How to get more out of my system: Brainstorming session

[cattus]

Good day.

So I had a little system installed about 3-4 weeks ago. One thing I’ve learnt is my calculations were very conservative. In any case, here’s my dilemma:

Bottom line, I’m not using nearly enough of my PV power. In fact, close to none. And I want to solve this. But not sure where to start…

Quick system overview-
4x 385W Panels (2S2P)
MPPT 150|35
1200VA Multi
Pylon US2000C
Cerbo.

My system was meant to provide safe power, for in Pta East we’ve had regular power failures lasting hrs, days, weeks, it’s for a desktop (one of us works online) and a fridge, maybe a few lights, charger etc. And it does! Easily. I can run the desktop, fridge and washing machine all at once, midday, no probs.

At present though more than half of my power consumption for this rig is coming from the grid (see screenshot attached: “Consumption-17/06/22”) and this annoys me. Further complications are that we just don’t consume a lot of juice during the day, so it’s hard to add consistent loads onto PV’s production. Most consumption’s from the regular bandits…geyser (150L/3kW), old school stove/hob, nuke and kettles. So here are a few ideas I have, in no specific order, and most certainly open to critique and input, yes pls…

1. Cut ties with the grid by dropping the switch on DB breaker &/or AC-in on my installation’s AC combiner box.

2. As above, and should need arise, add another US2000C.

3. Somehow, somewhere, (and I haven’t figured out how) drop the % of use from the grid via the Remote Console, ESS thingy.

4. Here’s a nifty one…I have an extra unused geyser, 80-100L?, perched on the studio roof, the wiring/thermostat got fried. I’m wondering if I could insert a 1kW element and use the PV to fire this baby up, then no longer use the 150L. Does this sound doable?

Home Layout.
It’s a smallish house with two outbuildings: Storeroom and Studio. 2pax. On the DB1 (main house) there’s an “Outbuilding” breaker going to the Storeroom. The storeroom has another DB2, from here 2nd fridge, lights/plugs for two buildings and possible Studio-roof geyser, plus overnight lights in yard.

The installation AC is currently not wired back into DB1 but has a plug adaptor attached from Multi AC-out (via AC Combiner Box) that feeds the fridge/desktop. Wiring AC-out back into DB1 and linking other plug/light breakers there to feed off the installation is also an option, but hardly any load will be drawn from them which, I suspect, will simply continue the trend of leeching off the grid and PV lying dormant. Though I stand to be corrected on this.

“Edit”
I should add that on DB1 there are three Plugs breakers, 1 for the house, 1 for the kitchen (hence fridge on adaptor) and a 3rd, I’m guessing it’s the unused/disconnected underfloor heating. This 3rd could be an option, except we have a double volume pyramid shaped interior, underfloor heating will do diddly squat.

I understand that it’s hard to explain to, or inform strangers of, one’s system, house set up etc. So any further info is at hand, just ask.

For me, in my ignorance, the simple solution would be to sever ties with the grid, temporarily, and incrementally add on appliances to use the system. Should I find myself in a pickle I can turn the grid supply back on. So I must ask, “Is there any technical reason to not do this?”, as in…

“Oh my God Cattus, you’ve broken the internet!!”
“But how? I just flipped a switch”
“Well, because of TPdTT feature, with it’s non-phased 01:3* factor lay-over feed-on/feed-through optimiser resort protocol, and the ESS bindback multi-dip excess log you’ll not find Scarlet’s love no more.”

Thanks for reading my ramble.
Regards, c.

[TheTerribleTriplet]

@cattus

Bottom line, I’m not using nearly enough of my PV power. In fact, close to none. And I want to solve this. But not sure where to start…

Cactus, now before you go and spend anything more, if I was you with what you wrote above, switch off the main breaker on the DB, and feel where your inverter, panels, and batts take you.

There is nothing like seeing it yourself, for yourself, in your own home.

BUT … the 1200va Multi would probably be challenged ito house loads so maybe keep the kitchen on the main DB, so just take the rest of the house off-grid like all the lights, entertainment, internet, PCs, alarm, chargers.

“Feel” how that goes, the loads on the Multi and the batts, and if it can be recharged, whilst powering the loads the next day.

EDIT: Obviously there are maths to do it all, but hey, do it with real-life actions, then match that back to the maths. It can be quite fun let me tell you.

[Sc00bs]

The first thing I would do is to measure the power usage so I would have an idea as to how much power based on the time of day. How much power am I using during the daytime and how much at night.

