graememk
12 September 2020 14:23
1
This would be a feature request really.
As there is a solar Divert that knows how much “spare” solar there is, or whatever way you can configure the input.
Would there be another option for normal charging that could prevent overloading of the installations supply as not to pull more that X kW from the grid.
I know that it could be done currently with the solar divert , if you can feed it a value of MAX Load - Current load.
Or is there not enough room on the ESP8266 to allow this? Would there be space on the ESP 32?
I don’t require this feature, but thought it could be a useful addition to the openEvse system
This is something I’m thinking about. My mother is thinking of going EV in a 2 car household and they expect a pure EV in the garage and a hybrid on the drive one day. They also have a 60A service head, so load limiting between 2 EVSEs and the house load would be ideal.
Agree, this would be a useful feature. There are already issues open for this:
opened 09:22AM - 12 Apr 20 UTC
enhancement
At least in the Netherlands, but probably also other places, it is fairly common… to have grid connections with rather low current limits on the main breakers, e.g. single phase 35A or 40A or 3 phase 25A for the whole household. If there are other significant loads present, this means that the EVSE would have to be set to a low pilot current in order to avoid tripping the main breaker for the house.
Some commercial EVSEs support a "load balancing" mode, where they monitor the grid current and dynamically adjust the EVSE current to not exceed the limit. I would like to suggest adding this feature to OpenEVSE as well.
This is quite similar to the existing eco divert mode and the changes implemented in #54, but there are a few differences:
* This would always be active, also (especially) when not in eco mode.
* This would be based on the grid I/E information, but instead of aiming for 0 import, you want to keep the imported grid current below a configurable limit.
* This limit needs stricter enforcement: If you exceed it for too long (on the order of seconds, depending on how much it is exceeded?), the house is left without power.
* Because of the previous point and related to #59, I would suggest that the EVSE enters a "safe" state when no message has been received on the grid I/E topic for a certain amount of time. The safe state could be a low current limit or completely disabling charging until information becomes available again.
* The maximum current allocated to the EVSE should still not exceed the configured value. E.g. house has 40A main fuse, EVSE is on a 32A circuit. Then we should never go over 32A pilot current, even when more is available from the grid.
This feature will be required for redundancy:
opened 06:01PM - 29 Feb 20 UTC
enhancement
I have an open source project for RV'ers which permits load sharing between thei… r RV and EV charger. ( EV4RV.org ) The system works by adding an energy monitor to the RV's incoming power feed and calculating 'spare' current, after deducting 10% overhead for the breaker, it sends the remainder value over MQTT RAPI ( $SC ) to the OpenEVSE.
The code detects an absence of current feed from the energy monitor and disables the EVSE ( $FD ) on this loss of feed and re-enables the EVSE ( $FE ) when energy readings return. However, there's nothing that protects the upstream breaker should the OpenEVSE lose comms to the MQTT server.
The request is -- An option provided in the MQTT config dialog to disable the EVSE after X seconds of no MQTT connection ( 30 seconds seems sane ), then re-enable once a connection is re-established.
graememk
14 September 2020 19:21
4
Oh i missed that, will keep an eye on it, havent done much coding since i left uni 10 yrs ago
