 1994 Ford F150 pickup. Two days ago, the battery light came on and the battery gauge on the dash was at the low end of the meter when I started the truck after work (it had been sitting for about 9 hours). I assumed it was a bad battery, so I had the battery replaced at a chain auto place.

Everything seemed fine until I got out of work that night (after the truck had been sitting for about 9 hours) and the problem was exactly the same. The alternator seems to be working, as the battery gauge goes up to where it belongs if I let the truck run for about 20 minutes. There are no lights left on (glovebox, dome light, etc). It seems that, when the truck is off, something is drawing power from the battery.

When the gauge is low, the dash lights dim, and the windshield wipers are slow and sluggish. When it's charged back up, everything is normal again.

While I'm letting the truck idle to charge up the battery, the gauge will go up slightly if I rev the engine, but goes back down when I take my foot off the gas. Once it's fully charged again, revving the engine has no effect.

Both before and after getting the battery replaced, the truck started up just fine (no problem at all), even though the battery light came on and the battery gauge was low.

Once the battery is charged up again, turning the truck off for ten minutes-a half hour has no effect; the battery is still charged normally after that length of time.

We'll be taking it in to the mechanic on Monday, but with holiday errands and visits pressing, we'd love to get a headstart on the diagnostics over the weekend.

Some specific questions

1. Aside from the things we've checked (dome light, glovebox light, ashtray light, radio), what could be draining down the battery while the truck is off? Especially, do you know of any idiosyncratic drainage problems with the Ford F150? (We're also checking the forums on a Ford-specific board, but any hints would be helpful.)

2. Are there any simple home diagnostic tests we could make? Again, anything specific to the Ford F150 would be useful, but not necessary.

The fact that the truck starts normally (that is, readily and vigorously) seems to make this a different question than previous AskMe questions (which all seem to include a car that won't turn over) about a drained battery or dying alternator... or am I wrong? If the alternator is faulty, would the car be starting normally?

UPS and battery reference on the large scale

thewalrus — Thu, 17 Dec 2009 05:04:11 -0800

I would like to learn more about large-scale UPS systems, particularly the battery strings used in traditional RBOC/Telco applications. These are the sort of beasts that use huge strings of 6V 220aH deep cycle batteries, or even large numbers of 2V 400aH batteries on very strong earthquake-resistant shelving wired up to create a 48V mega-battery. Can anyone point me to the most definitive reference materials on the subject?

Freezing my ass off!

Eicats — Wed, 16 Dec 2009 11:58:26 -0800

Have you had any experience with in-car extra heaters like the ones on the linked page? example types I live in the frigid north and although I have a garage (unheated), I still suffer through starting a freezing car. Especially when it's parked outside my office all day. So I wondered about getting an extra dashboard or under-the-seat heater. From the linked page, it looks like there are a wide variety.

My first question: since most seem to run off the car's 12v plug, won't that drain the battery? Especially in below zero temps when the car is vulnerable to dying anyway? If it's not a problem, how long can you keep them running: all night so it's warm in the morning? all day while I'm working?

If you have one, let me know how it has worked for you and which one you would recommend.

Thank you much!

Honda Civic Hybrid battery problems

empath — Mon, 14 Dec 2009 08:43:51 -0800

2004 Honda Civic Hybrid won't start, but battery isn't dead. I ran down the battery a few weeks ago from leaving the lights on, and had to get a jump and ever since then, it seems like it's been harder and harder to get it to start.

Today (even though I didn't leave the lights on or anything) it wouldn't start at all, but there's definitely juice left in the battery, the horn honks (but somewhat weakly) and and lights work when i turn them on and it makes a clicking sound when i turn the key.

I looked at the battery terminals and the positive one looks like it has a bunch of gunk on it. I'm going to try cleaning that when I get off from work (advice for that is useful to), but aside from that, what else should I look at?

Should I just replace the battery? I can walk to and from work, so it's not really urgent that I get it fixed immediately.

