r/solarenergy

I've been trying to understand battery storage better, and I'm realizing that just knowing a home's daily electricity usage doesn't seem like enough to determine the right battery size.

If someone wants solar primarily for backup during outages, how do you actually decide how much battery capacity they need?

Is the main thing looking at average daily kWh usage, or do you focus more on the specific things you want to keep running during an outage? And how much do things like cloudy weather or the length of a typical outage factor into the calculation?

I'm curious how people with solar and battery systems actually approached this when sizing their setup.

Location, California, Bay area. PG&E

Household is mostly retired people and working from home.

energy usage around 625kwh/month

Heating and water and stove and dryer run on gas.

We have little energy usage after sunset

Trying to get a passive solar system with 12 panels and microinverters that I can buy and own. All the installers are trying to upsell me on a 5 year PPA financed system with a battery.

I am just not convinced that I need one, since its twice the price, and dealing with financing.

If I just need to offset daily usage and slowly charge an EV that's used as a local commuter, would a no battery system be sufficient?

Are they just trying to upsell the battery system to get more from the rebates? Or does it make actual sense?

Batteries come with the own issues too, they have a limited cycle lifespan, they can get damaged/stolen/ and its another fire hazard to deal with. I just dont know if it makes sense to charge a battery then use that battery to charge a car.

DTE Energy has completed the 100 MW Cold Creek Solar Park near Coldwater, Michigan, a $194 million project funded through Ford's commitment to buy up to 650 MW of clean power. By the end of 2027, every Ford vehicle built in Michigan is meant to run on 100% carbon-free electricity, though the timeline slipped from the original 2025 target and neither company explained why.

The park can power roughly 23,000 to 25,000 homes, with a 75 MW battery system coming online to store daytime solar for evening demand. Ford's participation is estimated to offset up to 600,000 tons of CO2 annually once fully implemented, part of a broader push to move all its global factories to carbon-free power by 2035.

I'm posting this so others know what to expect from EnFin Corp (serviced by Launch Servicing LLC).

Background: I signed a 25-year PPA with EnFin in August 2025, installed by Axia Solar. If you sell your home, the buyer can take over the PPA, but only with EnFin's approval. There's no buyout option until year 5.

I'm selling my house in California. Escrow depends on getting the solar transfer sorted, and here's what that looks like.

Email is the only way to reach them. There's no phone line to call. They took 7 days to answer one simple question. I'm now waiting again on the next reply, with no timeline given. In this housing market, an EnFin PPA can make your home much harder to sell. Buyers already hesitate to take on a 25-year solar contract. Add a company that answers one email a week, and the deal can fall apart before it closes.

If you're thinking about an EnFin PPA: Ask how they handle transfers during a sale, and how fast. "Subject to approval" means they control your closing timeline.

If you're selling with one: Email them the day you go under contract. Send all your questions in one email, keep copies, and loop in your agent and escrow officer right away.

Has anyone gotten an EnFin transfer through recently? How long did it take, and did anything speed it up? Are there any legal options?

Please help! I have to make a decision today for prime deals. Here's my options. I want something to use at home for light, charging devices, box fan, heated blanket, possibly a microwave here and there. And I want it to be expandable in the future if I get more money and can buy more. This is only for home use, specifically in a power grid failure.

Bluetti elite 200 V2 with 2 200 panels. $1199

Ecoflow delta 3 classic with 1 220 panel $659

Bluetti elite 100v2 with 1 200 solar panel $649

Jackery home power 1000v2 with 1 200w solar panel $699

Jackery 1000v2 with 2 200 panels $949

Ecoflow delta 3 max with 1 220 solar panel $1039

Ecoflow delta 3 plus with 1 400w solar panel $1019

Planning to get a 3kW solar setup for my home. It’s a small 2BHK with normal fans, lights, WiFi and that’s pretty much what I need to run on backup. I don’t have a lot of knowledge about solar, but from whatever I’ve researched, I’m currently considering a Luminous Mono PERC halfcut setup. My budget is a bit tight, but I have enough rooftop space, and I’m getting the Mono PERC at a pretty good price. So should I just go for it, or is it better to wait a bit and spend extra on TOPCon bifacial since it’s a one-time investment and i have heard that Topcon bifacial is a bit more effective in the long run and requires less maintenance as well so what do you guys suggest ? and also will 3kW be enough for my use or should i go for a higher variant after some time ?

Hoping to crowdsource some ideas because I feel like I'm stuck in a "replace a part and hope" loop with my installer.

System: Enphase microinverters, came with the house. Owned the house ~2 years, first year was totally issue-free.

Timeline:

• December: First trip. Diagnosed as a loose cable / water getting into the wiring during the rainy season. Fixed.
• Ran fine for about 6 months after that.
• A few weeks ago: Main panel breaker started tripping again, cutting power to the system. Supplier sent someone out who replaced the breaker. All cabling checked and called "fine."
• A few days later: Tripped again.
• Last Friday: A different engineer came out and did three things: (1) found Permission to Operate (PTO) was somehow switched off and turned it back on, (2) found my Enlighten app access had been revoked on their end and restored it, (3) pushed a software update.
• Less than 24 hours later: System's down again — no power at all reaching the Enphase combiner panel.

What's already been checked, with nothing found:

• My builder confirmed the solar wiring is on its own dedicated circuit, separate from the rest of the house.
• The builder's own electrician has separately inspected the wiring — including a full check of the house wiring, not just solar — and found no fault.
• There's also been a recurring burnt-wire smell in the first-floor bathroom, on two separate occasions. Each time, the builder's electrician came out, checked the house wiring, and found nothing.
• A solar tech visit in August inspected the solar wiring specifically and also found nothing related.
• The engineer from the original December visit suspected pigeons on the roof may have disturbed some wiring; the most recent engineer did a visual check and found nothing disturbed either.

So at this point: a new breaker, a PTO reset, a software update, an app-access fix, and no visible fault found across at least three separate inspections (builder's electrician, solar tech in August, most recent engineer) — and it's still recurring, now within a day of the most recent visit.

Specific questions:

• Does a PTO flag showing "off" ever point to something other than a simple status toggle — could it be a symptom of a deeper comms/relay issue rather than a standalone setting?
• Could the software update itself have caused this (bad push, reset config)?
• Is a burnt-wire smell somewhere that's supposedly unrelated to the solar circuit (first-floor bath) worth taking seriously as connected, or is that more likely a coincidence?
• What should I be pushing them to actually test — insulation resistance, thermal scan — instead of another visual check?

Appreciate any input, especially from anyone who's had Enphase chase a trip like this across multiple "fixes."