# WiFi relay to DC motor

I'm trying to use a 12 volt WiFi relay setup to control a 12 volt DC motor. The WiFi relay has eight 10 A SPDT relays in it and the motor is 15 A. I understand how to wire it directly to the two relays that are in the box, but I'm lost after that. Here are my questions:

1. Since I'm using two 10 A relays at the same time to control the motor (positive through one and ground through the other), does this mean that I have a 20 A capacity with the relays?

2. How else could I wire this up to increase the relay capacity (or run the signals from the WiFi relays) to other relays and protect the WiFi relay box?

Here's the info on the WiFi relay:

• In that circuit, the full motor current will flow through each relay, so your 10 Amp relays are not adequate to control your 15 Amp motor. – Peter Bennett Sep 30 '14 at 17:55
• thats what I was thinking, but i figured i'd ask. – Maurice Edmondson Sep 30 '14 at 18:14
• As Peter Bennett has said the relays are in SERIES in your schematic. PARALLEL would IN THEORY halve the current through each, but in reality they don't switch at the same time (biggest concern) and they don't have the same internal resistance (smaller concern). Edit: Looks like venny's answer has covered it all... – Mister Mystère Mar 30 '15 at 11:34

1. Combining several relays in parallel is not good, because the contacts do not switch at exactly the same time, and it will cause arcing at the faster one. Another thing is that the motor is an inductive load and needs more current than the rated $15\,\mathrm{A}$ during startup.