Charging a Laptop.

[Carmel2]

Carmel2,
If you have a vernier handy could you measure the connector you need and post the sizes? I have a fair collection from 2 or 3 12v universal chargers

It's not the dimensions of the connector, it's what's inside, it has 2 small slots which lead to 2 tiny contacts.

 

[VicMallows]

I believe that there is a way round this by soldering a capacitor across the centre pin or something but I can't be bothered.

HP laptops with the 7.4mm conector with recessed centre pin just need a 120k resistor connected from +ve (the inside of the barrel) to the centre pin. The correct plug is included with many of the multi-tip packs which often come with cheap chargers BUT the centre pin is usually not connected to anything. It's not too difficult to open the plug up and solder a wire to the centre pin. (or find a scrap mains charger with the correct plug!).

(I have come across all sorts of convoluted claims about the centre pin - from digital coded signals sent from the 'genuine' power supply ...... to theories that the voltage on it controls the processor speed to stop the psu overheating. I can assure you that a 120k resistor works fine though)

 

[RobbieW]

It's not the dimensions of the connector, it's what's inside, it has 2 small slots which lead to 2 tiny contacts.

Got two that fit that decription, probably identical but from different kits. Both are round connectors of 4.7mm OD & 1.5mm (ie a 1.5mm drill goes in and a 2mm one doesnt) ID with two slots leading to contacts that would touch the central pin on the laptop plug. Certainly one of those is from a Trust brand kit. Sound like what you need ?

 

[vyv_cox]

Vyv...re: my PM on this from last year: did you check out the Nikkai A33HU from maplin when you got back to the UK? The included 7.4mm adapter (labelled "k") works for my HP dm1

Seeing posts at the time, and just above this, concerning other issues about this plug, I decided to use the inverter and charge it via the mains plug, as we always enjoy a surplus of power. However, in the end I bought an iPad and did not take the laptop to Greece at all. It has worked out reasonably well, always some minor issues of not having all my info with me, but not too much of a problem. Thanks for your info, which may well turn out to be valuable for the camper van.

 

[Carmel2]

Got two that fit that decription, probably identical but from different kits. Both are round connectors of 4.7mm OD & 1.5mm (ie a 1.5mm drill goes in and a 2mm one doesnt) ID with two slots leading to contacts that would touch the central pin on the laptop plug. Certainly one of those is from a Trust brand kit. Sound like what you need ?

Thanks Robbie, I think we might be getting somewhere yes those connectors are along the right lines, I will report back.

 

[Carmel2]

I think this may work for you as well Vyv, I am going to give one of these a go http://www.amazon.co.uk/BEST-SELLIN...02773&sr=8-18&keywords=car+adaptor+for+laptop