Post #1739906

2026-04-28 08:16 UTC

@dch@bsd.network I'm a month and a half into my solar system. So far I'm pleased but also I probably undersized my setup a little. On the other-hand, I have a small roof area and a tiny house so its probably the best I could do with what I have. In the upper part of a Wellington valley, I can charge the 6kwh battery in 4 hours in autumn/winter on a sunny-ish day. Unfortunately running my water tank & putting the heater on will suck the battery dry in 5-6 hours so its empty again in the morning (it has a 15% reserve to be fair in case of grid-outage). I do need to do some re-cabling to split my water cylinder onto its own circuit (shared currently with half my lounge; joys of an old house!). to use the timer I added to the fuse-box & reduce the tank-temp. If you can measure your tank/heater draw before you put something in that will help the calcns. Idling, my house uses 0.2 - 0.5kw (no heater/cylinder + empty house or me WFH but ymmv).

Replies (3)

@irix@cloudisland.nz 2026-04-28 08:40

@dch@bsd.network Another consideration (minor in my analysis) is to ponder the systems open-ness, check the community forums, integrations with home-automation systems etc. I suspect most setups are black-boxes but I know there are/is an open-solar movement to create open-systems you can build/query etc. Otherwise the black-box will likely have an app and/or cloud based interface (again, may or may not be a concern). The installers often don't seem to know some of the stuff you'd typically ask a supplier/vendor installing expensive kit into your IT environment (maybe I'm being overly critical but I kind of want to know where the data goes, what happens if the vendor goes bust, what are the creds, what does the device do on the network etc - you probably won't get great answers but I did get confirmation the unit will operate standalone if it can't talk to the internet but I'm not what visibility you get if the vendor cloud is down).

Open ##1740307
@dch@bsd.network 2026-04-28 09:07

@irix@cloudisland.nz I have a non battery setup since 2022. We generate about 8MWh and use around 5MWh locally, most of it going directly into water heating. There is substantial variation throughout the year but even in Dec/Jan we still get almost 200kWh/month and it is almost double that in the shoulder months.

Open ##1740932
@dch@bsd.network 2026-04-28 09:22

@irix@cloudisland.nz we have 2 people WFH almost full time and last year I had a half rack mini datacentre temporarily. Our idle usage is quite high around 400W even overnight during that time and I need to figure out what else uses power then. Over winter we use about 20kWh a day, about 14 during spring and summer. This would be the main benefit of the battery to move off peak usage into free sun energy!

Open ##1741856