DIY Retracting Charging Cable. Took me 3 days to figure it all out.

[Dylankjustice]

Wow! Mechanically it is very slick. But electrically, I worry about the super long cable.

Haha! I guess time will tell if that 2.12 volt drop is going to cause issues!

***When I calculated the voltage drop, I only figured the additional 25 feet I added. I did not figure the stock length of the cable at 25 feet already... so at 50 feet on a 6 AWG conductor at 247 volts... it should be more like a 2.12ish voltage drop.

 

[AlanSubie4Life]

I guess time will tell if that 2.12 volt drop is going to cause issues!

Definitely won't be a problem, as you say! You'll probably see more voltage drop than that in the car as it ramps from 0-48A, but it'll be dominated by your service line and other resistances. For example, I see about a 7V drop for a 0-40A ramp, and only half of that is after my meter, last I checked. (And calculating the resistances in my specific situation, that seems about right.)

stock length of the cable at 25 feet already

Stock cable can take 80A continuous, so it is fatter than 6 AWG wire, isn't it? (No idea what it actually is, haven't looked it up, but presumably whatever the electrical code requires for that...) I guess you would know, since you just wired it up...

 

[Dylankjustice]

Thanks for sharing.
Have you seen a similar retraction mechanism before or was this approach designed from scratch?
I tried a tool balancer and was not particularly happy with the results.
I was wondering what your background is, now it makes sense (you must be a mechanical engineer as well).
Very clever!

I had some ideas in my mind before hand, I thought of using a tool balancer. I wanted to be able to ratchet it into a fixed position without constant tension though... When I started I though it was a great idea and why know one had thought of it before... then I stopped to think.. "someone probably has... I just haven't seen or researched it yet"... sure enough there were people that had already constructed their own set up. I did take inspiration of a simple mechanism where someone used a counter-weight that lifted a pulley that lifts the charger cable. They even have a nicely done set of drawings to look at... I'll see if I can find it and post it on here... its on this forum somewhere. Anyway, I liked the simplicity, but unfortunately I didn't have a high enough attic to have that particular set up. So I had to figure out how to do it horizontally rather than vertically.. and this is what I came to.

Actually I'm a service electrician. I have a journeyman license, but as of about a month ago I passed my masters test. So officially I'm a licensed master electrician, Woo hoo! However, as of earlier today, I was accepted for a promotion to project manager. When it comes down to it I am a jack of all trades... master of.. one. Haha!

 

[Dylankjustice]

Definitely won't be a problem, as you say! You'll probably see more voltage drop than that in the car as it ramps from 0-48A, but it'll be dominated by your service line and other resistances. For example, I see about a 7V drop for a 0-40A ramp, and only half of that is after my meter, last I checked. (And calculating the resistances in my specific situation, that seems about right.)



Stock cable can take 80A continuous, so it is fatter than 6 AWG wire, isn't it? (No idea what it actually is, haven't looked it up, but presumably whatever the electrical code requires for that...) I guess you would know, since you just wired it up...

Good point! The stock cable does take up to 80A. I imagine the insulation and rating of that... we'll call it SO cable allows that 6 AWG to be rated much higher than lets say 6 AWG THWN in conduit... but yeah... its like a 6 AWG 3 conductor and has.. I want to say 5 #18 AWG conductors as well (only 4 of them are used, if you cut it open you'll notice a white wire is just cut short inside) But yeah.. I think the insulation and finer strands allows it to be rated higher. I would like to find some specs on that cable though, or where to order it!

 

[darth_vad3r]

**Advice for anyone buying a home, beware if the previous owner was an electrician, plumber, or HVAC tech.**

LOL

 

[Dylankjustice]

Definitely won't be a problem, as you say! You'll probably see more voltage drop than that in the car as it ramps from 0-48A, but it'll be dominated by your service line and other resistances. For example, I see about a 7V drop for a 0-40A ramp, and only half of that is after my meter, last I checked. (And calculating the resistances in my specific situation, that seems about right.)



Stock cable can take 80A continuous, so it is fatter than 6 AWG wire, isn't it? (No idea what it actually is, haven't looked it up, but presumably whatever the electrical code requires for that...) I guess you would know, since you just wired it up...

Yeah, the stock cable is 6 AWG.
So, last night I figured I'd go check to see what voltage the car was reading while charging. Sure enough it was about 2 volts drop from my service to the end point (the car).

 

[AlanSubie4Life]

Yeah, the stock cable is 6 AWG.
So, last night I figured I'd go check to see what voltage the car was reading while charging. Sure enough it was about 2 volts drop from my service to the end point (the car). View attachment 453152

Nice healthy voltage. You must have a robust service feed (apparently I do not - even though it isn't that far from the transformer on the street). More than half my ~7V droop occurs right at the entrance to my 200A panel. I have about 50 feet of 6/3 Romex after that to the Wall Connector. So that portion should only be 3V of drop at 40A including the Wall Connector cable, at least using the online calculators (I have not cross checked with an actual resistance calculation looking up all the parameters but I'll believe them).

Anyway, we've come a long way from discussing your awesome installation. Which is sweet. I have no idea whether it is to code and maintains the UL listing (probably not!) but looks pretty safe to me and looks good.

 

[jstjohnz]

Once the product is altered the UL certification no longer applies, but homeowners insurance cannot deny a claim because of that, because of electrical work not to code, not permitted, done in a shoddy fashion, etc.

Remember it is not just the homeowner who is insured. If the house has a mortgage then the mortgage company is an insured party also. If a house burns down they need to know that they will be paid, regardless of the cause of the fire.