Charging two cars

So I'm looking at finally getting a level 2 charger, and I want to plan for expansion if my wife ever gets an electrical car as well ( I know it will eventually happen).

I'm thinking about a dual car charger, but are they are smart enough to charge both cars at once without drawing twice the power? They also seem to be quite expensive; only one I did manage to find was over 3 grand!

Would it just be best to get to single car chargers and make sure my circuit has enough power to handle both simultaneously? It would definitely be cheaper.

What you are asking for is a "dual connector" EVSE with some smarts to only charge one car at the time. To the best of my knowledge this does not exist today.

IF it was to exist, I'd be willing to bet that the extra cost of having a dedicated 240V-40A circuit for a basic separate EVSE would be negligible compared to the cost of such a fancy unit. IMHO.

Yeah, even the electrician I was talking with said I might have to buy commercial grade to get a dual charger, which would be seriously expensive.

So does a 20 or 30 amp single charger take less time to charge than a 40 amp? And if so, what kind of time difference are we talking about?

You want The Hydra. Unfortunately this would be a DIY project (or pay someone to do it for you), as there aren't any good off-the-shelf options for this right now. Or you could repurpose this old beast, but it'd also take a little DIY and the asking price is way too high.

Either way, if you want to future proof and you need to install a new circuit for a level 2 EVSE anyway, just have your electrician install a 100-amp subpanel in your garage and/or an extra 14-50 outlet. That way installing a 2nd EVSE somewhere down the road would be a breeze.

Nick Sayer designed the "Hydra" dual charging adapter. The EVSE plugs into it and it sequentially charges 2 cars. I thing he charges a Leaf and a Fit. All of the J1772 stuff makes it expensive.

You can find a link in the OpenEVSE forum wiki under other.

Here you go and only $795 . . .

http://www.ebay.com/itm/171332101499

dsinned said:

Here you go and only $795 . . .

http://www.ebay.com/itm/171332101499

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and only 50 amps! not bad, not bad at all.

Think about the cables laying on the floor and the risks asociated with that.

http://www.mynissanleaf.com/viewtopic.php?f=30&t=14894" onclick="window.open(this.href);return false;

Get two EVSEs.

camasleaf said:

Think about the cables laying on the floor and the risks asociated with that.

http://www.mynissanleaf.com/viewtopic.php?f=30&t=14894" onclick="window.open(this.href);return false;

Get two EVSEs.

Click to expand...

That would happen with two single chargers a well if its put on one side of the garage. I plan on having the charger placed in the middle of the back of the garage. So either car might need a whole 4 foot cable to charge.

You can get current sensing relays on ebay. Use 2 normal EVSE s each wired through their own normally closed contactor and current sensing relay. The current sense relay for one pulls the contactor for the other and disables it while the other one is charging. Or you could just run 2 circuits. It would probably be cheaper.

Limey said:

dsinned said:

Here you go and only $795 . . .

http://www.ebay.com/itm/171332101499

Click to expand...

and only 50 amps! not bad, not bad at all.

Click to expand...

Pretty cool!

Only one cable is a J1772 unit. The other looks to be for older cars. This is a total waste.

GlennD said:

Only one cable is a J1772 unit. The other looks to be for older cars. This is a total waste.

Click to expand...

Yes, you'd have to replace the Avcon cable with a J1772 cable (or just the connector itself - not recommended) so count on at least another $100 or so. I'm sure it originally had 2 Avcon connectors, but for some reason one was replaced with a modern cable and the other wasn't. These older units followed what was substantially the same J1772 protocol, so it should work with modern cars, but there's no guarantee. My friend picked up one of these (single cable version) and put on his own J1772 cable, and was able to charge his 2012 Leaf, but for some reason it wouldn't function with the Leaf's charging timer. Eventually he upgraded to an openEVSE. FWIW, he paid $100 for his old EVI, which I think is much more in line with what a fair price would be for what's probably a 20-year-old piece of hardware.

Get two EVSEs on two separate circuits. Way less money and hassle vs. all the work arounds.

smkettner said:

Get two EVSEs on two separate circuits. Way less money and hassle vs. all the work arounds.

Click to expand...

I could imagine some situations where adding that 2nd circuit might be prohibitively costly (if it required a panel/service upgrade, for example) and would therefore justify figuring out a shared EVSE, but of course most of the time just getting two circuits would be the easy answer.

johnrhansen said:

You can get current sensing relays on ebay. Use 2 normal EVSE s each wired through their own normally closed contactor and current sensing relay. The current sense relay for one pulls the contactor for the other and disables it while the other one is charging.

Click to expand...

This actually sounds doable for some that want to share with a clothes dryer.
Someone from Open EVSE or Quick 220 needs to get a kit together on this.

Most of those current sensing relays are only good for 5 amps, but you can get a overload grade current transformer (not metering they cost more) pretty cheap. If you can only find a high current one loop the wire through the donut a few times to amplify the ct's sensitivity.

Dont make fun of my panel now. This was a long time ago. Google "john's load shed" for a interesting (to some) video on similar system using cts and current sensing relays.

Come to think of it, switching between a clothes dryer and a evse is very easy. You put a normally closed relay on the evse power wires, and a current sensing relay on the neutral leg of the dryer, you dont even need a ct because the motor draws less than 5 amps. You turn on the dryer and it cuts the evse off line.

I was thinking two sensors, two relays. If either device is drawing power it would cut the relay to the other device. First come first served as either in operation would lock out the other.
The issue I see is the dryer cycling the heater and getting dropped out. Sensors don't have a wide enough range but using the neutral could work assuming it is a 120v motor.