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Discussion Starter #1
Now that I'm learning about EVSEs and just bought a Siemens versicharge, I'm running ideas through my head. I noticed the versicharge has a charge inhibit set of contacts inside the cover. What's that good for?

In my case I have a hot water heater in my garage with 220v service. All I have to do is install a 220v relay on the heating element power such that when the heating elements are running the versicharge is inhibited. When my tank is full of hot water, the car will start charging.
That way I can load share the 20amp 220v line that already exists in my garage.

Another case that comes to mind is load sharing two chargers (if the wife ever gets an EV). You can link these chargers together so that when one is running it inhibits the other.... so for example, one charger has priority and the other starts charging when the first is finished. This might work well for people with peak consumption rate penalties who want to keep their peak demand under some threshold.

Any other EVSE's using dry contacts to remotely inhibit charging?
 

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Any other EVSE's using dry contacts to remotely inhibit charging?
When I spoke with Juicebox last year, their Juice Box pro 40 has a smart circuit load balancing capacity that never exceeds the limit of your electrical supply circuit. The tech sent me a electrical wiring diagram, but I can't find it now. Basically, a single 50A (or perhaps other Amperage) circuit can be wired in such a way that two JuiceBox EVSE's can share it. And balance the load between the two.

Best bet is to call Juicebox as they will have a far more intelligent explanation.

:confused:
 

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Tesla's chargers can be configured to "share" a single breaker - up to 4 chargers - 1 master and 3 slaves - you can plug in up to 4 cars and they will share the load and all charge simultaneously
 

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Discussion Starter #4
Thanks... I had no idea! wow... learning every day. Thanks guys!
 

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My charger (sorry, EVSE) does that. In my case a 25 amps breaker is shared between washer, dryer and EVSE. You can see the individual heating cycles of the dryer:



The control box measures total load on the mains feed and throttles the charging process when needed. Much better than just inhibit. It can also be in a master slave configuration with three other EVSEs. In that case, it will share the available power, but currently, it has no priority settings.
 

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The control box measures total load on the mains feed and throttles the charging process when needed. Much better than just inhibit. It can also be in a master slave configuration with three other EVSEs. In that case, it will share the available power, but currently, it has no priority settings.
Which control box and EVSE is this?
 

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Discussion Starter #8

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Here is a sweet system at Caltech. It uses 54 OpenEVSE's on a power sharing and load balancing setup. Cheap, easy, and the most flexible system out there if you are going for circuit sharing. I'll be using this is we ever go for multiple EV's at home, or if we setup an office space for future business ventures.
Thanks. I know from experience it will work without contactor too. But don't tell anyone, as it is a security risk >:)
I'd be interested in the theory behind this security risk you mention, that sounds unlikely.
 

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I'd be interested in the theory behind this security risk you mention, that sounds unlikely.
The 120 / 240 volt contacts will be hot, even when the plug is not even plugged into a vehicle. Imagine dropping the plug in a pool of water you are standing in. Personally, I am not to concerned about it. But probably not the best fool proof solution.
 

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Ohhh, I get it. I was thinking security flaw, like some kind of leet hacker biz... Yeah, leaving the contactor out is "unsafe" since it disables all the safety features, but it's still functional. In general it doesn't make much sense not to have one, it was the literally the cheapest line item part in the entire EVSE build I did, like $11. If you leave it out of a power sharing arrangement and the EVSE cuts power and then restores it later, some cars might get angry and refuse to auto-restart charging until you unplug/plug the connector to reset if the contactor is missing or welded. It would be worth testing if the Bolt will auto-restart once the pilot comes back if you ever plan to do any load sharing/shedding like this.
 

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I can't see why you'd skimp on the contactor for safety.... they are about $10 on ebay. https://www.ebay.com/itm/2P-40A-220V-230V-400V-50-60HZ-Din-rail-Household-ac-contactor-2NO/262470265078?hash=item3d1c7268f6:g:zWYAAOSwOtdYUUja . Heck they aren't probably reliable so buy two so you have a hot spare.
Wouldn't that be buy 4? For US split-phase systems, you'd need one contactor for one 120V line (red) and another one for the other 120V line (black). Then another 2 for your spares.
 

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Wouldn't that be buy 4? For US split-phase systems, you'd need one contactor for one 120V line (red) and another one for the other 120V line (black). Then another 2 for your spares.
No, just one, it's a DPST relay (two contacts).

Well, in case you didn't get a spare in the first place and the one you had blew up .... then you would. Temporarily, that is. :crying:
It's always good to have the capability to keep your car charging! Makes it hard to get around otherwise if you get a dead battery and no good way to top it up.
 
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