Dumb battery switch question from a newbie!

[jamesferg78]

Hi All, this may be a stupid question but appreciate the help - when plugged in to shore power at the marina, should I switch the battery switches to off?

 

[BurleyCove]

Yes and I had the same dumb question. Here is the other tip I learned from posts on this site, Turn on the main circuit breaker panel and the A/C invertor switch and it will charge the batteries while plugged into shore power.


Best of luck to you.

 

[jamesferg78]

Appreciate it thanks Bill!

 

[dicor]

Tip#3 alternate batteries each time you go out. Once you get to where your going switch to the other battery and use that as the house battery, before you restart the motor switch back to the battery that got you there.

 

[Bucit]

Hi All, this may be a stupid question but appreciate the help - when plugged in to shore power at the marina, should I switch the battery switches to off?

No. Some items only run on DC voltage. Leave the house battery on and make sure you turn on the charger. This way everything in your boat will be operational.

 

[BurleyCove]

If you're not in the boat why do you want everyhting operational? Is ther something in the DC circuits thats needs to be left on while the boat is not in use?

 

[AMFM3]

Hi Bill..gotta ask...is "Burley" your name? Excuse my ignorance as to where you're from. I only ask as Burleymis my last name!

James, As to batteries...you need the house batteries on for some things on board while plugged in. For example...radios, some lights. If you're not on the boat, shut 'em all off.

Mark

 

[jamesferg78]

All good feedback thanks everyone! While we're on the subject of newbie electrical questions, and I realize this is entirely dependent upon what I'm running (figure just the stereo, amp etc.) but how can I figure out how long the batteries will last when I'm on the hook - I have two AGM 12V 55AH 785 MCA which were new a few months ago.

 

[CliffA]

All good feedback thanks everyone! While we're on the subject of newbie electrical questions, and I realize this is entirely dependent upon what I'm running (figure just the stereo, amp etc.) but how can I figure out how long the batteries will last when I'm on the hook - I have two AGM 12V 55AH 785 MCA which were new a few months ago.

you can use this web site to get a general idea of how long you can run different things off of a battery...one of the links goes to a calculator......this is assuming you are using a power inverter instead of a direct power draw off the battery but it will give you an idea of time....the process of converting DC power to AC power looses some of the energy so using an inverter is not quite as efficient as using a direct battery connection..

http://www.donrowe.com/inverters/inverter_faq.html


cliff

 

[chandalen]

+1 for leaving a house battery on even if your gone.

Why?
Imagine leaving your boat with everything off... your thinking, the bilge pump float is attached to constant battery power.. what could go wrong? Well.. thoes wires corroded and seperated, or a splice broke, or whatever.. now your float does NOT have constant 12v. Then it rains... or you have a small leak... or a flock of seagulls pee in your bilge.. a bilge that no longer has a pump that gets power. Now your bilge fills up, and floods into your aft cabin, well THAT pump is not directly wired to the battery, and doesnt turn on... then the water fills the midship locker, where again that pump is not connected to constant power.. now your boat is sinking at the dock.

All this can be avoided by leaving a house battery on, with a charger going. Ask me how I know...

 

[Frostman]

One more suggestion for a newbie would be to turn off the stereo memory breaker in order to be sure the pre-amp for the 3rd pair of stereo speaker is indeed OFF. We learned the hard way that turning off the stereo at the stereo local on/off switch doesn't turn off the preamp in the forward closet! It only shut off when using the dashboard remote off button. Thanks to our electrical engineer boating friend we troubleshot this problem after mysteriously ending up with a dead battery and noticing how hot the preamp was purely by accident when a bottle of wine stored near it in the closet was too hot to enjoy.

I've since switched the preamp powered speakers to the pair above the berth and have all 4 exterior ones on so the balance and fade controls work in the cockpit. The pre-amp has an output adjustment that was out of whack but you can adjust it so all 6 speakers work at a reasonable level.

How old are your batteries??? Change them before they let you down. 3 years seems to be a reasonable useful life for Walmart deep cycles. If you don't know how old they are check the voltage with your voltmeter (if you don't have one buy one, you're gonna need it some day).

Bon Voyage!

