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battery switch on E34

HerbertFriedman

Member III
Question about the 1-2-all-off battery switch, the E34 manual says this switch is located on the DC electric panel in the Nav station, but clearly mine is located next to the battery box in the aft stateroom area, are we talking about the same battery switch. Also the manual says that if one battery is weak, switch to the other battery, start the engine and then switch back to the weak battery to charge it. Will operating that switch while the engine is running damage the alternator diodes. I know that turning that switch to the off position while the engine is running will damage the diodes but will turning the switch from one battery to the other or both damage the diodes if I stay away from the off position?
 

Rocinante33

Contributing Partner
This has been discussed here before. It was said that those switches are "make before break." That is, the power will be maintained as you switch between battery banks.
 

HerbertFriedman

Member III
I sensed this was the case because I could not hear any disruption in radio reception as I turned the battery switch but has anyone actually tried to change the battery switch from one battery to another (for charging purposes) while the engine was running with no damage to the alternator diodes? I would hate to try that test if negative results were reported.
 

supersailor

Contributing Partner
Battery Switch Location

The battery switch on my E-34 is also at the front of the aft cabin berth just ahead of the batteries.

Bob Morrison
Terra Nova
 

Loren Beach

O34 - Portland, OR
Senior Moderator
Blogs Author
Master Switch trivia & guesses

I seem to recall that in the early 80's Ericson was installing the master switch on the "main panel" and allowing/causing a longer cable run to the pair of batteries.
Only a guess, but in those days higher-end builders wanted to impress customers with the "completeness" of the yacht's electrical system. Even then, many "discount" boat builders were still putting in skimpy panels, often with screw out fuse holders for a very small number of circuits.

Later, boats like our '88 model had the master switch completely separate from that panel and physically much closer to the battery banks. Ours is in the aft cabin, on the side of the engine/battery compartment and within a foot of so of the batteries. This shortened the un-fused cable run a lot.

This scheme seems safer to me, and given that we only want to access that big switch once a day or so, seems plenty convenient enough. Of course by the later 80's the main AC and DC panel(s) were extensive enough and well enough populated with breakers to impress most Ericson buyers.

(And, 25 years later, we'd all like even more... breakers... !)
:rolleyes:

Cheers,
Loren

ps: remember that old am radio song that went: "breaker breaker, any takers, CB Savage calling!"
??
:)
 

Christian Williams

E381 - Los Angeles
Senior Moderator
Blogs Author
actually tried to change the battery switch from one battery to another (for charging purposes)

Start the engine on either Battery 1 or 2, then switch to Both for charging. That's the standard recommendation if you have a basic setup.
 
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Tom Metzger

Sustaining Partner
Start the engine on either Battery 1 or 2, then switch to Both for charging. That's the standard recommendation if you have a basic setup.

Yes, for a 'Basic" setup which has two similar batteries. Herb is installing a reserve (starting) battery which is not "basic".

From his previous thread I said: "FWIW, most people I know use the "start" battery as a "reserve" battery and start the engine with the house bank." This saves having to deal with the switch on a regular basis.

In answer to the original question in this thread, as has been said by others, yes, you can operate the battery switch while the engine is running as long as you don't go to or through "Off".
 

clp

Member III
Another way to answer your question is, yes. I've switched the batt switches back and forth from 1-2-both so many times the finish is shiny on the knob. Zero broken alternators yet..
 

Christian Williams

E381 - Los Angeles
Senior Moderator
Blogs Author
]I just took my old 1980s stock alternator off. The placard may have contributed to the widespread confusion.

Motorola 51a alternator early 1980s.jpg
 
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Rick R.

Contributing Partner
Confusion

I'm really confused about the proper battery switching procedure. Maybe we need a pole to see what the majority says to add more confusion?

Can one operate the switch with the engine running? I've heard "never", now I read that it's ok as long as you don't go through "off". Yet Christian's alternator says don't do it......

Do you switch to the start battery for firing the engine then switch to the house bank when the engine is off to operate your instruments when sailing? (I do...is this wrong?)

Someone in authority tell us what to do...lol! Like the government or a Ralph Nader:soapbox:
 

Loren Beach

O34 - Portland, OR
Senior Moderator
Blogs Author
Actually, the printed warning is about not "changing" the batteries while the alternator is charging.
In simpler terms, just do not have the alt. charging without a battery load on the receiving end - not even for a second.
At least that's what I've been told.


Loren
 

Randy Rutledge

Sustaining Member
I do not recommend running the engine with the battery switch in both, I was motor sailing a couple of years ago when the Atomic 4 died, I noticed the bilge blower was barely running and the starter did nothing, after the initial moment of concern I switched to the other battery and all was well, I had a loose alternator belt that allowed the first battery to get low enough that the engine would not run, If I had been running with the switch in both I would have depleted both batteries and been stuck with dead batteries and no way to start the engine.
 

HerbertFriedman

Member III
From what I have been able to tell, if the Perko Battery switch is used, it generally is a make-before-brake type switch meaning as long as you do not switch to the "off" position, it is OK to switch from Batt 1 to all or from all to Batt 2 and there is no time when no battery is connected so the alternator should be OK when the engine is running. A friend says that he switches from Batt 1 (starting) to all and then to Batt 2 (house) when the engine is running with no problem. This is sort of a poor man's Automatic Charging Relay which is what I want to accomplish. The ACR eliminates the need to manually switch from starting to house but I do this so infrequently that the ACR is just wasted money for me.

I think you can tell if the Battery switch is make-before-break by turning on the radio, then switching the battery switch and listening for an interruption in the radio, I did that and heard no interruption.

I agree with the previous owner who says it is bad practice to run with all the batteries connected unless it is absolutely necessary and then if the engine starts, better to switch to Batt 1 or 2 depending upon which battery needs charging.
 

Rick R.

Contributing Partner
Crazy Question

Does the battery switch position 1 or 2 affect which battery is getting the charge from the alternator or battery charger when on shore power?

i was told that on our boat, both batteries get a charge and that position 1 or 2 only controls the output.
 

Loren Beach

O34 - Portland, OR
Senior Moderator
Blogs Author
Does the battery switch position 1 or 2 affect which battery is getting the charge from the alternator or battery charger when on shore power?

i was told that on our boat, both batteries get a charge and that position 1 or 2 only controls the output.

Good question. When I first wired in a new charger I pondered just where to direct the charge output. Since most all modern chargers have two (or maybe more) output posts, I wired a #10 or #12 wire to each battery directly. I also have a fuse within a foot (or less distance) of each battery post for these leads.

Later, I thought over the fact that I have slightly different battery chemistry for each bank -- And took the Emergency battery out of the charging scheme. It's a spiral-cell agm battery and I just charge it off the engine alt. several times a year.

Caution: there may be more than one acceptable answer to the question.....
:nerd:

So, first look at exactly where the charger wires go.

Regards,
Loren
 
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HerbertFriedman

Member III
which battery gets an alternator charge depends upon the specifics of the wiring. On my boat, and I think most others, the alternator output goes to the starter motor which is fed by the output of the battery switch. So if the switch is on battery 1, battery gets the alternator charge. Some people argue that the alternator output should go directly to the starting battery and then rely on a ACR (automatic charging relay) to distribute that charge current to both batteries as needed. In this case, the alternator output goes to the starting battery no matter which position the battery switch is in.

For the battery charger powered by the shore power, usually (for dual output chargers) the outputs of this charging source are wired directly to each battery and that battery charger charges both batteries no matter what position the switch is in, even the "off" position.

At least this is my understanding, if I am mistaken, someone out there correct me. Thanks,
 
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