[jacquesm]

6 strings of cells, hooked up to two inverters, one handling two banks on a very high roof, peak production there is 4KW, one inverter handling four strings on covered outdoors space and the garage. The last four are at very shallow angles, so less than ideal but total surface area really makes up for that. We draw about 300W on average and the peak production capacity for the whole setup is close to 15KW (or even slightly higher in full sun in March). Over the last 11 months the system produced 12 MWh on about 4 MHw consumption so net 8 MWh returned to the grid.

34 of the panels are brand new 370W glass-glass panels, the remaining 16 are much older (probably a decade old, maybe more) that still work pretty well rated at 265 W each (but probably closer to about 220 or so).

[icy_deadposts]

> We draw about 300W on average

Dude, teach me. Forget solar panels, if you can explain how you're living on ~1/10th the power of the typical home around here I'd power my house on a hamster wheel.

[jacquesm]

Lol. Ok: first, you get 25 hamsters...

No, more seriously: we started off by pulling all the breakers and to go 'from scratch', then every time I re-connected a breaker I monitored the increase in power draw. This took a bit of time but after a while we figured out there were a number of really bad consumers: my PC (which had a very high end graphics card in it from a machine learning project a couple of years ago), the NAS (which had 12 bays), an older fridge (though I thought it was quite energy efficient, but this really wasn't the case), a water heater hidden under the kitchen cupboards (that one took forever to track down), some smaller loads but still considerable (a couple of studio monitors, game computer that was on standby when not in use, a large studio mixer, a massive pump for the infloor heat that worked just as well (or even better) with the lowest setting as the one that it was on) and then a large number of really small loads that were always on but rarely needed.

Removing all of those saved us 2/3rds of our power draw, we went from 30 to 35 KWh to around 8 to 10 KWh / day. After that it was relatively easy to get to '0' using solar panels and another batch of them and we were suddenly offsetting our gas usage with surplus electricity (which the power company buys).

No hamsters were harmed in the preparation of this message.

[wrycoder]

Thanks for this. I'm averaging a kw in a small house and don't understand where it's going. When we put in a hot tub, it only raised the monthly bill about 10% (it's worth that). Gas heat, gas water heater and stove. Most lights are LED at this point. Using laptops, no big graphics machines.

I need to do what you did, though I was thinking about hacking up a clip-on ammeter and some monitoring software to examine the various breaker branches.

[jacquesm]

Oh, as for laptop: I ended up buying a second hand W540 which is pretty beefy when you want it to be but normally it sips power (about 29 watts continuous draw, the screen is off because I have two external monitors connected). Oh, and about those monitors: I've reduced the backlight intensity from the default quite a bit and that made a real difference as well (besides the usual power saving and desktop lock settings).

[jacquesm]

> I was thinking about hacking up a clip-on ammeter

The easiest spot is right on the distribution wires, they usually are pretty beefy and that means you don't have to re-hang your meter after every breaker. They're also very well insulated so the chances of shorting something out diminish a lot (but if you do the effects will be far more spectacular ;) ).

In the end I installed a 'Shelly' three phase current meter permanently with the pickups around the mains wires. That gave me very precise logging (and given that the distribution board passes those three wires roughly balanced out across the breakers it is already quite fine grained). It also allows you to spot intermittent consumers and for the money I wished I had installed it earlier during my hunt.

[chrisweekly]

What's your geography, and what'd it cost up front?

[jacquesm]

Netherlands.

Panels cost about 210/each for the new ones and the old ones were pretty much free. Inverter: the one upstairs is a new one, 500 Euros ('second chance'), three phase 4KW, the one downstairs is a monster, it's 17KW with up to six strings and cost another 500. The panels on the high roof were installed, about 1000 to do the job and the rest I did myself, add another 500 or so in cables, tubing etc. The power bill went from 8500 / year to 3500 / year, and all of that is the remaining gas usage. We're looking into using any surplus in nov/dec/jan/feb to help heat the house to further offset the gas usage but the economics aren't really there yet as far as I can see.

And even in November we are still offsetting about 75% of our electricity usage, which somewhat surprises me, I'd expected far worse.

[chrisweekly]

thanks!

[jacquesm]

You're welcome. I've done a bunch of these by now if you are ever in the market for a setup and want to bounce ideas of me then feel free to mail, email is in profile.