after you start the engine can you switch from #1 battery to both or to #2 battery or will it hurt the alternator,or any thing else?
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yes you can
or should I say I have had boats as far back as I can remember and I have never had a problem switching from one to two. Just don't turn it to "off" with the motor running. Jack
or should I say I have had boats as far back as I can remember and I have never had a problem switching from one to two. Just don't turn it to "off" with the motor running. Jack
If the switch is a make before break...
If the switch in question is a make before break type switch you should be fine. This type of switch will actually parallel both batteries prior to switching to the new battery. If not, you run the risk of blowing out the rectifier in on the alternator.
If the switch in question is a make before break type switch you should be fine. This type of switch will actually parallel both batteries prior to switching to the new battery. If not, you run the risk of blowing out the rectifier in on the alternator.
Nah, don't risk it and ...
why would you want to to that? Instead of having the 1-2-B switch decide which battery gets charged, install a PDP at the + side of your house bank, and lead all of the charging sources to that point, and also install a combiner or echo charger and be done with the switch altogether. Once done, you can use that same switch to parallel the banks if you need to do so. Think about it. You have a basic question which can ONLY be determined by YOU as to how your boat is wired, i.e., alternator output to switch or elsewhere? In order to best answer your question, we need to know how your alternator output is wired. Unless we know, all the answers about the switch are meaningless. This is because if the alternator is wired directly to your house bank, AND the ONLY use of the switch is for the output of the house bank, it doesn't matter. If, however, your alternator goes to the switch and THEN to the batteries, then NEVER MOVE THE SWITCH WHEN THE ENGINE IS RUNNING. Buy a book that explains this, my fingers are numb. Buy Calder's Boatowner's Manual for Mech and Elec Systems. Stu
why would you want to to that? Instead of having the 1-2-B switch decide which battery gets charged, install a PDP at the + side of your house bank, and lead all of the charging sources to that point, and also install a combiner or echo charger and be done with the switch altogether. Once done, you can use that same switch to parallel the banks if you need to do so. Think about it. You have a basic question which can ONLY be determined by YOU as to how your boat is wired, i.e., alternator output to switch or elsewhere? In order to best answer your question, we need to know how your alternator output is wired. Unless we know, all the answers about the switch are meaningless. This is because if the alternator is wired directly to your house bank, AND the ONLY use of the switch is for the output of the house bank, it doesn't matter. If, however, your alternator goes to the switch and THEN to the batteries, then NEVER MOVE THE SWITCH WHEN THE ENGINE IS RUNNING. Buy a book that explains this, my fingers are numb. Buy Calder's Boatowner's Manual for Mech and Elec Systems. Stu
Why switch?
Get a battery combiner from West Marine. When the starting battery is recharged its voltage rises and the combiner connects the house bank to the system for recharging. Since you run all your loads off the alternator when the engine is running you can leave the switch in the #1 position all the time, your house bank will get charged too. After you drop the hook, switch to the #2 bank and party hearty, after you have run the house bank flat, switch back to #1 and you have a fully charged battery to start the engine and re-charge the house bank. No need to even think about switching while the engine is running. Takes much of the drama out of the whole process.
Get a battery combiner from West Marine. When the starting battery is recharged its voltage rises and the combiner connects the house bank to the system for recharging. Since you run all your loads off the alternator when the engine is running you can leave the switch in the #1 position all the time, your house bank will get charged too. After you drop the hook, switch to the #2 bank and party hearty, after you have run the house bank flat, switch back to #1 and you have a fully charged battery to start the engine and re-charge the house bank. No need to even think about switching while the engine is running. Takes much of the drama out of the whole process.
Jack is right
Jack is right as long as you do not turn the switch to the off position when the engine is running.Rod
Jack is right as long as you do not turn the switch to the off position when the engine is running.Rod
Battery combiners
These things are a real pain. yea they let you ignore the position of the battery selector switch but they also suck down about 1.5 volts doing it. So while your navstation volt meter is reading 14.4 volts and you think the batteris are both charging, the actual voltage going to both is 12.9. Unless you crank up your alternator ( and battery charger) voltages you will have cronic low battery problems. That is not that hard to do IF the regulator is one of those that lets you do it at all, most don't. For the record, the admaral routinly turns off the ignition on the boat trying to "turn off" the motor. My diode pack is fine and I have never had any problems. I'm beginning to think we need to call in Mythbusters to actuall determine if "turning off the batteries while the engine is running blows the diode pack" is a true statement. the regulator is going to regulate even without a battery referance right, it will not let the voltage go up beyond 16ish volts in any case so what is the concern. My regulator takes its' referance off the alternator output not the battery. With no battery in the circut there is not going to be any current pass so no current and no over voltage and no problem. You know WM and others are in the business of selling battery switches. Have you ever noticed that every three years or so they come up with a new and better arangement of battery switches and combiners that will "make your boat soooo much easier to use....."