Just want to emphasize that this is a hybrid car, in case that makes a difference.

Mazda3 won't start, don't think it's the battery. What could be wrong?

misskaz — Sun, 01 Nov 2009 10:46:30 -0800

My 2004 Mazda3 hatchback with about 20,000 miles on it won't start. It was last driven across the street to move for street cleaning on Wednesday with no problems. We just got in the car to go somewhere and it won't start. As you can tell by the mileage, we don't drive it a ton - mostly once or twice a week to get groceries or go to Target or something.

Symptoms:
1. Battery appears to be ok - all lights and accessories come on, remote entry works, etc.
2. When I first turned the key it made several strange clunks and clicks. All the dash lights flashed. Did NOT ever turn over. Subsequent attempts just make a loud click. Personally I think it sounds like more than just the battery clicking but maybe it's just really loud in this car. (To me, when the battery doesn't have enough juice to turn the starter, it makes a light "tick" sound, but this sounds more like a louder "clack" or "clunk" sound to me. Or I could be crazy.)

It has been really rainy for a few weeks now and the car is parked on the street. The tank is about half-full. I made sure it was in Park (automatic transmission).

Any thoughts about what this could be or things we can try to get it to start so we don't have to tow it to a mechanic? Are we missing something obvious to check? We live in an apartment and do not have a garage so getting under the car is difficult, but we do have some tools and are willing to poke around if there are simple things to try.

What kind of iPhone usage burns battery?

zachawry — Mon, 26 Oct 2009 08:08:08 -0800

iPhone battery life: I'm flying across the Pacific tomorrow with a 2 year old and a 5 year old. They are iPhone fiends (god help them), but I need to know if there is a huge difference in battery consumption between the education apps they usually play ("Find the sheep"..."Baaaa") and videos. I suspect that videos will use up battery life longer than these really simple apps, but I'm not sure. Anyone know?

Would an embedded internal wireless 3G modem draw significantly less power from a laptop battery than an external USB wireless 3G modem?

gttommy — Mon, 12 Oct 2009 16:05:27 -0800

Would an embedded internal wireless 3G modem draw significantly less power from a laptop battery than an external USB wireless 3G modem? Generally I would assume, an integrated device will draw less power, but these wireless modems just use up a lot of power regardless so the difference may be negligible.

However, some actual facts or links would be useful.

Thanks!

I need more power!

lockedroomguy — Thu, 08 Oct 2009 07:45:42 -0800

How do I connect the replacement batteries in my UPS? I have a Belkin f6c1500-tw-rk UPS. It needs two replacement batteries, which I have. But the original batteries were removed by someone else, so I don't know how they were connected.

I do have the manual. See Figure 3 for my model. The directions say to connect "red to red and black to black."

There are 4 battery terminals (2 on each battery) Each battery has one red and one black terminal of course.

There are 4 cables. Two (one red, one black) are connected to the UPS itself, that means I have 6 cable ends free.

The diagram shows that two of the cable ends are plugged into each other.
At first I thought I would do this for a series connection:

Red end from UPS to red (positive) terminal on Battery 1
Black (negative) terminal on Battery 1 to red (positive) terminal on Battery 2
Black (negative) terminal to black (negative) end coming from UPS

That uses up 4 of my cable ends, with two left over. So it seems that, as in the diagram, I need to plug two ends in to each other. But how would that work? Should one cable just be an extension?

I don't think I can hook them up in parallel because there aren't enough terminal connectors, plus if I hook it up in parallel then I need all 6 cable ends for the terminals, and wouldn't have two cable ends plugged together as in the diagram.

Options for a small & cheap Mac laptop?

attercoppe — Fri, 02 Oct 2009 14:01:07 -0800

What are my options for a cheap, small Mac laptop? I'm on a tight budget, but would love to get a laptop. I've been looking at netbooks because I love the light weight and small size. However, I may be about to get a job at my school, which basically is an Apple campus, so now I'm considering a Mac instead. I'd still like to find something cheap, small and light, and with some serious battery life. Of course one option is to buy a used or refurbed Mac (maybe an Air?). Could I also buy a netbook and install OS X? Or install some *nix - how compatible (not look and feel but interoperability) would this be?

