power question

[Johnboy2004]

hi folks , got some questions,, here re power....comsumption.

i got a new 21 foot yacht and have installed the following.

navtex
fm radio
laptop running bluechart - powered from inverter connected to battery.
garmin gps
vhf.
cabin lights / nav lights
dept speed log
compass back lighting.
im planning also to get a CARD radar detector.

i got the above gear running from the battery. the engine is outboard and supplies 3 amp charging power , with rectifier. would a standard marine battery be up to the task to power these items while sailing.....?

then also would the 3amp output from the outboard be enough to charge the battery to keep it topped up? or would getting a 2nd battery be bit of an overkill?



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[sailorman]

u need another means of providing power as 3 Amps u have @ present is nothing like enough.
i would guesstimate u are using in the region of 10 Amps with all equipment on.
y not install a simple amp meter to monitor the situation.

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[scarlett]

and your alternator would be pushed to cope with another battery. I understand they can charge a battery ten times their amperage.

If based in Britain and you don't live on the boat [vibration and noise ] try a wind generator.

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[VicMallows]

Hey Folks. This is clearly a wind-up from Dublin!

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[Johnboy2004]

no wind up i assure u

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[tony_brighton]

Assuming it isn't a wind up - you need to figure out the current draw for each of the itmes and how long you would have them switched on (e.g. Nav/cabin lights = X Amps x Y hours) and add them all up to give total Amp/hours required per day.

Then you need to look at the battery rating and make sure its big enough (should be at least twice the size of your daily requirement as you shouldn't really drain them below 50%.

Then you need to look at your charging mechanism. How long will you be running your engine? You obviously need to be putting back in as much as you take out so thats 3Amps x Z hours. Will you really be running your engine for that long?

BTW - of the items listed, the lighting and laptop will really suck the juice.

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[ships_parrot]

I have a 3A(max) charge from my outboard, and in my experience, unless you do a lot of motoring, I'd say the 3A charging is the limiting factor. Consumption can be reduced by things like flourescent cabin lights, or LED ones (LED nav lights are also available). The laptop is also a big drain in itself - worse if you add an inverter.. Is it really necessary?


Robin.

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