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Aside from their cars, I really wished they released a low cost 1-2kWh powerwall. I would love to have a power bank without buying all the bulky AGM batteries a

Aside from their cars, I really wished they released a low cost 1-2kWh powerwall. I would love to have a power bank without buying all the bulky AGM batteries and capable to charge with <400W of solar panel capacity for emergency purposes.

dev_dull 8y ago
Do you want it hooked up to the grid? Otherwise that’s fun DIY project with 18650 batteries.
- syntaxing 8y ago
  Yeah, I saw on YouTube that some guy was trying to build their own power wall. Do you have suggestion for a good tutorial? The thing I like the most about the power wall is the power transition. The moment the power kicks out, the power wall kicks in.
  - dev_dull 8y ago
    Agree! One of he better selling points especially over things like a genny. For that you’ll need a professional. It’s really dangerous (and illegal?) if your system backfeeds the grid.
- ant6n 8y ago
  Sounds like an incredible time sink and a fire hazard, for not that much of a benefit. Sometimes it's just easier to go into a store and buy something.
  - syntaxing 8y ago
    Yeah, that's the downside of DIY. 2kWh of power is alot of energy to release.
    - ant6n 8y ago
      I hear the total chemical energy hound in batteries is much higher than the usable capacity.
      - dev_dull 8y ago
        I wouldn’t ever want to be on the receiving end of a lithium fire. I’m pretty sure it would melt the side of my house off.
- retSava 8y ago
  Also a potentially sparking invitation to the fire department for a visit! Working with lithium batteries is not to be performed without lots and lots of caution. The amount of energy in such cells that can be delivered, in a very surprising manner that is guaranteed to catch attention, is dangerous to say the least. And that's just from a single cell, a failing bank of cells is guaranteed to be a great conversation starter! I'm sure there are those that can safely work with the stuff, but I'd not bet the house and family on it. Play safe! (okok, enough with the puns now)
driverdan 8y ago
Build your own. At that size it wouldn't be hard. You could use large LiFePO4 cells to save time at a slightly increased cost. For $500 you can have a 1.4kWh bank of 100A cells. Or you can buy used electric car packs for less per kWh. Keep in mind something that small is not capable of running a whole house. You'd drain them very quickly, especially with HVAC running.
- syntaxing 8y ago
  1.4 kWh sounds perfect for me. I just need enough to keep the essentials up without setting up the generator. Any recommendations where I can get some of the parts you are talking about?
  - driverdan 8y ago
    Search for CALB 100Ah LiFePO4. There are other manufacturers too. They're about $125/cell.
blacksmith_tb 8y ago
I would happily go for one, if the current 13.5kWh costs $5,900 (plus $700 'supporting hardware') you'd think they could do something like you're asking for in the $1K range. I imagine they don't because they assume people are using so much power in their homes that a pack like that would only keep things on for a couple of hours. Of course, it sounds like the cost of the cells is a very small part of the price, some of which is the inverter and cooling, some of which is recovering R&D costs, but you'd think their profit must still be significant... ($6,600 installed, of which ~ $1,350 is battery, apparently).
- syntaxing 8y ago
  Yeah, the sub-1K would be a resonable price point. A lot of place (including where I live) does not have peak metering. Essentially it will take over 20 years for me to breakeven for the power bank which really does not make sense at a financial point of view. I think a lot of people would want a 2 kWh battery hooked up to their existing solar setup just for emergency purposes. I live on the east coast and it would be perfect for the essentials. Just enough to keep the boiler going for hot water and a couple lights until the power comes back up. We get these short term blackouts (especially during snow storms) which is just long enough to be annoying (like 2-3 hrs) but not long enough to make bringing out the generator worthwhile.
hinkley 8y ago
I haven’t looked at UPSes in a while and their ratings are, I see, still essentially a lot of horseshit. Sifting through the impressive sounding numbers, it looks like you can buy an online UPS with about a tenth of the KWh capacity of a powerwall for about the same price. Now I want Tesla to build online UPSes...

dev_dull 8y ago

Do you want it hooked up to the grid? Otherwise that’s fun DIY project with 18650 batteries.

syntaxing 8y ago
Yeah, I saw on YouTube that some guy was trying to build their own power wall. Do you have suggestion for a good tutorial? The thing I like the most about the power wall is the power transition. The moment the power kicks out, the power wall kicks in.
- dev_dull 8y ago
  Agree! One of he better selling points especially over things like a genny. For that you’ll need a professional. It’s really dangerous (and illegal?) if your system backfeeds the grid.
ant6n 8y ago
Sounds like an incredible time sink and a fire hazard, for not that much of a benefit. Sometimes it's just easier to go into a store and buy something.
- syntaxing 8y ago
  Yeah, that's the downside of DIY. 2kWh of power is alot of energy to release.
  - ant6n 8y ago
    I hear the total chemical energy hound in batteries is much higher than the usable capacity.
    - dev_dull 8y ago
      I wouldn’t ever want to be on the receiving end of a lithium fire. I’m pretty sure it would melt the side of my house off.
retSava 8y ago
Also a potentially sparking invitation to the fire department for a visit! Working with lithium batteries is not to be performed without lots and lots of caution. The amount of energy in such cells that can be delivered, in a very surprising manner that is guaranteed to catch attention, is dangerous to say the least. And that's just from a single cell, a failing bank of cells is guaranteed to be a great conversation starter! I'm sure there are those that can safely work with the stuff, but I'd not bet the house and family on it. Play safe! (okok, enough with the puns now)

driverdan 8y ago

Build your own. At that size it wouldn't be hard. You could use large LiFePO4 cells to save time at a slightly increased cost. For $500 you can have a 1.4kWh bank of 100A cells. Or you can buy used electric car packs for less per kWh. Keep in mind something that small is not capable of running a whole house. You'd drain them very quickly, especially with HVAC running.

syntaxing 8y ago
1.4 kWh sounds perfect for me. I just need enough to keep the essentials up without setting up the generator. Any recommendations where I can get some of the parts you are talking about?
- driverdan 8y ago
  Search for CALB 100Ah LiFePO4. There are other manufacturers too. They're about $125/cell.

blacksmith_tb 8y ago

I would happily go for one, if the current 13.5kWh costs $5,900 (plus $700 'supporting hardware') you'd think they could do something like you're asking for in the $1K range. I imagine they don't because they assume people are using so much power in their homes that a pack like that would only keep things on for a couple of hours. Of course, it sounds like the cost of the cells is a very small part of the price, some of which is the inverter and cooling, some of which is recovering R&D costs, but you'd think their profit must still be significant... ($6,600 installed, of which ~ $1,350 is battery, apparently).

syntaxing 8y ago
Yeah, the sub-1K would be a resonable price point. A lot of place (including where I live) does not have peak metering. Essentially it will take over 20 years for me to breakeven for the power bank which really does not make sense at a financial point of view. I think a lot of people would want a 2 kWh battery hooked up to their existing solar setup just for emergency purposes. I live on the east coast and it would be perfect for the essentials. Just enough to keep the boiler going for hot water and a couple lights until the power comes back up. We get these short term blackouts (especially during snow storms) which is just long enough to be annoying (like 2-3 hrs) but not long enough to make bringing out the generator worthwhile.

hinkley 8y ago

I haven’t looked at UPSes in a while and their ratings are, I see, still essentially a lot of horseshit. Sifting through the impressive sounding numbers, it looks like you can buy an online UPS with about a tenth of the KWh capacity of a powerwall for about the same price. Now I want Tesla to build online UPSes...