Build Your Own iPod Battery 318
OmniVector writes "With various complaints about the iPod battery's life, and its mere 10-8 hours of charge many of us are left looking for a way to keep the tunes kicking a little longer. Drew Perry has come up with a novel solution which can only run you a few bucks for an extra 10 hours of battery life out of a box of playing cards and a everyday batteries. Not bad for that long car trip where you just don't have a firewire charger handy."
Sorry, that looks awful (Score:4, Funny)
The Right Way To Build An External Battery Box (Score:5, Informative)
It's obviously not the work of a professional engineer, but that's what makes it neat. Taking a just barely functional knowledge of what's going on and solving a problem using available tools. I suspect this guy isn't going to be the professional EE you all think he should be for at least 4 more years
Actually, I've seen a lot of EEs do the same thing, with no more understanding than the basic voltage drop analysis. You have to keep in mind that an engineering degree confers exactly the *opposite* thing to the practical knowledge required in the real world. Those people who make good engineers already got their practical knowledge from playing with Lego and hacking their bicycle.
You see, the reason why a D cell is bigger than a C cell is bigger than a AA cell is bigger than a AAA cell despite all putting out ~1.5V is because of current capacity. A modern D cell will put out 1.5V into a 1A load for many (~15) hours, while a modern AAA cell will put out 1.5V into a 1A load for around an hour and ten minutes.
Trivia question: why is there AA, AAA, C and D but no A or B? Answer: The A battery was a big 1.5V lantern battery used to heat the filaments in radios before rectifier tubes were practical to allow the radio to be plugged in to a regular outlet, and the B battery was a 30V, 45V or 90V battery used to provide the plate voltages for the tubes in these radios. The B battery stuck around until the early transistor radios of the late 1950s replaced all the tube portables. You can actually still buy both battery types but generally only through big electronic parts suppliers.
(Quoting Duracell's alkaline battery data sheets [duracell.com], difficult to link directly to the PDF so click on "Technical Bulletin" and scroll to page 9/13, D cell 15Ah (15,000mAh) and AAA cell 1.15Ah (1,150mAh).)
Go to Radio Shack and buy a multimeter. Stick it in current mode, and measure the current consumed by the iPod. Then look up the mAh (milliamp-hour) ratings for the type of battery you wish to use - NiMH, Energizer Lithium, Duracells, whatever. Do not mix battery types (brands, chemistries, etc), ages (new batteries and old batteries should never be put together in series), or sizes (AA, 9V, D-cells, etc.) because you will have some discharge faster than others, sometimes to the point of actually trying to "recharge" the weakest cells off the strongest cells.
Figure out which battery size you need to use based on whatever you consider to be an acceptable battery life for long trips, and use it. Of course, there will be design trade-offs in order to achieve a reasonable size - shorter battery life or bigger and heavier batteries - some compromise will probably have to be reached. If all you care about is battery life, for example, just stick the iPod directly across a car battery.
Get appropriate sized battery holders at Radio Shack or any number of electronic parts places - MCM Electronics, All Electronics, Digikey, Newark, Electrosonic, etc. Connect them in series and build them into a plastic or aluminum box, properly secured and screwed down. Use heat shrink tubing instead of electrical tape for all connections, and use a grommet (those little plastic things where the power cord enters your kettle or toaster [glowingplate.com] or whatever) to prevent the wires getting frayed.
And, most importantly, once you know the current the iPod consumes, multiply that number by two and buy a fuse with that rating. Put it in a holder in the battery box - that way, if the power cord to the iPod gets caught and damaged, or if the iPod fails catastrophically - there won't be a fire.
good luck... (Score:5, Funny)
Re:good luck... (Score:5, Informative)
contrary to popular belief, batteries do not look like explosive devices.
this diy-playing-card-battery-charger might raise a few eyebrows for its 'concealment' factor, but then, you don't have to use a playing-card box. you could just as easily use something else that actually looks like a plastic case designed for carrying batteries.
this is a clever hack, anyway. the schematics are where the value is - whats the bet it won't be long before you can get these plastic cases in the akihabra back-streets, selling as 'cheap firewire-device rechargers' or whatever
Re:good luck... (Score:5, Funny)
Excellent! I'll make an explosive device that looks like a battery then.
Foolproof!
