Laptop computer and 12v charger/invertor problem

Hylda&Jon · Guru

Laptop computer and 12v charger/invertor problem

valiant81 · Senior Member

Hi all;

Sounds like your little inverter is way to small to run your lap top's power supply and or the inverter is not pure sine wave, this alone is impotant with a lot of computer power supplys nower days.

One would up grade to a better inverter of at least 300 watts and pure wave,I got a pure sine wave inverter for my caravan for the Vast decoder and worked a treat( I now have a 12 Volt Vast receiver )and the inverter is not used now, but why not go the way I've done and use a 12 Volt to 19 Volt up converter ( got mine from jaycar ).

This has a 12 Volt input and a 19 Volt output, can be adjusted +/- and with the supplyed adaptors works fine for just about all of the common laptops, just check your computers working voltage as some need a lesser voltage.

Plendo · Guru

Hi Jon,

you state that your charger needs 2amps at 240V, that would be up to 480 watts, and your inverter is rated as 100 watts, that would be the reason.

Thre would be a couple of options:

1. Get a bigger inverter (recommend at least 600w)

2. Get a 12v laptop charger, they are generally cheaper, and just save the hassle of using an inverter.

I hope this helps.

Spydermann · Senior Member

12v laptop charger or 12v laptop? Older laptops take 19v or thereabouts.

rockylizard · Guru

Gday...

Jon, I used to have a 180W inverter to charge my Toshiba laptop - usually when in the car. I finally decided it was a bit of a "waste" of energy ... taking 12V and making it 240V and then having the 240V 'adaptor' that comes with the laptop to break it back down to 19V for the laptop

I now have 12v sockets in the van and use this. So now the 12V is changed to 19V and charges the laptop from less than 10% battery to 100% battery within 90mins.

Works excellently -

http://www.jaycar.com.au/IT-Products/Connectivity/Power-Products/150W-Car-Laptop-Power-Supply/p/MP3472

It has an inbuilt 'anti-surge' so it is safe to use it to charge the laptop and to safely use the laptop at the same time.

Cheers - John

jules47 · The Happy Helper

I have a HP laptop, and have not been able to get a 12v laptop supply as mentioned by Rocky Lizard above. Have tried about 150 of those little plug in bits, and none fit my laptop. So I have an inverter. The first one I purchased would only get to 4% and the alarm would go on. I took it back, thinking it was faulty, they game me another one the same - 300 I believe, same problem. They wouldn't give me my money back at first, but went to their head office, and got a letter to take to any store, and get money back. I purchased another one, from a different company, and it has been going well for about two and half years, but has finally decided enough is enough, and it died.

Went back and bought the same size and brand,, got a good deal, they knocked $80 off the original price.

Hylda&Jon · Guru

Thanks guys.

I would have thought a 12v charger/inverter made specifically to charge laptops would be capable of charging a laptop but I guess I'm wrong.

I was trying to avoid buying a 12v direct to 19v charger because I already have this thing and the one I would have to buy that will manage 19v & 6.3amps needed for this laptop are about $80 each and I needed one for me and one for my wife's computer & on a pension I try to do things cheaply plus, since I have 240ah batteries and 320w of solar spare to use I didn't mind the extra power usage.

The other choice, of course, is to get a 600w pure sine wave inverter.

Oh well. Such is life.

Thanks all for your help.

Jon

Gundog · Guru

1st off you dont need a pure sine wave invertor. Just for the record my Toshiba ac adaptors specs are imput 100-240v @ 2A output is 19v @ 6.32A. If my laptops SOC is between 90 -100% it happily runs off a 100w beer can invertor BUT it will not advance the charge it will only assist in maintaining SOC. I would suggest if you want to charge from 12v then get a good 12 to 19v car charger its worth the expense in the long run. They are available from ebay for $26, its a better option to use it rather than ac power supply and invertor

spida · Guru

Best advice I was given re charging is to never let the power drop down then start charging - always on charge when I use it. Has made a huge difference. I have a big 19v Toshiba that I charge on 12v with the correct charger, and find it works better on 12v than using the beercan inverter.

