They arrived about 10am, and just left now about 6pm. Four guys doing the install. We have 10 panels, five on the front and five on the back of the roof so should get good coverage, and a 5.5kW lithium battery. Alas they finished as the sun was going down so there was barely time for it to charge, but the battery did charge to 20% while they were hooking things up to it. We also have an app to check everything.
Before he started, he said he'd keep the hot water geyser (heater) and the stove on the grid, they usually don't hook those up to the panels at all because they're such big power draws. Then while they were hooking everything up he noticed that we barely have anything running and suspected there would be plenty of excess from the panels to handle them, if we manage them with sunlight levels, so he's put them onto the inverter. He then also noticed that our geyser was -
barely drawing any power, so I said we both had showers yesterday then I had a bath last night, and it heat up the water since then and once the water's hot it stays hot for a few days and doesn't use much power after, and he was amazed at that :D So yeah, we can just turn the geyser on to heat the water when the panels are in full sunlight.
The battery charges with a trickle from the grid when there's nothing coming from the panels, if the battery isn't full -
but we can also turn that off, or tweak the settings, etc.
The app isn't quite real time but refreshes every 10 minutes or so, which is near enough real time for us to get good metrics of use from it :) (Or we can just look directly at the screen on the inverter, which is real time.)
The battery is set to never go lower than 20%. It's currently 25% and we have loadshedding at 8pm so we'll see how it does with the lights :)
We're also just going into winter, and we have a mountain near us that shaves about 30-60 minutes off sunrise time in the mornings, then houses close behind us that hide the sun close to sunset, but also this is South Africa and even in winter it can be heckin' sunny most days. We don't have much rain forecast this week, a little bit Sunday morning and a bit Wednesday afternoon, with a 'partly cloudy' forecast throughout, so we'll see how it does. :D
Ooh, also interesting - this is getting so big here now that all the solar companies are fighting for components. The batteries and inverters are made in the Western Cape, but then they're shipped to this company's HQ which is in Joburg on the other side of the country, and the installers on this side have to beg for them back. He said AC components are easy to get, but DC components they're waiting on them every day on a day-to-day basis -
this morning they were late showing up because they were literally waiting for the parts delivery that was supposed to get to them at 7am ready for them to start installs at 8 - 9am, and then they left part way into the day to go scouring the local hardware shops for something else they needed. Which is great, I guess it means it's creating loads of jobs here!
The battery charged to 45% on a trickle from the grid in about two hours, then the power went off for loadshedding. It's been running the fridge/freezer, air purifier, lamp, and my desktop with one monitor on watching TV, for an hour and the charge dropped 1%. Now Jaco's turned his puter on for the second hour, we'll see how it does. ^.^
I'm running the washing machine now, and got my PC on. It's set to draw from the grid if our consumption exceeds the solar input, so that the battery stays charged (you can configure all those paramaters, but they set it up to make sure the battery is always full because we're having some 4 hour loadshedding slots). I can also just flip the grid switches off so it never pulls from the grid, but want it to keep doing it while we manage the system.
9am, the sky is partly cloudy with thin hazy clouds, and solar production is up to 310W. Consumption is fluctuating between around 300W and 2.5kW, spiking when the washing machine heats water. It's drawing a teeny 18W from the grid to manage everything and keep the battery charged. \o/
Sun has broken through the clouds and we've shot up to 1.34kW production at 9:30am :D (The capacity of the panels on the SE-facing side of the roof is about 2.2kW, but the roof's slope is shallow and when the sun gets high enough it'll start hitting the ones on the other side too. \o/)
Right, washing machine finished, we run the coffee machine (it's a big commercial one that heats the water with an element so it's high power use for the 10 mins it takes to heat the water), and Jaco ran the kettle to heat water for porridge - battery dipped to 95% while the washing machine was pulling a lot, and we pulled some from the grid, but now that those are out of the way, we're generating 3x more than we're using so I've turned off the grid entirely.
Here are our metrics for the morning. Red is consumption, blue is solar generation. The big red spikes are the washing machine heating water, the last thin red spike farthest to the right is the coffee machine running for the second time. The left flat red section is when just my PC was on, then when that red baseline climbs higher it's when Jaco turned his puter on too. We're averaging about 350W consumption right now, and generating 1.7kW.
