4 ms·

The 3 to 5x difference between those cells and commercial offerings make me hopeful we'll see the market for home batteries take off relatively soon. LFP are id

The 3 to 5x difference between those cells and commercial offerings make me hopeful we'll see the market for home batteries take off relatively soon. LFP are ideal for the application and are already cheap. With the cost of rooftop solar continuing to dive, getting a house to be much more energy independent, or even fully off-grid will become almost easy in the next 5 years.

guerby 6y ago
For a long time LFP prices stayed at $200-$300/kWh but mid-2020 new vendors with $100-$150/kWh delivered appeared. I don't know the story behind these cells but so far no bad experience reported on youtube or forums. Here is one of the first buyer who just measured his pack after 6 month of use: https://diysolarforum.com/threads/eve-280ah-6-months-later.16863/ https://diysolarforum.com/threads/eve-280ah-6-months-later.1...
guerby 6y ago
Before electric cars it was hard to really use solar PV produced energy. But with one or two electric cars and the appropriate amount of battery you'll get way higher PV production use by just charging after work and week-ends. If my 14 kWh pack does 4000 full cycles that's 56 MWh so 0.03 USD/kWh out of the battery. $600-700 for a 5kW hybrid inverter (stackable) PV panels are about $0.4/Wpeak and depending on location, in France 1 Wp will produce about 1kWh/year. Which brings price under $0.10/kWh for a DIY solar + battery system of 4 kWp PV and 14 kWh battery.
- pedrocr 6y ago
  Not sure what you mean by needing an EV to use the energy. With an A/C system you can heat and cool the house with electricity efficiently. Since that works even if your car is away with you at work the battery size is reduced making that load a better business case. The same for heating water, which is a cheap battery in itself. If anything EVs seem particularly unsuited for home solar because the solar panels should instead be wherever the car spends its day so the car battery can be charged directly instead of needing another battery to buffer the energy for it.
  - guerby 6y ago
    In France you don't need heating/cooling for most of the year with a moderately insulated house. Thats's why electric car charging changes the equation. And about no heating/cooling at all with a Passive House :). I agree about charging during the day when the sun shine is way better but it's under the control of your employer which may or may not provide chargers, and might not install solar PV at all for various reasons. PV and battery at home, you can do it right now.
- throwaway81523 6y ago
  Tesla apparently voids your battery warranty if you use the car as a stationary power source. That's mentioned in tiny print in the warranty documentation someplace. I haven't seen this myself, but people mentioned it during the recent Texas blackout where many people had the idea of using a BEV as a battery bank.

guerby 6y ago

For a long time LFP prices stayed at $200-$300/kWh but mid-2020 new vendors with $100-$150/kWh delivered appeared. I don't know the story behind these cells but so far no bad experience reported on youtube or forums. Here is one of the first buyer who just measured his pack after 6 month of use: https://diysolarforum.com/threads/eve-280ah-6-months-later.16863/ https://diysolarforum.com/threads/eve-280ah-6-months-later.1...

guerby 6y ago

Before electric cars it was hard to really use solar PV produced energy. But with one or two electric cars and the appropriate amount of battery you'll get way higher PV production use by just charging after work and week-ends. If my 14 kWh pack does 4000 full cycles that's 56 MWh so 0.03 USD/kWh out of the battery. $600-700 for a 5kW hybrid inverter (stackable) PV panels are about $0.4/Wpeak and depending on location, in France 1 Wp will produce about 1kWh/year. Which brings price under $0.10/kWh for a DIY solar + battery system of 4 kWp PV and 14 kWh battery.

pedrocr 6y ago
Not sure what you mean by needing an EV to use the energy. With an A/C system you can heat and cool the house with electricity efficiently. Since that works even if your car is away with you at work the battery size is reduced making that load a better business case. The same for heating water, which is a cheap battery in itself. If anything EVs seem particularly unsuited for home solar because the solar panels should instead be wherever the car spends its day so the car battery can be charged directly instead of needing another battery to buffer the energy for it.
- guerby 6y ago
  In France you don't need heating/cooling for most of the year with a moderately insulated house. Thats's why electric car charging changes the equation. And about no heating/cooling at all with a Passive House :). I agree about charging during the day when the sun shine is way better but it's under the control of your employer which may or may not provide chargers, and might not install solar PV at all for various reasons. PV and battery at home, you can do it right now.
throwaway81523 6y ago
Tesla apparently voids your battery warranty if you use the car as a stationary power source. That's mentioned in tiny print in the warranty documentation someplace. I haven't seen this myself, but people mentioned it during the recent Texas blackout where many people had the idea of using a BEV as a battery bank.