Electrical power that is.

Does anyone understand how much power I am going to use with my laptop runing MAPTEC navigations software.

Do I need an inverter, will it help?

Should I add a battery, and just have a dedicated connection to it?

I have a CAL 31, with a Yanmar 3G, not sure what the alternator puts out, but damn its a sailboat, and I never use the engine! Unless the beers getting warm, of course (disclaimer).

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IMHO a laptop as a primary nav tool is a bit of a waste.  A chartplotter is cheaper cost wise and more amp friendly.  A laptop in the cockpit is just begging to get wet and most laptops are more difficult to read in direct sunlight than a chartplotter.

If you do go the laptop route you can use a small inverter from Radio Shack (100 watts is plenty to charge the laptop).  What kind of battery set up do you have now?  My laptop will run for 3 or 4 hours on a charge.  Thats fine for doing internet crap but if i used it for navigation and only glanced at it every now and then it seems that you wouldn't be getting much of a return for the amps spent.  


When I charge my laptop it takes less than 3 hours at between 3 an 5 amps an hour.  I never really paid attention to it that closely.  But I would say that generally its full for about 10 to 12 DC amps spent.  Not really that much but you could do better.


s/v Veranda

I use a laptop for navigation, as it also serves as my movie viewer and music storage, not to mention my internet connection. I have a dedicated Kingston charger/inverter for the laptop (works on AC or DC). I also have a wind generator, so if there's wind for sailing, then there's generally enough to keep up with the amp drain. If not, then the engine is running.

I don't use the laptop in the cockpit, it stays at the nav desk which is right inside the companionway. I use the chart program (Fugawi ENC) for establishing general heading and checking my course. I don't steer by it. The compass and depth gauge are the only aids I look at when at the wheel.

While the chartplotter is more amp friendly, for me it would be redundant since I need the laptop for more things. So for me, this arrangement works best.

I have Polar Navy on my laptop.  I used it, ActiveCaptian; when available, along with a hand held GPS, and a chart book when coming up from Florida.  The laptop sat below, hand held GPS along with chart book were at the helm.  At night I used ship's batteries to power the laptop through the inverter without problem.  With two solar panels mounted on the aft hand rails along with the engine running all day as we motored north the batteries stayed topped off.  I suspect that I'll get a chart plotter that combines everything into one display at the helm and keep the depth, speed, wind, and computer below decks as a backup.  On the other hand, I might just revert to sextent and a wet finger, along with a lead line.


Everyone thanks for your input!

The bottom line for me is that the navigation software has great voyage planning features.I want to use it.

I do use charts for navigation, and have not wanted to spend the money on a standlone GPS by the helm. I just purchased an inverter, and I am going to keep the laptop below deck, use it as necessary, and keep the charts next to me.

I did some research and figured the amperage I will need, and for just one item running, I am sure a laptop, wont give me any problems. Glad I have two batteries,so I am not worried, I will do alot of trial and error work, and see what works best.

O.K. I probably will buy the standalone GPS, glad I got that out!

I also looked into some solar cells, which may suffice for as a secondary back-up. Its just I like the software, and expect to get my use from it.If I start spending the cash, I should just buy tthe GPS and do the voyage planning before I leave.

Oh who knows its Sunday!!

Thanks for all who answered, stay tuned for my next set of questions! 

You can get a GPS receiver that plugs into a USB port for under $100 dollars. Mine sits inside the cabin and has never failed to pick up satellites.

Radio Shack might have the converter I use so you wouldn't need an inverter, though having an inverter also comes in handy for other stuff too. The converter has a voltage slider to select the voltage of your laptop, and a varied assortment of plug ends to match your laptop. Either your charger, the back of the laptop or product info will tell you what DC voltage your laptop is, and make sure to lookfor the C that will have a + or - sign in the middle indicating positive center or negative center and match the plug.


My laptop uses 65 watts.  That's 5+1/2 amps per hour.  A small inverter uses about 1/2 amp per hour.  You can use half of a standard battery's rated amperage before it needs to be recharged.  Using more damages it.  Personally, I never use the engine battery for anything other than starting the engine.

On our first trip, 6 years ago, we used a laptop interfaced with a handheld GPS for navigation.  Our second trip, we just used the handheld and paper charts.  Slow, but accurate.  Then, we got a chartplotter.  There is no comparison.  A laptop is a power hog and it is down below and virtually useless.  Paper charts are great when you also have a GPS.  But a chartplotter at the helm?  Oh yeah!  Is it infallible?  Nothing replaces good research before heading into unknown waters.  Use and understand the paper charts before relying on a chartplotter or a laptop navigation program.  Laptops are OK, but definitely a cumbersome second best to a dedicated chartplotter at the helm.

Try the iPad 2 3G with Navionics Nav system. User friendly, power friendly, It is great.

Don't trust Navionics in the Bahamas!

normal laptop runs t 6-10 amps per hour.  netbooks are too small to see bu use hardly any electricity---is your choice--for me, is either  nav lights or laptop.  either garmin or  laptop. i choose  garmin,  simrad, and  nav lights , thankyou.   i see no reason to use my laptop  for nav work.

put a small solar panel on the boat  , for about 100 bucks you will get what you need




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