 

[GrandMaster]

+1 for leaving a house battery on even if your gone.

Now your bilge fills up, and floods into your aft cabin, well THAT pump is not directly wired to the battery, and doesnt turn on... then the water fills the midship locker, where again that pump is not connected to constant power.. now your boat is sinking at the dock.

All this can be avoided by leaving a house battery on, with a charger going. Ask me how I know...

I'll bite...how do you know?

 

[chandalen]

haha.. happened to me last year (just after I got the boat)! Got a call from the people docking next to us... your stern is way low in the water... We drove up to the boat.. sure enough the bilge was filled, and the aft cabin had about 2" of water on the floor.

ALL because the stupid constant 12v wire to the bilge pump broke in a splice. As soon as I turned on the batteries, 3 pumps started working...

Problem fixed now!

 

[rcon]

Hopefully this isn't too much of a hijack, its mostly in the same vein.

No. Some items only run on DC voltage. Leave the house battery on and make sure you turn on the charger. This way everything in your boat will be operational.

Another newbie question coming up.

New purchase and I know "stuff" has been done that probably isn't by the book. I'm looking to map out my DC system so I can have some confidence on the water. You mention "make sure the charger is on" ... actually, I think I just answered my own question here.

Below is a pic I was taking for general condition during inspection, however I think I just worked out (yes, I'm really new at this) what the white/blue box is a charger.....? I know the black one, white writing is one, and I assume is hooked up to server as an alternator to the genset battery.

Is the white/blue one here likely to be a charger for the house batteries, hooked to shore power? This would follow what you're suggesting....


Whilst we're on this subject of newbie battery Qs, any tips for mapping out my 12v system? I'll start a thread with pics and diagrams once I've collected some info this weekend.
View attachment 25808

And I think I'll need to sign up for an account if I want to post some photos!

 

[BurleyCove]

Hi Mark,

Sorry for taking so long to reply I was traveling on business. I live on Burley Cove so thats the tie to my log in. Also my Sea Ray stays on a lift, so I am less concnered about it sinking while I'm away. I left the battery switches on because i didn't know any better when I first got it and I had problems with a drained battery. Since I've been turning off the batteries switces and leaving the A/C convertor on no problems. I check the direct connect bilge pump in the spring and fall to make sure its working correctly.

 

[rcon]

Hopefully this isn't too much of a hijack, its mostly in the same vein.

Another newbie question coming up.

New purchase and I know "stuff" has been done that probably isn't by the book. I'm looking to map out my DC system so I can have some confidence on the water. You mention "make sure the charger is on" ... actually, I think I just answered my own question here.

Below is a pic I was taking for general condition during inspection, however I think I just worked out (yes, I'm really new at this) what the white/blue box is a charger.....? I know the black one, white writing is one, and I assume is hooked up to server as an alternator to the genset battery.

Is the white/blue one here likely to be a charger for the house batteries, hooked to shore power? This would follow what you're suggesting....


Whilst we're on this subject of newbie battery Qs, any tips for mapping out my 12v system? I'll start a thread with pics and diagrams once I've collected some info this weekend.
View attachment 25808

And I think I'll need to sign up for an account if I want to post some photos!

And own question answered properly.

You need to turn on the "Converter" switch on the 240v (120v) switch board to turn that power point on in the engine bay and the battery charge sorts it out - there is a switching charger attached to the two house batteries, and a straight charger attached to the generator. Apparently I need to disconnect that before starting the genset, or buy another switching charger.

All this I discovered last night after running down the house batteries whilst connected to shore power - the TV switched to audio only and the batter registered only 8v (yeah, needs a change over soon) after about 3 hours. Then mate an I tore boat apart thinking that wasn't right that we couldn't run the boat whilst on shore power (this goes back to some things running off the switches in the cockpit, which I associate with teh 12v, having to be turned on). So this means the "converter" switch turns on a circuit that allows for the charging of the 12v system (ie, the battery charger) whilst connected to either shore of generator power - something I complete missed in my first assessment.

Hope this might answer some other newbies questions who find this thread - me being the complete newbie to boats needs some things spelled out *real* easy like.

I'll be posting some of my discoveries in a thread once I sign up for membership/donation and can post some photos.