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How much did that installation cost you, if I may ask? I know the price of (residential) solar panels around here (roughly € 1k-3k, depending on size and qualit

by tremon 6y ago

How much did that installation cost you, if I may ask? I know the price of (residential) solar panels around here (roughly € 1k-3k, depending on size and quality), but have no idea what the battery costs would be.

katmannthree 6y ago
Depends on your usage and how long you want the batteries to last, generally anywhere from ~5k USD for a day's worth of backup power (using average-ish USA residential consumption, adjust accordingly) to 75k USD for a week (assuming you're using quality LiFePO4 cells with a good BMS).
ed25519FUUU 6y ago
I bought a sol-ark inverter so I could DIY the battery. The inverter can be both a bms and charge controller so it saves on additional hardware. I can hook LFP up to it (current system) or in the winter use flooded lead acid. The goal was a minimum battery necessary to use the solar power during the day (solar systems typically need a battery in order to produce power without the grid)
Loughla 6y ago
We just had solar and battery backup bank quoted for our home (November/December 2020). For enough power to run the fridge, freezer, AC intermittently, and charge/power for electronics (1 laptop, 2 phones), the cost of batteries for up to 1 week's supply was ~65k USD. We simply could not afford that. (subsequently, the solar to offset our ~200/mo power bill was ~65k on its own. Just outrageously expensive).
- ed25519FUUU 6y ago
  You need more quotes. Though with a $200 month bill the payoff should be quick. It takes a lot of amps for that equipment and not a lot of “off the shelf” inverters will support those types of batteries. If all you want is to keep your freezers running during an extended outage (Texas situation) consider the Sunny Boy inverters by SMA. Each one has a 2 kWh outlet that can be used without a battery or the grid. Your freezers will run during the day while there’s solar, at night leave them closed.
  - jononor 6y ago
    > Though with a $200 month bill the payoff should be quick For a 65k expense, and 200 a month saving, that is like 27 years to break-even? How do you get it to be "quick"?
    - ed25519FUUU 6y ago
      To clarify, I'm recommending you skip the battery and use something like a Sunny Boy w/ 2 kWh convenience plug. Depending on your electricity costs and whether or not your utility supports net metering, you should be able to build a system at a fraction of that cost ($20k before federal credits) to generate your power.
- quickthrowman 6y ago
  You could buy a Generac generator (either NG or diesel) and have a contractor install it for about a tenth of that price. With diesel, you could have a storage tank, NG you’d be relying on the utility to maintain service (don’t do this in TX for obvious reasons). A 120/240 genset that puts out 100A should easily power a fridge, freezer, 15A outlet, and a/c compressor/furnace fan. Hell, for $65k you could buy a brand new F150 with the 7.2kW generator onboard and install a manual transfer switch and emergency panelboard, and then manually cutover the power yourself by running the truck and flipping the transfer switch. Doesn’t help with a lack of gasoline though.
- BoiledCabbage 6y ago
  Serious curiosity, what's the use case for a week's worth of backup power? If the grid is up and running, depending on where you live, if the sun isn't out, it seems like a two days backup would be enough to keep you off the grid most of the time. Assuming there is a blackout, what's the likelihood it will last one week? And would you still need to maintain your normal electricity consumption during a week long blackout in your area? Wouldn't you be able to scale back? I've never looked into this, but I'm curious what are the scenarios people are planning/preparing for when looking at solar and battery backups?
  - Loughla 6y ago
    So I live in a pretty rural area in the US (closest town (population 600) is ~30-45 minutes away, closest 'city' (population 40k or so is even further). We lose power when it's windy, sunny, rainy, stormy, or just because it's Tuesday. Often, it takes them 3-4 days to figure it out. That happens 2-3 times a year, at a minimum. The worst was two years ago - we went about 6 weeks total all year without power. We have a lot of meat and produce in the freezers. It makes me uncomfortable to have that much food without a backup.

by tremon 6y ago

katmannthree 6y ago

Depends on your usage and how long you want the batteries to last, generally anywhere from ~5k USD for a day's worth of backup power (using average-ish USA residential consumption, adjust accordingly) to 75k USD for a week (assuming you're using quality LiFePO4 cells with a good BMS).

ed25519FUUU 6y ago

I bought a sol-ark inverter so I could DIY the battery. The inverter can be both a bms and charge controller so it saves on additional hardware. I can hook LFP up to it (current system) or in the winter use flooded lead acid. The goal was a minimum battery necessary to use the solar power during the day (solar systems typically need a battery in order to produce power without the grid)

Loughla 6y ago

We just had solar and battery backup bank quoted for our home (November/December 2020). For enough power to run the fridge, freezer, AC intermittently, and charge/power for electronics (1 laptop, 2 phones), the cost of batteries for up to 1 week's supply was ~65k USD. We simply could not afford that. (subsequently, the solar to offset our ~200/mo power bill was ~65k on its own. Just outrageously expensive).

ed25519FUUU 6y ago
You need more quotes. Though with a $200 month bill the payoff should be quick. It takes a lot of amps for that equipment and not a lot of “off the shelf” inverters will support those types of batteries. If all you want is to keep your freezers running during an extended outage (Texas situation) consider the Sunny Boy inverters by SMA. Each one has a 2 kWh outlet that can be used without a battery or the grid. Your freezers will run during the day while there’s solar, at night leave them closed.
- jononor 6y ago
  > Though with a $200 month bill the payoff should be quick For a 65k expense, and 200 a month saving, that is like 27 years to break-even? How do you get it to be "quick"?
  - ed25519FUUU 6y ago
    To clarify, I'm recommending you skip the battery and use something like a Sunny Boy w/ 2 kWh convenience plug. Depending on your electricity costs and whether or not your utility supports net metering, you should be able to build a system at a fraction of that cost ($20k before federal credits) to generate your power.
quickthrowman 6y ago
You could buy a Generac generator (either NG or diesel) and have a contractor install it for about a tenth of that price. With diesel, you could have a storage tank, NG you’d be relying on the utility to maintain service (don’t do this in TX for obvious reasons). A 120/240 genset that puts out 100A should easily power a fridge, freezer, 15A outlet, and a/c compressor/furnace fan. Hell, for $65k you could buy a brand new F150 with the 7.2kW generator onboard and install a manual transfer switch and emergency panelboard, and then manually cutover the power yourself by running the truck and flipping the transfer switch. Doesn’t help with a lack of gasoline though.
BoiledCabbage 6y ago
Serious curiosity, what's the use case for a week's worth of backup power? If the grid is up and running, depending on where you live, if the sun isn't out, it seems like a two days backup would be enough to keep you off the grid most of the time. Assuming there is a blackout, what's the likelihood it will last one week? And would you still need to maintain your normal electricity consumption during a week long blackout in your area? Wouldn't you be able to scale back? I've never looked into this, but I'm curious what are the scenarios people are planning/preparing for when looking at solar and battery backups?
- Loughla 6y ago
  So I live in a pretty rural area in the US (closest town (population 600) is ~30-45 minutes away, closest 'city' (population 40k or so is even further). We lose power when it's windy, sunny, rainy, stormy, or just because it's Tuesday. Often, it takes them 3-4 days to figure it out. That happens 2-3 times a year, at a minimum. The worst was two years ago - we went about 6 weeks total all year without power. We have a lot of meat and produce in the freezers. It makes me uncomfortable to have that much food without a backup.