2 battery setup

[wcasey5]

I have a 1988 Bayliner capri 1952 cuddy, 3.0. It currently has one battery and I would like to go with a 2 battery setup with a switch. Question

1. I only have room to put the batteries on one side of the boat (the port side). Will this screw up my weight distribution?

2. Can I charge both batteries while running the boat if I put the switch in "both"

3. Can I switch the switch while running the engine? Or am I stuck with whatever mode I choose before starting?

Thw switch I was looking at was the perko 8501dp. Or if someone could recomment a switch that would be helpful.

Thanks

 

[Silvertip]

Re: 2 battery setup

Yes (it will change distribution - but it probably will not screw it up), Yes and Yes. But once again don't get all wrapped around the axle with having to fiddle with the switch. Unless you are anchoring for several hours and running a killer stereo or other accessories, set the switch on BOTH, start the engine and go boating. If you stop for just a few minutes or even an hour, your boat won't catch fire, the batteries will not go flat, and the stars won't fall out of the sky. Anythime the engine is running the batteries will be charging. Set the switch to 2 if you are anchored for several hours to protect the start battery. When ready to go, chances are BAT 2 will still start the engine so leave it there and the full alternator output will go to BAT 2. No need to put BAT 1 on-line since it is already topped off. Look at the switch as though it's a traffic cop for electricity. It will tell the electricity where to go when charging and where it should come from when operating accessories.

 

[wcasey5]

Re: 2 battery setup

awesome! thanks!

 

[Flynny]

Re: 2 battery setup

Make sure you don't accidentally turn it to off while the engine is running however, that can blow the diodes(?) in the alternator. Because of that, I would hesitate to touch the switch at all while the engine is running. You shouldn't need to, anyways.

 

[UncleWillie]

Re: 2 battery setup

Make sure you don't accidentally turn it to off while the engine is running however, that can blow the diodes(?) in the alternator. Because of that, I would hesitate to touch the switch at all while the engine is running. You shouldn't need to, anyways.

+1

You will notice that the order of the positions on the switch are ... OFF <> #1 <> Both <> #2
If you have the need to switch from one to the other while running, the switch will naturally connect the Other Battery(Both) before disconnecting the Current Battery.

Just do NOT go to OFF with the Alternator operating.
Many use the Battery to help maintain regulation.
Without the Battery the alternator may just shut down (Good!) or it just may freak out and deliver 60 or more volts (Very Bad!)

Say goodbye to most of your electrical system in that case.

Your Alt may be fine running without a battery, can't say, but do you really want to find out the hard way.

 

[palace]

Re: 2 battery setup

You should avoid running on both because if one battery has a greater charge it will drain it (batteries should be the same age, size and series) and alternator may not put out enough amps to charge. I have a 3.0 "87" 1950 Capri. Put in a Blue Sea switch and run on one or two. Never ran battery down. Get your cables from the guy on ebay, he has marine grade cables and crimps the ends. Picked up 2nd at Sams interstate marine. There are good diagrams on here. Blue sea has good diagrams and info on their website as well. Does not effect balance of my rig.

 

[UncleWillie]

Re: 2 battery setup

You should avoid running on both because if one battery has a greater charge it will drain it (batteries should be the same age, size and series) and alternator may not put out enough amps to charge....

If you have two batteries in Parallel, one fully charged, and one not; The lesser charged battery will have a lower internal Charge Impedance (resistance) and Terminal Voltage, and take the majority of the charge.

The greater charged battery, with the higher Charge Impedance and Terminal Voltage, will take less of a charge.

Both batteries will charge as if the other one were not present; provided the charging system has enough capacity to deliver.

On ther other hand, if the charging system is not operating (Motor Off) the Battery with the Higher Terminal Voltage will discharge into the Lesser Battery, charging it until the Terminal Voltages equalize.

 

[wcasey5]

Re: 2 battery setup

Awesome info! Thank you, I think I am ready to tackle this project!

 

[Blacksting]

Re: 2 battery setup

On ther other hand, if the charging system is not operating (Motor Off) the Battery with the Higher Terminal Voltage will discharge into the Lesser Battery, charging it until the Terminal Voltages equalize.
This is what i learned about batteries and how they're supposed to charge . ,..its like water seeking its own level . and once they're charged , they reach saturation . also , once fully charged , current flow stops . and w/o current flow , theres' no heat build up . so , 'cooking' a battery is impossible . one more note* , batteries in paralell add the two currents together . in series , the voltages add .