What size inverter?

Tomkat17

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I have a old Dell laptop running navigation software and wireless internet card. The laptop has a special power connector therefore I went down the inverter route. My inverter is a 230v -50Hz 300w Continuous but it alarms as soon as I switch on the laptop. Is the inverter too small?
 

cliff

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Just looked at my Dell pack and the input is quoted at 1½ amp so on that basis you are on the limit.

Try booting up the laptop on battery power and once up and running then plugging it in to the mains.

Failing that get a 12-20V adaptor and run the laptop off the boat's batteries (or get a bigger invertor)

One other thing to try is to hard wire the invertor to the boat's batteries - some invertors are supplied with cigarette plugs or crocodile clips. I had a similar problem running a small TV until I hard wired the invertor and threw the ciggie plug away.
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I think that the answer is simply - Yes.

Judging by the amount of heat given off by the power supplies on older laptops - My old Packard Bell's PSU drew 1.5 amps at 240volts which is well over your 300watts. My son has a new Toshiba which will easily recharge from his 300watt inverter on the back shelf of his sports car on his morning commute.

Steve Cronin
 
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It is probably not too small - the Dell almost certainly takes a bit of a surge on switch on and it is quite common for inverters to alarm for a second or so before settling down. As long as it does settle down without the alarm then size is not your issue (and I would be staggered if a 300W inverter was too small for any Dell laptop).

However - and a BIG 'however' - some laptop supplies, including my Dell supply (there are dozens of different types of Dell supply all designed and built by third parties) will not run safely on square wave or modified sine wave. I had one blow up - it drew too much current and got hot, and blew up. So unless your inverter is a pure sine wave the extra current is a fault current.

I never, ever run electronics from anything but a pure sine inverter now. Square and modified sine are totally safe for tungsten bulbs (and some fluorescents) and buzzers. Otherwise, avoid unless you are prepared to take a risk. Lots of people do risk it and good luck to them. I risked it and was lucky that only the Dell supply failed and not the whole laptop.

A 150W pure sine inverter should quite big enough for you.
 

cliffb

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You could try running it without the battery installed. It may be trying to charge the battery as well as power the laptop....and this could push it over the top. Otherwise I think Lemain's answer very worth thinking about.
Best of luck.
 

Tomkat17

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Thanks for all the comments. The inverter runs the laptop OK on battery recharge alone but doesn't like it when I start up the laptop. I tried starting on battery then switching to inverter when loaded but still got intermittent alarms. Looks like I will need to upgrade capacity.
 
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I don\'t

He has expressly refused to face the arithmetic. These old laptops need 1.5 amps and since inverter manufacturers are always optimistic, it clearly can't cope.

When trying to solve a problem, suggesting a reduction in the magnitude of the problem isn't always an answer but providing a proportionate remedy always is.

Steve cronin
 
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