Is it possible to power laptop by DC through battery stage?

Question

Problem: Power controller of my Asus laptop is burned out (it is a long story how it has been achieved), so now standard DC input doesn't power the laptop nor charge a battery. But the laptop still works from battery!

The idea is to pass DC through the battery "channel". I figured out the options:

1. Charge battery by myself. (Since charging li-ion batteries is tricky)

2. Connect DC through battery plug instead of a real battery. (I've read that each company/model line has it's own proprietary information exchange between laptop and battery, which I think is not so obvious to emulate)

3. Connect DC instead of battery banks. Another words, take a real battery, remove banks, connect corresponding DC instead of the banks.

The questions are: Would it work? Is there any caveats with this way?
Maybe there are other options besides this 3?

P.S. Buying a new motherboard for the laptop is a cheating =)

Answer 1

If I were you, I would find a cheap lithium ion battery charger and solder that in permanently to the battery. An alternative to that is to buy a "weak" power brick that can charge the li-ion batteries. If you know the amp-hours of the batteries and you know how many cells there are, you can figure out what the 1C charge rate would be. 1C would be safe for li-ion's. Then just find a power brick that outputs a voltage very close to the max output of your battery supply that's only rated at 1C or below. In this way, you're kinda making a cheap constant-current, constant-voltage li-ion charger. Only major caveat to this plan is don't let your battery get too low on charge. Li-ion's like to be slow charged if you go too low (below 3V per cell).