280 DA Battery Switches - Off or On?

[fins1up]

Yesterday when I was covering the boat, my neighbor noticed I turned off both battery switches and then removed the keys. He has a 40' Trojan with a similar setup and says he seldom turns off his switches and asked why I did it. I really didn't have an answer other than that's what the delivery captain told me to do. I've had zero battery problems but now that I think about it, I'm wondering how everyone else manages their 12volt system.

The boat has a total of 3 batteries. One for port and one for starboard that are connected to Switch 1 with positions OFF -1 -BOTH - 2. I leave it on BOTH when under way and OFF at the dock. Switch 2 controls the other battery and has OFF and ON, which I set to ON when I start things up and OFF at the dock. The boat stays in the water year round in my dock connected to shore power. The engine room battery charger keeps all three batts charged without boiling them over. Underway, the alternators keep things charged as will the generator and charger when we are at anchor. With both switches off, I have double checked the bilge pumps and the CO2 detector to insure they are directly wired to the 12v, so even with the switches off they will still operate.

Since it's not broken, I'm just curious if anyone has other thoughts on a better/different management method?

 

[jimdavi]

I leave them both on, shore power on to trickle charge the batteries. Also, if shore power drops off, my beer will stay cold in the fridges...at least for a few days.

 

[dpvandy01]

I turn both off and switch off all D/C systems at the pannel. If we loose dock power I don't want to fully discharge my batteries since Sea Ray set me up with two cranking batteries rather than one and one.. Cranking batteries do not like to be fully discharded and don't recover well when they are. I still plan to modify the system to 2 Deeps and 1 cranking but that's a tall order so I'll hold off until I really need to.

 

[Stray Cat]

Shore power on, ac converter (battery charger) on
Both battery switches off, dc panel breakers on
Both fridges empty and off when we leave

 

[Bridog]

This is what I do. Shore power on. All DC switches off. AC converter and refrigerator on. Battery switches off. If you lose shore power (like someone unplugging your cord because it dips in the water you wont drain your batteries. You will lose the stuff in the fridge but that's cheaper to replace than a battery.

 

[NorthvilleJim]

I turn both off and switch off all D/C systems at the pannel. If we loose dock power I don't want to fully discharge my batteries since Sea Ray set me up with two cranking batteries rather than one and one.. Cranking batteries do not like to be fully discharded and don't recover well when they are. I still plan to modify the system to 2 Deeps and 1 cranking but that's a tall order so I'll hold off until I really need to.

When I leave my boat at the dock:
1) My boat is always connected to AC shore power
2) I also turn off all DC switches at the panel in the cabin. Mainly, for fear of running down a battery if I lose shore power.
3) I never turn off the round battery dial switches in the cockpit.
4) I do turn off the keys to prevent the kids from bumping one of the start buttons and firing up an engine.
5) I keep the AC converter switch on so that the batteries stay charged.
6) I keep the AC refrigerator switch on to keep the items in the fridge cold.
7) I turn on the AC Air Conditioning switch and set the thermostat to HU (Humidity Control) mode

So far, no problems.

 

[Dave S]

This is what I do. Shore power on. All DC switches off. AC converter and refrigerator on. Battery switches off. If you lose shore power (like someone unplugging your cord because it dips in the water you wont drain your batteries. You will lose the stuff in the fridge but that's cheaper to replace than a battery.

I do the same and concur with Brian's explanation.

 

[gerryb]

I do the same and concur with Brian's explanation.

Same here.. with ac on and set to HU mode.

 

[boatmailster]

Shore power on, ac converter (battery charger) on
Both battery switches off, dc panel breakers on
Both fridges empty and off when we leave

Leaving all dc breakers on is the easiest way to kill LED lights and light bulbs. They really don't like voltage drop which occurs when you turn all 12V systems at the same time

 

[Henry Boyd]

We are on a mooring, so all panel switches and batteries off when we are not there. Also keep in mind that a number of electronic devices continue to draw power when they are 'off' (e.g. GPS antenna), so switch the main power off is the only way to stop the draw.

Henry

 

[Cap10Pat]

It's been a while since I looked at twin engine / twin battery setups, and my boat is a single. But I would wonder about having both batteries connected while underway, anchored whatever, by setting them to "Both" as described. A weak battery, alternator, electrical problem or something could draw down one battery and then the other leaving you with nothing. I think I'd rather not have the two engine batteries connected. Battery isolators may accomplish that but you didn't mention having those.

I have 2 batteries but never run on Both. I use one for starting and one for house service whenever anchored (by switching to "1" or "2"). My charger keeps both fully charged at the dock. And I turn the battery switch off when away. When I rarely leave the fridge on the boat is plugged in and the battery switch off. The hell with the beer, I want any remaining power available for the bilge pumps and the Mercathode system.