Re:good luck... (Score:3, Funny)
Re:good luck... (Score:5, Funny)
Do you work for Nokia, by any chance?
Re:good luck... (Score:4, Funny)
Dear Lord! We use that stuff to tin our soldering irons in North America. You guys *eat* that stuff?
And people wonder why we call you guys strange...
Re:good luck... (Score:4, Interesting)
Two recent examples for you:
1. A passenger from Germany who was stopped and detained for having wires protruding from her jacket. It was nothing more than an ordinary electric jacket as used by bikers for the last twenty-odd years but that didn't stop the security guys from treating the passenger like a terrorist.
An example of them getting it wrong by going overboard.
2. A Sudanese man who was stopped at Heathrow with five live bullets in his coat. The man had just travelled from Washington DC, and the fact that someone was carrying live ammunition onto an aircraft was totally missed by the security in DC. So, security at Washington is so tight that you can get munitions onto a transatlantic aircraft without being spotted.
An example of them getting it wrong by making basic mistakes.
Remember, these are the people who insist on everything going through an x-ray machine, even materials that are highly sensitive to rays and easily damaged, because they know best and because the machines are "harmless".
Re:good luck... (Score:5, Interesting)
How many thousands and millions of times did Airport Security Personnel accurately spot and identify a battery/electronic posession of a passenger and determine that it was in fact safe?
Just because you've 'heard of this in the news' doesn't mean that your analytical powers are sufficient to accurately determine reality in a scenario you've had no direct experience with. You're not looking at the entire scene here: count the success as well as the failure and then compare.
Personally, I've known quite a few very intelligent security people, and had no problems with them whatsoever.
Your two anecdotes prove your argument, though. Sharp...
Remember, these are the people who insist on everything going through an x-ray machine, even materials that are highly sensitive to rays and easily damaged, because they know best and because the machines are "harmless".
"I'll ignore the fact that most 'x-ray machines' installed at major airports are in fact far more than 'x-ray devices' and do more than just 'x-ray' things, and imply that because those passengers (such as myself) are so smart, they're bringing super-sensitive materials with them through the airport security screeners, who are all sooooo stoooopid
Re:good luck... (Score:3, Insightful)
Yes, anecdotal. No, I'm not fucking kidding you. You're being an idiot for making such blanket assessments about the security industry on the basis of "what you've heard in the news". Look it up. [reference.com] (Hint: Based on casual observations or indications rather than rigorous or scientific analysis)
Your assessment that security people are stupid is based on anecdotal evidence - i.e. NON-SCIENTIFIC
Were it non-anecdotal, you would include, along with your 'counter-view', th
Re:good luck... (Score:4, Interesting)
Have you actually tried to request this?
Last year, I tried requesting a hand inspection of a box of floppy disks, because I was afraid of possible X-ray damage (they were about 20 year-old 5.25" disks with programs that it would be hard to replace these days.) The security person said "sorry, we can't do that. Put it through the machine or you can't take it on the plane."
I decided to not start a fight over this, since I don't relish the idea of being arrested 3000 miles from home. I consider myself lucky that the disks didn't get damaged.
Re:good luck... (Score:5, Interesting)
My bag got flagged by the security staff and so first I was ordered to sit down in some waiting area type place while they swabbed my bag (I presume for trace explosives or something) and put it through the scanner again.
I was then given a pat-down body search, my shoes had to be taken off, put through the scanner and then swabbed, my bag was then taken away by one of the staff and I was told to wait while they tested that the batteries were actually batteries or something. I wasn't told, just ordered to sit and wait.
So after 30mins of my time wasted they decided to let me go on my merry way. What really got on my nerves is that there were no 'please' or 'thankyous' uttered by any of them, I felt as if I had done something wrong or was being treated badly just for having batteries in my bag.
Re:good luck... (Score:5, Informative)
I would suggest that anyone carrying extra batteries for a personal device, put them into the change cup.
I've said it before, and I'll say it again...
What highjacked those planes was not box cutters, but fear, weak doors and historial compliance to anyone. The Heroes of Flight 93 showed what really happens in the "new reality".
Re:good luck... (Score:5, Informative)
When I fly I carry all kinds of change, several AA's, tokens, pens & what not. To get around having to haul all this stuff out for inspection all the time (esp for connecting flights) I usually carry a ziplock bag or two and stuff anything that might remotely go into the change box. One item, no fussing & my pockets are lighter.
