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-   -   shore power battery charger (http://www.sailnet.com/forums/gear-maintenance/55540-shore-power-battery-charger.html)

samhamt 06-21-2009 01:41 PM

shore power battery charger
 
I just bought a boat and found out that the battery on it is not hooked up to the shore power. How do I hook it up so that the shore power charges the battery?

Vasco 06-21-2009 01:46 PM

If your boat doesn't have a battery charger you will have to buy one and connect it to your AC (shorepower) and the batteries.

Vitesse473 06-21-2009 02:24 PM

SamHamT needs to post the battery bank type and size. If it's a small to medium size bank, than I have a Dolphin 40amp charger I'd be happy to offload for very cheap.

Whatever you do, make sure you know what you are doing when connecting all the cables. Using incorrectly sized cables can lead to a fire. Just be knowledgable and thus safe. It's actually a simple project if you research and size it properly.

sailingdog 06-21-2009 03:56 PM

As stated previously, the battery charger size is usually determined by the size and type of battery bank you have. A good brand of reasonably priced chargers are the Iota brand, which have been recommended by several sailnet members, including myself.

Boondoggle30 06-22-2009 12:27 AM

Killed my charging system??
 
So I'm still learning... haven't run into anything but stupidity and experience are tough teachers.

Today was my first 'solo' without anyone along who knows what the %#$% sailing is about (only 2 passengers, one my wife!).

Up to now my 'teacher' has had a series of duties and I have the lion's share (being the student). Well today I forgot to do one of the duties he NORMALLY does FOR ME...

I started the engine and put it to idle... left it running for about 4 minutes and noticed that I was still on shore power.

Yes ouch. I immediately killed the engine, unhooked from shore and carried on. Once we returned (an ugly approach to the slip!) and were back on shore power I switched the batteries to all banks (starter and house) and then selected "test" and the power meter went into the green and 'charge' area. Now without knowing how the boat is wired (because I can't tell you!) did I fry my charging system??!! How can I tell??

I left the shore power plugged in over night and the frig is running. I figure that if the system is N/S then the frig will drain the house batteries and show me the error of my ways.

Suggestions??

If you think experience is good teacher... try stupidity.

Al

mitiempo 06-22-2009 02:04 AM

The main thing is to run your engine, and therefore your alternator, with one or the other of your batteries (or both) selected so you don't fry the alternator's diodes. It does no harm to start and run your engine while on shorepower. So the important question is whether or not at least one of your batteries was selected when the engine was running.
Brian

jarcher 06-22-2009 03:56 AM

Quote:

Originally Posted by mitiempo (Post 498759)
So the important question is whether or not at least one of your batteries was selected when the engine was running.

Most likely yes, since he was able to start the engine.

To test your charging system, select ALL on your battery selector (if you have one - not all boats do), disconnect the shore power and fire up the engine. Take a volt meter (a cheapie from Radio Shack will do fine) and measure the voltage. Just put the black test lead on either battery negative terminal and the red one on the same battery's positive terminal. Make sure the meter (1) is set to measure DC volts and (2) that you have it on a scale that is more than 14 volts (most have scales that max pout at 10 volts, then another at 50).

You want to see 14 volts DC or slightly more. If you are not sure how to read the meter, note where the needle is and shut the engine down. The needle should move down a bit, to 12 or so volts.

If you see no change in voltage with and without the engine running, you probably have a charging system problem. If you see a very high voltage with the engine running, you probably have a problem, in this case a damaged voltage regulator.

From what you described though I think thr odds are high that you're fine. Of course I don't know how your boat is wired but I am playing the odds.

Boondoggle30 06-22-2009 09:54 AM

Charger issue
 
Thank you much. At the time I did this, I had the selector set to BOTH for all batteries - not sure if that is better or worse!

Anyway, I will either track down a volt meter or buy one. I am reassured though by your comments. Just another lesson learned I guess.

So the 'bad' part of starting while connected to shore power is what?? if no battery is selected? What is the issue? just for my knowledge.

Thank you again.

Al

jarcher 06-22-2009 12:05 PM

Quote:

Originally Posted by Boondoggle30 (Post 498798)
Thank you much. At the time I did this, I had the selector set to BOTH for all batteries - not sure if that is better or worse!

.
.
.

So the 'bad' part of starting while connected to shore power is what?? if no battery is selected? What is the issue? just for my knowledge.

Well if you had the battery selector set to "ALL" and if your boat is wired correctly, then you have nothing to worry about. Your engine has a charging system that generates about 14.5 volts DC to charge your batteries. If it does not have batteries connected to it when it runs then the charging system can be damaged.

Likewise, depending upon the type of selector switch you have, moving it while the engine is running could damage the charging system as well. If it is the type of switch that does a "make before break" then its fine to move it, because as you switch, for example, from "1" to "ALL" or whatever it will connect battery 1 before disconnecting ALL/battery 2. NEVER turn the switch off while the engine is running. If you are not sure, set it to ALL before you start and don't move it until after you shut down.

Regarding shore power, this depends entirely on how the boat is wired, but most likely it is not relevant to this issue. If you have an AC battery charger it will charge the batteries when you plug in, and that's fine. I can't speak for every model of charger, but I have not seen a charger damaged by running the engine while it was turned on.

Most likely the AC charger is not sufficient to start the engine if both batteries are dead. Such chargers do exist but most that you install just charge slowly.

If you do have a dead or defective battery you need to switch away from it to start. So if battery 1 is dead, start with battery 2 alone, assuming battery 2 can start the engine. There are house batteries and starting batteries. You may want to check and see which is which, or if they are the same. If you have one of each, start the engine using the starter battery IF you have a make before break switch you can switch to "ALL" while the engine is running. That way, both batteries get charged by the engine.

jarcher 06-22-2009 12:09 PM

Quote:

Originally Posted by Boondoggle30 (Post 498742)
... I switched the batteries to all banks (starter and house) and then selected "test" and the power meter went into the green and 'charge' area.

This is probably a volt meter. If so, you don't need another. Even if it is not marked well, see if the reading with the engine running is higher than the reading without the engine running.


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