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OpenEVSE Solar PV divert feature request

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When charging from solar could we have the option to stop charging once the charge rate drops below 6.5a for 10 min. We have battery storage and once it drops 6a it starts to empty the batteries.

I know previously it was discussed but now the DemandShaper “OpenEVSE” has the option to pause charging every 30 min if needed.

This is currently being worked on: https://github.com/OpenEVSE/ESP32_WiFi_V3.x/issues/54 and also see Solar PV Data Sample: OpenEVSE solar PV divert simulation

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This is great news! @jeremypoulter

Here is another interesting one. could the demandshaper take solar into account. the other day it was charging in eco mode (dont worry about the 0 i unlocked the car) one we were at 6amps i manually stopped the charge, but at 16.54 it decided to start charging at full rate.

it would be nice if they was a way to control how the charger get its “source”. so we could say all from solar and not from the demandshaper this would allow the car battery to charge over several days or charge from solar and then topup over night by thre demandshaper. many be an app or simple webpage.

We i need one of the new wifi esp32 for the new features?

I get a similar problem.

I use the “charging options timer” hours feature.
If I “pause” the charging because of a partly cloudy day, the next time the sun comes out and the export goes up, the charger turns on again. The only solution is to unplug the car and try to remember to plug it back in before the next day.
Would be handy to have a “no more charging today” option.
Also, If I plug the car in outside the “charging options timer” hours and it is not set on ECO mode, then it immediately starts charging.
Thirdly: can the charging rate be reduced below 6 amps. On my Tesla M3 I can reduce the charge rate to 4amps if using the granny charger cable, the OpenEVSE lower limit is 6 amps.

@Pukka not quite sure I understand about selecting the source, if you do not want the demand sharper or solar then these can be turned off.

The new divert code will play nicer with other ‘sources’ and hopefully not conflict with them.

We i need one of the new wifi esp32 for the new features?

The initial version will be on the ESP32 but once stabilised and tested will be back ported to the ESP8622

@shallowal
The new code should be much better at managing the charge so hopefully you will not need to interact with it. For the existing version I would suggest switching to ‘Normal’ mode rather than unplugging the car.

Thirdly: can the charging rate be reduced below 6 amps. On my Tesla M3 I can reduce the charge rate to 4amps if using the granny charger cable, the OpenEVSE lower limit is 6 amps.

@glyn and I have spoken about this. Officially the min charging rate is 6 amps, but we know at least the Tesla can go lower. Any change in this area would need a firmware change on the EVSE, not just the WiFi module.

Thanks for the reply Jeremy. The reason I would like it lower is to better follow the sun at the start and end of the day, especially in winter.
I should say that the tracking above the minimum is amazingly quick. If I monitor the grid import during a full charging session and slightly cloudy day, it astounds me how close to zero the OpenEVSE manages the import/export.

@jeremypoulter @glyn.hudson

What is the lowest charge a model 3 Tesla will accept, out of interest.

Sure, absolutely the lower value the better. In an ideal world we would be able to take the amps down to 0 instead of pausing the charge, but this is out of spec so we need to see how different cars behave when >6A is signalled.

4 amps is the lowest I have been able to configure on the M3 dash interface.

I’ll have a test and see how low it will go.

If you let me know how to make the change on I will happily try our BMW i3 UK. with our old charger and having a switch to add or remove resistors on the CP line i could make it pause charging.

I was thinking if the system knew how sunny it would be during the day it might no charge the car over night and instead turn on eco mode so when they was an excess of solar it would start to charge the car, but if it did not charge X Kwh during the eco period it would topup that night.

Car needs 10Kwh of power
1 am “will be sunny tomorrow”
10.30 am excess of solar “start charging”
1.00 pm sun goes in “pause charging”
1.15 pm sun back out “start charging”
6 pm sun goes down “pause charging” total input 7Kwh
Demandshaper cheap electric 11pm till 4.30am
11pm start charging “stop when reach 3Khw”
1 am “will be sunny tomorrow” set charger to eco mode