charging laptop

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voyager35

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What is the easiest way to charge my laptop (18.5V 3.5A required) Most of the 12v chargers on Amazon have lousy reviews,are the cheap inverters any better?
I don't want to spend a lot on this as i very rarely use the pc on the boat
 
The 12v dc to dc converters are generally very reliable in my experience. They are designed for cars running at 13.8v so they can get a bit hot if you run them with very flat boat batteries, especially if the computer battery is low and the laptop is also running, so this combination is best avoided.
They are cheap anyway.
If you are not using the laptop on the boat much I would simply get a small inverter. You will use more power than a dc to dc converter ( about 30%), but the inverter is more versatile and will charge camera batteries etc

For either method make sure the wiring to the cigarette lighter plug is ok for the current which will be about 5.5 A. Many older boats have small wiring suitable only for low current devices. The cigaret lighter sockets are normally rated at 10A, but many struggle as they get older with much over 5A so check the socket is not getting too warm.
It's often a good idea to mount a new socket in the most convenient location for the laptop ( or on a long lead ) and make sure the wiring is adequate.
 
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never had any probs

voyager35 said:
What is the easiest way to charge my laptop (18.5V 3.5A required) Most of the 12v chargers on Amazon have lousy reviews,are the cheap inverters any better?
I don't want to spend a lot on this as i very rarely use the pc on the boat
Click to expand...

never had any probs with my 12 volt charger

although I use a 12 volt to 110 converter from america and then plug the main laptop lead into that - most of them work at 110 and 240

stepping up to 110 as opposed to 240 seems to drain the battery less

certainly the 110 volt inverter runs cooler than the old 240 I had

I am sure some-one wil tell me that I am utterly wrong... but it works for me, it is smaller and cheaper than a 12 volt to 240. It means that I can plug all my mains camera battery chargers in to the 12 volt socket

Dylan
 
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voyager35 said:
What is the easiest way to charge my laptop (18.5V 3.5A required) Most of the 12v chargers on Amazon have lousy reviews,are the cheap inverters any better?
I don't want to spend a lot on this as i very rarely use the pc on the boat
Click to expand...

The Amazon ones are usually OK unless you have an HP or Dell with the newer 7.4mm connector with a centre pin. I had to buy a different 12v converter for my HP with a dedicated 7.4mm connector which I finally got to work after much BIOS updating etc etc. It still doesn't work 100% with No.1 son's Dell whereas No.2 son's Samsung seems to work off anything.

All our laptops work fine of a cheap inverter so that's certainly the way to go if you have the new connector.

Richard
 
I ran my previous laptops on the Maplin in-car device that others recommend, never had a problem. The DC input to my present laptop has an unusual size plug that I cannot source for one of these units. I am now charging it with a small inverter, also used for iPad and other 230 volt chargers. The solar panels are belting current into the batteries so the small additional draw of an inverter is no problem.
 
If you are buying an inverter (i.e. 12V DC to 240V AC), make sure it is well oversized if using it to charge laptops. In my experience you need 300W inverter to cope with a 60W laptop charger. I guess they produce an unusual load for the inverter which has a hard time - and buzzes and shutsdown due to overload.

I have had this with two different (cheapish) inverters. I am sure if you go for an expensive sine wave converter you will have less problems - but it is cheaper to go for a higher output cheapo inverter.

DC to DC seems to be a better solution.
 
RichardS said:
unless you have an HP or Dell with the newer 7.4mm connector with a centre pin.
Click to expand...

Yes, a really unnecessary pain. After extensive research online and by experiment I determined that a resistor from +ve to the centre-pin was all that was needed. I feel pretty sure I used 120k ohms, but could check. Next pain is then actually sourcing a suitable plug. Fortunately I found one on a duff PSU which did not in fact use the centre-pin, but was able to open up and modify the plug. Failing that a Google search will find a supplier in the US who will sell you one.
 
pcatterall said:
I did have a problem with DC to DC when the PC delayed start up to tell me that I was using an unrecognised power source, however it seemed to accept it after a while but although it ran ok it didnt seem to charge the battery.
Click to expand...

That's the usual result of using the non-manufacturer (Dell, HP) power supply if the connector has the centre pin. The PC will run OK but the battery will not charge.

Sometimes you can "persuade" the laptop to recognise the power supply eventually but a hardware solution as suggested by Vic Mallows may be the only way.

I would not buy another laptop with a centre pin!

Richard
 
Just get a Kensington charger - they send it out with a numberof tips for different laptops and will send out more if you change mnufaacturer.

I'vealways Haas excellent service from them and the charger always works in car or boat.
 
I have a Maplins job, think it is a Bandridge ( on boat so can not check ) and the plug I needed was not one of the many supplied so phoned Bandridge and they sent me correct one free of charge. Great service.
 
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