There was much to be explored in terms of charging the car.
It is important to understand what options are available and what their
limits are, because not every recharging situation may be in a comfortable
known environment.
What do you do, for example, if you're visiting friends for a weekend who
are just beyond round-trip range and/or you want to do some driving around
their area while there?
Or that urgent mission to the middle of bumfuk
District 13,
and you want to be confident you can get the hell out of there before
the Peacekeepers show up?
Being able to charge in an optimal way at a destination is important,
which is why it's called "destination charging" and is often associated
with an existing installed EVSE or high-power outlet.
But we don't always have that, and the wheezy little "granny charger"
that comes with the car may not be enough to support local activities
and/or getting back home in a reasonable timeframe.
My Tour de Sol buddy up north had seen rumors that the small EVSE that came with his Bolt could run on 240V and double the charge rate of the car. This sounded entirely reasonable, as it's really just a relay box with some support and interface stuff added. Modern low-voltage switching power supplies, such as for the electronics to handle the J1772 protocol and energize the relays, often have wide ranges of input voltage so that they can run in US or European markets unmodified. Further supporting evidence can be found in this long-running thread at insideevs. I briefly looked at cracking the lid off the glued-together box of mine to look at the innards, but decided that doing so would probably be fairly destructive and that there were other ways to externally and safely test this theory without blowing the thing up. |
Next experiment was the potential for "rescue charging" on the road, using portable power packs I'd recently acquired for outdoor events. This *would* be a 120VAC scenario and thus slow, but each kilowatt-hour you could bring to a stranded EV could potentially get it four or five more miles down the road. Thus, perhaps these boxes could be like a very tiny gas can in the trunk. | |
There was a problem, though: these packs have a big empty hole where the
ground pin of an inserted cable fits, and no ground connection.
An EVSE needs a solid ground for fault detection and the pilot reference,
so this wouldn't work as issued.
The Yeti pack output is fully floating, however, and either side of it can
be connected to a "fake ground" to simulate a normal grounded outlet.
The small wire hanging out of the floating connection in the first picture is a copy of the "neutral" lead, or the lefthand prong of the box. With it floating free, the EVSE indicates a ground error. With the small wire connected to the shell of the outlet, thus creating a ground equivalent to the neutral lead, the EVSE is now happy. The fake ground wire can be tiny, because it's only a reference and will never carry much current. |
I then hauled that whole rig out to the car for a test, and the Yeti pack could charge the car at the full 12A setting on the EVSE -- maybe not quite 12 amps for real through this lashup, but the Yeti boxes are quite solid and can deliver an honest 1500 watts steady-state as advertised. So in theory I'd get close to its rated kilowatt-hour out of it top to bottom, less minor losses in the charging chain. | |
As I said, it's nice to know all of one's charging options, and by going
through all of these tests I had functionally explored several of them
and put together the right adapter widgets to make it possible.
To summarize:
and that doesn't cover any of the high-power public charging options. Rapid charging is extensively explored in a subsequent section. If you stop and think about this, that's still quite a bit of power we're casually talking about here. What household appliance normally draws over 7 *kilowatts*? Dryers and water heaters are usually 5 kW or less, and intermittent. Maybe a big hot-tub or wall-mount heaters in an all-electric home? I already knew that home charging would probably double my electric bill or more, but it's still much cheaper per mile than gasoline, even in a competently-driven Prius. |
In search of more cross-compatibility
There are various forum tales of people needing to charge a J1772 vehicle, such as overnight at a motel on a roadtrip, but arriving to discover that there are only Tesla-style "destination" charge points available. There's also plenty of information on how to get around this with adapters, which have evolved from the earliest homebuilt "Tesla tap" lashups to convenient commercial products. As long as I was building a "road kit", even with a relatively remote possibility of myself ever needing to charge at a Tesla point, a few more months into ownership I decided to pick up one of the adapters that were now commonly on the market. The prices on such things were clearly coming down; I went for the Lectron product at far less cost than what the others were demanding. |
This is it; looks simple enough, just changing one plug into another. Seems fairly solidly made, and conveniently short to throw in with the rest of the widgets in the back boot of the car. |
So I really had no idea if I would run into difficulties with this, and the
only way to learn would be to go find a Tesla EVSE and try it.
I hopped on
Plugshare
to search around, and the nearest public one appeared to be in Methuen.
On a bleak day, bleaker still as the gravity of the coronavirus problem
was starting to become clear to everyone, I tooled out there to give it
a whirl.
It wasn't occupied, so I pulled right up for a look.
It's actually a dual-head post with two destination chargers, and another
one with two J1772 heads near it serving a total of four parking slots.
And the post had power, shown by the green standby light.
On examining the Tesla plug and my adapter, it seemed likely that they'd
fit together without issue.
To Tesla's credit, they did design a fairly sleek and capable connector type, with quite a large contact area on the high-current parts. |
_H* 191003, 200325