MacGregorSailors.com

I've seen lots of diagrams on the Internet...

02 mac26x.
2 batteries joined for parallel use
Perko 1 2 all off

If I connect as follows:
Neg posts joined, and then run to all neg leads (house, motor).
Batt1 pos to Perko 1
Batt2 pos to Perko 2
perko common to all pos loads (house, motor)

If I leave the perko on ALL to share the load , I'm really not using "opposite corners" of the bank, is this OK?

If I set perko to 1, is batt1 ONLY carrying the load (even though negs are joined), thus preserving batt2 charge?......OR is the connected neg somehow defeating or dangerous?

jazaddict wrote:If I leave the perko on ALL to share the load , I'm really not using "opposite corners" of the bank, is this OK?

I don't see why it wouldn't be ok, but it's the same as wiring two batts in parallel, which defeats the purpose of the switch other than as a disconnect.

jazaddict wrote:If I set perko to 1, is batt1 ONLY carrying the load (even though negs are joined), thus preserving batt2 charge?......OR is the connected neg somehow defeating or dangerous?

Yes, batt 1 is the only one working. Batt 2 is disconnected, and is neither charging nor discharging. There is no circuit, or complete out and back loop.

That's how I run mine - always one, fully charged, in reserve. Same as my fuel tanks.

So u use ur perko?

And both batteries' negative are connected to each other then out to the panel and motor?

The purpose of the switch is to use either or both (or none), so why is this scheme defeating the purpose of the switch ? Isn't one of the purposes to use the batteries in parallel?

jazaddict wrote:So u use ur perko?

Yes. I'm the energy management system.

jazaddict wrote:And both batteries' negative are connected to each other then out to the panel and motor?

Yes. That's the only way I know of to do it, since the battery switch is single-pole (only switches the + conductors).

jazaddict wrote:The purpose of the switch is to use either or both (or none), so why is this scheme defeating the purpose of the switch ? Isn't one of the purposes to use the batteries in parallel?

I was referring to wiring the batteries in parallel. If you have the switch already, then there's no utility in wiring the batts in parallel, since the switch will do that if that's what you want, but allow you to keep them separate too.

Some folks use just one DC batt, and an emergency power pack as a backup. For day sailing, it's all you really need. But I had the space and the wiring when I got the boat (with one dead battery), so I keep two batts and no backup, as one is always fresh when working off battery power. But I also don't overnight at anchor, so my power needs are really pretty small, and for a couple of years after I got the boat, I only used one battery.

Excellent info. Thx.

This may also help.

Ray

http://www.perko.com/sstv_video/sstv_ba ... or_switch/

Thanks Ray.....if I'd found that video to begin with I wouldn't have posted

Mebbe somebody else will need this info.

Great help fellas.

Please allow me to add a little extra regarding the battery selector switch. DO NOT ever change the battery switch settings while the motor is running. You run about a 90% risk of blowing your regulator/rectifier. It does not appreciate being disconnected from the battery while it is running/charging.

Interesting claim. How would one know that happen? Just asking, so please don't take anything personal. I'm sure many of us have done that; I know I have

Ray

NiceAft wrote:Interesting claim. How would one know that happen? Just asking, so please don't take anything personal. I'm sure many of us have done that; I know I have

Ray

You won't know it has happened until you're realizing your battery is not charging! The regulator/rectifier will usually have a burned or bubbled area on its case. But the easy test is...the engine no longer charges the battery.

The same thing can happen if you disconnect one of the engine battery cables from the battery while it is running. Poof!

Nothing taken personal It's all good! Actually...good question.

I am sure many folks switch things with the engine running. Some systems are more sensitive to having the power disconnected while the engine is running. Since most folks don't actually monitor the charging output while the engine is running...it may be weeks or months before they realize the battery is weak. My Yamaha F90 is so sensitive that I don't even like talk about it where it can hear me. I've replaced two in it, 1 because I went stupid and and switched it off because I thought I smelled something. Two week later it failed to start because of a weak battery. The other occasion was because the mechanic failed to tightened the cable back up at the solenoid (under the cover) and the cable fell off. Suddenly I had no power to any gauges, trim, etc. Fortunately the terminal did not ground out to anything. But it fry the rectifier...they bought that one.

Hello,
They make two kinds of perko switches. The one to get maintains connection to a battery at all times unless switched off (labeled OFF - 1 - ALL - 2). So a connection to battery 1 is made before battery 2 is disconnected and of course there is no connection when off. I have one of these in my boat and I can switch batteries at will as long as I don't switch it off.
The reason the rectifiers blow (with engine running not connected to a battery) is because the battery is the voltage regulator in many outboards. Without the battery in circuit the voltage exceeds the rating of the rectifier diodes and *POOF* they are goners.

Don T wrote:Hello,
They make two kinds of perko switches. The one to get maintains connection to a battery at all times unless switched off (labeled OFF - 1 - ALL - 2). So a connection to battery 1 is made before battery 2 is disconnected and of course there is no connection when off. I have one of these in my boat and I can switch batteries at will as long as I don't switch it off.
The reason the rectifiers blow (with engine running not connected to a battery) is because the battery is the voltage regulator in many outboards. Without the battery in circuit the voltage exceeds the rating of the rectifier diodes and *POOF* they are goners.

Thanks for clarifying. I have the label "OFF - 1 - ALL - 2". I cruised as a trawler on #1 for an hour outbound, then switched to #2 with the motor running for the one-hour inbound return to port. The Perko Owner's Handbook warns of not turning off the switch while the motor is running, and of course, the OFF position is located safely away from an accidental turnoff.

Don T wrote:Hello,
They make two kinds of perko switches. The one to get maintains connection to a battery at all times unless switched off (labeled OFF - 1 - ALL - 2). So a connection to battery 1 is made before battery 2 is disconnected and of course there is no connection when off. I have one of these in my boat and I can switch batteries at will as long as I don't switch it off.
The reason the rectifiers blow (with engine running not connected to a battery) is because the battery is the voltage regulator in many outboards. Without the battery in circuit the voltage exceeds the rating of the rectifier diodes and *POOF* they are goners.

Don,
Thanks for chiming in on this. Many of the older switches had the off in the middle which means you had a disconnect somewhere between 1, 2, & all. Some of them were designed as break before make...so regardless of the position, they would disconnect between all settings.

The main thing is to just be aware. I personally just don't change the selector switch while the motor is running. That is much safer than accidently needing to replace a very expensive rectifier!

Thanks!

Whew. Good to know.

Unless you know your switch is make before break, you shouldn't even make the 1 to 2 change, or any other change to the "perko" switch with the engine running. The only way to be sure is to measure the voltage or resistance with two VoMs while you toggle. You would have to check each selection in each direction too. It's also possible for make before break functionality to get lost on aging depending on designing the switch from my experience in non marine high voltage. All this is Neptune trying to tell up you not to do this. Substitute " the force, karma, John Lennon, or my Admiral" as appropriate.