How to modify a battery bank output to 20V to support my Lenovo laptop

[tako_chanz]

Hi all,

I have a battery bank (iPower EM-929L) came with my old laptop (DeskNote A928).

This battery bank takes DC input: 19V-20V/90W and DC output: 12V-20V/90W.

I want to use this battery bank for my Lenovo laptop as a portable power backup.

I don't understand is that when a wall AC adapter(19V 4.74A) plugged in to it's input, it will output 19V but when the AC adapter unplugged, it only gives 15V output.

Anyone know why?

Is there a fix to this? like a adding a jumper wire will make it's output to 19V or 20V?

If attached image not show up, please refer to this one:
http://i.stack.imgur.com/I0YWb.jpg

Thanks in advance,

 

[davenn]

hi there
welcome to the forums

because the 19V AC adaptor is charging the batter(s) to the 19V and you will see that on the output. but when the charging from that adaptor is removed, the battery bank is dropping to its normal operating voltage.
IF its supposed to put out MORE than 15V DC when not being charged, then it is indicitive that the battery bank is aging and not holding a charge as it used to

Dave

 

[tako_chanz]

Thanks for the info. I've tried to measure the voltage that come out of each cap bank and they all measure to 3.8v, so if one got aged it should have different voltage output? maybe less than 3.8v? There's a PIC IC on it, do you think will that PIC controlling the voltage output? like when there's no load it will operate at 15v and when there's load it will kick to 19v? I am just trying to see if this modify to output constant 19v so my lenovo laptop able to start. Any ideas?