A few months ago I planned and took my first road trip in my Model S. It was a somewhat stressful and exciting experience and my key takeaway was that I needed a better plan for destination charging. I’m happy to report that my improved plan worked and the return from the trip was a lot less stressful on my second visit.

Proper destination charging takes some advance planning.

Capabilities

As EV owners we’re learning terms like NEMA 14-50, know where to look up plug types, and are generally getting more and more comfortable with adapters and other approaches to get our juice fix. But our relatives, friends and other unsuspecting victims usually know little about any of this. This means its difficult to get the kind of information you need before your first visit. If the math doesn’t work you may need to go through that painful conversation, but otherwise i’d just plan on doing a careful survey on your first visit like I did to make the second visit even better.

On my last visit to NJ I found ready access to a 110V 15A plugs that add about three miles of rated range per hour and used those to charge for that visit. While I visited I scouted around for more power. Likely sources are dryers, welding areas, machine shops, RV hookups, etc. The most likely source you’ll run into are dryer plugs and there are a few different outlet types even for dryers.

Digging around behind their dryer I found a disgusting but promising plug. I found a good source online to help me identify the plug type as a NEMA 10-30. That was the good news.

Finding a high power outlet was the good news. The bad news was that I couldn’t use it.

The bad news is that I didn’t have any kind of adapter to use with that plug and the laundry room location was definitely more than 18 feet from anywhere I could park my Model S.

Official Adapters

My first reaction was to head on over to the official Tesla Motors accessories site and look for an adapter. Tesla has most adapters for the common plugs you’ll run into and they are an easy solution for basic adapter needs. Sure enough, they have the one for the outlet I found for $45 + shipping.

The problem with this solution though is that the adapter would go on the end of my UMC and would not reach my car. The UMC cable is 20 feet long, but with the tail on the end you have to assume you get about 18 feet of real distance. I needed about 40 feet.

Tesla’s official statement is to avoid using extension cords when charging.

Tesla’s official statement is to avoid using extension cords when charging, but the reality is that many owners have resorted to using extension cords for difficult locations. This was one of of those difficult locations and I needed a solution Tesla doesn’t offer.

I needed a solution Tesla doesn’t offer.

Unofficial Adapters

My next approach was to look for a site offering more options. I ran into EVSEadapters which specializes in adapters for people with EVs. They have a dedicated section for the Model S with many different options.

I went with a NEMA 14-50R to 10-30P adapter for $55 which converts the 10-30 outlet into a 14-50 outlet (see caution below). You can order these with a short stub of a cable or up to a 10 foot extension on them. Unfortunately 10 feet still wasn’t going to do it for me so I just got the shortest (cheapest) version.

The EVSEadapter folks put a very important reminder on the adapter that your max charge rate should be no more than 24A on this adapter. The reason for this is that outlets are rated at their max amperage but for continual draw (like a long charging session) you should only charge at 80% of that maximum. So a 10-30 outlet would not be designed or configured to sustain more than 80% x 30A = 24A of sustained draw.

Be very careful to set your amperage to the proper amount for the outlet you’re plugging into.

You’re probably thinking that you never had to worry about this before with your Model S UMC, why do you have to worry about it now? The reason is that this adapter confuses the UMC into thinking its got a NEMA 14-50 outlet and it will try to draw 80% of 50A or 40A from that poor outlet which can be dangerous. So you need to be very careful and dial down the amperage to the correct level for the outlet you’re using.

So now I had a small pig tail on the end of my 18 foot UMC, I still haven’t solved my distance problem. Why did I do this?

Extension Cords

If you want to extend high power over longer distances you need a beefy cord built for that purpose. The RV folks have been tackling this problem for years plugging their RVs into NEMA 14-50’s in tight spots around the country. The other reason to go with extending the NEMA 14-50 format is that Tesla gives you a NEMA 14-50 adapter when you buy the Model S so the combination works well to get a NEMA 14-50 extension cord so you can extend native 14-50 or anything adapted to NEMA 14-50 (like I did above).

Enter the Camco 55195 50 AMP 30′ Extension Cord with PowerGrip Handle. This super heavy duty (6 gauge) cord extends a NEMA 14-50 connection by 30′. It comes with a nice handle for carrying it and a strap to hold it together. You need all that because it weighs 24 pounds. This is one heavy duty cable! It costs about $100.

You want a really good quality cable to handle the kind of power you’re going to run through it without heating up which is at least wasteful but also potentially dangerous.

Solution

With the adapter and the extension cable I was able to make it to the driveway with length to spare. After getting things set up, before plugging in I dialed down the amps to 24. Then I plugged in and watched the charging start. I checked a few times early on in my charge at the outlet and at each connection point to make sure no heat was building up and the charging was going well.

The result? On this visit I charged at 18 miles/hour versus the last visit’s charge rate of 3 miles/hour. I was charging 6x faster than before.

I charged 6x faster on this visit.

With the improved charge rate I work up daily with my car “full” just like it is when i’m at home and had no worries running errors or using my car all weekend. Getting back to the Supercharger grid was simple with the oodles of range i’d stored up.

These improvements cost me a total of about $155 or essentially the cost of 2 tanks of gas I would have had to pay for if I had done this trip in my old SUV…

Good destination charging makes for happy EV owners.