240v female to 110v male adapter


Bionicman

E powertrain proponent
Likes
385
Location
WA
Have my pigtail adaptor 110v US wall plug male to 240v 4 prong female

That way I can just plug my fast charger into any outlet to top off bike without generator overnight ready for next after work special

 

Philip

Administrator
Staff member
Likes
4,045
Location
Lake Havasu City, AZ
I spent most of the day today researching various RV power outlets, NEMA connectors, and extension cords. Despite having an engineering degree, I was still pretty clueless about electricity. I am learning. And now I know just enough to be dangerous!

Today I finally understood what a "bridged adapter" is, where it is used, and why it won't work for the rapid charger.

This is how the 240V outlets work: Split-phase electric power - Wikipedia

And this is the schematic:
1533492440287.png

The 240V outlets are in effect two 120V outlets with a common (neutral) wire and two hot wires. The two hot wires produce the 240V power. This is what we need.

But you can also draw 120V power from the same outlet, as shown in this picture. Two circuits. And this is exactly what the big 50A RVs do.

But when these RVs arrive at campgrounds that have only 110V 15A outlets, they plug in those adapters that have the two Hot legs "bridged" or connected together. This way both of their 120V circuits are connected to the same two wires -- the Hot and the Neutral of the 120V 15A plug. This is what a typical RV "dogbone" adapter looks like:

1533438484312.png

Or like this, if they are using a generator cord:
1533492103983.png

The two hot legs are bridged, or connected together. If you use this thing to plug in your Rapid charger, nothing will blow up, but it will not work either.

This is how I would wire it (below, the red/black color have been updated)). The Neutral leg of the 4-post NEMA L14-30 connector (usually white wire, but I marked it gray) is not connected to anything. Do not try this at home, unless you understand what you are doing.

1533492245150.png

I hope I got this right. :p
 

schwankl

Member
Likes
336
Location
utah
@Philip - Not quite, the neutral is used, and your hot/black is on the wrong side. The hot (usually black wire) in a 5-15 would go to the connection by the "hook"/keyed side of the ground (lets call that X). And the white/neutral goes to the opposite side (call that Y). Confirmed by diagram in post 3 and 14 of this thread. In post 21 have the parts listed I used and works fine with the r-charger. Just make sure the ground/green goes to the one with the hook, black wire goes to the side with the hook of the ground, and white to opposite side from the black. Hope this helps.
 

snydes

Moderator
Staff member
Likes
2,795
Location
Pennsylvania
Unless I'm seeing it wrong, I believe that's what he's showing. The white (neutral wire) is used, but it's now the other "hot" wire. The neutral terminal of the 240v plug is essentially dead and connects to nothing.
 

snydes

Moderator
Staff member
Likes
2,795
Location
Pennsylvania
But when these RVs arrive at campgrounds that have only 110V 15A outlets, they plug in those adapters that have the two Hot legs "bridged" or connected together. This way both of their 120V circuits are connected to the same two wires -- the Hot and the Neutral of the 120V 15A plug.

I couldn't for the life of me figure out what the application would be for a bridged connector... thanks for that!
 

schwankl

Member
Likes
336
Location
utah
note black is on the keyed side of the ground...might not matter to the rectifier in the charger, but I am not going to test that out, and I followed the diagram that alta gave (post 3) like below.

240-to-120.jpeg
 

Philip

Administrator
Staff member
Likes
4,045
Location
Lake Havasu City, AZ
@Philip - Not quite, the neutral is used, and your hot/black is on the wrong side. The hot (usually black wire) in a 5-15 would go to the connection by the "hook"/keyed side of the ground (lets call that X). And the white/neutral goes to the opposite side (call that Y). Confirmed by diagram in post 3 and 14 of this thread. In post 21 have the parts listed I used and works fine with the r-charger. Just make sure the ground/green goes to the one with the hook, black wire goes to the side with the hook of the ground, and white to opposite side from the black. Hope this helps.
I was taking that the Neutral leg of the 4-post NEMA L14-30 connector (usually white wire, but I marked it yellow) is not connected to anything.

You are using the color convention of the NEMA 5-15 household connector, and I am using the color convention of the NEMA L14-30 generator connector. This is the difference.

I might have got the red/black hot wire colors mixed, it does not matter, but the diagram is still correct. Everything will still work even if they are crossed over. But I will double-check in those cases when it might be important.

This is how the Elite Motorsports' connector is wired too. I bought one to support the sponsor.
 

Philip

Administrator
Staff member
Likes
4,045
Location
Lake Havasu City, AZ
note black is on the keyed side of the ground...might not matter to the rectifier in the charger, but I am not going to test that out, and I followed the diagram that alta gave (post 3) like below.

View attachment 770
Ok, so it appears that I did mix the black and red colors. It should not mater functionally, but I will update my post and switch them.

Your diagram shows the same connections as mine.
 

Jon

Well-known member
Likes
74
Location
ColoRADo
A 5-15P (~$10 at home depot) and an L14-30R (~$40 at home depot... which is too much) and a little 12 gauge or smaller wire should get you going with a hot-hot/hot-neutral setup. I made it out the door for $50 with some free wire for the discard/cut-off bin and it works great.

Could probably do it for less with parts off amazon or ali baba, but I wanted it now :)
 
Top Bottom