Making a 4 wire Voltage Reducer "keyed"?

[davjaramillo]

Originally Posted by Sergio

That is the easiest way since You should not power the DC converter directly from the key switch.

Maybe the diagram below helps.

48v Relay:

http://www.mouser.com/ProductDetail/...HO3CeSfQ%3D%3D

1N4007 Diode:

http://www.mouser.com/search/Product...alkey1N4007-TP

I have a 36v cart trying to add a switched converter just like this. Any recommendations on which relay to use? Also what gauge wire should I use from battery pack to relay and converter imput?
Thank you in advance for any help!

[yawood]

The relay that Sergio recommended was the T9AP1D52-48-01 and all you need to do is get the 36V version which is T9AP1D52-36-01. You can get it from Mouser or any of the other electronics suppliers.

As for the wire gauge, look at your max output. For example I have a 30A converter on a 48V cart. Using Watts = Volts X Amps, this means that the maximum it will output is 30A at 12V which is 360W. The input will draw 360W at 48V which is 7.5A.

In your case you have 36V so if you have, say, a 20A reducer it will produce 20X12=240 watts. On the battery side it will need 240/36=6.7 Amps. So your wires need to be able to handle 6.7 A on the battery side and 20 A on the 12V side. Increase these for safety and I would use 15A cable on the battery side and 30A cable, in this case, on the 12V side to your distribution point (fused distributor). The wires to the individual accessories from the distribution point can be substantially lower.

[Sergio]

Good explanation yawood

Here is the link to the 36v relay (other sources available):

https://www.mouser.com/ProductDetail...hoCK0YQAvD_BwE

Chart to figure wire gauge size based on lenght:

[yawood]

Originally Posted by Sergio

Good explanation yawood

Thanks Sergio

[Fairtax4me]

Sergio do none of those relays a have built in suppression diode?

Most automotive style 12v relays have a diode already built in. Obviously they’re not going to work on a 36 or 48v system, just wondering if there’s a need for the external diode, or if there’s a reason the higher voltage relays don’t have them already.

[Roxyflash]

You can buy a standard bosch style relay in 12 24 36 48 volt coils with or with out a diode depending on what your running off the voltage reducer i was only running my healights so i wired it with a 48 volt bosch relay to the light switch which turn on the voltaged reducer to turn it on for the lights which are wired to the voltage reducer output side You can wire the key switch to the terminal 86 from key switch 85 from ground wire 30 from 48 volt power 12 gauge wire 87 12 gauge wire to voltage reducer which will turn it on when key is on 85 and 86 can be 16 or 18 gauge wire wire on 30 should be fused