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electrical:solar:frugal

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Frugal solar

FIXME [this is a dump of a reddit post I made; will clean up later. fs]

system sizing

Get used to turning loads off when they are not in active use. Add switches if necessary to prevent “parasitic” draws.

Reduce the size of your solar install (panels, batteries) by running your loads when the system has power to spare, not when it is trying to charge back up.

reducing supply

reducing load

test

  • Inverters
    • minimize the use of inverters by using 12v appliances and adapters when possible
    • turn inverters off when not in use
    • size the inverter to meet the needs of your biggest loads. Oversizing wastes power because bigger inverters have more parasitic draw.
    • use MSW unless your intended uses need PSW; MSW have lower parasitic draws.

solar panels

used panels may be found on craiglist and similar. Since they are older they will usually be rated for somewhat less wattage (ie, state of the art a couple years ago) but will cost less and someone else has already paid the insane shipping fees.

us.v-cdn.net_6024911_uploads_attachments_1005_574.jpg Grade B panels are apparently fully functional, but cheaper because they are not pretty to look at. If they are on top of the van you won't be seeing them much anyhow.

if you have room for them, residential panels (like 60 cell, nominal 20v panels) typically are cheaper by the watt. 72 cell are even cheaper by the watt but don't fit on many builds due to their large size.

charge controllers

the Chinese “Tracer” MPPT charge controllers made by EpSolar/EpEver and rebranded by Renogy and others are surprisingly decent controllers and a great value. Is something like morningstar better (and prettier?) Probably, but they are 2x the cost and overkill for my purposes. And their remote monitors are 3x the cost, battery temp probes 5x the cost, etc. Software cable adapter is 3x the cost and is serial instead of the tracer's usb. The Tracer PC software for reporting and configuration is free and also surprisingly good. I've had both cheap and expensive controllers over the years and I chose a sub-$200 40a 4215BN for my current build.

batteries

converter

electrical/solar/frugal.1500863427.txt.gz · Last modified: 2020/10/11 19:48 (external edit)