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Battery disconnect switch

imagineer

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Dec 13, 2015
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Location
Ohio
I want to add a battery disconnect switch for my 48v yard cart project, for 2 reasons . . . there is a small voltage drain from the motor controller that I'm concerned will eventually sap the batteries. I'm also concerned the motor controller could be damaged from connecting/disconnecting the battery charger.
To solve both of these concerns, I want use a marine battery selector switch. The type I want to use has 3 positions, Battery #1, Off and Battery #2.

I plan to hook it up backwards, such that the output is connected to the positive battery output. Position #1 would be connected to the power distribution block for the motor, motor controller and yard cart accessories. Position #2 will be connected to the positive side of the charger plug.

I found a nifty selector at a reasonable price but it states it's rated for 32v @ 350amp continuous. My system will be 48v and have a max amp draw of about 35 amps. https://www.amazon.com/dp/B07H8573R4/?tag=atomicindus08-20

Should I be concerned I'm overloading the selector switch contacts?

FYI, I bench tested the motor and drive this weekend...
 
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imagineer

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Ohio
I saw that too, but I'm thinking the rating of the contacts is based on watts, then my 1800 watt system is well below their 11.2k watts (32vdc x 350A cont).
 
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rlitman

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Oct 18, 2010
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Long Island
In one place it says "Operating Voltage" is 48, but in another place on the ad it's only rated for 32? Something fishy is going on.
The 48V part is for different items in the chart below. This is a 32V switch. Usually the voltage rating has to do with the physical separation of components for arc flash purposes.
 

Zeke

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Aug 13, 2009
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17,176
Location
Long Beach CA, the sewer by the sea.
Can you use a relay? Seems like lots of current is hard on (some) switches. I did a quick search and there is such an animal but it comes from the UK. It ain't cheap either.

Then there's a company called

48V 300A Large Current Discharge Power Switch Blue Sea Systems -

that's the verbiage in the Google hit but when you get to the page voltage ratings aren't there. Well, that's not the link I intended because it's a 2-position.
 
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