Re:good luck... (Score:3, Insightful)
Re:good luck... (Score:3, Informative)
Re:good luck... (Score:3, Insightful)
Ladies and Gentlemen, welcome to Anytown America airport. Security today was brought to you by the lowest bidder.
Re:good luck... (Score:3, Insightful)
On the other hand, there's the total incompetence of allowing a passenger to travel with live ammo.
I'd rather live in a world where fuck-ups were of the first kind tha
Re:good luck... (Score:5, Funny)
which there wont be any of...
so there wont be a problem.
Re:good luck... (Score:5, Interesting)
Then they just waved me through.
Re:good luck... (Score:3, Interesting)
Bomb material is generally much less dense than battery contents, for example. Plastic explosives have signature densities, and are displayed using a red tone on the monitor. It's funny, because meat has a desnity very close to that of plastic explosive, so it's highlighted red as well.
Batteries, made of lead are displayed black. They block x-rays very well--there's no mistaking batteries for any explosive material; unless they packed so
How about instead of voiding the warranty.... (Score:3, Informative)
Re:How about instead of voiding the warranty.... (Score:3, Informative)
Off-topic: Who said anything about dissection? (Score:4, Funny)
Naughty naughty, you didn't read the article did you
Re:How about instead of voiding the warranty.... (Score:3, Funny)
homebrew = 10$ for batteries
5$ for connector
133t value of being h4xxor = priceless
Re:How about instead of voiding the warranty.... (Score:3, Funny)
- Not compatible with iPod mini.
Sold!
Re:MODS, parent did NOT read the article (Score:3, Informative)
However, 70 bucks seems kind of steep for that thing. I'm sure you could make one with all or most of its functions and that looked as good for a lot less.
Or if you just want to go on the che
Nice (Score:3, Interesting)
Re:Nice (Score:5, Insightful)
In the first picture, there are a GP and a Varta 9V battery in parallel, with at least two cells, at least one of which is rechargable. So, 9 + (2 x 1.2) = 11.4 V.
In the second picture, there are two Varta 9V primary batteries in parallel, placed in series with two 1.5V Duracell alkalines. So, 9 + (2 x 1.5) = 12 V.
We can assume the difference in non-load voltage is not relevant. But when we consider the power available:
The capacity of each PP9 Varta is at most 450 mAh. (Rechargables are 110 mAh to 150 mAh). Taking the best case in parallel, therefore, 900 mAh. The rechargable AA's are about 1350 to 2300 mAh. If primary AA's are used, then figure on 2400 mAh.
So for an all-primary solution, the AA cells have 2.5 times the life of the PP9 cells. Basically, this design eats PP9 cells and there's no real way of telling which batteries/cells are running out at any given moment.
If one's going to go for a primary cell solution, then it would be better to have, say, 3 x 2CR5 in series or 3 x CR-P2 in series. But obviously a rechargable pack is the optimal solution because it's way cheaper in the long run. Buy them all together, Use them together, recharge them together. Check out packs used for digital cameras.
Re:Nice (Score:5, Interesting)
The two AA's are pretty pointless, as the iPod was rated 8 - 30V, suggesting they just used a 78l05 or similar power stabiliser (min. input voltage = output + 3V). 3.5" HDD usually only need 5V, any extra voltage is just going to get you some extra dissipated heat, and no extra playing time, because the power stabiliser has to dissipate anything above 8V.
For fsck sake, find yourself an EE 101 book or something.
Re:Nice (Score:5, Insightful)
two 9V batteries will not be discharging through one another. One of them can not go flat, they are in parallel, if one goes flat, THEN the other will discharge through it, in effect, charging it(if it were rechargeable). But the effect is negligable, they will reach equilibriun.
I would go personally with a bunch of AA batteries since they tend to have longer life under load. 9V seems to be passe for devices which have human interaction.
6 AA in series would do the trick, and you can likely get a package to hold them at Radio Shack.
And I would say he has passed EE101, it was a good freshman level attempt. On paper it works
Eight AAA cell would have been too easy? (Score:4, Insightful)
That will be even cheaper. And would last longer. And will fit into cardbox as well. And
bad electronician, no donut (Score:5, Insightful)
advantages (Score:4, Funny)
Not compatible with iPod mini.
straight quote.
