1-2-All Switch Wiring?

Question

Got this big DC switch (6"diameter) with the TC, not connected , no instructions. Been meaning to ask how to wire it up, so here goes:

On the front it has a big switch handle that can point to:
Off/1/All/2

Says it is good for 210 amps continuous, 315 intermittent, and "before switching to Off position, turn off engine."

On the back it has three posts:
"Terminal 1 NIDCO"
"Common", and
"Terminal 2"

I failed the IQ test for how to hook up two 12v batteries to this thing. and where do the pos and neg load wires go? Thanks!

(I am also worried it says "all" instead of "both" but it only has the two terminals marked 1 and 2. I am pretending I can't see that)

ca_traveler · Answer

Terminals 1 and 2 are for 2 battery banks, positive wire. Common is the output for non engine (dual engines) boat power, no negative connection. It's a common switch used in boats. All can be used to start a engine if it's battery is low, otherwise 1 or 2 can supply the boat house power which should include a third battery. At anchor Off is the desired position as the very last thing you want is a low engine battery.

s_davis · Answer

The wiring is as described above, here is a picture of my two battery bank switch.  One positive from each bank and common to 600amp buss bar.Battery switch

bfl13 · Answer

So the negs from each battery go to a buss where the neg load wire also goes (such as the RV frame)? And one pos wire to 1 and the other to 2, and the pos load wire goes to "Common" ?

In "All", that links 1 and 2, putting the two 12s in parallel, and in "Off" the links between Common and 1 and between Common and 2 are opened?

What was that about a third battery? Yipes!

s_davis · Answer

That sounds right, I have another 600amp buss that the battery negatives from both my banks and the truck/frame tie to for the charging circuit from the truck.

wa8yxm · Answer

1 and 2 go to the batteriesCommon goes to the "House" NOTE: I do not recommend isolating the two banks unless you need a "Back up" system. the reason is Peukert's law, which basically says the faster your draw current off a battery the faster still it runs down. So by dividing the load between TWO parallel batteries (or more) you get more power out of them before dead.But if say bank one is 4 GC-2 in series parallel and bank 2 is a single Group 27 just in case so you can start the Generator (with a Battery Tender or other small 3-stage charger on the 27) then by all means run off just bank one.

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1-2-All Switch Wiring?

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