P.S. I could probably do some research and get some good info, but I thought I'd see what ya'll can tell me first. I've read other questions here, and they seem to be either out of date or about desktops (or both).

How many amps do I need to start my car?

Solomon — Fri, 02 Oct 2009 10:21:29 -0800

Please educate me on car battery technology. I was looking for a new battery for my car, but the company I've decided to get it from has three different batteries available that will suit my car - a standard lead acid battery, a calcium battery and a silver battery.

I've been looking at the various different specifications, and it seems that the silvery battery is best. Money isn't a problem. However, I'm concerned about spending money on something that's not worth it.

Is having 160 extra startup amps (between the standard and silver batteries) really going to make a difference? What about in cold, damp weather? I think that the temperature of a battery makes a difference to how much energy it can produce - would buying the stronger battery mean that it can output more electricity at lower temperatures?

I'm pretty clueless about this kind of thing, so please feel free to educate me.

Macbook battery cover broken. Dangerous?

proj — Mon, 21 Sep 2009 13:03:14 -0800

The corner of the plastic cover of the battery on my Macbook has broken off. I have experienced numerous other cracks in the casing that other users have documented in the white Macbooks (~2006, 13") but this appears to be something different. You can see a little bit of the inside of the battery. Is this in a dangerous spot or can I put some electrical tape over it?

Here is a picture.

It is the corner closest to the user on the left hand side when the computer is open and sitting on a table for normal use.

Samsung Camera Battery Recharger in the Bay Area?

zevious — Sun, 06 Sep 2009 20:51:27 -0800

I have a Samsung TL320 digicam, but no battery charger. Where can I obtain a charger for it, ASAP, near Berkeley, CA?

BitLocker and the battery NomNoms

@homer — Mon, 31 Aug 2009 18:55:36 -0800

How much will BitLocker eat my battery? I've been using BitLocker on my laptop since Vista came out and continue to use it with the Windows 7 RC. In my experience the drive performance with and without BitLocker is about the same. What I don't know is if power usage is the same. I've read everything I can find about BitLocker and anything related to resource usage talks about disk reads and writes and system speed impact and how little impact there is. I can guess that since there is encryption and decryption that my battery life between charges is shortened. What I'd like to know is by how much. Are there any hard numbers from Microsoft or is there any way for me to calculate the extra load and figure out power usage from that?

Finding the right AC adapter.

brenton — Fri, 28 Aug 2009 16:46:03 -0800

Where can I find a 2/3a 700mAh 2.4v AC adapter? I am trying to convert my battery-operated rechargeable beard trimmer into a "wired" trimmer. (The battery was dying, and it wasn't able to run off AC, so it was pretty much useless.

If I can' t find the exact right AC adapter, which numbers can I fudge? Is it ok if the voltage is the same but it's 10 amps? If the amps are correct, can I get away with a voltage of only 1.2?

Can a Canon CB-2LV battery charger with output of 4.2v 0.65A safely charge a Canon Battery Pack NB-5L 3.7V 1120mAh(Li-ion)

CaptMcalister — Thu, 27 Aug 2009 07:24:39 -0800

Can a Canon CB-2LV battery charger with output of 4.2v 0.65A safely charge a Canon Battery Pack NB-5L 3.7V 1120mAh(Li-ion) if I cut the little bits of plastic stopping me out of the way?

