44 replies to this topic

[TenaciousDre]

OK so the eee already has good battery life but i wanted more and i already had the li-ion cells from an old p2 laptop. the only downside is the extremely long charge time (like 12 hours) and the battery meter doesnt work at all (it goes down to 0% and then the eee keeps going for 8 hours) but the biger battery does keeps the back end up off the ground so the eee stays cool. so without further ado here is the schematic and some pictures



note the grey box is the original circuit and the orange is what ive added










anyway i welcome any comments or sugjestions :Þ

[cmmike1]

that thing is huge! are you sure it's safe to use it like that? great job and it is truly a unique mod (at least to my knowledge!)

[gtisingh]

Wow that thing sure is big ! maybe a bit too big ....
... maybe down size it a bit - http://forum.eeeuser...ic.php?id=59426

How many hours do you get out of it now ?

[TenaciousDre]

im prety sure its safe since more cells means less strain on the individual cells during charge/discharge. though i do think the charge circuit is probably working harder but like i said the extra size improves the ground clearance and so the eee is about 5 degrees cooler and if i want portable i have a spare unmoded batery

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How many hours do you get out of it now ?

it depends with the cpu at 1107 mHz, backlight at ultrabright, fan 100%, wifi on, charging my mp3 player and wireless mouse, powering laptop skeakers from usb, 2 white keyboard leds and 8 red leds to light up the inside and the vents and playing a cpu/vga intensive game like halo basicaly trying to drain the batery as fast as posible i get 4-5 hours. if im just surfing the web with normal brightness and stock cpu and fan il get about 8-10 and with everything as low as it goes (cpu at 500 mHz wifi off fan off all mods off) i get 12-15

[gtisingh]

Wow those figures are impressive, i reckon you could easily add 50% to that if the cells were brand new.

[Fallingwater]

If those cells are as old as the p2 laptop they're only giving you a fraction of their capacity, but I guess you know that. That thing is huge... must weigh rather more than the computer itself.

[carmenara]

Hehe. Can I buy a crazy batt like that?

[kampion998]

:) you can also use it to boost cars and for emergency welding :D

[WarCow]

http://i.gizmodo.com...of-battery-life
http://portablemonke...up-to-15-hours/

You're in the news :)

Is that external antenna connectors you got on the lid?

[RandyLude92]

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One resourceful fellow on the EeeUser forums by the name of TenaciousDre has rigged his own 12-Cell battery for his Eee PC (looks like a 900 model) by ripping out li-ion cells from his old Pentium2 laptop and sticking them together with electrical tape.

This beast of a battery gives him up to 12-15 hours of battery life with hardcore settings (cpu clocked to 500mHz and everything off) and as a bonus the unsightly growth where the battery is supposed to be will deter any thieves.

this is the post from "portable monkey"

i just left my own little comments :D

seeing as how they think it's a 900 and all (morons)

[markp1989]

good luck geting that thought any airport:P

[TenaciousDre]

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If those cells are as old as the p2 laptop they're only giving you a fraction of their capacity, but I guess you know that. That thing is huge... must weigh rather more than the computer itself.

well it is pretty heavy. and as for the cells i know theyre old but the previous owner (my comp teacher) took exelent care of the p2 and its battery so theire in decent condition plus i think their high capacity beacause that p2 used tons of power and still had decent battery life

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Is that external antenna connectors you got on the lid?

yes. yes it is and heres a picture of the antenas i use

that grey one is a dlink 7dBi increase

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good luck geting that thought any airport:P

thanks but i think if i do take it to the airport theyre gona freak out more about the external battery i built (before i had the guts/stupidity to mod this battery) out of 64 NiCd cells that plugs in the 9.5V in the back

as always i welcome any comments or sugjestions and il leave you with some pics of my curent setup including the speakers and the behemoth (64 cell) battery


note on the right is the power cable fron usb to speakers and on the left is power from external battery (64 cells!!!) to power in jack theres also a cable from earphone jack to speaker but its hiden under lappy

here is the beast

lappy cozy in his bag

all closed up

[Metalmoore]

:O 64NiCd cells, holy shit. Good job altogethor on your mega batteries

[Easybeat]

Nice hack, now on Engadget as well.

Some questions for yourself and any other Battery experts out there, there appears to be a couple of ways to knock up home brew batteries:-
1. Add more cells to a standard EEE battery
2. Use cells as a 9.6volt replacement for the external PSU.

