Creative ways to waste energy?

OK - I knew I was overspecing my solar panels when I had a second string installed - I just did not realize how much so…

10:30 in the morning. Aircon is running full blast, batteries are full, geyser heated to 80C, and panels sitting almost idle at 1.5kW (of a maximum of around 6kW).

What ways could I meaningfully use the excess production?

I have the same issue. Got to love those sunny summer days.
I have a dehumidifier running being so close the the ocean, but that is only 600W. Then again I only have a 2kW solar array that I need to find work for :smiley:

I had one string, and calculations showed it as ‘sufficient’ for an average day (using solar irradiance numbers from SAWS) in all but mid-winter.

I wanted a little extra headroom, but the cost difference between a minimum length string for the MPPT voltage on the charger, and a full length string was fairly small - so I just installed a full string.

Now it is way over the top.

But I like the idea of a de-humidifier - perhaps I should look at some of the water from air options?

Not sure I’d want to waste the energy just because I have it? That would make your inverter run full steam for no reason, producing heat and shortening its life…

I’m trying to get to the point where I don’t need to use my batteries during the day (to make up for my PV peak being too low), because it is warm then and don’t want the batteries to heat up unnecessarily. I also want to reduce my energy demand as much as possible so that I don’t run my inverter full tilt for 95% of the time. I’d rather expand the lifetime of my components than artificially create a shorter “payback period”.

That is a good point. But even at full tilt, the panels are only 50% of the charger capacity, and 60% of the inverter capacity - so it should not be working anything particularly hard to use up that capacity.

Oh wow! You don’t have the pedestrian 5kVA MPII. Sorry, I’ll get out of your way. :sweat_smile:

Buy yourself a heat pump for your swimming pool.

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Excellent point! … unless it is for a good cause - and those causes being completely arbitrary and vastly different between users. :smile:

When I started in 2010 I had a 400w array - 2 x 200w panels.
Then I wanted more, could not get the same 200w panels, so I got 3 x 310w panels on 2nd MPPT.
= total potential of 1330w.
Never got even close to that being, at that stage, a off-grid system, because of cabling, small battery bank and just because …

So I sold everything and went grid tied.
Started off in winter with 2.1kw panels. Ran the system for a while, and promptly increase the array to 3.5kw.

Now I need ±500w more in the middle of winter. The cost of getting that 500w extra?
Option 1: Add 5 x 350w panels + instalaltion costs - keeping array 3S/5P
Option 2: Add 2 x 350w panels + installation cost and rewire to 4S/3P

All that now for ±500w exstra?

Issue started because I had a 150/100 when I bought the panels. 2S/5P made sense at the time, coupled with CoCT and max inverter size and all that, in that one could limit the array to meet the requirement , i.e. max of 3.5kw.

Then I had the opportunity to get a 250/100 … if I had that first round, and CoCT was “lit”, it would have been 4S/3P from the start = 4.2kw potential, optional expansion to 7kw 4S/5P - IF Eskom slips any further.

Option 3: Add 100/20-48V with the 2 panels (or 4). This MPPT cost ~R2500.

Cost would be the ± same for the panels and mounting … the ~R2500 the then additional cost.

You must have read somewhere about my: WANTS are more expensive than NEEDS … and HOBBIES have no price tag?

I’m at the WANT stage, as there is no NEED.
But if there was spare cash, no new BMS purchases, I would have opted for HOBBIES and just add 5 x bloody 350w panels and be done with this shiite! :laughing:

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You can chair our SA club (Solar Anonymous) :smiley:

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Am already chairing SA Solar Anonymous … see, Me, Myself and I, we have elected TTT as the chair a long time ago. :vb-cool2:

in the interest of the planet and our country one can only hope that you will be able to viably sell it soon.

That would be ideal - but I don’t think it will ever be practical in SA…

I don’t use that much electricity (even before any solar panels), so it would have been more expensive to switch from my prepaid meter to a monthly account and then sell excess power. It might have made sense if I used > 400kWh/month and if I did not need a battery to get past loadshedding.

Would have been great though. :frowning:

i capture my aircon water(also dehumidify) and can get a few liters a day to 25l one hot humid day(coastal) other than that i started using the tumble dryer to dry washing just to waste excess generation. The captured water(from AC) pumps to a tank that also captures my RO filter waste water and some rain water and that plums to toilets.

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Solar user issues - I generate too much power, what should I do with it :slight_smile:

We’re all in the same boat. I present my - fully charged by 11am graph for reference.
Thats a whole day of generation wasted as the MPPT throttles. I think I’ll get an aircon maybe…

Of course if we were on a sane planet, we could sell it back to the grid for others to use.


I installed two air cons and a few panel heaters and added them to my home automation to take advantage of the extra production.

Hold … Hold … the time seems to be coming … Big breakthrough: Some municipalities can now generate their own electricity

Any solution yet, I am curious as to see what you have decided.

Nothing yet. The best energy saver would be a cold water store to use in place of an aircon, but the water mass required would be impractical.

Next best option would be a water from air system. Commercial solutions are ludicrously expensive, but I am keeping my eye out for an old freezer to use for experiments.