Perko Switch 1, 2 Both question?

I have a single outboard. 2 Batts controled by a Perko switch with the 1,2 or Both selections.

Q: Are both Batts being charged by the alternator when I am in any of the 3 selections? And also what selector should I be in…does it matter. could someone break this down. Thanks.

First off, naming convention on what battery is #1 and which is #2 is as follows. Numbers increase from fore to aft. starboardbd is odd, port is even. So if they are arranged fore and aft they the one in front is #1, aft is #2. If aranged side by side, they the one on the starboard side is #1, port is #2.

Assuming that is it wired correctly (termininal 1 wired to battery 1 positive and terminal 2 wired to battery 2 positive)it should work as follows.

In position 1, the engine will be started on battery #1 and charge battery #1. Position 2 does the same just for battery #2. In the both position the batteries are paralled with doubles the available amperage. The engine will start on both. However, both batteries will not necessarily be charged; as soon as one battery is at full charge, the alternator will cut back and no charge the second or very slowly.

It is best to run on one battery for half the day, then switch to the other for the other half. That way they both get charged. Use the both postition only if needed to crank the engine over.

Iain Pelto
Edgewater 185CC “Jumpin’ Bean II”
Native Manta Ray 14

Excellent explaination Hairball.

Mark
Mako 262 Twin Yammaha F200s
Yeah, but do you consider a dog to be a filthy animal? I wouldn’t go so far as to call a dog filthy but they’re definitely dirty. But, a dog’s got personality. Personality goes a long way.

“Life’s tough…It’s even tougher if you’re stupid” John Wayne

if you put it on “both” and one battery is dead it will pull the fully changed battery down to a state of equalibrum between the two batterys . just like water it will flow to the lowest point and can result in 2 dead battries instead of one. most outboards don’t put out enough amperage to charge a battery fully.

green grass and high tides forever
jhp----- Murrells Inlet

Better yet, get a battery combiner; run all day without the “hassle” of remembering to switch your batt from one to two. Pretty inexpensive, and fool proof. There are others, but this guy is local:

http://www.yandina.com/c100Info.htm

good explanation from hairball, only thing I would question…
when you are on “both”, I dont htink you have double the amperage
you have double the capacity, I might be wrong on this, but i dont think you get double the cranking amps

I start on 1 battery, and switch to 2 run half day, switch back to 1

I’m now at www.teamcharlestonmarine.com

Sorry, my explanation was a little lacking. In the “both” position, the available amperage is the sum of the two batteries. It doesn’t mean that the current draw will be much different when cranking an engine, but the increased capacity does prevent voltage drop which leads starter, solenoid, etc. damage.

Iain Pelto
Edgewater 185CC “Jumpin’ Bean II”
Native Manta Ray 14

Iain,
if you had 2 1000 cranking amp batteries, and a perko, you have teh perko on both, would you have 2000 available cranking amps, or would you still have 1000 cranking amps, but the ability to use the 1000 amps for twice as long.
based on the load capacity I would think you would only have 1000 amps.
what say you?
I dont know for sure, and would like your ■■■■■■■■

I’m now at www.teamcharlestonmarine.com

Chris,

Batteries in parallel - voltage stays the same (12V), CCA gets added together (1000+1000=2000 CCA). Just because you have the ability to draw 2000 amps, doesn’t mean that is what is used. The amount of current draw is dicated by the load. For example, a starter may draw 100 amps. If the batteries are in parallel, the starter still draws 100 amps. However, since the capacity (CCA) is doubled you will have the ability to crank twice as long, or run a livewell twice as long, and so on.

Batteries in series - voltage gets added together (24V), CCA stays the same (1000 CCA).

Iain Pelto
Edgewater 185CC “Jumpin’ Bean II”
Native Manta Ray 14

I am with you on the, available versus used, being determined by the load, and parallel the voltage stays teh same. what I am questioning is the available cranking amps being doubled.
I guess I just am not getting that. lets use deep cycle for this discussion.
1 12volt battery will run a trolling motor for 2 hours
2 batteries in parallel would run same load for 4 hours
I get that
I also get if you put them in series you get 24 volts, and you would actually get a little more work out of the same available batteries, because 24 volts works more efficeintly than 12.
what I am struggling with is the double available cranking amps
these DC bat we have are 750 MCA if we run them in parallel, we could then have 1500 available amps?
obviously you would have to have cables big enough to carry the load.

I’m now at www.teamcharlestonmarine.com

Yes you would have 1500 MCA available and you correct on the cable sizing to take advantage of the increased capacity. Sizing cables isn’t obvious to a lot of people or they just don’t want to spend the extra for a heavier gauge.

Iain Pelto
Edgewater 185CC “Jumpin’ Bean II”
Native Manta Ray 14

thanks

I’m now at www.teamcharlestonmarine.com

All, thanks for the explanations. I like the idea of running on 1 then switching mid way to 2 for charging purposes.

180, I’ll look into the combiner - but I need to investigate a bit more about the advatages.

i put a combiner on mine. pretty neat. yandina was quite helpful as well. what you dont get is the ability to shut off everything when leaving the boat by using the off switch on the perko

jan

Always need to shut engine off before switching correct?? otherwise risk frying electrical system??

Key West 2300 SS
Yamaha f225

Triple ---- I think it depends on if the battery switch has a “make or break” switch…a lot of the newer switches have this.

My understanding is in order to check, without motor running, turn on a light or radio with batt switch in #1 position. Then turn the switch to #2…if it stays on continuously then you should be OK to switch while running motor. If the light or radio “blinks” when you switch, then do not switch while running.

That’s what I’ve heard but maybe one of the real mechanics can chime in on this.

It’s called fishing, not catching!!!

make before break.

green grass and high tides forever
jhp----- Murrells Inlet