You should be able to do it if you get a sub-panel with two 20A breakers fed by that 50A circuit.

 

You would not be able to run a 50 amp EVSE and 2 - 20 amp EVSE's on the same circuit, this would add up to 90 amps total. What is your final goal?

 

Charge 2 cars at the same time

 

The question is, what kind of cars. As far as I understand, it is the car´s built in charger that regulates the power demand. A VOLT will draw a maximum of about 14A at 240V, no matter how much the EVSE could provide. A Nissan Leaf on the other hand would draw double of that amount from the same EVSE. So, charging 2 VOLTS at the same time won´t be a problem, charging two LEAFs at 6.6kw each would be borderline. You would need an EVSE that limits the power draw to 20A max. Is the TurboCord rated for 20A or does it set a limit at 20A?

 

We would replace the existing evse

 

OP, do you know for sure that there is nothing else on the circuit? If so, what is the size of the breaker--40 or 50 amp? If 40, you might trip the breaker if you have two cars each drawing the max 20 amps. The odds of that are probably low, and the worst case is a tripped breaker. If you currently have a 40 amp EVSE, is nobody going to object to downsizing?

 

There is currently a 50 amp breaker there. No one will object.

I was trying to get around adding a sub panel

 

Ok, I just googled the specs of the Turbocord the OP mentioned. It limits the charge current to 16A. So, I guess he is ok with the one 50A breaker. However - 2 individual 20A breakers would be the safest way to connect the 2 EVSE to that service. Then each one would have its own protection.
Does that make sense?

 

What voltage will the EVSEs operate with and what cars will the EVSEs be hooked to? Determine the maximum current each car will draw and add them together. The total current must not be greater than 80% of 50 amps (48 amps). As long as the 80% rule is followed, I don't see the need for a sub-panel. Disclosure: I am NOT a certified electrician.
EDIT: not much of a mathematician either. It's 40 amps, not 48 amps 8^/

 

I wonder what a certified electrician would say.

 

Using worst case math, a Volt 2 drawing 3.6 KW at 208 volts requires over 17 amps. Allowing for imperfect EVSE and charger efficiency and a 20% safety factor, you aren't even close to OK. Then a 6.6 KW car taking the same EVSE plug shows up.

SPX installed my early Chargepoint EVSE under a GM contract for a single 2011 Volt 1 and the all the specs called for a dedicated 40 amp cable.

In multiple data centers, I never saw a 20 amp unit without it's own breaker.

I. too, am not an electrician.

Pull another cable.

 

2 devices that are limited to pulling 16A or less could be used simultaneously off a 50A circuit.

 

One is a Honda Fit ev and the other is a 2016 volt

 

Not a problem - just limit what each EVSE advertises to between 16A-20A. Getting OpenEVSEs can give you this flexibility.

 

being 208 volts you would require a breaker on each leg, so a 2pole breaker
50 amps to split in 2 would be 2-25/2 pole breakers , hard to get
25ampx208v=5.2kw x 80% for a derating factor =4.1 kw usable
20ampx208v=4.1kw x 80% for a derating factor =3.3 kw usable
2 pole 20 amp breaker easier to locate
0r you could stuff 250 volt fuses on each leg and stuff them in the box
20 or 25 amp fuses easy to get

 

I know a guy on the west coast who built a special box where you plug a working EVSE into it, then two j1772 plugs come out of it. It will automatically negotiate the current needed and charge both cars simultaneously, both at a lower current. When one vehicle completes, it will renegotiate and give the uncharged car whatever current it needs to complete. I think he built it himself, but maybe there are some schematics online. I've never had a need for such a box, but it looks like it would fit your application perfectly. Then you don't have to worry if one car is a tesla and the other is a volt.

 

The JuicdeBox Pro will allow two EVSE's on one 50 amp circuit and automatically adjust power to each based on what is plugged in. Their website gives an example if you had two Teslas and one was plugged in using 40 amps and your other one pulled in and plugged in on the same circuit it would give each 20 amps automatically. If one unplugged the other would get full power automatically.