I have a couple of cordless drills that have 9.6V batteries, could I therefore simply hack them to use as an external power supply for the Eee and connecting in through the standard external PSU jack. If so what negative effects could there be?

[RandyLude92]

not quite. you don't want to excede 2.5-3A easybeat. too many amps and you'll start frying stuff.
odds are your drill batts are pretty high

[Easybeat]

Thanks for that, I'm not too clued up on batteries so I will do some research before messing around.

[RandyLude92]

just remember that if you're working with Li-ion (lithium ion) cells, they take a good bit of care. you need to balance the ratings and charges before putting together an array or it could go boom boom.

[TenaciousDre]

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not quite. you don't want to excede 2.5-3A easybeat. too many amps and you'll start frying stuff.
odds are your drill batts are pretty high

actually the more amps the better as long as the voltage is right your eee will only draw as many amps as it needs for example my 64 cell bat could easyly output 10 amps continually and probably as much as 50 amps for a short period of time

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I have a couple of cordless drills that have 9.6V batteries, could I therefore simply hack them to use as an external power supply for the Eee and connecting in through the standard external PSU jack. If so what negative effects could there be?

first make sure you triple check the polarity (center is + outside is -) and that you're voltage is not too high (a 9.6V NiCd can be as high as 11.6V if its just coming out of a charge) mine is about 11.2 right after a full charge but it slowly decreases and stabilizes after about 10-20 minutes to about 10.8 (no current draw) and 10.3 with the eee plugged in which is a little high but i think +or- 1 volt should be fine. i have even heard of people running their 700 series eee with the 900 series charger which is 12V but i haven't tried it and i probably never will. so just check what the max voltage is on your batteries first and decide for yourself what your comfortable with

also be careful with the type of battery i recommend NiCd because their robust can handle high curent draws and have a pretty stable voltage (about 1.2V per cell even when their almost dead). NiMh are also good but are designed for higher capacity and not high current so you would need lots in parallel to split the workload . finally avoid making your own Li-ion battery packs since they are very finaky such as if you drain them too low they can explode(that's why Li-ion battery's all have little circuit boards witch constantly monitor the battery's voltage/temp and disconnects then if anything goes wrong). and if you insist on Li-ion use professionally made packs witch you can add cells to (that way you still get that safety circuit)

and finally
USE THIS INFORMATION AT YOUR OWN RISK!!! I TAKE NO RESPONSIBILITY FOR WHAT YOU DO AND KEEP IN MIND IM ONLY HUMAN AND MAY BE WRONG SO I RECOMMEND DOUBLE CHECKING ALL INFO WITH A DIFFERENT SOURCE IF YOUR GOING TO ATTEMPT THIS

[RandyLude92]

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i have even heard of people running their 700 series eee with the 900 series charger which is 12V but i haven't tried it and i probably never will. so just check what the max voltage is on your batteries first and decide for yourself what your comfortable with

and if you do a quick search on this site you'll find a ton of people complaining that the bigger adapters from 900's and up fried thier 70x. there are even pics of the reggies on the mainboard fried to a crisp.
i WAS one of those to run my 702 on my 900 adapter but after reading enough of those stories and asus' wishy-washy "the newer adapte SHOULD work" story i quickly changed my mind.

i'm not trying to discredit you. please don't get me wrong. i think what you have done is great.
i just don't want to see others brick thier eee because of info that i know to be incorrect.

Edited by RandyLude92, 03 February 2009 - 12:58 AM.

[TenaciousDre]

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i have even heard of people running their 700 series eee with the 900 series charger which is 12V but i haven't tried it and i probably never will. so just check what the max voltage is on your batteries first and decide for yourself what your comfortable with

and if you do a quick search on this site you'll find a ton of people complaining that the bigger adapters from 900's and up fried thier 70x. there are even pics of the reggies on the mainboard fried to a crisp.
i WAS one of those to run my 702 on my 900 adapter but after reading enough of those stories and asus' wishy-washy "the newer adapte SHOULD work" story i quickly changed my mind.

i'm not trying to discredit you. please don't get me wrong. i think what you have done is great.
i just don't want to see others brick thier eee because of info that i know to be incorrect.

no harm done i wouldn't run my 701 on 12v either i was just saying it might work and that i dont know since i havent tried it personally 10.5v is as high as im wiling to go and even that might shorten the life of my eee but only time will tell