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by pchew
162 days ago
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Yes, 48 amps at 240 is 11.5kw. Each Powerwall 3 is 11.5kw(edit: not to be confused with its capacity which is 13.5 kwh, one is a power output, one is a storage capacity. Just so you don't go thinking that's some amazing mixup between the comments). The original comment is all within your framework of 3 Powerwalls vs one EG4 18K with 3 batteries. That's 12kw AC for the EG4, and 34.5kw on 3 Powerwalls. I've never stated a single powerwall has more output than that(hell I even rounded down on the output of the 3 powerwalls to 34kw), only that they have a very impressive inrush and solar capacity. The incongruity of the comparison between the two systems is the entire origin of this discussion. Do you even remember what you posted and I responded to? You don't know how to use an amp clamp and don't understand the American split phase power grid. Stop consulting ChatGPT for 'gotchas' and actually read what you're writing. Just to be perfectly clear on your continued misunderstanding - each powerwall is also an inverter, it has its own AC power output. That stacks. The batteries strapped to the EG4 are all limited to going through the EG4. That means no increased output for adding more batteries. No stack. With 3 EG4s in the comparison you would have a similar standing load capability(36kw claimed), however you'd still only have roughly 1/3rd the inrush capability(190 amps). Honestly, I thought I started this conversation nicely enough and went out of my way to be informative and you've only tried to insult me and be snide while having the loosest grasp on the subject matter. |
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> The original comment is all within your framework of 3 Powerwalls vs one EG4 18K with 3 batteries. That's 12kw AC for the EG4, and 34.5kw on 3 Powerwalls.
And for the last time, you do not need 34.5kW continuous AC output for a house that is averaging 2 kW per hour per day. Yes, they have two EVs, but also these do not need to charge at their full potential if you plug them in every night. The author isn't generating enough energy from solar of their battery bank so it's pulling from the grid anyway for those loads, so a grid bypass (which EG4 supports up to 200A) means you don't need the inverter to pump out 34.5 kW to loads anyway.
The thing you keep glossing over is that the fundamental problem with a powerwall for scaling systems is that each battery bank you purchase requires you to purchase a built in inverter. The same nearly identical system from EG4 is an 18k + 15 kWh battery which costs $8k, and powerwalls cost $12k+. Thats a 50% premium to get you 185 LRA but 8 kWh less capacity. For an extra $250 you get an AC soft start and a 185 LRA is completed unnecessary and irrelevant.
> Yes, 48 amps at 240 is 11.5kw.
You keep saying these things like I don't understand the math.
> You don't know how to use an amp clamp and don't understand the American split phase power grid.
Lol. And you don't even understand that specifications ratings because they very explicitly say the amps at VAC ratings (120/240) because while it's entirely possible to reach the full potential of wattage... in real life, it's unlikely you will due to how split phase works with inverters. Inverters are rated by amps per leg because your loads on one 120v leg could be higher than the other one (unless all of your loads are 240v in which you would always be using the same amps on both legs).
So to conclude:
1. An identical system is $53k (Powerwall) versus $31k (EG4), which is still hilariously overpriced.
The only measurable differences are:
EG4 gets 6 more continuous AC amps (up to 1.44 kW more)
Powerwall gets much higher surge capacity (555A vs 195A)
EG4 gets 8 kWh more capacity
2. If you need more than 195A surge, you put a soft start in or just let the inverter bypass temporarily to grid.
3. You would never size this system with 3 inverters for someone averaging 48 kWh/day, so the author spent £7k on an additional battery and got an unnecessary inverter purchase which is now directly eating into his ROI.