Question on wiring 48V to 12V voltage reducer

PBB

Installing a 30A voltage reducer to convert 48V to 12 for lights, winch, 12V acccessory etc. Will the reducer draw current from the batteries when none of the accessories are in use? I have it wired straight to the batteries and then the 12V accessories wired to the reducer. Each accessory has it's own switch to operate it, but you can turn them on / off without using the key switch. Will it draw enough current to do any real battery drain?? If someone suggests installing a switch, where would you install it? On the 48V side or the 12V side? I really dont want to pull the dash back apart and wire it into the key switch. Any thoughts or is it not necessary at all? The directions with the reducer did not call for any relays / additional switches, but I have read where others have installed them. Opinions please.......

BGW

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scottyb

Most reducers draw power all the time....test your by disconnecting it and then slowly touch it to your power source. Any kind of spark indicates a draw.
Or if the unit is warm to touch hours after use? This may indicate a draw.
I use a relay (48v in my case) like from a battery charger. It turns mine on when the key is switched on.

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mcrownover

I wired an on and off switch for my reducer for this reason. Did not want them to drain my batteries when I wasn't using it.

Divebmbr48

I'm pretty sure if you want to just add a switch, put it on the 48v side. Between the batteries and the reducer. That way it turns off the reducer. Placing it on the 12v side would turn off all your accessories, but your reducer will still be drawing power. It's easy to check if you wired it correctly with a volt meter.

TheAspec

Please make sure your reducer it switched, besides the minimum draw it will use, even with all accessories off it's dangerous to leave them on 24/7, see this thread.

I recommend connecting it to switched power, this way you never forget to turn it off. ScottyB has the right idea -- I have mine wired though the key switch on my 2008 RXV. If the key is not turned to F, N, or R the reducer is off.

If you have the Forepar 3-498E reducer, which it sounds like you may based on the 30 amp comment (have not seen many other 30 amp reducers) the yellow wire is your switched connection. Wire it though a relay or find a wire in your key switch that is out putting 36-48 volts only when they key is turned ON.

Pats Fan Willy

Ok you guys are freaking me out. I currently have a 48v to 12v reducer that goes to a fuse box. I have the switch after the reducer but before the fuse box. So you guys are saying wire in a 48v relay from a switch before the reducer? Where do i find such a relay?

PBB

Thanks for all of the replies. I think I am going to just install a cut out switch between the batteries and the reducer. I found a HD switch today like we use on heavy equipment to totally disconnect the power. Most of those are 24V ssystems. I went to the HD truck parts strore this afternoon and the one they have says it is rated @ 175 amps continuos or 1000 amp instantaneous and from 6 to 36 VDC. My question is, i know i wont exceed the amps, but should i be concerned about the 48Volts? Does anyone know of a switch realtive to carts for 48V??

PBB

Just for clarity's sake, my reducer came from Nivel and is for 24,36,48 volt input, 12V 25Amp output. It only has (4) lugs on top and no other wiring coming from it. The lugs are marked 12V+, 12V-, B+, B-. I'm going to see if I can figure out who the MFR is and do some research on it.

JR_ECE

Thanks Scottyb! I found this old post and used the part number from the pic to find something equivalent for my 48V to 12V reducer.

This is what I ordered for anyone wanting to add a relay to their 48Vdc golf cart voltage reducer:

TE CONNECTIVITY / POTTER & BRUMFIELD T9AP1D52-48 POWER RELAY, SPST-NO, 48VDC, 30A, FLANGE

It's available from quite a few online retailers.

Should work.

Golfinw71

ScottyB, I like this setup. Any chance we could get a wiring diagram of some sort on how the relay is hooked up?!