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Discussion Starter · #1 ·
Anyone using a Semens Versicharge? In the manual it shows a "status output" and a "control switch input". I'm thinking of using a 220v solid state relay wired to the status output to given preference to the car over my hot water heater in garage. Anyone done this?
 

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I would wire the domestic hot water heater as the priority device vs. the Bolt that could take hours to complete it's charge.
Even if it takes the DHW heater 30min to recover from a shower, that's only 12mi of range for the Bolt.
 

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Discussion Starter · #3 ·
I see what you’re saying. My idea was that we tend to go to bed about the time off peak rates start, so if I programmed the car to start charging, it’d be long done by the time the hot water heater needed a full tank by 6am. Could go either way depending on your priorities though... the EVSE seems to give an option for either way.
 

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Might be easier to just put the heater and car on a timer with different time settings, with the Bolt set to charge when you are sleeping.

EDIT: Just found this:

https://www.homedepot.com/p/GE-24-Hour-Outdoor-Mechanical-Box-Timer-On-Off-DPDT-15135/202788238

You want a double pole double throw relay. The double-throw means that when one circuit is active, the other is inactive. Then you just set the timer so that the circuit with the hot water heater is active during the day, and then switches to the EVSE circuit at night when hot water is no longer needed.

Here's a digital version on Amazon:

 

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This seems like a good solution but be aware that the Normally Closed (NC) contacts (which is the failure mode) are only rated for 30A. If your water heater is rated for 30A (or ideally less) you might want to wire the water heater to that and wire the charger to the Normally Open (NO) contacts.

http://www.nsiindustries.com/UserFiles/Documents/Product/LI-885.D.DTU40instn.EN.FR.SP.090513.pdf

What I'd probably do is program the charger to come on right as soon as off-peak rates start and turn off again at 5AM which should be more than enough time for your water heater to come up to temp. Depending on when off-peak rates end you may want to start the water heater sooner so the big draw to heat up the tank will be off-peak.

If it were me I'd wire the charger via a plug and also install a second "always on" plug so I could charge at an unusual time without having to override the timer.
 

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Slightly OT, but our local utility bought the Siemens Versicharge for us and all we had to pay was the $165 installation. Their logic is to be able to gather data on when and how long we early adapters are charging. They feel EVs will be arriving exponentially in the near future.

Since we don't have any peak time rates, we don't need to use any of the features in the Versicharge; it communicates with the utility through a wireless amplifier to our home router via contract with Greenlots to manage the data collection and reporting.

jack vines
 

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If the breaker panel is in the garage near to where the car is charged, then I'd just install a dedicated circuit, assuming the panel has extra capacity. Materials cost is low for short runs, and it shouldn't be very complicated. I have attic access above the garage, so running a line up the wall and over the ceiling took just half an hour.
 

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Discussion Starter · #8 ·
Guys, I opened up my Versicharge unit and poked around a bit. There is a contactor above the circuit board clearly visible behind the plexiglass cover. The contactor inside has a 220v coil on it and some spare 1/4" spade terminal lugs. So it seems I can put another relay piggy backed on that coil to fire a relay to disable my water heater. Found this on Ebay.... https://www.ebay.com/itm/Yuco-YC-GP...rentrq:fd2ed6661620a8840bb5a196fffa25d4|iid:1 .

So I think what I'll do it tap in to 220v on the EVSE's contactor and when it turns on power to the cordset, another relay wired to my water heater will kill the power to it. The EVSE will have power all the time and so will my water heater... right up until the point the car wants to charge. Now I can share the water heater line with the car charger!
 

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Guys, I opened up my Versicharge unit and poked around a bit. There is a contactor above the circuit board clearly visible behind the plexiglass cover. The contactor inside has a 220v coil on it and some spare 1/4" spade terminal lugs. So it seems I can put another relay piggy backed on that coil to fire a relay to disable my water heater. Found this on Ebay.... https://www.ebay.com/itm/Yuco-YC-GP...rentrq:fd2ed6661620a8840bb5a196fffa25d4|iid:1 .

So I think what I'll do it tap in to 220v on the EVSE's contactor and when it turns on power to the cordset, another relay wired to my water heater will kill the power to it. The EVSE will have power all the time and so will my water heater... right up until the point the car wants to charge. Now I can share the water heater line with the car charger!
Well-done, MacGyver!

Did you also notice the little rotary switch to tell the EVSE to tell the car to take limited current? You can select 100% (32A default), 75% (24A), 50% (16A) or 25% (8A). This lets you use a 30A electric dryer outlet at 75% (24A) and still meet the NEC. It will charge at only 75% of the full rate, taking longer to charge. But who cares...you're probably sleeping anyway.
 
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