Battery procedure

danrod

I just purchased a 2008 28 ft ec and I am not sure how I should use the two batteries. Should I have both on when cruising, or just one and which one. When plugged into shore power, should both be turned off? When anchored which battery should I have one  on and the other one off and which one? 
I hear so many different answers. Can someone explain to me how it all works please.

jhofmann

If search "battery switch" on this site, you will find many threads on this topic. I can only tell you what I do. I was able to determine which of the batteries was #1 and #2 by disconnecting one battery and seeing what battery posistion still powered the cabin lights. I then installed a marine starting battery in battery box #1, and a deepcycle battery in posistion #2. When starting and running the boat, I switch to battery #1, when at anchor, I switch to battery #2, so if I kill battery #2, I can switch back to Battery #1 to start the engine. You cal also use posistion "both" to combine the two if they are both weak, and your trying to start the engine. They should both charge while running, and on shore power in either posistion. Since I trailer my FV 242 EC, I only use shore power to charge the batteries with an adapter, and not sure what is the best way when docked and away from the boat, but I'm sure others here will be able to help. 

Welcome to the forum!!

Cableguy Greg

Can you give is a picture of your switch? There are 2 flavors of the switch on our boats. One has Off-Batt 1-Batt 2-Both positions on the switch. The newer boats have a blue sea systems switch that has Off-On-Emergency Start. This particular one turns both batteries on at the same time.

I leave my battery switch on all the time, except when laying up for the winter. It's just easier that way. If you have the 280EC, there is a wiring diagram available for you to download here on the forum. If you want it, I can direct you in the right direction.

danrod

Thanks for your help. This is the way I was told to switch the batteries when I am on shore power and cruising and anchored. But I don’t think that is right.

212rowboat

the concept of separating the batteries is only complicated if you make it that way- and people do with a certainty.  

the basis is:

both on: max available battery reserve.  more importantly, both are charging while you're cruising. 

one off (one isolated): only using half of your reserve (if you've got two batteries only), and only one charging while you're cruising. 

you'll want to isolate (turn off a battery i.e. flip to only one) if you're moored and engine or generator is not running.  this leaves one battery (your starting battery) isolated and presumably fully charged as you deplete your 'house' battery.  when your about to start the engine, pull anchor and head back- you flip the switch to the starting battery or both.  this ensures you have power to get started and home.    

Willhound

@212rowboat I'd have to disagree with your statement that only the switched battery charges while under way. Some could be set up that way I suppose but my alternator feeds to the isolator which sends charging current to all batteries while running regardless battery switch position. 

danrod

Thanks for all your help guys!

212rowboat

Willhound said:

@212rowboat I'd have to disagree with your statement that only the switched battery charges while under way. Some could be set up that way I suppose but my alternator feeds to the isolator which sends charging current to all batteries while running regardless battery switch position. 

you're right i let my fingers type ahead of my figurin'... 

Cableguy Greg

Go with Al's advice. That first switch should be on the "On" position. When it is "On", it turns both batteries on. The "combine" position is only for emergency starts if the starting battery is dead. I have the same setup in my 280EC, minus the switch for the genny.

Spyderweb

So do I understand it correctly that in the "ON" position, and both batteries are on, they are still separated in that the starter battery is in use mostly only to start the engine, and the other (house) battery is running most of the 12 volt stuff?  Hence the house is the "sacrificial" battery that might get run down by using too much "stuff", but the "starter" battery should be set to go?

And the "Generator" switch simply turns On and Off the dedicated Generator battery?

Cableguy Greg

Spyderweb said:

So do I understand it correctly that in the "ON" position, and both batteries are on, they are still separated in that the starter battery is in use mostly only to start the engine, and the other (house) battery is running most of the 12 volt stuff?  Hence the house is the "sacrificial" battery that might get run down by using too much "stuff", but the "starter" battery should be set to go?

And the "Generator" switch simply turns On and Off the dedicated Generator battery?

If you have the same switch pictured above, yes, the switch turns on both batteries at the same time and keeps them separate. Your "house" would be the first to go. If they both were going, you can combine them to get the boat started. I had a problem last fall when my starting battery was starting to go. I used the combine position to get my boat started.

The generator switch turns the starting battery on/off to the generator. That's it.

Dude_Himself

I have the same boat, and thanks to a bad battery I've had some experience with it.

The left switch should be set to ON unless one battery has failed or is missing (not common). The right switch provides battery power to the generator to start/stop/operate. It'll provide AC power to the distribution panel in the cabin.

There's an isolator that allows the batteries to charge independent of the switch position. It's mounted to the starboard firewall, behind the generator exhaust. Look for the black thingy with a bunch of red wires attached.

When the generator is running and the battery charger is flipped on it'll charge through the same battery isolator.

If you leave the boat without shore power for a period of time you'll have the house battery drain down - there's a MerCathode system and a CO detector that draw about 1/10th of an amp - with a 110AH battery it takes about 22 days before your battery is 50% discharge, and past that point you're damaging the battery. Mine's a trailer sailor: when I leave it for more than a week I disconnect the batteries, top them off with a charger, and lower the hatch with a battery pack. I'm adding solar soon - but probably a dingy first.

howardrams

danrod,  with the main switch you have, "combine batteries" is only for the case where out on the lake your starting battery won't crank.  Turn to combine and the house battery helps out.  Otherwise, leave the switch "on" except when removing them or servicing the electrical system, or during long periods of storage when you are not on shore power.

danrod

So I think I got it..When I am hooked up to shore power should I have both (engine and house) and the (generator) switched to off Then when I disconnect from shore power I turn the (engine and house) battery to on and leave the (generator) switch to the off position. Is that correct? And when I am anchored  and playing music and lights are on etc. and then I go to start the engine and it does not turn over I switch the (engine and house) battery to Combine Batteries and leave the (generator) switch on off. Is this correct? Thanks again

howardrams

You've got it although I usually leave the engine and house ON even when docked and on shore power, all summer really unless I need to put it on the trailer for some reason.  I look at it like the battery is powering any 12v accessories like the bilge pumps, and the shore power runs the battery charger to keep them charged.  I know the battery charger could power these things but sometimes power goes out at the docks.

Cableguy Greg

I leave the battery switches on. If you shut the switches off while at the dock, none of your DC lights will work, such as the cabin lights. You won't be able to listen to the radio either. Also, if there is a power outage at the marina, the stuff in your fridge will stay cold.

danrod

Thanks you guys, so the only time I turn the generator switch on is when I use the generator?

howardrams

Yes.  It is Ok to have the gen battery switch ON, but leaving it OFF unless you plan to start it should help preserve your battery life until you need it.  Some people never use their generator, but test run it for a few minutes every couple of weeks to keep it in good shape.