Start a new topic

Can I use the 50A deluxe kit with 120V

I've just put together a 50A deluxe kit with a NEMA 14-50 AC plug and I'm using it happily for the last two days.  I was hoping to take this with me occasionally and use it with a 14-50 to 5-15 adapter. That 5-15 would be 120V, of course. Would this work? I don't know if the 40A contactor in this kit will operate on 120V. 


I just realized that I didn't say how I hooked up the 14-50 cable. I used only hot1, hot2, and ground, leaving the cable's neutral wire unused.

The 50A contactor operates at 208 to 240v. 

120v volts is not enough to close and hold the contactor.


That's what I was worried about. I'm not familiar with anything but automotive relays, are there

120V->240V contactors I could use?

If I did find one and replace the one in my kit, would everything "just work"?

Not really, if you were to use a 1:2 transformer for 120 => 240 when you plugged into 240 it would try to make 480.

You could swap the 40A relay with 30A relays, which are powered by 12v DC from the power supply. This will allow 240 charging at 24A and 120v charging as well.

Christoper, I did a check on the Contractor, and think I found the same one on Amazon.  It list the input as 24V.  Would it be possible to use a relay to activate the contactor, using the 12V from the open EVSE, then activate a relay connecting 120V to activate the contactor?  I would like to have a 120 12A 15A 20A and 240 12A 15A 20A 40A and 50A incase I get a Leaf later, which will need the 40A 240 to charge at max rate.


The contactor included in the 50A kit requires 208-240v 120v is not enough to close the contacts.

If you used a relay on 12v to activate the contactor you still need to get 208 - 240v to the main contactor.

The 50A kit is L2 onlt (208 - 240v)

The 30A lit is L1 or L2.

You could always build a 30A kit now and if you need more later the 50A contactor is only $12, pretty inexpensive upgrade.


Hi Chris, I have ordered the 30a kit. It sound like for me to be able upgrade this for higher amp cars I will need to locate the proper amperage contactor that can activate with 12v? I think I found some but they are very expensive. I'll need to locate a better cost option.

Yes, you could use a 12v relay as long as it draws less than 2w (160ma) which would be a of 75 ohms or higher. 

Sorry to drag up an old thread... but along the same lines -

How tight is the spec on the 160mA coil draw? I found these:

Both with 12VDC coil resistance of 70 Ohm

At 12VDC it looks to pull about 171.5mA. Going this route I believe we could get a single box that would handle 120VAC and 240VAC up to 40/50A depending on the fuses we use... all assuming ~171mA isn't going to kill the driver.
Thoughts? Just learning about EVSE and looking forward to having the most flexible option available.

Thanks! I think that's just what I need. I'm not sure there is enough power left to power the this relay. However I think we can use the original relays to trigger this! I have been busy and not looking for the right part. But I think this might work. I'll check it out more and give it a try!

70 Ohm should be okay, I ordered a couple of the 450BXX relays. I will test it out with WiFi (also drawing from 12v) and see how far I can push the 4w power supply. I am confident it will not be a problem at cooler temperatures, however it may be an issue when enclosure temperatures pass 60C.

1 person likes this
Fantastic! I'm also planning on the 450. Since you already beat me to the punch I'll wait for your results. I'm looking to order another 2 kits soon and I would love a single 120/240 solution that works up to 40a continuous!

@Christopher: Please let us know in this thread. If it works with the wifi module, I'll swap the Packard contactor out for one of these.

Anyone make any progress trying this out? I ended up buying a 30A Deluxe. Thinking about upgrading it with a 50A contactor, and trying to build a second smaller box like the old 30A basic for portable charging with the fuses and relays.

Login or Signup to post a comment