Basic Perko issue

[Sunset]

I am new to my boat, new to battery switches and the need for a house battery. But I have been reading some of the battery and electrical threads and I believe I have some sense of what is supposed to be what under the deck. So here's the thing:

The boat has a newish-looking Perko switch with thick red cables leading into it from each battery (starter and 115 AH house). However, whether the switch is on 1 (to start) or Off, all the house lights and other aux. items function. So if some passenger flicks a light switch, it will stay on until I notice it or the batts die.

Am I right in suspecting someone got the switch install all wrong?

 

[HopCar]

When in the off position, the only low voltage things that should work are the bilge pumps.

 

[Edelweiss]

Sounds like someone messed with the wiring. Either they have wired the lights and accessories directly to the battery or wired the battery directly to the busbar on the electrical panel. There are any number of ways to do this, if not familiar with marine electrical.

Start at the battery and make sure the cables go directly to the battery switch. Normally, the only other wires connected on the battery posts should go directly to the bilge pumps or possibly the bilge pump switch, but not to anything else on the electrical panel. You may have to trace them out to confirm thats what's happening.

If you can't find it, have someone who knows marine electrical check it out.

Larry B

 

[FlyWright]

If I wasn't 100% comfortable analyzing, modifying and maintaining the electrical system, I'd call in a professional for the job. It will provide countless hours of worry-free sleep. And if he lets you work side-by-side, maybe you'll learn more about your new boat!

I had a similarly miswired mess when I bought mine. (Sh) It happens.

 

[Sunset]

The comforting thing about these replies is - they at least confirm that I know enough to know what don't know! I am going to trace the wires to try to figure out what exactly is wrong, then take on the even more difficult task of locating someone convenient who is knowledgeable about 12V wiring. I also need to install 2 12V cig plugs for charging etc. (there are none) and my new small 750W inverter. The fuse panel is ancient and unlabeled.

 

[LaBomba]

I have seen a boat wired as you have described and the Perko only shut the power off to the motor start circuit from one battery while the other battery was hooked directly to the all the other aux equipment. This protects your start battery from being drained by the auxiliaries and allows the motor to be started from the other when needed. Not a great scenario but may explain what you have. As others have pointed out you need to trace the wires to see what feeds what.

 

[psneeld]

The comforting thing about these replies is - they at least confirm that I know enough to know what don't know! I am going to trace the wires to try to figure out what exactly is wrong, then take on the even more difficult task of locating someone convenient who is knowledgeable about 12V wiring. I also need to install 2 12V cig plugs for charging etc. (there are none) and my new small 750W inverter. The fuse panel is ancient and unlabeled.

Don't assume anything is wrong...there are thousands of ways to wire a boat..most aren't right or wrong...just what you prefer.

There are some "givens" where you need to protect wiring with fuses and size wire correctly...some get a bit carried away with it...but for safety reasons...sizing and fusing wire is a good idea...better than many other ideas on a boat...but your setup may be or may not be a bad idea...just depends.

 

[FlyWright]

Don't assume anything is wrong...there are thousands of ways to wire a boat..most aren't right or wrong...just what you prefer.

There are some "givens" where you need to protect wiring with fuses and size wire correctly...some get a bit carried away with it...but for safety reasons...sizing and fusing wire is a good idea...better than many other ideas on a boat...but your setup may be or may not be a bad idea...just depends.

He's asking for help here. How does he know if it's right or not?

 

[AusCan]

There are many ways to wire a boat - But I think the OP's doubts are valid. This way is wrong.
With the main electrical isolator off, everything should be isolated other than what is absolutely required; usually just the bilge pump. This minimises the chance of an electrical short, fire, or batteries draining due to a switch left on.

What the #1 & #2 selections on the switch isolate, are optional. A common set up is #1 for engine start only; #2 for house only. This makes sense and is easy to understand. Many boats (mine included) have wiring randomly tied into either circuit. Something I need to tidy up as well.

 

[BruceK]

Agree with Auscan to to how it should be set up, with only bilge pumps still hot when the main switch is set to "off".
Problem is, the wiring set up may be good initially, and then successive people fiddle with it. Black wires where there should be red, and vv, poor quality wire,even audio speaker wire, appears, temporary fixes "just to get us going to-day" become permanent, poor wire joining/extending/insulating, a litany of departures from good practice. Sounds like you are alive to what`s wrong and fixing it, work to do, good luck.There are helpful books on boat electrics incl wiring, I`ve got one by Ed Sherman, there are others perhaps newer. Even if you get pro help it is useful to read how/why things get done, I bought Nigel Calder`s Refrigeration book for info, though repairing and re powering the AC eutectic system was way beyond me.

 

[Conrad]

When we purchased our new to us NT back in February we brought in a marine electrician to check out our electrical system since we had a genset, inverter bank, house bank, and an anchor windlass/bow thruster battery. (This was a far more complicated system than we'd ever had before)
Good thing, as aside from the genset start battery, every single battery on the boat was connected together; the master switch was for decorative purposes only.

