Nema 40A OpenEVSE with RTC for sale

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Well-known member
Mar 23, 2014
NEMA 40A RTC OpenEVSE for sale

This unit has a Barbouri ver 4.2 main board, a 12V power supply, Relay board, fuse board, a multi function meter that indicated and stores KWH. It also displays power, voltage and current. The 240V contactor is a 63A Siemans unit for cool operation with over 50% reserve. Input power is by a 6FT 50A range cable with a 14-50 plug. The output is with a Jplug J1772 20 ft cable rated for 40A or less from Quick Charge Power. Everything is mounted in a Bud Nema case.

This unit is intended for fixed use inside protected from the weather. IT IS NOT WATER PROOF.

The display is a DIY RGB unit with a DS 1307 real time clock. It is loaded with firmware ver 3.11.3. The real time clock can delay charging until cheap tier time but even if you do not use it, it still puts the time of day on the charging screen.

This unit can be used with any J1772 compatible car at up to 40A. Currently only Tesla cars and Tesla powered cars draw 40A. Everything else is 30A or less. Quick Charge only sells the 40A cable since it is smaller in diameter than the 30A cable they used to sell.

I am selling this unit for $350 plus $25 for shipping. This is sold ASIS but I guarantee it will work upon receipt. You can inspect and pickup the unit in Anaheim near Disneyland.

Payment is cash for local pickup or Paypal if I ship the EVSE.

Hi GlennD,

JaosnA highly recommends you.

I have a friend who owns an Kia EV who might be interested in an openevse unit. Can I have your contact information so I can forward them in case they would like you to build them a unit?

Thanks a lot.
I do not know how much current the car needs. The one for sale will work with any car but it would be overkill for a plug in car like the Volt. I do have a cheaper 16A unit listed on the RAV EV forum.

Any J1772 compliant car takes as much current it needs. Thus a current Leaf will take the 27.5A even though the EVSE could supply much more.

If you need 30A then there is no point in wiring the EVSE to a 50A circuit. You would use a 40A circuit and set the EVSE to 32A (the max for a 40A circuit). Even then a car that only needs 30A will ignore the excess. My car that can take a full 40A would only charge at 32A since that is all the EVSE offers.

To fully charge a car the EVSE needs to supply an amount of current equal to the charger demands. My car will charge fully from a 40A EVSE or the spec max 80A. It will simply ignore the excess current.

Quick Charge Power stopped selling the 30A cable since their 40A cable is smaller and priced about the same.

I am: Glenn Drayer
714 393-6547 Cell
[email protected]
AS this EVSE exists it is a 40A EVSE that requires a 50A circuit. By setting the current to 32A it can be used on a 40A circuit. This can charge any non Tesla based car fully. All non Tesla based cars charge at 30A or less. For example a Leaf will charge at 27.5A and if it senses the offered current is more than it needs it will ignore the excess. Thus it will charge fully at either 40A or 32A.

A RAV 4 EV would charge fully at 40A or less at 32A. The car will respect the available offered current. If only 32A is presented then that is what it will charge at even though it could charge at a higher current. It could charge at 24A from a 30A circuit. All Tesla based cars follow the J1772 spec. You set the EVSE in 2A steps to match the supply current. Thus for NEC compliance you only set it for 80% so a dryer hook up is good for 24A. It will work fine but obviously it will charge slower than an EVSE on a 50A circuit.

The NEC is all about safety. To them it does not matter that most of the time the car will be fully charged in less than 3 hours. The rule is that an EVSE is a continuous load and requires the circuit to be derated to 80%.
Well I am currently driving a VW eGolf. My 40A charger charges the Golf happily at 30A. As long as the car is Ji772 complement it ignores the extra 10A and charges just fine. I realize only Tesla based cars charge at 40A but the car only takes what it needs and it ignores the extra 10A.

I could have a cheaper cable like rush's at $120 plus shipping but Tony's cable is much smaller. It is worth the small difference.
I was asked how the OpenEVSE timer works. OpenEVSE is totally open source and Goldserve added the timer and Lincomatic enhanced it.

This requires an !2C timer chip like the DS1307 or even better the DS3231. Originally separate timer boards were used but Chris at OpenEVSE added them to the display boards. Currently he offers a color board with the better chip. On some of the units a have built I have used VFD and Monochrome units with timer chips.

The OpenEVSE opens up a charging window with adjustable start and stop times. The defaults of 5 min after midnight and 5 min before 7AM work for most people.

With the timer enabled the display says waiting until the start time. Then it turns into an ordinary EVSE and it starts charging the car assuming it is plugged in. Most cars charge fully in less than 4 hours so the car tells the EVSE to open its contactor and the display switches to connected. At the stop time the window closed and it is back to waiting.

If you need energy right now a short press of the button returns the EVSE to normal. The operating window will stay open until the stop time rolls around and then it returns to waiting.

The whole point of the timer is to allow charging late at night when the costs are low.

With the timer disabled it says sleeping instead of waiting.