Solar PV Monitoring/Automation Thread

40W at 12v, nah the Eaton one won't do it as it's only 3A at 12v.

I like these Eaton ones:

But I have an APC 750 here and it's great as it supports my server and switches (70w) for around 40 mins. You can swap the batteries out for alarm type cells for 15 or 20 EUR each.

I have a whole house EPS with 18.9kWh of battery, but it doesn't solve the problem of sudden power loss to your devices. Unless you have an automated UPS changeover which I haven't heard of anyone having domestically in this country.

It's the changeover that's the issue, it's manual, EPS usually always off and when grid is restored it cuts out. So a canonical UPS (or laptop battery) is required to carry things through that manual changeover period.

I took a look at the manual and it says the EPS terminals are always powered from the grid when available and switch to PV/battery when grid goes down, but no indication of the latency for this switch. Also, you're limited by the inverter's output then (5kW?). So it's not really practical to run your whole house constantly off the EPS. Maybe a sub consumer unit? But that's a pain either way.

Maybe one of these threads

https://www.boards.ie/discussion/2058222496/solar-for-dummies#latest

Why not just let it charge to 100% from 2am-8am (when day rate kicks in)? Your night rate after 4am of 20c is close to the FIT you get paid. So you're not losing when you export during the day (when the battery is full). Then you've a full battery starting the 8am-11pm day rate.

And then load shift everything else to the 12c 2-4am slot.

@bullit_dodger is a 'math head' and he ran the numbers on his battery optimising before and it was pennies as you say. He sets it to check the forecast before the cheap slot and the software decides what % to charge. But he wrote that himself (software dev afaik).

True, I hadn't coped that "In summer the above will result in me unnecessarily using night rate for the base load of my house when it could be using the battery that was charged at the boost rate". You want it to discharge for when people wake up and start using juice. Good idea to just wait until you run out and then decide.

When you say the baseload between 4am and people waking up, is it not just 200w max between the fridge and freezer and a modem? Rest can be set for the cheap night slot.

Take Solcast and its ilk with a massive pinch of salt. Unless it's a clear sky all day long then it is wildly inaccurate. I live in the plain of a wide valley. It might be blazing sunshine up on the hills but down here I can be in fog until midday before the Sun punches through. Today, Solcast has me down for 28KWh. Outside, I see a blanket of fog so I know it's going to be more like 15KWh.

Also, the forecasts can never predict that one cloud that stubbornly sits between you and the Sun. At best, forecasts tell you if it's going to be overcast or not. i.e. batch cooking and washing machine day or not.

The best way to determine charge time is by using averages. For your first year it will be monthly based. As you get more years of data then you can increase the resolution of your forecast. Make a note (on paper or automated database) of when the battery started to charge and when it got to 90% (better than 100% as your inverter might start to export at over 90%). Calculate monthly averages and you will have a good idea of the seasonal variation. Overtime your average will be more accurate than anything Solcast can provide you.

Or rather I used to do this. Now, I just instinctively know what I can do in any particular month. HA just turns the hall light on at sunset, turns the immersion on in the winter when the solar thermal is inactive and allows me to keep within a self-imposed 5KW limit when using multiple high-power devices so as to avoid grid import.

If you are a big power user then you are probably charging your battery at night even at the height of summer. I am sure average usage can help there too. If you are all over the place with your usage then nothing is going to help you.

It's best to have a daily routine and to try to fit into the seasonal solar average, making as much credit as you can for the winter.

I hope that helps. Everyone's system and routine is different so everyone else will do it differently.

Makes sense. I do not feel the need to overly fine tune on a daily basis unless it is super easy. My battery is only 10kwh, so realistically only 7 or 8 usable, so its a case of I am charging it on night rate or not, I wont worry about trying to charge it to 72.22% or whatever. High user of energy so every day in winter is a full night charge, so its September/October that any automation will benefit, and I guess if I can forecast an overcast summer day the I might load shift during summer too.

Before any of that I need to learn how to actually link in solcast or met.ie and make a card/dashboard. Likewise, how to get HA tracking my solis hybrid- i think this is the hard part?