Now that we've stopped running the coffee machine and washing machine, and the sun is higher and clearing the cloud, or production has outpaced our consumption so much and on 100% battery that we've turned on the hot water geyser, and our battery is staying stable at 100%. :D
So the hot water heater took about 1h30m to fully heat the tank, at which point it stopped drawing power. During the first half of that it drained the battery to 75%, but then the clouds cleared and the battery recharged back up to 100% for the last part. We know it keeps water hot for 2-3 days, so we can just have it on for two hours during the day when it's sunny and that's our hot water sorted \o/
An interesting thing has happened. There's still sun on the back panels but it has stopped producing, more or less. The battery is staying full, though, and our consumption is a stable 400W. So it must be something that just stops it pulling in when there's excess that has nowhere to go, since it doesn't go back into the grid.
Edit: confirmed with solar peeps, yeah, if there's no load and the battery is full the panels won't produce ^.^
We went to bed at 10pm-ish, at which point the battery was 70%. At 7:30, when I got up, it was at 51% and the panels were just starting to produce again. ^.^
So - yay! We've got some leeway to do some extra stuff in the evenings, or on cloudy mornings :)
This is fun, these are the fridge-freezer spikes :D
I had turned the temperature of the fridge-freezer colder to compensate for being off for a few hours several times a day during loadshedding (and stopped keeping things in the freezer entirely) - it was nice being able to turn it back to normal yesterday, AND now I can start keeping things in the freezer again: O
Much cloudier day today than yesterday, and a power hungry morning with the garden here running the strimmer which used up to 1kW-ish, in bursts. We've turned the grid trickle on to compensate just to help charge the battery until there's loadshedding at 12, then we'll turn it off and rely on solar.
We're producing about a third to a half of what we were yesterday with the extra clouds.
Despite it being much cloudier overall today, we produced more solar energy o.o It cleared up pretty well in the afternoon and we were almost producing at max capacity for a couple of hours.
As Jaco pointed out, this graph also nicely shows Eskom the middle finger XD
Heavy rain overnight, and as the sun came up it was still drizzling a bit. We went to bed an hour later last night, and the battery was at 60% compared to the previous night's 70%, but getting up at the same time this morning, the battery was 45% so it drained less over night.
Not much production this morning due to the cloud, but we were still out-producing the house's baseline needs (idling fridge/freezer and the air purifier) - consuming 34W and producing 50W :D
@welshpixie we’re still barely managing 80W here next to Signal Hill even though the clouds have lifted. I see the same kind of difference compared with family’s installation not far from where you are. I think it’s a combination of newer panels and just much better light over there generally.
@stefanf28 Oh interesting! I wonder if the smog in Cape Town is having an influence - when I walk on the beach here in the mornings there's almost always a layer of smog over CT and I can't imagine it helps solar production :/
@welshpixie I think so yes, but also sometimes the low fog from the Atlantic that covers the City Bowl, or the edges of the table cloth when it gets big.
It always strikes me just how much crisper the light seems when I visit Som West. Now we have data! 😁
Our morning graph. Started rainy, the clouds have been gradually clearing up, but that spike at 10:40am there was direct sun on the roof for a bit and production soared to 2.54kW, which is a good indication of what we can expect to be generating on clear days :D
Trying something new today. Instead of only running the hot water heater to heat it up fully then turning it off until the next day, we're keeping it turned on, because when it's not heating it actually uses zero electricity.
Points described in the alt-text. You can see that once the water is done heating the heater doesn't use power, and now our production (blue) is high above consumption. Need to see how often the geyser turns on to heat the water again, and how long it takes.
Forgot to include the reasoning and I just replied this to someone else so I'll put it here too -
My thinking behind doing it this way is, if it needs to stay on for 1-2 hours to fully heat the whole tank from cold, the high power usage outstrips what the solar can manage. But by keeping it constantly on such that it only needs to reheat for brief bursts, it's a more manageable power draw that the solar can cope with.
For the second day (since last Thursday) we've reached the point in our production again, with a battery that's been at a stable 100% for a few hours and the panels producing far more than our consumption, where the panels have gone 'Eh, you got this, we're gonna sleep for a bit'. ^.^
Add comment