600w inverter - how long can i charge laptop before i should run the engine?

Submitted: Friday, Jun 08, 2012 at 09:11
ThreadID: 96106 Views:3733 Replies:5 FollowUps:9
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The title pretty much says it all. I have a normal car battery and a 5 yr old dell laptop. The adaptor says 90w but im not sure how meaningful that is as the 300w inverter was not enough power.

So yeah, just wondering how long i can leave the laptop charging straight from the battery without draining it or lessening its life expectancy.

Thanks!!
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Reply By: Been-Everywhereman - Friday, Jun 08, 2012 at 10:47

Friday, Jun 08, 2012 at 10:47
I have stopped the engine and setup camp.
I have forgotten my 600watt invertor was on still and in the morning woke up and made brekkie, kicked some rocks over till smoko time and then started the car and when I have gone to turn the invertor on I have noticed it still on.
No problems and I have done that about 30 times.
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Follow Up By: Eager2CAuswithdog - Friday, Jun 08, 2012 at 11:15

Friday, Jun 08, 2012 at 11:15
Great. Do you have to replace your car battery often? :)
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Follow Up By: Eager2CAuswithdog - Friday, Jun 08, 2012 at 14:40

Friday, Jun 08, 2012 at 14:40
Was just thinking - i suppose one laptop battery is charged it stops puling power so wouldnt matter if it is 3 or 30 hours...yes?
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Follow Up By: Racey - Friday, Jun 08, 2012 at 15:30

Friday, Jun 08, 2012 at 15:30
The drain on the battery is directly proportional to the load on the inverter. Battery charged, the inverter would be drawing minimal current.
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FollowupID: 763171

Reply By: Ross M - Friday, Jun 08, 2012 at 11:23

Friday, Jun 08, 2012 at 11:23
Most efficient way to charge a laptop is to use a 12v to 19v dc to dc converter. Jayca, Super rubbish etc have them. only one change of power loss and compact too.

Ross M
AnswerID: 487932

Follow Up By: Eager2CAuswithdog - Friday, Jun 08, 2012 at 12:05

Friday, Jun 08, 2012 at 12:05
My lappy uses 19.5v. Would that be an issue?
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Follow Up By: garrycol - Friday, Jun 08, 2012 at 12:30

Friday, Jun 08, 2012 at 12:30
Most have variable voltages - mine has selections ranging from 15 - 24v.
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Follow Up By: Member - Bruce C (NSW) - Friday, Jun 08, 2012 at 16:10

Friday, Jun 08, 2012 at 16:10
Hi Eager,

I have had one of those 12 volt laptop power supplies for a few years now and cannot recommend them highly enough. They have variable voltage setting, usually on the back.

To run a 12 volt to 240 inverter you have to use more power than you will if you use a straight 12 volt laptop power supply. There are losses going up to 240 volt and losses coming back down to 19 volts. You will halve the losses at least if you only convert from 12 to 19 volt.

You will also use a lot less power in your laptop if you double the RAM in it if your unit only has the basic amount. These modern versions of Windows are RAM hungry. Lots of power used running swap files where RAM is the better solution.

Here is a link to the type I am using. In a word, brilliant. Comes with various tips to suit many different brands of laptop. Some laptops use a special tip but I am not sure . There was a post on here a few weeks back covering that issue.

http://www.ebay.com.au/itm/12V-NOTEBOOK-LAPTOP-POWER-SUPPLY-CHARGER-CAR-/400142546607?pt=AU_Laptop_Accessories&hash=item5d2a5ab6af

Hope this helps, Bruce.
At home and at ease on a track that I know not and
restless and lost on a track that I know. HL.

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Follow Up By: Bigfish - Friday, Jun 08, 2012 at 16:35

Friday, Jun 08, 2012 at 16:35
Eager2CAuswithdog
Totally agree with Bruce...Absolutely no need for an inverter.

Use the KISS principle...Keep It Simple Stupid!!!

Laptop use very little power.
Google it or use Bruces links.

cheers
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Follow Up By: Eager2CAuswithdog - Friday, Jun 08, 2012 at 17:04

Friday, Jun 08, 2012 at 17:04
Ok cool. But i already have the inverter. Will be grinding coffee beans too :)
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Reply By: Member - Michael P (QLD) - Friday, Jun 08, 2012 at 17:40

Friday, Jun 08, 2012 at 17:40
Hi,
Just be aware that with a Dell laptop, You may not be able to use a generic brand 12v charger.
I have a Latitude D830 a generic would not work. Dell have their own brand which I now use without any problems.
Your model may be different I am quoting mine and what I was told by the Texpert that I use.
By the way I have successfully used a 300w inverter.

Regards Mike.

.
AnswerID: 487969

Reply By: Member - Shane D (QLD) - Sunday, Jun 10, 2012 at 09:49

Sunday, Jun 10, 2012 at 09:49
I have a 300w inverter in my camper and it uses 0.1 amp (measured) when running in stand by mode, but when charging the laptop, it uses around 8 amps,
my laptop only needs an hour or 2 to charge

Shane
AnswerID: 488068

Follow Up By: Eager2CAuswithdog - Sunday, Jun 10, 2012 at 12:23

Sunday, Jun 10, 2012 at 12:23
i charged my lappy and used it one day

was greedy and tried to charge the next day without running the engine.

battery flat :(

only one real way to find out i guess :)
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Reply By: oldtrack123 - Sunday, Jun 10, 2012 at 10:48

Sunday, Jun 10, 2012 at 10:48
HI Eager

If your 300W inverter will not run the battery charger , the inverter type is possibly the problem ,not the WATTs capacity
Depending on the lap top,it may not be possible to charge DIRECT from the battery, most likely may need a more efficient method such as a voltage converter as mentioned by others
The voltage required should be on the lap top
Peter
AnswerID: 488069

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