Two battery sport cruiser..best way to use the Perko Switch?

[ejbpesca]

On board my 250 '96 Sundancer

I have: Perko 1 - 2 - ALL - Off switch. Two deep cycle marine batteries and a shore Power run battery charger, no generator.

What is the best way to use the battery switch? Switch it to ALL for any use or switch between 1 and 2 each time used or...is it best to say use battery 1 for cranking engine, then battery two while on shore power at dock to power all DC devices?

At dock I will be using many 12v devices including electric commode in head and 12v water system along with over a dozen 12v lights while the charger keeps the batteries up. Should I use ALL for that or just one battery so as not to draw down the other battery keeping it good and hot for cranking? I have no manuals or instructions for the Perko switch's use. If you have a similar set up please tell me how you use yours.

Any advice would greatly be appreciated.
jb

 

[JVM225]

My port motor has just one battery that does nothing but start the port motor. My starboard motor has two batteries, and they power everything that is 12 volt on the boat.
I run with the battery switch in the "Both" position. When I drop the hook, I switch to either "1" or "2". Then switch back to "Both" before I start that motor.
At my home dock I'm plugged in to electric, so I leave the switch in the "both" position.

 

[ejbpesca]

My port motor has just one battery that does nothing but start the port motor. My starboard motor has two batteries, and they power everything that is 12 volt on the boat.
I run with the battery switch in the "Both" position. When I drop the hook, I switch to either "1" or "2". Then switch back to "Both" before I start that motor.
At my home dock I'm plugged in to electric, so I leave the switch in the "both" position.

Is it correct that your dock your electric shore power charger will charge all your batteries no matter what position the battery switch is in?

 

[Bt Doctur]

if its a twin engine with only 1 battery switch, you need to fix it correctly with a second battery switch. At the very least isolate each engines charging system

 

[ejbpesca]

if its a twin engine with only 1 battery switch, you need to fix it correctly with a second battery switch. At the very least isolate each engines charging system

It is single engine, two batteries. Never have found instructions for the best way to use the 1-2-Both-Off switch.

 

[BurgundyS24]

It is single engine, two batteries. Never have found instructions for the best way to use the 1-2-Both-Off switch.

I have single engine dual battery. I use 1 when i crank and am running. Sitting still i switch to 2 to run radio.... switch back to 1 to crank and run.

Sent from my SAMSUNG-SM-N900A using Tapatalk

 

[Bt Doctur]

you have the option to use #1 on odd days and #2 on even days
you can add a ships battery to power all the DC circuits and leave the engine starting alone.
or go out on 1 and come back on 2
or one of these https://www.bluesea.com/products/category/35/Automatic_Charging_Relays

 

[bbwhitejr]

I have a single engine and 3-batteries. 1-cranking battery to start the engine and that is all it does. The other 2-house batteries run everything else. Charger will charge all 3-in any position.

Bennett

 

[ejbpesca]

I have single engine dual battery. I use 1 when i crank and am running. Sitting still i switch to 2 to run radio.... switch back to 1 to crank and run.

Sent from my SAMSUNG-SM-N900A using Tapatalk

Sounds good. How about at dock with shore power charger connected? What position for your switch then?

 

[JVM225]

Is it correct that your dock your electric shore power charger will charge all your batteries no matter what position the battery switch is in?

Yes, that's how mine is set up.

 

[trflgrl]

Is it correct that your dock your electric shore power charger will charge all your batteries no matter what position the battery switch is in?

If wired properly, this should be the case. The switches should manage the output from the batteries to engines/lights/appliances/etc., not the input from a charger.

Sounds good. How about at dock with shore power charger connected? What position for your switch then?

Some people leave their batteries in the Off position while on shore power. We leave our switches on what we've selected as the "engine/starting" position while at the dock, so they're ready for when we want to launch. After we get to our destination (usually at anchor/rafted with others), we change to the "house" setting.

In your case, if you choose setting 1 to start the engine, and setting 2 to run radio, etc., you could leave it on 1 while at the dock.

 

[peachypete82]

Do any of you change battery selection once you have started the engines? i use a 3 battery house bank on selector 2 for when on the hook, and i switch to 1 to start, and then once its started i switch to both.. ive heard that its not a good idea to change selection once its started? Any truth to that?

 

[bbwhitejr]

I don't do it often but, occasionally I do to give the house bank a boost. I have been told that as long as you do not go through "Off" you are good to go. I have never gone through off and never had a problem.

Bennett

 

[peachypete82]

yeh thats what i thought.... i had a really wierd issue one when i was idling around the marina at night, engine just stopped and all lights went out... no power. had to turn switch to off and then it would only work on 1 or 2, but not both? then the next day it was fine again... never had a hiccup since...

 

[Jonnyboy]

As a habit - batteries off when on shore power - run one battery on the way out and the other on the way in. That way I can check both while starting the engine and always have a backup while running accessories and sitting offshore.

 

[trflgrl]

Do any of you change battery selection once you have started the engines? i use a 3 battery house bank on selector 2 for when on the hook, and i switch to 1 to start, and then once its started i switch to both.. ive heard that its not a good idea to change selection once its started? Any truth to that?

What's the objective/what's the value in changing the battery selection setting after starting the engine(s)? If it's to charge both batteries, it may not be happening as desired. I'm not an expert but I've had similar questions, have been reading a lot, and have found conflicting info. I do my best to cull down to the most conservative combination of what seems logical (barring anyone hosing up the wiring, which also is a possibility with any previously owned boat), to maximize charging and minimize risk of getting stranded. This excerpt about how alternator charging works is something to ponder (link to source page provided):

Some battery switches have an area that says both. It is important to keep in mind that both does not necessarily mean you are working both batteries equally. The way your alternator is designed is to recharge a battery. If you have your boat battery switch set for both, your alternator will choose less work and simply keep a charge going to the fullest battery. In the end, choosing both could still leave you yelling for help….

http://www.discountmarinebatteries.com/marine-battery-switches-explained/

My interpretation: while running, choosing setting 1 or 2 instead of both guarantees you're getting a charge on the battery you've selected. So alternating battery selections from day to day or out/back makes more sense to me, unless there's technology in place to tell the alternator to choose the weaker battery over the stronger one, or the alternator is specifically designed to charge equally until each is full.

Still learning, though!!!

 

[2000SR380]

Do any of you change battery selection once you have started the engines? i use a 3 battery house bank on selector 2 for when on the hook, and i switch to 1 to start, and then once its started i switch to both.. ive heard that its not a good idea to change selection once its started? Any truth to that?

Google VSR Battery switches, or Boat Battery VSR . There are some really cool switches that will automatically switch over to charging your house batteries once the engine batteries make full charge. I would not recommend switching manually, because if you accidentally ground a running charging alternator, or simply open the circuit, you can be replacing the alternator, or at least the diode block pretty fast.

 

[Sangster]

I have 2 batteries and a switch. Every time I take the boat out, I switch to the other one. So each battery gets used every other trip. All i'm doing with it is starting the motor and powering the radio and Lowrance.

 

[Bt Doctur]

1 for odd days, 2 for even days best to have an isolator or combiner to have both charging at the same time.

 

[Lazy Daze]

ive heard that its not a good idea to change selection once its started? Any truth to that?

It depends on the specific make/model of your battery switch. Sea Ray uses a "make before break" switch. Meaning, when the switch is turned between 1-2-Both, the connection is actually being made on the next selection before the original selection is broken. Turning to Off would be bad, as would a switch that is not "make before break". The reason is that the alternator has nowhere to send it's juice so it backfeeds on itself. You may very well have the proper switch, but you'll need to check it out to be sure.