Sanity Check on DIY solar generator

[Toodles222]

Hi! I am just about ready to commit to a small-ish solar generator setup to get my feet wet. Unfortunately, I rent, or I'd probably be committing to a full size grid-tied solar installation, but what can you do.

I'd really like some folks more experienced than me to give me a sanity check on the configuration that I'm thinking of. The biggest limitations are that the solar panels can really only been long-term-temporary installed or only pulled out when needed rather than permanently installed. I was thinking of T-Posts and bolting everything to that, on the south wall of the house - is this a bad idea? There are several wall penetrations that are mostly filled with duct seal that I could run the PV wires through and re-duct-seal.

My main use case would be to take my indoor hydroponics off-grid, but with a grid fallback if I run out of solar/battery, and to use as a general solar generator on longer power outages (freezers/fridge/phones).

For equipment:

• 4x Eco-Worthy 195W Bifacial - Probably the best deal for physically small panels I've found, which can be turned into a DIY suitcase if a not-quite-permanent mount is not a good idea. Reviews that I've found say they are a little over-rated and get more like 180W, but even so ~$0.50/w is not bad for new smaller size panels from my research. Not as good as full sized used panels, but I'm very limited even for temporary mounting as I rent. I'm considering a second set of 4 always in a suitcase config to throw on the back patio in case of longer term emergency to bring the total array wattage up - assuming that I can semi-temporarily mount the first 4 as above. I've probably only got sun space for ~4 panels on the patio and ~4 panels on the south wall.
• 2x 12V 150AH Eco-Worthy LiFePO4 batteries in series - insane $/wh price for a finished battery while on sale, but going to have to keep in balance semi-manually in a 24V system?

I'm most uncertain about the controller. I've looked at a several, and am leaning towards the features of the Sumry but hate that it can't really be meaningfully monitored. It seems like both the Sumry and PowMr allow fallback to grid, but the documentation on all these cheap AIOs seems to kinda suck, so it's a little unclear. As far as I can tell, there's no fallback option for the standalone charge controller.

• Sumry 3600 ECO-LV (~$270 on Ali) or Sumry 4000W HGX-4K (~$280 on Ali) - Definitely the most inexpensive configuration, 24V AIO, with a wide voltage range for PV inputs (55-350V), meaning I can run it with 4 in series and just add another 4 in series if needed without having to muck about with a combiner and higher amperage. Downsides are no support, no monitoring integration since the RS232/RS485 protocols are completely undocumented. This has a major advantage to my current thinking - specifically it has a low enough minimum input voltage that I can get away with only 3 panels in a string at the hottest temps (22.65Voc if I did my temperature math correctly), and up to 14 (~26.35Voc) on the coldest. Plus, cheapest.
• PowMr 3KW Low Frequency (~$450) - I've heard that Low Frequency is desirable, but I'm not sure I understand why. Upside is that SolarAssistant claims to be able to work with PowMr (where it doesn't the Sumry), but vendors seem to be all over the place and support seems to be non-existent and generally it doesn't seem to be a particularly good company. Has a decent input voltage range (60-150), but only fits ~5 per string of the panels above, meaning that any kind of semi-serious expansion from the initial 4 panels brings back the parallel wiring and combiner.
• Eco-Worthy Charge Controller 60A (24V mode) + 3KW inverter (~$390): very low minimum (26V with 24V battery) input but only 150V max, with the same problem as the PowMr above. Upsides here is definitely the modularity, but the downside is a lot more breakers and terminals and wiring. Biggest downside is there doesn't seem to be a way to fall back to grid power if I run out of solar/battery.

Are there other controllers I should be considering? I would like to keep the total system with 4 panels < $1500, which all these options scrape by.

 

[12VoltInstalls]

heard that Low Frequency is desirable

It’s better for electric motors
It can sustain high surge better

Are there other controllers I should be considering?

For cheapo new stuff I like powMR

 

[Toodles222]

It’s better for electric motors
It can sustain high surge better

So, if I was planning to use this for powering the furnace blower, it would help with startup and such? That would be a nice capability.

For cheapo new stuff I like powMR

What vendor do you recommend? Most of the ones on AliEx seem... sketchy AF by the reviews, and it doesn't seem like they have an official storefront at any of the big places.

 

[12VoltInstalls]

So, if I was planning to use this for powering the furnace blower, it would help with startup and such? That would be a nice capability

I would not be stuck on the low frequency inverter idea. I’ve been using high frequency inverters full time since 2019. I just use a big enough wattage that that starting any motors is not an issue. 3000W starts my tablesaw just fine; household stuff is way under that load.

What vendor do you recommend? Most of the ones on AliEx seem... sketchy AF by the reviews, and it doesn't seem like they have an official storefront at any of the big places

I would recommend Amazon, watts247, signature solar, current connected, altEstore, or some other domestic retailer where in the unlikely death of your inverter has helpful people available and (relatively) instant solutions.

 

[jcollman]

I did something similar - see this thread. 4x 200W bifacial panels, 1x Victron 100 | 50 SCC, 2x 12v 2kW inverters, 2x 12v 100Ah batteries, 2x 12v 165Ah batteries, & 2x 300A Class T fuses. It's modular with everything portable by one person and is designed to be stored in the attic & temporarily assembled when needed.

Each panel is mounted on one of these and folded flat for storage. When needed I just put them directly on the ground and hook everything up with Anderson Powerpoles to charge. For what those mounts cost complete I couldn't even buy the materials.

 

[Toodles222]

I did something similar - see this thread. 4x 200W bifacial panels, 1x Victron 100 | 50 SCC, 2x 12v 2kW inverters, 2x 12v 100Ah batteries, 2x 12v 165Ah batteries, & 2x 300A Class T fuses. It's modular with everything portable by one person and is designed to be stored in the attic & temporarily assembled when needed.

Each panel is mounted on one of these and folded flat for storage. When needed I just put them directly on the ground and hook everything up with Anderson Powerpoles to charge. For what those mounts cost complete I couldn't even buy the materials.

This is beautiful! Thank you for the links; not sure why it never showed in any of my searches because it's perfectly tailored to what I was looking to do.