increase voltage in laptop charger?

[gasfree]

Good morning guys.
Just wondering if anyone knows hot to increase the voltage on laptop/notebook chargers. The one's I currently have all read 16.42 - 16.44v I am trying to get them to 16.65. These are the ibm ones. Thanks.

 

[fechter]

If you post a pic of the insides, I might be able to point out where you can tweak it.

There seems to be a large number of variations on the designs, but they all have the same basic operating principle.

On the secondary side, there will be a zener diode or IC voltage detector that triggers the emitter side of an optocoupler. Tweak the zener/voltge detector. It may be difficult to get the output precisely where you want it with fixed components.

If you are lucky, there will be an adjusting pot on the board you can just use a screwdriver to adjust.

 

[gasfree]

Thanks fechter. I will do that when I get home. I posted this just as I was about to leave for work and ended up being a little late opening up the store.
I can't wait to get this stuff going.

 

[gasfree]

here are the pics hope this is helpful. I hope they are big enough to see. Thanks.

 

[fechter]

That looks nice and simple. I don't see all the parts I expect, so perhaps there are some on the bottom. I guess a bottom side picutre would help.

 

[gasfree]

I hope this helps.

I for fun tried a lifepo4 charger to charge 7 of them in series. It seemed to work on fortunately I only got 2.325ah out of it, was hoping for more. Might be that the batteries are on their last legs. Will try a different batch later.