5 ms·

The Tesla powerwall is 13.7 kWh. I would bet this will be priced better per kWh because there's less of a status symbol to it, but 8.7 is a lot smaller.

epistasis 4y ago
A bit smaller is probably good for right-sizing the install. The option to put 2-4 on a larger house is great.
toast0 4y ago
Hard to know from this PR, but I'd assume you can get two or more of these if you need more storage or more output. IIRC, Tesla does 1-3 powerwall units in their standard sales process? Storage capacity needs will vary based on the use, but over an hour of use seems like it would take care of a lot of people's needs in my seat of the pants estimate. And for many of those that don't have their needs met with 8.7kWh, 13.7kWh isn't going to do it either.
- vwoolf 4y ago
  I was just talking to a relation about this, and he said Tesla's guy said he needs two Powerwalls to replace a generator in the event of power interruption. Is that true, or a sales guy thing? I'm not sure and haven't investigated.
  - toast0 4y ago
    It depends on your relation's power usage, I'd imagine. I believe the spec is 5.5kW max output, which is probably insufficient if you've got any sort of large load. My well pump is rated for 30A @ 220V, so startup would likely overwhelm a single powerwall, and I think my air conditioners have similar startup needs (and I've got multiple units); we managed to trip the overcurrent protection on our 35 kW whole house generator during one of our early outages (it's unfortunately not connected to the well pump, overcurrent was just from using multiple heat pumps and washing/drying clothes; dryer heat is from propane. We had a nearly 3 day outage our first winter. However, at my previous house, I didn't have any substantial electric loads, other than an electric water heater in an underused ADU, so 5.5kW would have been likely been fine, and our typical energy use was around 1kW, so we would have had several hours for service to be restored, which fit within the experienced outages.

epistasis 4y ago

A bit smaller is probably good for right-sizing the install. The option to put 2-4 on a larger house is great.

toast0 4y ago

Hard to know from this PR, but I'd assume you can get two or more of these if you need more storage or more output. IIRC, Tesla does 1-3 powerwall units in their standard sales process? Storage capacity needs will vary based on the use, but over an hour of use seems like it would take care of a lot of people's needs in my seat of the pants estimate. And for many of those that don't have their needs met with 8.7kWh, 13.7kWh isn't going to do it either.

vwoolf 4y ago
I was just talking to a relation about this, and he said Tesla's guy said he needs two Powerwalls to replace a generator in the event of power interruption. Is that true, or a sales guy thing? I'm not sure and haven't investigated.
- toast0 4y ago
  It depends on your relation's power usage, I'd imagine. I believe the spec is 5.5kW max output, which is probably insufficient if you've got any sort of large load. My well pump is rated for 30A @ 220V, so startup would likely overwhelm a single powerwall, and I think my air conditioners have similar startup needs (and I've got multiple units); we managed to trip the overcurrent protection on our 35 kW whole house generator during one of our early outages (it's unfortunately not connected to the well pump, overcurrent was just from using multiple heat pumps and washing/drying clothes; dryer heat is from propane. We had a nearly 3 day outage our first winter. However, at my previous house, I didn't have any substantial electric loads, other than an electric water heater in an underused ADU, so 5.5kW would have been likely been fine, and our typical energy use was around 1kW, so we would have had several hours for service to be restored, which fit within the experienced outages.