Thread: Problems powering notepad with UPS in cabin

How about a 12v car laptop power supply to step up from 12v to 19v?

Something like this -
100W Universal Car Cigarette Powered Adapter/Charger for Laptop/Cell Phone/PDA - Free Shipping - DealExtreme

Although I wouldn't necessarily recommend Dealextreme for speedy delivery or reliability of product, or even guarantee that if it arrives it will be the right thing. Lovely surprise when their stuff turns up and works, though.

30 meters for 12v seems to be a long way.

Have you actually checked the available amps & voltage at the end of the string?

IIRC, 20m is about the absolute maximum for 12v.

Also, what are the ratings of the UPS? You need to keep in mind that their primary function is to allow a soft shut-down of computers in the event of a mains fail. I am guessing that you are using the batteries in the UPS, through its own inverter, to give you power to plug your laptop adaptor into.

Your other alternative is to get some bigger batteries for the UPS, and then charge them from a solar panel.

Hi,
I have just bought a 12V universal power supply from Jaycar for my Lenovo laptop.
Previously I was running it satisfactorily via a elcheapo Dick Smith 150W inverter with no worries, but was trying to get better battery economy and get rid of some of the wires.
I'm very happy with the 12-19V step up, my only complaint is the plug is easier to dislodge than the original 240V power supply plug, but it beeps to let you know.
The beeping does drive the Mrs nuts if she is using it on her lap to navigate though.

I would recommend the Jaycar 12V power supply.

cheers

You should have set up the camper to run on 24V, then you would be stepping down to 19V.

Thanks for the replies, but now i'm confused. What I've been calling a UPS is in fact the cigarette lighter socket car DC adaptor for laptops.
I haven't charged the batteries for around 24 hours but just checked the voltage readings at the batteries and the DC adaptor. There is some loss, 11.6 volts at batteries vs 11.2 volts at DC adaptor input.Still reads 19.2 volts at DC output.
I'll drag it all out and try it in my vehicle later. Bloody hell! It's supposed to be 'Wireless Internet' but it's like spaghetti junction around here.
Bill.

Originally Posted by wagoo

Thanks for the replies, but now i'm confused. What I've been calling a UPS is in fact the cigarette lighter socket car DC adaptor for laptops.
I haven't charged the batteries for around 24 hours but just checked the voltage readings at the batteries and the DC adaptor. There is some loss, 11.6 volts at batteries vs 11.2 volts at DC adaptor input.Still reads 19.2 volts at DC output.
I'll drag it all out and try it in my vehicle later. Bloody hell! It's supposed to be 'Wireless Internet' but it's like spaghetti junction around here.
Bill.

Bill - You're referring to a Universal Power Supply (DC to DC converter)

What a UPS actually is, is an Uninterrupted Power Supply for Server PCs etc..

This is where its lost in translation!


I'd suggest you are either running low on power of that cable length (What actual size cable are you running?)

Or your DC->DC converter is not capable of pushing enough current for your laptop.

Take a look at your Laptops Mains power supply - What current output was it??? 19v @ ???amps...

Perhaps the new supply is not up to the task....

Thanks for clearing up my misunderstanding Tombie.
I set it all up in my vehicle and it worked fine, so as you say, the length of the cable is the culprit. Aside from the 30 metre long lead from battery supply to cabin, there may be that much again in the cabin wiring before it reaches the wall sockets.
The DC convertor has a capacity of up to 24 volts at 3.5 amps.
The mains supply to the laptop is 19 volts at 3.42 amps.
Thr connecting lead wire diameter is around 2.5 mm, 4mm insulation diameter.
Interior cabin wiring is similar.
Looks like I'll have to move the batteries and noisey Briggs powered generator much closer to the cabin. But at least I should only have to fire it up much less frequently than when using the invertor.
Bill.