Then work out what loads that are currently running at night I can move to the day time. Geysers for example do not usually need to run at night as they can be heated up during the day.

Once I have optimised my power consumption for during the daylight hours.

Make sure I can generate enough power from my panels to power all my regular loads plus some extra power so I can charge my battery fully.

If you don’t have enough panels at the moment to power you loads and charge the battery you can just keep your battery charged for load shedding and run as much of the houses load form the panels as you can during the day (It doesn’t sound like you have enough panels at the moment from what I can see)

[Louisvdw]

Perhaps give some detail on your PV panel setup. Is it on the roof, north facing, full sun or getting shade. Show you MPPT and battery graphs from your VRM (under Advance section).

Things are always the worse in winter. The sun angles are lower and the duration of sun hours in the day is less. During summer this will be more.

From what I can see something on your PV does not look correct. You only get 0.22kWh for the last 24h. I would expect this to be much more.
Here is a rough calc I did. In real life you should expect around ±300W from those 385W panels and this would be less in winter, so lets say conservative 250W. You have 4x so if you have full sun on those panels around mid day for 1 hour that would give you 1000Wh (1kWh)
But your setup show you only get 220Wh?!

I have a 100/20 MPPT with 4 330W panels also 2S2P and during winter they are in the shade for most of the day. And they give me 1kWh. If your panels are in the sun for 5h you should see closer to 4kWh-5kWh.

[cattus]

Thank you all for feedback thus far.

@Louisvdw
My panels are North facing, some morning shade…but let me cut to the chase (and I will show some graphs soon):

As I understand it - as it was explained to me - my load is very small, so the full PV power is not being used, if I increase my load more PV will be taken. Or, put differently, the system sees no need so the MPPT throttles incoming Watts. I guess it’s like your water mains, the water’s there, but you’ll only see it if you open taps.

This explanation makes some sense to me for in moments when my battery was low, first day of installation at midday, and in other instances when I added a washing machine to the load, I could see on my Dashboard that the PV fed through roughly between 800-1200W. So I know I can get it, just been scratching my head as to how, consistently.

Which brought me to the question of how to perhaps throttle the grid AC instead and use PV mainly. To that end, I did this…

I dropped the breaker on the DB that feeds AC to my system. Did this 9h00am 18/06. Here’re two images off the Dashboard, “System Overview” and “Consumption”.

[cattus]

As you can see there’s still plenty of juice lying up there.

@Louisvdw
Panels on roof, north facing, 30degree angle or so, some morning shade, hence the 2S2P arrangement (ie one pair is in full sun a good hour or so longer)

Here are graphs as promised, for June. You will see slight change on the 18th, when I dropped the breaker and went Off-Grid.

regards
c.

[Louisvdw]

It does not seem that you are using the batteries much. What are the Min SOC value you use in your ESS settings? For lithium batteries this should be around 20%-30%

If your batteries are full, then only the usage that your device draw will be powered by the MPPT. Then during the night you battery will be used and in the morning it will be charged.
So if your battery is accepting charge (I think 27A for that model) and you use another 800W from the inverter (16A) that should give you 43A that the PV panels can power.
If you deplete your battery low enough that will take longer to power the batteries back up and thus you will use more PV to do that. That is what your last 2 days also show.

[cattus]

@Louisvdw

What are the Min SOC value you use in your ESS settings?

50%
Very conservative. Could be lower of course.

Battery discharges overnight to about 60% by 8am.
100% charged by 11h30am…that last 5% from 95 takes about 40minutes to an hour.

[_a_a_a]

Do you have a carlo gavazzi to monitor the usage for circuits not on the output of the Multi?

[cattus]

@_a_a_a

Do you have a carlo gavazzi

Nope

[_a_a_a]

Then that would be my first step. Then you should be able to backfeed excess solar to the rest of your house.

[cattus]

@_a_a_a
I’ll look into it. Sounds like a pair of shoes.

[plonkster]

@cattus

pair of shoes

It was impressed again on me, earlier today, the importance of walking a mile in another man’s shoes. It has at least two advantages, the first being that it puts at least a mile of distance between yourself and said man, but also secondly, that you are now in possession of his shoes.

[cattus]

Thiefsiz!!

[JN.V]

I think that should be your next purchase, a ET112 to measure your consumption and exactly see what is what.
This will take quite a lot of guessing out of the game.