Voltage Reducer to Tow switch

[jakesnake27]

So as some of you know I've been thinking about the wiring on my cart lately.
Right now, my reducer is connected to main battery connections with the yellow trigger wire to the key switch. I recently found out that the trigger wire only controls the 12v output and doesn't cut power to the +48v input. I am wondering if I can somehow wire the input side through the Tow switch, that way it isn't pulling on the pack all winter. The reducer is a 30 amp, does anyone know how many amps the Tow switch is rated for?

[Revolution]

I personally would not do what you are suggesting. If you insist on having them on the same switch use a double pole single throw switch in place of your current run tow switch to keep the controller and reducer separate. make sure its rated to run the full draw from the reducer.

[jakesnake27]

I was thinking I could replace the current switch with a bigger one.
I am just trying to keep the number of switches down...

[jakesnake27]

Ok like this?

http://m.acehardware.com//product/in...a=pla_17486182

Except I just noticed it's only 20 amps...

[Sergio]

If You are only concerned about long term unattended winter storage, just pull the fuse off the converter input side.

The current draw is very small, much less than the battery self discharge rate, so normally is not an issue.

[jakesnake27]

Wow that is low, I may just go the fuse route...

[scooterman]

Originally Posted by jakesnake27

Wow that is low, I may just go the fuse route...

Certainly less to wire up

[jakesnake27]

Yep

[jakesnake27]

Originally Posted by Sergio

kenacp,
Those kind of converters use a common negative, so the black wire is the 12v load negative as well as the 48v input negative.

The yellow wire or "trigger" wire is a low current +48v input signal to tell the converter to turn the 12v power on/off. It is a convenient way to turn all of the accessories OFF when You turn the key switch OFF.

Some folks like to put a switch on the +48v (red wire) for long term storage. The parasitic load is very small once the converter capacitors are charged, someone measure theirs in the few milliamp range.

If do use a switch for the red wire, it only needs 10amps on the +48v, so a 20amp switch would be more than enough.

Quick question here, why would the supply only need a 10 amp switch if the converter is a 30 amp?

EDIT: I may have answered my own question. So for 30 amps at 12v, the max wattage would be 360W. 360W divided by 48v is 7.5 amps at 48v. Is this correct? I'm no electrical engineer and am learning...

[Sergio]

Originally Posted by jakesnake27

Quick question here, why would the supply only need a 10 amp switch if the converter is a 30 amp?

EDIT: I may have answered my own question. So for 30 amps at 12v, the max wattage would be 360W. 360W divided by 48v is 7.5 amps at 48v. Is this correct? I'm no electrical engineer and am learning...

You nailed that one

I would only add to assume the converter is no more than 90% efficient, 80% to be conservative if You ever push it to the max 30 amps.

So I would fuse it for 450W.