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-   -   Use a DC Power Supply? (http://www.sailnet.com/forums/electrical-systems/67255-use-dc-power-supply.html)

Tree 08-11-2010 10:40 PM

Use a DC Power Supply?
 
Hello....
I have 3 amp trip lite dc power supply that puts out 13.8 V.

When my batteries are out of my boat during winter, any reason why I shouldn't use this for 12 V power on the boat?....as in drop the battery switch pos and neg leads on to the power supply terminals and plug it in?

I know 3 amps isn't much but all I'd be using would be radio, lights, CD player, propane sniffer/switch etc.

Thanks!!

SlowButSteady 08-11-2010 11:05 PM

As long as your boats total electrical load never exceeds 3 amps it shouldn't be a problem. However, if you use regular (incandescent, xenon, etc.) bulbs, and you have a fairly powerful stereo, you could easily exceed 3 amps. Also, a fixed-mount VHF will likely draw 6+ amps while transmitting.

The other thing to consider is that your trickle-charger might not have been engineered for long-term continuous use.

pedcab 08-12-2010 02:12 AM

Quote:

Originally Posted by SlowButSteady (Post 631582)
As long as your boats total electrical load never exceeds 3 amps it shouldn't be a problem. However, if you use regular (incandescent, xenon, etc.) bulbs, and you have a fairly powerful stereo, you could easily exceed 3 amps. Also, a fixed-mount VHF will likely draw 6+ amps while transmitting.

The other thing to consider is that your trickle-charger might not have been engineered for long-term continuous use.

I'll double that.

You can, nevertheless, build your own heavier duty supply if you're a bit familiar in DIY electronics...

I did that myself for when my boat is ashore for maintenance and it is yet to let me down...

http://www.farnell.com/datasheets/11454.pdf

Classic30 08-12-2010 02:56 AM

Quote:

Originally Posted by Tree (Post 631577)
Hello....
I have 3 amp trip lite dc power supply that puts out 13.8 V.

When my batteries are out of my boat during winter, any reason why I shouldn't use this for 12 V power on the boat?....as in drop the battery switch pos and neg leads on to the power supply terminals and plug it in?

I know 3 amps isn't much but all I'd be using would be radio, lights, CD player, propane sniffer/switch etc.

Thanks!!

Is your boat IN or OUT of the water during winter??

Only reason I ask is that, if it's this one and you're IN the water, you'll need to make sure that the -ve terminal is isolated from earth or you could end up with electrolysis issues..

If you've got power available (and obviously you have), is there any reason you couldn't leave the batteries in the boat and simply hook up a battery charger to both charge the batteries and do what you want them to do??

Tree 08-12-2010 12:14 PM

Thanks for the replies.....

Yes, the boat is out of the water in the winter. But I did wonder if there could be any possible application when in water. The electralisis concern is a good point.

I'm very far north and we can see minus 25 F in the winter. I have always figured that it's safer to bring the batteries inside the house where I can monitor their state of charge and insure that they are not freezing.

I only asked the question because several years ago I had purchased this little power supply when I had picked up a new gps unit for my airplane and I wanted to "play and learn" with the gps (and not eat up the double a batteries in the gps unit). Well, long story short, I didn't really ever use the power supply. The gps was easy to learn. So 10+ years later I came across this little power supply hiding in the back of a cabinet and I said to myself.... possible aplications???? ....hmmmmm could I use this when the boat is decommisioned and sitting in the back yard?...... ya know, shoulder season when it's not so cold and I'm working in the boat and want music.... or to test new gear that requires a little DC power.....

kd3pc 08-12-2010 12:46 PM

tree

contrary to what others say, this is not a trickle charger...and while it puts out 13.8 vdc nominal it is most likely not well regulated and is NOT a battery charger. Given it's age and lack of use, you may have bad caps in it as well.

The more current the little gem is asked for, likely the lower the voltage it will provide. It may or may not have shunting or shutdown...difficult to say with out a model number. That can damage sensitive gear.

It was made to use with automotive equipment - lights and some of the sniffer/switches may fail with use of this supply.. all depends on how lucky you feel. You would be better served to use the battery with a real trickle charger in place..

this is not marine quality and may not play well with your gear.

Tree 08-12-2010 05:30 PM

geeez kd3pc...... how about rainin' on a guys parade :(

All I really wanted to do was go out on my boat some evening and pretend I'm still swinging on a hook. Maybe light the heater..... turn on a tune.

;)

kd3pc 08-12-2010 06:56 PM

Just hate to see you burn up some gear or worse the boat, when the PS fails to shut off...even if you flip the switch...

One of the jump boxes or a small PV system would be a safer bet for what you want to do..

Not to mention if something does happen, and your insurance company finds out you left an unregulated PS on, overloaded..

Your boat, your life, you just asked why you shouldn't use it.....My opinion only...quantity trumps quality these days any way..

YMMV

mitiempo 08-12-2010 10:42 PM

I agree with kd3pc. It is a low output power supply and will likely choke if it nears its max output. The cd player can exceed 3 amps by itself probably.

Classic30 08-13-2010 01:07 AM

Quote:

Originally Posted by mitiempo (Post 631972)
I agree with kd3pc. It is a low output power supply and will likely choke if it sees a real load like a battery that needs charging.:eek:

MIT, I don't think anyone was suggesting this unit be used as a battery charger - since it clearly isn't..

Quote:

Originally Posted by kd3pc (Post 631736)
tree
contrary to what others say, this is not a trickle charger...and while it puts out 13.8 vdc nominal it is most likely not well regulated and is NOT a battery charger. Given it's age and lack of use, you may have bad caps in it as well.

Why would you say that when the web site clearly indicates it is "precision regulated"? Can you get any better regulated than that?? :confused:

As I see it, there is very little reason he couldn't use it for what he wants, within it's limitations, but, to my mind, he might be better served leaving his batteries on-board and running a battery charger instead. ;)


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