Home Solar Experiment

So I’ve been busy building a new solar array, mostly as a hobby and its been crazy fun. Electrocuted my self twice, but luckily nothing too bad.

I’ll write up some more detail round the build, the metric collection and the things i have learnt over my time.

Keep in mind that NZ is in the southern hemisphere, so its winter as i’m writing this. Low sun hours! Stats publicly available via grafana here – https://grafana.sigtar.com

For now a quick summary of my build below;

Build Details;

  • Solar Controller 1 x EPEver MPPT (Max 30A, 720W @ 24v)
  • Solar Panels 6 x 100W (5.2A 19.25V) – 600W in series & parallel (10.4A x 57.75V)
  • Battery 4 x 6V (US Battery 232AH @ C20) – 24V in series
  • Inverter 1 x EPEver 1000W (Pure sine wave) – 24V DC -> 230V 50Hz AC

Controller Settings;

  • Boost and Equalize duration : 120M
  • Over Volt : 32
  • Equalize Charge Volt : 29.6
  • Boost Charge Volt : 29.2
  • Float Charge Volt : 27.6

Software details;

  • Influx DB – 90 day retention
  • PHP script polling Solar controller every few seconds – parsing results into db
  • and of course Grafana!
  • all docker images on UNRAID server

Whats next?

  • ATS – maximize my solar power with 24hr loads :p
  • Batteries – Switch to LiFePO4 batties (Lead acid suffers from small DOD of approx 50% and voltage drop under under load)
  • Wind – hard to find anything that would work in my urban area. Must retire to the hills before i get into that! ;)

Flashing si3114 to sata only bios

This is the perfect controller for adding additional sata drives into opensolaris (well in terms of price, the bandwidth of the PCI slot is the only negative part). The si3114 comes with the default bios that supports various raid configs, but this requires additional drivers to be loaded.

Essentially the “raid” on the card is called fakeraid as it does not actually process any data itself, but hooks into the cpu via a driver and lets your cpu do all the work.

Instead we will flash the bios to be a sata only controller (no raid). If we are using ZFS its better to just present the disks and let the OS take care of the work.

You will need these tools;

bio-003114-x10_5403 – the various bios’s for the si3114 card

siflashtool – the flashing tool

Note : you must plug in a hard drive into the card or else the flash will not work.

From the zip above you want to grab this file for the bios flash “b5403.bin” the other is for raid and can be ignored.

Now you’ll need to grab your trusty bootable flash drive / usb stick. If you dont have one check out HP’s tool for creating one (else you could use a floppy boot disk if you still have one). Copy the files onto it, and boot it up.

The instructions say you can flash in windows, but i never had any luck with that – instead found booting to dos a much more reliable method. This is the commandline to run it;

SiFlashTool /File:b5403.bin

Done.