What went wrong when I tried to replace my car battery?

jacobm — Wed, 19 Aug 2009 11:28:41 -0800

I just changed my car's old dead battery with a new, just purchased one following the directions here. Even though I clamped the connectors down hard enough that I can't move either of them, the car seems to be completely dead --- it doesn't appear to be getting any power whatsoever. Any ideas what could be wrong? Long extended explanation, just in case people are interested / think there's a larger problem:

We have two cars, and one of them hardly ever gets used. Last time I used it was in May, after it had been sitting unused for probably several months. When I left home, it had trouble starting up (but ran fine once it started); and I needed a jump to get it started coming back. I tried to start it again the next day, and it wouldn't start.

So I ignored the problem until today. Tried to start it up again, and got some lights to turn on, but the engine wouldn't go. I jumped it with the good car, and it ran fine; I let it run for about 40 minutes (with the engine running above idle for at least 15 minutes that time). Then I turned the car off and immediately on again, but it still didn't start --- if anything, it seemed more dead than before.

I concluded the battery couldn't hold a charge, so I went and bought a new one. I followed the directions, but the car is now completely unresponsive; I see no evidence that it's drawing any power whatsoever.

I'm assuming I installed the battery incorrectly. Does that sound plausible, and if so what should I do about it? If not, what should I try instead?

Like a pencil, but with longer battery life

itstheclamsname — Sat, 15 Aug 2009 15:59:44 -0800

My dream device has only one function: you type on it, and it saves your text to be downloaded into a laptop later. It does this for a week without being plugged into the wall. Does it exist? I would like to write while hiking, but would rather not scribble down text and transcribe it later. While I doubt the perfect device exists, I'm wondering if anything out there (or some combination of devices) might score well in the following criteria:
1) Long battery life: 3 hours of writing per day for up to 5 days, without being plugged in. I'd consider alternate charging systems, if they work.
2) A keyboard: I'd like to be able to type relatively normally, not thumb-type or poke a phone keypad.
3) Transferability: there should be some straightforward way of getting the text file on to a laptop later.

Also factoring into the mix are 4) affordable, 5) weather-resistant, and 6) lightweight. Current data points: my Macbook can't eke out more than 5 hours, and a Palm Tungsten with a folding keyboard attachment wasn't good for more than about 10.

I don't care if this device does anything else; in fact, the simpler the better. It could be something that was sold 10 years ago; all it needs to do is allow me to write while I'm away from electricity. Does anyone have any ideas?

Just as an aside, posing this question reminded me of the old chestnut about how NASA spent 1.5 million dollars to develop a pen that could write in zero gravity, while the Soviets solved the same problem by using pencils. Alas, it turns out to be just a myth. What a shame.

MBP with unrecognized battery

kalapierson — Thu, 06 Aug 2009 02:43:18 -0800

Aging MacBook Pro not recognizing its battery. Not under warranty. Is resetting the PMU my next step? It's a 3-year-old MBP (mfd summer 2006).

Battery icon in Apple Menu is a battery with an "X" inside it. This icon's dropdown menu reports "No batteries available." Disconnecting AC causes instant hard shutdown (so this isn't just battery being wrongly reported as inaccessible).

Some threads I've found suggest resetting the PMU, but Apple's instructions stress several times that this is a last resort. Why? Can the reset process go wrong globally enough to make the MBP unusable? Data loss isn't a concern, but I definitely can't be without my only computer. I also definitely can't afford a new battery.

Should I try the PMU reset or try something else?

----- Some questions you might want answers to, based on my googling so far:

• I'm fully current with system updates and I'm running 10.4.11.

• I've restarted (normally) many times with no change in the battery problem, which has lasted weeks now. I can't pinpoint when it started (or think of a specific reason it would've started). Battery is slightly bulged out (no longer flush with the back of the MBP) and I also don't know when that started to be the case.

• I can't report how many charge cycles the battery has gone through (because all System Profiler says about the battery is "batteries installed: 0"). But this machine has had a pretty desktop-bound life. Prior to this, the battery wasn't holding much of a charge but it certainly held enough that I could sleep the machine, then unplug it, then keep it asleep for a few hours, and then wake it up successfully next time it was plugged into AC (which is all I really care about being able to do).

