Early Electric Car Charging
By Scott Wilson
What follows is what I’ve learned on the subject of how exactly the first generation of antique EVs were charged. This is interesting, since there are many striking parallels between how charging was done then and how it’s done now.
If I had a Detroit Electric or Baker, or any of several electric cars in the early 20th century, how would I charge it? One possibility would be that the dealer would keep it charged for me at their own charging location.
Cars would either be charged with the batteries on board, or the batteries would be removed and charged centrally in the “battery room.” Batteries were also swapped for electric trucks and taxi’s.
This is the Garage at Cooke and Stoddard, at 1138 Connecticut Ave NW in Washington DC, which sold Baker electric.
Notice the three bulbous, glowing mercury arc rectifiers, whose purpose is to convert AC power to DC power. We’ll explain how they work later.
Chargers designed for a garage.
But, what if I wanted to buy my own charging outfit? The charging equipment I used would depend on whether I had DC service or AC service at my residence, since both were available. Both the DC and AC chargers looked similar. This is an AC charger:
You can spot right away it’s an AC charger since it has the same mercury arc rectifier shown above, labeled “rectifier tube” on the drawing.
The DC chargers are similar in appearance:
Here’s a more useful view of how these devices worked. More details below.
In my garage or parking spot, I would set up my charging outfit,
the same as we do today.
with the connector.
There have been many connector standards over the years. What did plugs look like back then?
This shows the two dimensional size standards, the smaller rated at 50 amps, the larger at 150 amps.
The upper male connector was on the cable, the bottom female socket was on the car.
Compare, for example, with SAE J1772.
Here’s another example of a charging outfit. This was GE treasurer Samuel Whitestone’s garage at 7 Douglas Road in Schenectady, NY, 1911.
You can tell it’s AC by the rectifier shaker switch in the center of the slate panel.
Support hardware for the main charger.
Another example from Newark, NJ, around 1910, with the charger highlighted.
Then again, there was Andrew Carnegie’s garage, complete with uniformed staff.
This the spec sheet for GE automobile chargers,
and chargers for smaller ignition batteries.
You could order custom chargers. Here is the form for ordering a charger from GE:
Here are some more GE examples. Notice the modularity.
This is a close-up showing the rectifier tube and circuit. Note lots of exposed electrodes and wiring.
A brief aside on how mercury arc rectifiers work:
First of all, here’s what it looks like in action:
Here is a detailed examination of a charger owned by the Edison Tech Center, Schenectady, NY:
Here’s how the tube works, courtesy of General Electric. It’s actually pretty clear.
You may ask how AC electricity is converted into DC nowadays? After humanity discovered the amazing properties of nearly pure silicon with tiny amounts of added group III and group V impurities, we invented silicon diodes, which are one-way “valves” for current. The equivalent operation today is performed by a circuit called a bridge rectifier, made out of an arrangement of four diodes:
There was also the “Electrant” or electric hydrant, made by General Electric, which has a creepily familiar look to today’s EVSEs. It was meant to be public charging as common as police call boxes and horse hitching posts. It would deliver 2.5 kWh of energy for 25 cents, which, at 10 cents per kWh, is also oddly similar to todays electric rates. (Edwin Black)
Here are some of the modern embodiments of the same idea.
Here are examples of surviving chargers. First, the America On Wheels Auto Museum, Allentown, PA.
The Edison Tech Center, Schenectady, NY.
Collector Randy Ema has a General Electric No. 79811, 30 amp Type MS charger.
Here’s a nice view of the mercury rectifier.
From the Detroit Historical Museum:
And, in the UK,
This unit has it’s rectifier front-mounted, which was used for charging small ignition batteries for gasoline cars.
Here’s a beautifully restored charger.
From the LeMay – America’s Car Museum, Tacoma Washington:
Then, as now, you arrive home and plug it in, just like we’re rediscovering today.
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