Infinite battery (Score:5, Funny)
Re:Infinite battery (Score:3, Funny)
Re:Infinite battery (Score:3, Interesting)
I tried this idea already... thought I could make millions... instead I wasted $150... ugh.
putting two batteries in parallel is not good (Score:5, Interesting)
Re:putting two batteries in parallel is not good (Score:4, Insightful)
Theoretically, if two batteries rated for the same voltage are connected positive-to-positive and negative-to-negative, no current will flow between them. In practice there may be a small difference in the potential at the positive terminal of one with respect to the other which would result in some current drain. At some point however the differential would vanish due to the discharging and current would cease to flow.
I propose that batteries in parallel are fine as long as you replace them simultaneously.
Re:putting two batteries in parallel is not good (Score:4, Interesting)
You are correct, however, that effect is not too bad if the batteries are closely matched (i.e. bought from the same package at the same time and always used together so they discharge equally).
Re:putting two batteries in parallel is not good (Score:5, Informative)
Just get 10 NiMH AAA batteries and wire them in series. They're 1.2 volts, so you'll get 12 to start off. It'll end up being about 1.75"x1.875"x.75" if you don't use holders, otherwise you can use two 4-cell holders and one 2-cell holder in a small box, which would make it a lot easier to pull out the batteries for recharging. This gets you about 600 extra milliamps, I have no idea what the iPod drains. If you used AAs instead, that would get you up to 1800ma. But 10 AAs are a little heavier.
Might as well go for the 12 volt lantern battery!
Card box? (Score:4, Interesting)
That's me being paranoid, but I recently heard of a colo facility destroyed - burned to the ground - by exploding batteries.
Re:Card box? (Score:3, Insightful)
Charging Problems UNSAFE (Score:4, Informative)
There are 2 x 1.5 volt cells in series
And 2 x 9 volt cells in parallel
I know for certain this causes heat problems during charging or discharging because of the charge inbalance between the cells.
This could lead to explosions in extreem cases.
If you need to build one, I would suggest removing one of the 9 volt cells or adding 2 more 1.5 volt cells in parallel
Re:Never have batteries in parallel! (Score:5, Interesting)
Nothing wrong with parallel connections as long as you charge them either conservatively or intelligently. Note the final design shown in this article actually shows primary cells. Firstly they're nominally non-rechargable, secondly their internal resistance prevents any thought-provoking excursions in the temperature and noise domains.
batteries in parallel can be ok (Score:5, Informative)
He chose this configuration only because he was trying to be clever and fit it into a playing-card pack.
As to what you're assuming - no. Battery voltage is determined by the chemical type of the battery. Size doesn't matter. So for example, standard alkaline AA, AAA, C, and D batteries all put out 1.5V, but Ni-Cads put out 1.2V. Lead-acid like your car battery is 2V.
Therefore, a 9V battery is just six tiny 1.5V batteries in series. Get some tin snips or whatever, and carefully cut open the outer casing on a 9V and you can see for yourself.
Also, you *can* safely run batteries in parallel. The only gotcha is that you can run into problems if you try to charge the batteries in that configuration when they are not evenly discharged. His picture looks like he isn't using rechargeable batteries, though. Or if you had rechargeables, you could pop the batteries out and charge them individually.
Personally I think it'd be more straightforward to just wire up 8 AAA batteries in series and forget the 9V nonsense. Probably would get longer battery life too. I don't know if they'd fit in a playing-card pack, but they wouldn't be much larger.
Re:Charging Problems UNSAFE (Score:3, Interesting)
I'll bite: just to explain the problem with connecting batteries in parallel:
The 9v batteries in parallel have the same nominal voltage, but almost inevitably will slightly differ in actual voltage. The difference voltage tends to drive current around the circuit composed of the two batteries in parallel. There is only very low impedance in that circuit if the batteries are reasonably new and full of charge.
As a resul
If you have a 1 or 2G ipod... (Score:5, Interesting)
Re:If you have a 1 or 2G ipod... (Score:3, Informative)
You would have to disconnect one battery or the other before charging a pack. Lithium chargers are designed for specific battery combinations as they can explode if not charged properly.
Re:If you have a 1 or 2G ipod... (Score:4, Informative)
Alternatively... (Score:5, Informative)
That's Right. 40 [batterytech.com]
Re:Alternatively... (Score:3, Informative)
They say this because, as they also say, it uses a Lithium-Ion battery.
