Community
OpenEnergyMonitor

Community

OpenEVSE Solar PV Divert (Eco Mode) Improvement Suggestions

3 small requests.

  1. Add a stop after X minuites if below 6amp (so when the sun goes down it automatically stops)
  2. Always start in eco mode.
  3. A quick way to change to normal mode with timer at night

Long term idea.
look at office365 calender for tomorrows apointments work out number of miles needed, check remaining mileage in car and charge over night if needed + 10%.

Paul

2 Likes

+1 on item 1 and 2. :+1:

Hi, Thanks a lot for the suggestions. Feedback is very useful

There are pros and cons to doing this. Our main concern when implementing Eco mode was that a user might plug their car in when it’s sunny in the afternoon but the solar PV would not produce enough to sufficiently change the EV before nightfall. The decision was made to keep the car trickle charging at 6A until it’s full. We also made the decision not to pause the charge if the solar PV drops below 6A since starting/stopping a charge very often would cause the EV’s contractors to wear.

In Eco mode’s current implementation there are two workarounds:

  1. If you know the sun will set in X hours after staring an Eco Mode charge, you can use the OpenEVSE’s charging limit timer to set the charge to stop after XX hrs
  2. Use the EV’s onboard limit to set a max SOC

I think a good solution for future development would be to pause the charge after maybe 1hr or zero solar PV gen, then have an option to resume charging during the night at a specific time to make topup the EV and make the most of low rate night time tariff.

Yes, it would be good to have an option for this. The reason we made reverting to ‘Normal’ the default was to avoid a user expectig a normal fast charge but only receiving 6A!

Yes, agree. I mentioned this in my comment above.

Thanks again for the feedback.

Hi Glyn,

I tried the timer with eco mode, after 1 hour the charger stopped and then started again as the solar was still above 1600w.

Would it be possible to try setting the charge rate to 0 if less than 6A? ie would the car stop charging without disconecting the contactor.

Can you make the pause option time configurable, This is so we do not take an hours worh of power out of our solar battery

1 Like

Another request, if possible, is for it to power up in the same mode it was in at power down.
I like to charge my Leaf only to 80% charge. I did that yesterday and when it hit 80% I turned off Eco mode and Paused the charge.
Then at 5:47 this morning there was a 10 sec long power cut. When the OpenEVSE powered up again, it went straight to 32A charging from grid power and charged the car to 100%.
I would prefer it to remember that the charging was paused and Eco was off.

I have found a bug with the Eco charging mode.
I started an Eco charging session and then set the “Energy Limit” to 4 KWh.
When the Energy hit 4 KWh it stopped charging, but then immediately started again,

Bumping to support this idea. I’ve got a Model 3 LR that will be here shortly and would love to run in a similar mode to the Zappi where its aiming for 100% PV unless I tell it to fill at full speed.

The Tesla has enough capacity that I rarely need 100% for my daily commute so I’d rather it didn’t use grid power at all unless I told the EVSE to do this specifically.

With regards to comments from the developers about contractor wear - wouldn’t the inverter in the car drop to zero current if you stopped the pilot signal before you opened the contactor?

Currently the OpenEVSE will revert to “normal” charging mode when an EV is unplugged, this was a design decision to ensure that the user does not accidentally forget that Eco mode is active and does not receive the required charge. It’s possible to tun on Eco mode via MQTT if you wanted to automate turning it on.

Thanks for reporting, we will get this fixed

Correct, the current is reduced to zero before contactor is opened. We are more concerned about contactor wear in the car rather than the EVSE. Each time a charge is paused the HV contactors in the cars battery pack will open. Starting and stopping a charge many time more than normal would accelerate wear on these contactors.

However, I agree it would be good to have an option to pause charging once solar PV has dropped below a limit for e.g at least 30min.

I think the design decisions that have been made so far have been okay for older EVs with limited battery capacity. But with my Model 3 I can keep commuting fine for several days - probably over a week - if the sun isn’t shining. Delving into MQTT to get something functionally equivalent to Zappi Eco++ mode seems a bit extreme.

Is there an option to sponsor some development effort to make it happen?

Depending on the contact material, it is often desirable to have a small current to “whet” the contacts and keep them clean and burn away any surface contamination. If the contactor is designed correctly, there will also be some rubbing movement as the contacts open and close, again with the intention of preventing the build-up of tarnish and keeping the contacts in good condition.

I have somewhere a book about relays that goes into this in great detail.