These things are a real pain. yea they let you ignore the position of the battery selector switch but they also suck down about 1.5 volts doing it. So while your navstation volt meter is reading 14.4 volts and you think the batteris are both charging, the actual voltage going to both is 12.9. Unless you crank up your alternator ( and battery charger) voltages you will have cronic low battery problems. That is not that hard to do IF the regulator is one of those that lets you do it at all, most don't. For the record, the admaral routinly turns off the ignition on the boat trying to "turn off" the motor. My diode pack is fine and I have never had any problems. I'm beginning to think we need to call in Mythbusters to actuall determine if "turning off the batteries while the engine is running blows the diode pack" is a true statement. the regulator is going to regulate even without a battery referance right, it will not let the voltage go up beyond 16ish volts in any case so what is the concern. My regulator takes its' referance off the alternator output not the battery. With no battery in the circut there is not going to be any current pass so no current and no over voltage and no problem. You know WM and others are in the business of selling battery switches. Have you ever noticed that every three years or so they come up with a new and better arangement of battery switches and combiners that will "make your boat soooo much easier to use....."
Test the switch first.
With the engine NOT running,turn on some lights. Then try switching the battery switch from 1 to 2 to BOTH and, again, by reversing the process. If your lights flicker on/off during the switching, this will indicate that you have an old switch and the "stagger" WILL NOT BE GOOD for the aternator. Otherwise, switching is OK to do while the motor is running. (Learned this in my diesel mechanics course).
With the engine NOT running,turn on some lights. Then try switching the battery switch from 1 to 2 to BOTH and, again, by reversing the process. If your lights flicker on/off during the switching, this will indicate that you have an old switch and the "stagger" WILL NOT BE GOOD for the aternator. Otherwise, switching is OK to do while the motor is running. (Learned this in my diesel mechanics course).
Not all combiners drop the voltage 
The West combiner does not drop the voltage to the battery. It is a voltage sensitive relay (not a diode). When the primary battery voltage goes above the set point, the relay closes and connects the house bank. When the voltage drops below the set point the relay opens and the two banks are separate. My voltmeter shows the same voltage at either battery when the system is working. It is a solid state switch that does exactly what a manual switch would do if the engine was started on "1" then switched to "All" after the starting battery is recharged. There is no more voltage drop across the combiner than a battery switch or other high current relay.
The West combiner does not drop the voltage to the battery. It is a voltage sensitive relay (not a diode). When the primary battery voltage goes above the set point, the relay closes and connects the house bank. When the voltage drops below the set point the relay opens and the two banks are separate. My voltmeter shows the same voltage at either battery when the system is working. It is a solid state switch that does exactly what a manual switch would do if the engine was started on "1" then switched to "All" after the starting battery is recharged. There is no more voltage drop across the combiner than a battery switch or other high current relay.
Bill, Moody is right
What you're probably referring to is an isolator. An isolator does drop voltage somewhat but isn't the same animal as a combiner. Also, be aware that when you turn your key off (with the engine still running) you're actually disconnecting power to alarms/buzzers/guages/tach/etc. as well as the regulator. With no power to the regulator your alternator shouldn't be putting out amps anyway. Even if it were your alternator would still be connected to the batteries (assuming you haven't shut off the battery switch) which means that any output from the alternator still has somewhere to go. That's why your alternator hasn't been hurt by just shutting off the ignition key. If your alternator is putting out amps and it is disconnected from it's battery THATS when you'll cook things.
What you're probably referring to is an isolator. An isolator does drop voltage somewhat but isn't the same animal as a combiner. Also, be aware that when you turn your key off (with the engine still running) you're actually disconnecting power to alarms/buzzers/guages/tach/etc. as well as the regulator. With no power to the regulator your alternator shouldn't be putting out amps anyway. Even if it were your alternator would still be connected to the batteries (assuming you haven't shut off the battery switch) which means that any output from the alternator still has somewhere to go. That's why your alternator hasn't been hurt by just shutting off the ignition key. If your alternator is putting out amps and it is disconnected from it's battery THATS when you'll cook things.
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