Replies: 7 comments 7 replies
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What are your DPL settings? What are your power meter settings? Please share a portion of your logs from the web console. The DPL explains why it shuts down the inverter. |
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@oldman4U how is the Voltage or State of Charge coming into OpenDTU-OnBattery? |
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Thank you all for your replies. @schlimmchen There is no power meter. |
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DPL, dynamic power limiter, tries to limit your inverter output so that you only produce as much as you need right know. How should this work, if you don’t have a power meter reading? |
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openDTU reads the battery voltage from the inverter and can control it. So it is my understanding that turning the inverter off based on the battery voltage should (technically wise) be possible without a meter. Based on the answers I got - a meter is needed to start/stop the inverter based on battery voltage. Correct? |
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at the moment DPL limits the power dynamically, depending on what power would be needed. A "discharge the battery to voltage X" is not provided or possible so far. This could possibly be solved with an external control and logic via MQTT or Web API. so, to come back to your question "what is the minimum hardware required to start/stop the inverter - based on battery voltage": a external voltage monitoring relay (as this only needs a battery, inverter and the relay, no DTU and no external server) if you want to use something like this, cut AC power from the inverter, so that the inverter stays connected to the battery. otherwise, the inrush current while reconnecting the battery to the inverter may damage the inverter inputs. |
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Hello spcqike, Thank you for your reply. So currently the connection to a meter is required to start/stop the inverter, but there is no technical reason for this and it could also work without? Maybe I should have mentioned it, but now that you all try to help me. What I miss is a bit is the simplicity in this project. openDTU alone can read the data from the inverter and manually control it, so basically what you also can do with a DTU Lite. To do slightly more, you need additional hardware, software and a lot of time to setup a system, which finally controls the openDTU. For me this makes it complicated and maybe even slower than needed. Reading all the PRs and Discussions I ask myself if its wouldn't be better to do it (if technically possible) the other way around, and do all the logic on the openDTU and just send the results to external devices. just my 2 cents |
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You write correctly "could be taken"... lets check the code if the DPL CAN DO THAT. |
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Of no VE.direct is present and no CAN battery, it uses the panel I put voltage as battery voltage. That’s also what the correction factor is used for. DPL stops, when no valid power meter reading was received within the last 30 sec. I mentioned in another post, that it may ne good to have a switch to toggle some behavior. Like what to do, if no power meter reading comes in. One could e.g. use a fallback value (lower, upper or a new limit). When I mentioned this, it seems as if nobody wanted or needed this. But in cases like this one (simply produce like fixed 150W, but stop when battery voltage is going low) or in situations with unstable WiFi / systems, where it can happen that you don’t get a new power meter reading within 30s, this would be great. |
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If you implement it, I could test it. With and without Victron if you want |
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@madmartin As @spcqike wrote, the DPL cannot work without a valid and recent power meter value. And to be honest, I don't understand what this discussion is about. The DPL is not designed to do what @oldman4U is asking. What's the use-case? Enable the inverter at a fixed power limit when the battery reaches the start threshold and stop the inverter if the battery reached the stop threshold? Is that really a useful scenario? I think that adding a power meter to your setup is always a good idea, not too much work or cost, and makes the whole setup much more useful. |
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One could also have a use-case, where one starts the inverter at 18.00 via mqtt (or AC smartplug), and wants to simply discharge over night or whatever with a fixed powerlimit. of course, thats not the most efficient solution, as you loose some energy while charging and discharging, but thats what a lot of people seem to do for a cheap night feed-in. another use-case would be my very first experience with openDTU-onBattery :) i wanted to simply discharge a battery and measure its remaining capacity. but i didnt wanted to deep-discharge it. as this can't be done with openDTU-onBattery, i had to use an additional battery-relay inbetween. (i cant find my original question right know)
thats true, a power meter would be the better and more efficient solution, but its not always possible (if you rent a flat and the meter is down in the basement or whatever, you cant simply put a S0/D0 tasmota device or even install a Shelly). and, if its just for cheap night feed-in, the disadvantages (power losses while charging/discharging) are cheaper than a new / additional meter. considering a 24V 100Ah battery and an energy loss of ~20%, thats 0.4kWh a day (if you manage to fully charge and discharge it daily), thats ~0.14€/day (at 0,34€/kWh). a Shelly costs like 100€ so your break even is ~2years. as proposed here , a switch with a fallback threshold might be an option. not only in such an edge use-case, but also for everyone. i dont see, why the inverter should stop completly, if WiFi (router / access point/ network switch / ...) or your smartmeter (tasmota/ shelly / power brick / in case of tibber users, who use tibber API and HA/Node-Red to publish power readings via MQTT, cloud provider or ISP / modem / ....) fails. most people know their typical baseload (50-500W, 200W in my case) and they could still feed-in this baseload, as long as the battery is charged accordingly. TBH, in my first tests with openDTU-onBattery, i thought lower powerlimit was exactly this. like "feed at least 200W, regardless of anything else (except battery voltage or SoC is to low) but, thats not the case 😄 whats the reason for the lower powerlimit behaviour, as it is? whats the use-case where you say "only feed-in if you feed in at least x W"? i would imagine, that most people have a lower limit of 0W or whatever is the lowest possible limit. |
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Hello Schlimmchen, Sorry for all the confusion. My initial question was based on the wrong assumption, that a part of the DPL function could be available without the need to have all the hard- and software needed for DPL. Knowing that this is not the case I started the discussion if it would make sense to make certain functions available, based on the ESP alone. This would make the openDTU usable for non tinkers/geeks like me, and could eventually provide an even better technical solution. |
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This discussion has been automatically locked since there has not been any recent activity after it was closed. Please open a new discussion for related concerns. |
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Using a 24V battery without CAN Bus and no Victron, it does not matter what I define under DPL, openDTU turns off the inverter immediately.
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