Battery Draw

[Sugo]

On my boat to run my GPS system I have a netbook and a external monitor that are being powered at 110 volts by an inverter from my 12 volts batteries. The cord from the inverter to the external monitor converts the 110V AC back to 12v DC. Would it save battery life bypass the inverter, and the AC/DC adapter and wire it directly to my 12 volt system. The cord suggests the monitor draws 3 amps, other than a fuse, would I need some type of surge protector?
Thanks for any info

 

[Bondo]

Re: Battery Draw

Would it save battery life bypass the inverter, and the AC/DC adapter and wire it directly to my 12 volt system.

Ayuh,.... Common sense would have Us All runnin' our 'puters off a car battery,...
Pretty much All of 'em are 12v powered...

Common Sense, would also say yer plan oughta work,...
But,... I ain't no electronical Engineer,...

I'm just a Re-engineer.... Interestin' question Sugo,....

 

[Jlawsen]

Re: Battery Draw

Double check that, the netbooks and elitebooks I have run on 18v. HP is notorious for this. You can get a cigarette lighter adapter that has an inline step-up transformer but it draws about the same as your inverter. After fighting the problem for a couple of year I finally decided to carry two identically configured EliteBook 2530p's and use a docking station. I run mine on the comptuer battery and when one gets low I swap it for the other one and put the one that's low on the charger.It's shut down and only uses enough current to charge the battery. I store my data on a thumb drive so all I need to do is fire up the fresh one and I'm right where I left off. You can find Elitebooks pretty cheap now. New, they'll still run you about 2500.00.

FYI, these are luxury items for me, I run HDS Head Units and use the PC's to make personal bottom contour maps and Surf the internet when I'm bored and have a Cell tower with data nearby.

 

[NYBo]

Re: Battery Draw

Yes, you can run the monitor directly from 12V, but some sort of voltage regulator to prevent voltage spikes sounds like a good idea.

 

[Sugo]

Re: Battery Draw

If I do wire the monitor directly to 12 V do you think it will drain the battery slower than using the inverter?

 

[Silvertip]

Re: Battery Draw

If I do wire the monitor directly to 12 V do you think it will drain the battery slower than using the inverter?

Yes - it will drain the battery slower. Inverters are not 100% efficient so you have the loses in the conversion to deal with.

 

[bruceb58]

Re: Battery Draw

Your netbook is probably drawing in the neighborhood of 20-35W. The inverter is going to add 20% to that number so your total draw would be 3.6A instead of 3.0 if you decide to get fancy and go straight to 12V. What you have to realize is that the voltage on your boat will vary from 12.6V with the engine off to over 14V with the engine on so it is very possible that your netbook won't tolerate that. Many DC/DC adapters step up the voltage from 12V and regulate it down to a known voltage.

Personally, I would just stick with the inverter or ditch the netbook method and just get a marine GPS.

 

[Sugo]

Re: Battery Draw

Thanks for the info. Your comments conclude what I suspected. I do have a small Garmin GPS on my dash. The net book, external monitor and inverter, I picked up second hand for $150. This system gives me a 19 inch color display on my dash rather than the 5" black and white as well as the use of many more charting tools. (using a wireless mouse) An equivalent marine GPS will start around $2500 When you have champagne taste on a beer pocket book you must be a bit crafty.
Thanks again