• My MBP does fall within the date range of the MBP battery replacement program, but that program seems to have ended (?).

One Battery, Multiple Tools

sjuhawk31 — Fri, 31 Jul 2009 10:14:39 -0800

One battery, multiple tools: for what line of power tools did I see a commercial that featured one battery that you could switch out between the tools? Two that stick out in my mind are a mower and a screw gun.

Bonus questions: has anyone used this series of tools or something like it? How well do they work?

Truck battery cost

Kam1761 — Mon, 27 Jul 2009 16:30:17 -0800

My 18 year old son went to Express Oil Change to have a new battery put in his 2004 Ford Explorer Sport Trac. His battery was dead and when jumped off, it would not hold a charge. They put an MTP-65 Interstate battery in and charged him $146 for the battery alone. With installation, charging system testing fee, and taxes, the total cost was $208.93. Does that sound high? I was expecting to pay half of that.

Why won't my laptop charge?

Emera Gratia — Sun, 12 Jul 2009 16:13:13 -0800

My Aspire 3680 (crappy laptop PC) doesn't want to hold a charge anymore, with either battery. How do I determine if it's my laptop, my batteries, or my charger? (I have a VOM and know how to use it).

Keeping the phone charged on the go

crapples — Fri, 10 Jul 2009 10:53:25 -0800

Will a Verizon brand car charger ruin the battery on my new Blackberry Curve? I have read and heard in various places that car chargers are bad for batteries for various reasons. However, the Verizon folks say that the cheap Walmart chargers are bad because they never stop pumping the juice even after the phone is fully charged. They say that their chargers, purchased from their stores, are "smart" enough to lay-off once the phone is charged. They say that using them won't hurt my battery at all.

Are they feeding me a line?

On Monday I'm headed out on a week long camping trip and would really love to have a charged phone during the drive and whenever we're near the car. Thanks.

Pumping water with batteries

kamelhoecker — Thu, 02 Jul 2009 07:45:22 -0800

Small pump. For liquids. Battery powered. Inexpensive. Does such a thing exist? I've been searching for pumps and haven't found much available. I've found several pumps for garden fountains, that are basically a small paddlewheel on a fast motor that flicks water. Far too inefficient for battery power.

I've found homebrewers making their own peristaltic pumps which could be shunk down.

Any other simple homemade pump designs or sources for cheap pumps?

Aztek Battery Woes

soelo — Wed, 01 Jul 2009 10:47:19 -0800

What is draining the battery in my 2001 Pontiac Aztek? I am part owner of a 2001 Pontiac Aztek (I know you think it's ugly, don't really care) and am having trouble with the battery. Before we got the vehicle, it sat idle in a garage for about six months, having been driven once or twice in that time. It started right up in January and was fine for a few months, until I let it sit for about 48 hours in April. The battery was dead, but after a jump start, it ran fine again. Ever since then, if it sits for more than about 36 hours, the battery needs a jump.

I assumed I was leaving something on, taking care to turn off everything I could think of before turning off the engine, but we still had the same issue. Two weeks ago we bring it in to be checked, the shop says they checked the "whole start-up system" and the battery (which was 3 years old) itself was the problem, so they replaced it. Then Monday night it happened again, the new battery is dead after sitting for around 36 hours.

I have been over and over the thing looking for anything left on or plugged into a power socket but can't find a problem. I think it may be the headlights, which we leave on "Auto" all the time. When I shut it off, the radio and lights stay on after I remove the key. The radio turns off when I open my door and the headlights turn off about two minutes after I shut the door. I'd turn them off completely but there is no "off"!

My sister had the same issue and was the one who brought the car in, so she will be calling the shop to tell them their fix did not work and ask what they are willing to do. I think we should get some of the money for the two hours of labor back and bring it somewhere else.

Do you have suggestions of anything else we can do to find out what, if anything, is draining the battery? Does it sound like it's a drain, since the jump starts always work? Is there some other headlight setting we should use? Thanks