[Swansea Hackspace] New Project - Powerpack for a laptop

[Justin Mitchell]

On Fri, 2014-09-12 at 07:50 +0100, Richard Morgan wrote:
> Hi All,
> I'm looking to 'make' a battery pack that I can use for travelling and
> charging up my kit (iPhone, iPad, Mi-Fi and laptop) - laptop is a
> priority.

Laptops have some pretty crazy and varied voltage inputs, so purely off
the shelf parts is unlikely.

You'd need a fairly large LiPo battery, but these are cheap and easy to
get from the likes of HobbyKing

Charging, your going to need a fairly sophisticated multi-cell lithium
charging circuit, preferably one with a thermistor and auto-shutoff if
it starts to over-heat.  as charging is the most dangerous point.

for discharge, either you have enough cells to get close to the right
voltage, or you use a custom switch mode psu circuit, or a buck
convertor, linear regulators suck for efficiency.

but i'm no expert, and this is a project i would be wary of working on.

if you were to bodge something simple, use a stand alone dedicated
charger for the battery, and then just build, possibly from off the
shelf parts, the dc output stage, it would be a lot simpler.