However the question here derives from a misunderstanding of how battery chargers work.
Oh dear
mike-wsm, I'm an retired electronic service engineer, and know perfectly well how to charge batteries, my question was a sarcastic comment on the previous post that said "Remember -
less volts is fine, more is not!"
The charger (bad term really) required to run and also charge up the battery is, for an HP Pavlion, one that supplies 19VDC @ 4.74A
The battery charging parameters will be handled by the laptop circuitry.