Run a laptop of some old batteries

Step 5: Testing the new power

It has to be said that I had to use the A/C power connector to boot the laptop but after that it worked fine without the A/C power, I don't know whether this was because the laptop is old or it couldn't recognize the batteries to boot the laptop, but it did recognize the batteries with the A/C power plugged in and the laptop off.

Comments

[f1dd13r]

do you leave the original old battery cells in or remove them?
I think it would be cool if you could remove them and fix a suitable transformer straight through the battery board instead of using the DCin Jack.
We have a laptop in which the DCin has broken and the board has got damaged in removing it or maybe when it was dropped. Any thoughts on how to sort it to at least make it useble? The machine still runs off battery power but the battery cant charge via DCin through the motherboard anymore. 

[f1dd13r]

well I experimented and found that by wiring a jack to plus and minus pins on the battery connector on the main motherboard, I can still power the laptop anyway. This doesn't need the battery present but doesn't charge one either. 

[FreeTom]

New batteries are expensive, even 68 bux is a bit steep for an older laptop.

I would suggest a high degree of caution with this stuff though. Lithium-ion battery cells can explode (or spew fire) really easily if not handled carefully, even moisture from your skin or even high humidity can cause this to happen.
I'm guessing by the mere fact that you opened it is why it won't boot with the battery w/o the PSU in. That little board you wired up the new cells to is very picky and designed to kill the battery all together in most cases of any kind of tampering because of how volatile Li-ion cells can be. When replacing the cells it can sometimes take 2 or 3 charges before it gets back to normal. But as long as the voltages are the same as the OEM one it should "work" but the computer may not be able to see the charge level and may not be able to charge it at all.

Older computers may not all have Li-ion's in them, but if you are reading this and thinking of replacing your laptop cells instead of buying new, I'd recommend also reading this guide.
http://www.electronics-lab.com/articles/Li_Ion_reconstruct/index_3.html

Great work with the mod. Is it still working? Did you figure out a way to charge it?

[Matt4_16]

thats pretty sweet, it would be even better if you had it running off a potato or sumthing

[csmiler]

Wonder how many potatoes it would take!

[ReCreate]

id guess about 500 of them maybe take up a whole room

[ll.13]

Far too many. :)

[hunrichs]

nice work. I have to think, though, that it might have been easier to hook your batteries into the computer via the "AC" terminal (which at that point is in fact DC). You could avoid messing with the battery packs altogether. And it's not too hard to scavenge appropriately sized barrel connectors from unused wall warts.

[edmond_facho]

very helpful. good work. Could u also include how to charge a laptop battery externally using a home made charger?

[wi-fi astronomer]

That's easy. You find the voltage of your laptop's power supply at the end of the cord. At that point, it goes to a switching supply inside the laptop to run it and charge the battery. Because of that, the voltage is less critical than with the instructable. You can use 2 12 volt batteries with some large diodes in series to get a voltage drop to decently match the original voltage.

[ll.13]

I don't know, I do want to try replacing the original cells with standard rechargeable AA batteries, the only thing is it'll be expensive...... -Glad you found it helpful. ;-)

[jongscx]

Well, considering that a new battery is around $68 for older models and much much more for newer ones, it may be worth it... PLUS, if you're crafty and use a battery holder and make it "open-able" (not thinking right now), you could also swap out regular batteries in emergencies...

[joshikins]

If you were to do this, make sure you DO NOT, I repeat, DO NOT, plug in the charger. Rechargeable batteries are designed differently than normal batteries. If you put normal batteries in and try to charge them chances are they WILL explode.