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geekhack Community => Other Geeky Stuff => Topic started by: chimera15 on Sun, 05 December 2010, 16:10:17
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Would this be possible do you think? I have a lot of oqo 01+'s now, some that I've been able to build from spare parts that I might be willing to try this on.
If you just add cells to a battery pcb in parallel will it charge them just as if they're normal or will the pcb say no?
Would you have to build your own pcb to do it? Anyone know what that would entail? I want to build a battery that will last on my oqo 01+ for at least 8 hours that I can fit in my pocket.
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The weight of the laptop battery would make it not "pocket" viable, if anything goes wrong, your clothes will be incinerated and as you're wearing those clothes..........
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lol Well obviously I would test it. The oqo's a handtop, so it doesn't draw a lot of current like a normal laptop. It's meant to fit in a jacket pocket. Also I think normally before something like that happens the batteries get really super hot which I would be able to tell.
Currently the battery lasts about 3 hours and is only a quarter inch thick. I would think if I added 8 cells to it it might be about the thickness of the oqo itself, and maybe I could put it in a different pocket and use wires...
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I think I could make this work with the car power adapter and a 12 volt sealed lead acid battery, but the sealed lead acid battery would have to be a thinner type, and I'd need a good charger for it which I currently don't have. Anyone know a good type with lots of amp hours?
That way of course you loose a lot of time in the conversion. It would be better if I could come up with a method of just modifying the battery. But it would be safer.
This looks possible:
http://cgi.ebay.com/12Volt-2-2amp-hour-12V-2-2ah-Sealed-Lead-SLA-Battery-/290506717874?pt=PCA_UPS&hash=item43a38cbab2 (http://cgi.ebay.com/12Volt-2-2amp-hour-12V-2-2ah-Sealed-Lead-SLA-Battery-/290506717874?pt=PCA_UPS&hash=item43a38cbab2)
2.2 amp hours is what, 2200 mah? Or more? That's less than what the laptop battery would be though.... strange.
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(http://www.kingofbombs.com/pictures/nuclear-bomb-explosion.jpg)
(http://207.199.174.56/img/tjgBtGVNoR_okay-that-was-pretty-****ing-stupid.jpg)
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I've modified and repaired a lot of batteries before, never had any problems. The one time out of dozens of modifications I had problems the battery got super hot and I pulled it before it caught on fire.
Yeah so 2.2 ah = 2200 mah. The standard oqo battery pack is 4500 mah. That's crazy that a huge ass lead acid battery is less mah than a tiny lithium ion laptop battery. Hmm
So I guess I'll go with the battery packs. 2 of these are what is in a standard oqo pack.
http://www.batteryspace.com/highpowerpolymerli-ioncell37v1500mah355585-7c525wh10adrainrate.aspx
Oh I know why.. It's cause that one is 12 volts and the lith ions are 3.7. So 12 volts per hour is 3 times higher than the lith ions. So it would if I could hook it up directly last 3 times as long. Probably even with the conversion through the power supply my guess is that it might still last 2 times as long which would be like 5 or 6 hours.
I trained as an aircraft and power supply technician. We learned all about batteries, how to recondition them and such. The only thing I'm shaky on is how the recharging circuits in laptops, and specifically the oqo works, and how it senses how much capacity a battery has. I'm not sure that it matters. I've repaired batteries on pda's before and put in larger capacity batteries and at least in those pdas the recharging circuit didn't seem to notice.
I know there are double capacity batteries for instance for the oqo that do exactly what I want to do, they just stack 4 cells instead of 2 into the battery, but the question is if it's a different pcb running those batteries.
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Ill answer your question in about 4 years..
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My first thought upon reading this title was... don't.
It's dangerous, time consuming, and the end result really wouldn't be worth it.
If you're that desperate, go buy a laptop from a manufacturer which supports large capacity batteries (lenovo probably does).
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The odds are that if you are qualified enough to do something like this, you probably wouldn't be asking us about it.
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The odds are that if you are qualified enough to do something like this, you probably wouldn't be asking us about it.
Couldn't have said it better myself
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We used to do this (see Julle's video) with Psion Netbooks and HP Jornadas. Easy enough to do and you can't really mess anything up provided you can solder. You just switch existing cells with better ones.
Cheers
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I have a bit of experience with litium ion batters, and let me tell you, you don't want to mess with these things until you know what you are doing. They have roughly the same energy density as dynamite, and if you accidentally short one, it can explode. There are many documented cases of lithium ion batteries spontaneously exploding for no discernible reason whatsoever. The simple act of opening up a laptop battery and replacing one of the cells is much too risky. A small difference in in cell capacity could cause serious problems for the entire battery pack. If you are set on doing this, do some serious research on lithium batteries and charger circuits. Those chargers are a lot more complicated than they look.
Don't believe me? http://www.youtube.com/watch?v=jjAtBiTSsKY
I recommend you rely on an external lead-acid or nickle-metal-hydride battery backup that you can carry around. These will be much cheaper, safer and less complicated.
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The odds are that if you are qualified enough to do something like this, you probably wouldn't be asking us about it.
Brilliant quote.
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Does this help?
That's what I've been doing for years now on dozens of different machines. What I was asking about in this though is how many additional cells can you add if any at all to increase the capacity, or does the pcb take this into account. I know you can up the capacity on the individual cells, if you can find them(max I've found that fits the oqo is 2000mah), but if you can just stack cells together at infinitem to get a massive stack, or will the pcb somehow stop this.
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I have a bit of experience with litium ion batters, and let me tell you, you don't want to mess with these things until you know what you are doing. They have roughly the same energy density as dynamite, and if you accidentally short one, it can explode. There are many documented cases of lithium ion batteries spontaneously exploding for no discernible reason whatsoever. The simple act of opening up a laptop battery and replacing one of the cells is much too risky. A small difference in in cell capacity could cause serious problems for the entire battery pack. If you are set on doing this, do some serious research on lithium batteries and charger circuits. Those chargers are a lot more complicated than they look.
Don't believe me? http://www.youtube.com/watch?v=jjAtBiTSsKY
I recommend you rely on an external lead-acid or nickle-metal-hydride battery backup that you can carry around. These will be much cheaper, safer and less complicated.
I actually found a couple things in this video to be pretty interesting, I'll talk about it in my other thread.