 

[psneeld]

There are many ways to wire a boat - But I think the OP's doubts are valid. This way is wrong.
With the main electrical isolator off, everything should be isolated other than what is absolutely required; usually just the bilge pump. This minimises the chance of an electrical short, fire, or batteries draining due to a switch left on.

What the #1 & #2 selections on the switch isolate, are optional. A common set up is #1 for engine start only; #2 for house only. This makes sense and is easy to understand. Many boats (mine included) have wiring randomly tied into either circuit. Something I need to tidy up as well.

Most of what you say is true but without knowing more of his system just saying a "generically" wired system is right or the best...may not be true for his boat....you certainly can't say it's "wrong".

If he wants to redo it the way you suggested...that's fine also....as long as it's not a cut and paste job to get it that way.

I have seen boats wired where the 1/2/all/off switches ARE just for the engine and another cutoff switch is for the main panel.

From just the original post..I would suspect he may be correct that someone just miswired the "newish" batt selector switch....but without seeing his whole electrical system setup...I would be doing him a disservice to just suggest changing the switch wiring without more info.

 

[RickB]

Considering that there is no requirement to have a battery isolation switch for the branch circuits, the argument about what is right or wrong is moot.

Furthermore, the OP's boat is <26 feet so the builder was not even required to deliver it with a starting battery isolation switch. If someone added one, that's nice, but anything beyond that is just fluff.

My advice ...Learn to turn off the lights before leaving or hire an electrician to install a branch circuit switch.

 

[Sunset]

I appreciate the various comments here. I suppose what is important for me to know, at the least, is: exactly what function does position 1 vs position 2 perform? I haven't tried to systematically check that. It would be especially useful to know which batteries are being charged while underway for each switch position. Having no charger.

 

[bglad]

I appreciate the various comments here. I suppose what is important for me to know, at the least, is: exactly what function does position 1 vs position 2 perform? I haven't tried to systematically check that. It would be especially useful to know which batteries are being charged while underway for each switch position. Having no charger.

A battery (or battery bank) should be connected to pole 1 and another to pole 2. The common then goes to whatever you want to power with the switch. You use the switch to select the battery you want to use.

You will have to trace out your alternator output lead to see where it goes so you can determine whether the switch affects how it charges your batteries or not. If the charging lead goes to the engine starter then your alternator charges whichever battery the switch is toggled to. If it goes to a battery isolator it manages the charge regardless of the switch position.

Best thing to do is to google up some diagrams that show equipment similar to yours then compare to see how they match up to how yours is done. Once you know a little more about it you can change your's to suit if necessary.

One big thing is to have you bilge pump(s) on a separate buss powered all the time regardless of battery switch position so when you leave the boat you can toggle the battery switch to the off position and know your batteries will stay up to run your bilge pump.

 

[skipperdude]

The 1,2, both can be confusing in itself and the big warning sign that says "Do not turn off when the engine is running"

I went with 3 simple ON Off switches.
Switch # 1 is labeled house.
Switch # 2 is labeled Start.
Switch #3 is always off but turned on to combine the banks if needed.

No need to worry about what position to set the switches on.
Or if someone else on board switched something while you weren't looking and drained your start bank.

SD

 

[FF]

While working out what you need be sure to look at the rear of the rotary switch and be sure the two little terminals are there and hooked to wires.

These will cut the field current to the alt should someone accidentally turn the switch to OFF with the engine on.

The usual setup on a small boat is a start batt ,#1 and a deep cycle batt (the house batt) #2.

The engine is started on #1 , and then placed in both for the cruise.

AFTER engine shut down #2 is selected to operate .

A $15 low voltage alarm on #2 will give some indication of when to stop using the #2.

Almost nothing should be on a batt direct hookup , although some folks will wire a bilge alarm or thief alarm to an always hot position.

 

[Sunset]

FF, that has been my understanding as well. If only I had a trained pet gremlin to follow the wires for me - and take notes. I intend to look behind the curtain but may not know where to go from there. I would love to be able to invest in a brand new on-the-wall fuse panel and have it wired up and labelled pro. Don't see that happening tho.

 

[Sunset]

Update

I thought I might as well update my progress on the electrics. Shortly after the previous post I had the marina mechanic go ahead and re-wire the switch so it now operates as it should: off means off, 1 connects everything to the start battery and 2 to the deep cycle. Fine as far as it goes.

This Fall I signed up for the Canadian Power Squadron Marine Electrical Short Course and have completed 3 of 4 sessions. I have bought a Blue Sea Automatic Charging Relay kit Add-A-Battery Kit - 120A - Blue Sea Systems and will install it soon while the boat is here with me over the winter. I'll also replace some of the cables with those of a more substantial gauge. This one for example, which is damaged and is the power supply from the switch to the main positive bus:

 

[HopCar]

I used the Blue Sea Add-A-Battery kit to actually add a battery to my boat.

I originally had two size 4D batteries. One was used as a start battery and one was the house battery.

I combined the two 4D batteries into one house bank and used the Add-A-Battery Kit to add a group 31 battery for the start battery. Seems to work well.