That's the standard answer for *any* Lithium-Ion battery.
300-400 charges, for full charges, less than 30% charge remaining when you recharge it.
500-600 charges, for partial charges (generally defined as 70%+ charge remaining when you recharge it)
If you want more charge cycles, you don't w
How about rechargeable CR-V3 batteries? (Score:3, Insightful)
How about this? (Score:4, Insightful)
Left out of the article: Pin assignment (Score:5, Informative)
Need to know which ones are the power pins, right?
Anonymous Joe
Also, a source... (Score:3, Informative)
I haven't ordered from these guys (yet -- I'm definitely building a battery pack) but a few minutes in Google found them:
NTC Distributing [ntcdistributing.com]
Comment removed (Score:5, Interesting)
Re:Problems, problems, problems... (Score:3, Insightful)
--
Re:Problems, problems, problems... (Score:4, Informative)
Most of them are very concerned about things ending up in the trash which are not supposed to be in the trash, and are quite helpful when questioned.
Its a helluva lot easier to help someone properly dispose of something than it is to try to recover it out of the landfill once its presence has been detected.
Re:Problems, problems, problems... (Score:4, Informative)
Re: (Score:3, Informative)
Re: (Score:3, Interesting)
Comment removed (Score:5, Informative)
Others have said don't do this (Score:5, Informative)
Instead, either use two 4-way AA cell holders in series with non-rechargeable cells(for a total of 12V), which are available from most electronics distributors, or a combination of 2 and 4 way holders to allow the use of 10 NiCd or NiMH AA or AAA cells - also for a total of 12V since these cells run about 1.2V each. With a diode and a resistor you can trickle charge this arrangement through a car lighter plug, since car batteries run around 14.5V. It's a kludge but a feasible kludge.
I wonder if anyone has looked at modifying the works of a Freeplay radio (wind up dynamo) to act as a charger for small appliances like iPods?
Belkin Backup Battery (Score:5, Informative)
Backup battery pack [belkin.com]
LotD
Re:Belkin Backup Battery (Score:3, Informative)
The problem is that as soon as the batteries start to wear (2 out of 4 on the chargers battery charge meter) the ipod crashes. I've noticed my ipod acts funky on l
I wouldn't trust this guy.... (Score:3, Funny)
Upgrading Portable Players, Laptops, PDAs (Score:4, Informative)
Awful design (Score:3, Insightful)
2) The circuit is hardly clever or novel; no lights to tell you when the batteries are reading the end of their useful life.
3) Gluing plastic on cardboard.... does this pass for elegent or clever? If so, let me show you some really "clever" things I've done with a fanbelt at 3 AM to keep my car going.
4) is this was
Car battery (Score:3, Insightful)
A different arrangement... (Score:3, Informative)
batteries and two regular NiMH batteries.
Battery Mod (Score:3, Interesting)
I made a similar pack... (Score:3, Informative)
I thought of going the 9V route, but then it occurred to me that it's kinda pointless to have two 9Vs - 9Vs don't hold that much charge; their main benefit is that they're small. They're actually 6 tiny (and therefore inefficient) 1.5V cells in parallel. So there is no purpose in having two.
Anyone else notice.... (Score:3, Troll)
Which pins to use on the firewire socket? (Score:3, Interesting)
On second thoughts, I suppose all it takes to discover this is a multimeter and the Apple charger.
Still, it would be a nice addition to the article if he would explain that.
Danger! Warning! Fire risk! Pleeease mod up!!! (Score:5, Informative)
Yet another dumb slashdot article (Score:3, Informative)
Doh what part of 8 x 1.5 or 10 x 1.2(NiCads) doesn't he get?
And his solution is to mix different types of batteries together.
Belkin Battery Pack (Score:5, Interesting)
The difference?
The belkin packs [belkin.com], as you may have noticed, use only 4x1.5V. They don't charge the iPod battery, they power the iPod, getting 15-20 more hours of playtime, a better solution to me. This is probably done by jumping a pin in the proprietary dock connector of the iPod.
If someone could figure out which pin to jump or otherwise how to make this, it would be a wonderful solution.
