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Hi

Will it be safe to plug my laptop into a 150w inverter that will be plugged into my 12v system in the caravan or will it drain my battery.  Only going for the weekend and expect laptop will be used for approx 3 hours in the evenings.

Not sure if that will be ok or if I should have another leisure battery

adb71

My laptop 16v 4.5A.  If you have an 85Ah Leisure Battery and nothing else connected and not being topped up, you will drain your battery completely after just over 6hrs.  So after 3hrs your getting very near danger point, i.e. draining your battery below 40% of its capacity is not very good for the battery itself.

2hrs max to be on the safe side using an 85Ah Leisure Battery or your ok with 3hrs if you have a fully charged 110Ah leisure Battery.

PS.  Remember your inverter when pluged in and running even with nothing connected, will pull around 0.3amps.

Thanks for your replies.

Quote: Originally posted by Mick+Tina on 21/9/2007

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adb71

My laptop 16v 4.5A.  If you have an 85Ah Leisure Battery and nothing else connected and not being topped up, you will drain your battery completely after just over 6hrs.  So after 3hrs your getting very near danger point, i.e. draining your battery below 40% of its capacity is not very good for the battery itself.

2hrs max to be on the safe side using an 85Ah Leisure Battery or your ok with 3hrs if you have a fully charged 110Ah leisure Battery.

PS.  Remember your inverter when pluged in and running even with nothing connected, will pull around 0.3amps.

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Bill, When you use an inverter to convert 12v DC into 240v AC you WILL also have some losses. Same thing goes when you then plug in the laptop's charger to the 240v AC as it has to convert it to 16v (ish) DC.

I have a  150Watt inverter and it has an INPUT rating of 15Amps!

The laptop charger is probably around 75Watt output so would take  80-85Watts as an input. At 85Watts the inverter is using 8.5Amps. On an 85Ah battery thats 10hrs until totally flat, or 6hrs until there's 40% charge left in the battery.

Real time figures in all probability will be even less than that.

Chaz

Quote: Originally posted by charlichoo on 23/9/2007

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Bill, When you use an inverter to convert 12v DC into 240v AC you WILL also have some losses. Same thing goes when you then plug in the laptop's charger to the 240v AC as it has to convert it to 16v (ish) DC.

I have a  150Watt inverter and it has an INPUT rating of 15Amps!

The laptop charger is probably around 75Watt output so would take  80-85Watts as an input. At 85Watts the inverter is using 8.5Amps. On an 85Ah battery thats 10hrs until totally flat, or 6hrs until there's 40% charge left in the battery.

Real time figures in all probability will be even less than that.

 

Chaz

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I realize that theoretical maximums for a battery to be drained are not practical, but I questioned the advice that all you could expect to get was about 2hours usage from an 85 amp battery. I use my laptop when away on it's internal battery and recharge the battery using my 150w inverter, I have never measured how long the battery will do the job for but I frequently go away for a fortnights holiday on sites with no hook up. One 110 amp battery usually lasts me 5 days and would probably do more until I set out to charge it either by talking nicely to the site owner and asking him to charge the battery for me, or bu putting it in the back of the car for a few days and chraging it whenever we go away. I tend to swap back to the first battery after another 5 days. Never been a problem for me.