Battery Switch

[Libations Too]

I have a Perko battery switch on Libations and two group 27 batteries. When sailing I normally switch to one of the two batteries and hold the second in reserve. Then, when it is time to start the engine I turn the Perko switch to "all" before starting the engine. I have done this since owning the boat and everything seems to work just fine.

Occasionally I forget to turn the Perko switch to "all" before starting the engine. Again, no problem. But this prevents my "reserve" battery from being charged. When I notice my mistake I stop the engine, turn the Perko switch to "all", and restart the engine so that both batteries are being charged. This has been my practice because someone once told me to never turn the Perko switch while the alternator is charging.

Recently someone told me that stopping the engine was not necessary as long as I did not turn the Perko switch to "off". The presumption being that it is acceptable to switch from "1" to "all" to "2"....but not to "off".

Any comments? What is the real truth here? I assume my Perko switch is original equipment but I am not certain.

Thanks,
Richard

[Dolce_Vita]

The truth is ... it depends.

Some switches are built so that they "make before break".  These are safe to switch between 1-all-2, but not "Off".

Even newer ones have a "field disconnect" contact that essentially de-energizes the alternator while switching or off.

The oldest ones could potentially go open momentarily while switching between any of 1-all-2. This is the condition that can blow out diodes or the regulator.

I don't know which style was OEM'd on our P-323s, but given their age, I'd suspect its the last of the threee types above.  I always treat mine as if that is the case.  It should be possible to test, but you'd need to have access to an oscilloscope to do it right, as the open time is very short.

[Libations Too]

Ed, that's what I suspected.  As for the oscilloscope, I have enough boat toys as it is....

[GusF16]

So, there could be an issue with starting with the switch in 1 (my start battery) and then switching to 2 (my house bank)?

[selene]

Hopefully somebody out there has a 'silly scope.  Now we are all worried....I have never dared touch my switch when the engine was running.  But AFAIK both batteries are charged regardless of the switch position, so I have not needed to. Yeah, not the most helpful post 

[Dulcinea]

I've been looking at something BlueSea makes called Add A Battery.  It automatically isolates house and starting battery at the appropriate times.  Has three positions: On-Off- and Manual Combine.  Looks like might solve a potential problem that has always concerned me. 

[Dolce_Vita]

Defender has it for $129:

http://www.defender.com/product.jsp?path=-1|328|51495|299265&id=750169

Wholesale Marine for $118:

http://www.wholesalemarine.com/p/BSS-7650/?utm_source=feed&utm_medium=cpc&utm_campaign=google&gclid=CJnh0s3F9bYCFSJlMgoduCkADw

Go2Marine for $113:

http://www.go2marine.com/product/167731F/blue-sea-system-add-a-battery-7650.html?WT.mc_id=gb1&utm_source=googlebase&utm_medium=productfeed&utm_campaign=googleshopping&gclid=CJDhnuXF9bYCFTSVMgodSUgAPQ

[Libations Too]

At the risk of hijacking my own thread, I'll ask another question:

In my original post I based my question on the assumption that the battery switch controls not only which battery is being used but also which battery is being charged while the engine is running? Is that assumption valid? Could it be that since the 323s were built with two battery banks the regulator for the engine-driven charging circuit was chosen to charge both batteries simultaneously?

I ask because having recently installed a solar panel I went through a considerable effort to understand how a single controller can or cannot charge two batteries. It turned out that charging two batteries simply required selecting the right controller...and the battery switch has nothing to do with the charging circuit. Is it the same with engine-driven charging circuits?

[selene]

As always, your mileage may vary...but on Selene the engine charges whichever battery the switch is set to. I'll check again next time I am there, but I have a Xantrex monitor, and as I recall with the engine running the voltage on the battery selected by the switch is higher than that of the other battery (I still have 2 G27 batteries, but want to add a starter battery one of these days...)

The AC battery charger charges both batteries, irrespective of switch position.

As you said, with the right controller, the solar can also charge both.  With the wrong controller, as you so eloquently described, it is less easy!

You can also set up an ACR (like AddABattery), Duo Charge or Echo Charger - that way generally the alternator is always wired to the house battery,  and the charge automatically shifts to the other battery when needed.  I have not looked into this for a while, but as I recall these also protect frying of diodes.....

Added 9/5/13: I confirmed yesterday that on Selene when the switch is to "2", the engine charges battery "2" only.

[Sea Haven]

I've retrofitted with, and used the BlueSea Systems "Add A Battery" on my last 3 sailboats. Haven't looked back since.

The latest unopened package is sitting on Sea Haven and will be installed as soon as she's hauled. This will be my 4th installation.

Easy, peasy, lemon squeezy!

Is that a valid recommendation?

FWIW, since I'm on a mooring, I use 2 PowerFilm R-14 Rollable Solar Panel Battery Charges, one for the house battery and one for the starter battery. They, along with the bilge pump and Main feeds to the Power Switch, are the only items connected directly to the Batteries. Yes, they are fused as well. They lay flat, athwart ships across the  Dodger, one to port, one to stbd, and and are merely held in place by bungees.  They are bungeed together with both of their respective electrical connections inboard. outboard they're bungeed at the fore and aft corners each to the nearest stanchions. The electrical connections  continue aft on the dodger to the main-sheet to which they are strapped to using velcro-wraps. Down to the fwd drain opening of the port sea locker into the battery space. It's important to have them rest somewhat the cockpit floor then back up to the locker forming a "drip loop" so rain water doesn't follow them in. To keep them from getting pinched by the locker hatch as I open or close it in-port, they are simply held in place at the fwd locker drain with a piece of "Egg-crate" packing foam rubber stuffed above them.

Prior to starting the engine, I unplug the harness up by the Panels, roll the harness up neatly and hang them from a dedicated hook in the very same port locker (female connectors so they WON'T short). The panels are quickly removed, rolled and stored to port as well.
Original Panel installation time: 10-15 minutes mostly sizing the bungees
Setup and take down time: < 2 minutes.
Laying forward while they're setup may seem like a PITA at first, but you quickly get use to unhooking one, then the next bungee as you move past them.

I've had NO charging issues as the R14 seems to float charge Group 24-31 batteries adequately w/o regulation.

If anyone is interested I'll post pictures

"Sub" (no battery worries) Ed

[Dulcinea]

I'd like to see pictures of your ACR installation.