It's a plus (Score:3, Insightful)
While I'm wiring this thing up.. (Score:3, Funny)
this seems like an expensive hack (Score:4, Informative)
Re:10-8 hours of charge? (Score:5, Interesting)
All the recent CD players I have seen last 4 hours but have 1 Meg buffers, 2x read speed, feature, feature etc.
I'm sticking with my old CD player, It works as I want and has the only features I need (long battery life).
Re:10-8 hours of charge? (Score:5, Interesting)
Re:10-8 hours of charge? (Score:3, Informative)
Re:10-8 hours of charge? (Score:3, Interesting)
Re:10-8 hours of charge? (Score:3, Insightful)
But I agree. I think that for example, the cast-benefit ratio is better for buying a cd-player that play's mp3-cd's than a HD-based player right now.
Re:10-8 hours of charge? (Score:5, Insightful)
I'm just curious; where do you listen to your iPod or any music player for that matter 7 hours a row? Traveling maybe? I'm quite sure you would able to use external power source part of that time.
Personally I can't get up to 7 hours a day even if I listen every moment I can.
And would people please stop to post these iPod battery stories? The whole is has become highly exaggerated.
Re:10-8 hours of charge? (Score:3, Interesting)
I mean, at work I generally can't listen to 7.5 hours straight (those annoying co-workers won't leave me be for that long), but if I stop and start the thing accordingly I reduce the life to around 5-6 hours.
Plus, I don't WANT to recharge the goddamn thing, ok? I want to charge it like my phone, maybe once every 4-5 days, not every single night.
Plus, what about:
- long bus/train trips
- flying places (I do this a lot,
Re:10-8 hours of charge? (Score:3, Insightful)
Would you claim that a 12 inch PowerBook isn't really a portable comptuer because you can't run it the whole day on just batteries? I think it is silly to bash Apple, just because you don't WANT to use an external power source. It would have been an option you would have got for free. And there are still other options for you if you can't use/don't want to external power source like this story and TheRaven64 [slashdot.org] points out.
Re:10-8 hours of charge? (Score:4, Insightful)
Where do you find the time to listen to music when you are on the phone that much?
Re:10-8 hours of charge? (Score:5, Interesting)
If the cost of a longer battery life is a larger unit, then I'd rather not have one. If I need more battery life, there's always the Belkin Battery Pack ($59.99 from the Apple store) which delivers an extra 12-15 hours of charge.
Re:10-8 hours of charge? (Score:3, Interesting)
My 2 cents: buy a minidisc player. Better battery life, physically tougher, smaller. What's the point of having 10,000 songs if you can only listen to 7 hours worth in a sitting?
So a MD player will give you 10-12 hrs, or whatever, But in that time, you'd have to change disks ten or so times, unless you were a) listening to the same tracks over and over, or b) using MD compression, which gets pretty poor results IMO.
I switched from MD to iPod, and it works great for me. A lot of the time, my laptop is
NetMD (Score:4, Interesting)
Don't believe the hype (Score:3, Interesting)
With NetMD, using Sony's (admittedly pretty shite) software you can easily transfer MP3s onto minidiscs in no time. The program takes your MP3, converts it into a (seperat
Re:10-8 hours of charge? (Score:5, Interesting)
on the downside, they currently have no remote and cant work as a USB harddrive without the use of additional software. fortunately, rio are constantly updating the player with new features, and are in the process of making it work as a usb harddrive.
Minidiscs are alright (i own a sony N10 [top model]). It depends what you like though. They do have great battery life, but this is at the expensive of the amp.. so thanks to their weak amps, the sound quality isn't great. they're really good for the average joe, who (shock horror) uses the stock earbuds, and is happy with things like 128kbps mp3.. but as a music fan the weak amp annoys me (which is why i'm buying a karma, and have just built a portable amp)
Re:10-8 hours of charge? (Score:3, Interesting)
Re:What? (Score:3, Insightful)
Just because advertisers DO lie doesn't mean they SHOULD lie.
Re:What? (Score:3, Informative)
I recently flew from LA to Melbourne, a brutal 14 hour flight. I turned on my 1st gen iPod immediately after we left LA, and, much to my surprise, it kept working until our approach in Australia. Yes, I didn't skip around very much, and I'm sure that helped battery life. But 14 hours of non-stop playback is 14-hours of playback.
Re:10-8 hours of charge? (Score:4, Insightful)