Hylda&Jon · Guru

Gundog wrote:
1st off you dont need a pure sine wave invertor. Just for the record my Toshiba ac adaptors specs are imput 100-240v @ 2A output is 19v @ 6.32A. If my laptops SOC is between 90 -100% it happily runs off a 100w beer can invertor BUT it will not advance the charge it will only assist in maintaining SOC. I would suggest if you want to charge from 12v then get a good 12 to 19v car charger its worth the expense in the long run. They are available from ebay for $26, its a better option to use it rather than ac power supply and invertor

Thanks Gundog.

Though many say that using modified sinewave inverters for a laptop is ok I would never use anything but a pure sine wave inverter as there are just too many experts that say not to risk charging a laptop on the modified one and for my $1000 laptop. It's best to spend a few more dollars to be safe.

To get a 12 to 19v inverter I would need to pay well over $50 if I want one that handles the 9amp that the Toshiba needs. The cheaper ones are around 3amp or below, I have one of those and it doesn't work either.

BTW. I have just bought the charger that Rockylizard recommended but from ebay not Jaycar as it was a bit cheaper -$54.40. (Thanks for the link John I didn't know about those ones).

Cheers.

Jon

PeterD · Guru

Try this, switch the computer off. Then connect the computer to the inverter and power it up. Do not switch the computer on. Let the battery fully charge and then switch the computer on. The inverter may be good enough to charge the battery if the computer is not running. When the battery has charged there will be less power demand and then the inverter may cope just powering the computer when it has a fully charged battery.

-- Edited by PeterD on Tuesday 11th of August 2015 12:15:02 PM

greyhoundtom · Senior Member

Very interested in the discussion so far as I will have problems in a couple of weeks when we hit the road full time charging the laptop batteries, and was ready to buy one of the 12 to 19 volt chargers and plug it into the outlets in the car thinking the laptop charging problem was solved.

Unfortunately I noticed that the charger is 150 watt and the 12 volt outlets in the tug clearly state 120 watt. Bugger!

Looks like I may have to organise another 12 volt outlet with heavier wire directly from the battery.

greyhoundtom · Senior Member

Further to the above; picked up a DC laptop charger today from Jaycar that is supposed to be able to charge our laptop battery, and it is rated at 90 watt.

At least it's within the limitations of the vehicles current 12 volt supply sockets, but just how effective it will be in charging the laptop battery at that lower current remains to be seen.

Cheers,
Tom

Jaahn · Guru

PeterD wrote:
Try this, switch the computer off. Then connect the computer to the inverter and power it up. Do not switch the computer on. Let the battery fully charge and then switch the computer on. The inverter may be good enough to charge the battery if the computer is not running. When the battery has charged there will be less power demand and then the inverter may cope just powering the computer when it has a fully charged battery.
Hi
That is the good way to get the laptop to work OK on a limited power dc charger. I do that with mine when using it at night. During the day when the solar is charging and the voltage is high then my charger works well and will charge the batteries and power the computer. But at night when the voltage has dropped it will struggle if the battery is not fully charged. So we just have it plugged in when the sun shines or when driving and then it is good to go when ever we want.
Jaahn

KevKim37 · Senior Member

I have a S.E.A 150 watt Full Sine Wave Inverter purchased in 2001 for $560 and this little unit has been operating two Acer Laptops for the last 13 yrs. It never goes into Intermittent Full Load use and the Cooling Fan only operates momentarily when on. I think this unit is a Good Quality older style compared to what I have seen some Cheaper Store and Ebay type FSW Inverters of larger wattages that either would not operate a Laptop or last very long.

Cheers Kev.

jules47 · The Happy Helper

Kev - hi to you and Kim - I remember when I had trouble with my inverter, we charged my computer up on your inverter - no problem, which was when we realised mine was not up to the job.

See ya soon!

KevKim37 · Senior Member

Sure will in Seabird Jules.