Is the status of the element available? (on/off)
Yeah it was there 2nd from the top. More data after element switched off (below). Can’t control the element directly. I control the Power (bottom switch). Which only turns on element if it’s (significantly) below the GeyserMax set point which is 75 here.
Here the power is kept on despite PV falling because the element has switched off earlier as the geyser reached the target temp already.
I have the Geyserwise PV system using 4 x 360W panels. This has a dual PTC element: A low voltage element fed directly from the PV volage (with MPPT) and the other is 220V.
The PTC element’s resistance goes high at 75°C so you can’t get a higher temperature.
This is hot enough but not unsafe or bad for your geyser. The regular Kwikot geyser has a design life of 5 years (I think) so that isn’t very long.
If you have invested in a better geyser (of which we don’t have much detail) then I would check with the manufacturer about the effect of high temperature.
I have Geyserwise Max with hot water panel and pump. Panels on roof and geyser below so I need a pump to circulate.
The geyser is a 300l Solatherm. Probably at the end of its warranty (10 year) and has been replaced in warranty already. I believe the company is gone broke or closed up. Probably due to defects resulting in the warranty not lasting. They were painful in replacing the geyser already when I did. They were clearly looking for any installation issue to void warranty as they wanted tons of pictures when it went.
I presume you have set your inverter for zero export to the grid?
Is there any indication in the Sunsync data that this is limiting the PV power??
I don’t see an indicator for it but you kind of know very easily when it is happening. I.e. when you have the following conditions all true:
- PV Power > 0 (i.e. we have PV power being generated).
- Battery power = 0 (we are not charging and we are not using the battery)
- Grid power = 0 (we are not importing, nor exporting).
If these are all true we are using PV power for something, presumably the load (which is the only balancing item remaining) and the PV power then = the load. This can only really happen if we are capping the PV power to the load power (unless by pure chance available PV power happens to be exactly the load power, which happens every now and then right).
So that’s how I derive it.
Practically you need tolerances on all of these as there is also trickle feeds happening (i.e. Sunsynk always imports 20w from the grid to avoid accidental export triggers on the meter). Plus it may “trickle” charge or discharge the battery on low wattage levels. Not sure what that is technically.
A fairly well detailed article on solar irradiance sensing
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I’m joining late here but what I did while my weather station was out of commission was to pull a nearby station’s Solar and UVI Values to Node Red (I’m now back to my own local EcoWitt Station). It is then real time info. I also find the SolCast forecasts very useful (and accurate) and this I get via a HA Integration.
Always good to revisit previous discussions on this subject: Geyser Power Source Selector
That reminds me, we keep on forgetting about Victron’s forecasting.
It gets pretty accurate when the AI(?) has gathered enough data on your particular install/orientation of the panels.
My system, weather here in Cpt = forecasting is impossible.
Other area in Cpt, it could be spot on today.
… add more panels “they” said …
Me like: Go jump off the cliff. NOTHING works if the sun cannot get to the panels.
… week after week this has been going on now.
Forecasts are useless with clouds in Cape Town. There is 100% cloud cover and then there is it almost being dark at 10am like today.
Forecasts can’t tell the difference.
While I still get voltage/current limited, I do so later in the day.
I have a Victron Multi, which lets me see when it’s limited, but I don’t don’t know by how much.
I schedule my geyser to turn on at 11:30 so it run’s when there is peak sun (most of the time). Could also turn it on when PV exceeds the Geyser power. Either way, I don’t prioritize the battery first, because of the problem you presented. It will get full throughout the day. Pool pump and everything runs as soon as there’s sufficient PV.
Once the geyser has done it’s thing the pool pump turns on again and the battery gets full usually by 13:00
It’s not perfect, but it get’s me there most of the way.
You could use a heater on a on a smart plug and turn it on for a minute whenever you hit the voltage/current limit to measure the “loss”, then turn it off and turn on another device.
Haha. Indeed, the MPPT also doesn’t know by how much. It just knows that right now it cannot follow the maximum power point, because then it would exceed some other important limit (eg voltage or current) 
But even this info is better than nothing!
At least it’s local to your system. If the MPPT limiting is easy to access then simply use this signal to switch on your element.
Then use another parameter to switch it off (e.g. grid consumption…)