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Show HN: We built a Plug-in Home Battery for the 99.7% of us without Powerwalls

pilaenergy.com

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Re: Show HN: We built a Plug-in Home Battery for the 99.7% of us without Powerwalls

#101

Post by Nextgrid »

CharlesW wrote: post #54

From your site: "For homes with electricity prices that vary throughout the day, Pila optimizes charging to help manage your utility bills." Based on experiments like https://www.youtube.com/watch?v=jtNq-0kV8YM , I'm extremely skeptical. Can you back this claim? Also, why are people going to spend $1,300 on this when a good UPS is a fraction of the price, and (for example) an Anker SOLIX F3800 Plus is $3,200?

That video's conclusion is misleading - he's only shifting his fridge's energy consumption. That's not actually much in the grand scheme of things - it's a well-insulated box that is already a thermal battery. In fact, he only discharged his power bank to 64% at the end of the day, so he didn't even use up his full capacity (that he paid for and is factored in his spreadsheet).

Batteries can provide significant savings but for that you need to actually use them fully, either by load-shifting significant loads (if you have enough to fully consume the battery capacity), or just charging/discharging the battery directly into the grid (essentially acting like a grid storage system - charging the battery to full when energy is the cheapest, and dumping it back when it's the most profitable). Even better when you have solar - instead of selling that energy at low feed-in prices, save it in batteries and use it once the sun goes down so (if you have enough battery capacity) you never ever need to actually "buy" any energy from the grid.

I believe the Pila can technically do the above, although its battery capacity is probably too small to ever recoup its purchase price on this type of arbitrage. However, the underlying concept is absolutely workable and profitable with the right equipment.

Re: Show HN: We built a Plug-in Home Battery for the 99.7% of us without Powerwalls

#102

Post by tzs »

coleashman wrote: post #37
Kon-Peki wrote: post #35

Earlier quoted context omitted.

I have well water and the pump is 1.5 HP on 230 volts. In a power outage situation I doubt it would run for more than a minute at a time, maybe 4 or 5 times a day.

Often well pumps and sump pumps can be wired for either 230 or 120V, so Pila could be an option with some added effort and a conversation with an electrician. But in any case, looking forward to building the 230/240V version!

What are the environmental requirements for Pila?

My well pump is 120V, but I don't keep it in my house. It's in a shed out back built over the well and tank. The shed is not insulated, but does have a 400W space heater plugged into one of these [1] that tries to keep it above freezing in there. I think most of the time it succeeds but it is possible that for a few days a year it might get below freezing for a while.

I have no idea what the humidity is like, or how hot it can get in the summer.

Would the current Pila be OK in that kind of environment?

[1] https://www.amazon.com/Farm-Innovators-TC-3-Thermostatically...

Re: Show HN: We built a Plug-in Home Battery for the 99.7% of us without Powerwalls

#103

Post by jaggederest »

coleashman wrote: post #70
amluto wrote: post #65

Two questions: 1. Have you considered building a “microgrid interconnection device” to go with this to allow the batteries to backfeed a house in the event of an outage? (This would require native 240V split-phase capability and/or an auto-transformer.) 2. Have you considered removing the fade-in-when-scrolling abomination on your website?

1. I'm actually hopeful we see a generic MID standard emerge with folks like ConnectDER well positioned to support that, so more homes can benefit and households can gain the ability to flexibly try different batteries without ripping out their panels every time. If not, we could definitely build our own (helped build 2 generations of Tesla's MID as well as 3 generations of SPAN Panels with MID functionality). Happy…

MID = Microgrid Interconnect Device ?

DER = Distributed Energy Resource ?

SPAN = an energy device company https://www.span.io/ ?

Just had to check the definition of some acronyms and thought others might find the results helpful inline.

Re: Show HN: We built a Plug-in Home Battery for the 99.7% of us without Powerwalls

#104

Post by rtkwe »

CharlesW wrote: post #54

From your site: "For homes with electricity prices that vary throughout the day, Pila optimizes charging to help manage your utility bills." Based on experiments like https://www.youtube.com/watch?v=jtNq-0kV8YM , I'm extremely skeptical. Can you back this claim? Also, why are people going to spend $1,300 on this when a good UPS is a fraction of the price, and (for example) an Anker SOLIX F3800 Plus is $3,200?

That conclusion all depends on how much extra power the UPS uses while acting as a pass-through. I think the SOLIX doesn't directly pass through the power so it's having the inefficiencies of conversion to and from AC-DC-AC, maybe this version has a more efficient pass-through system?

Re: Show HN: We built a Plug-in Home Battery for the 99.7% of us without Powerwalls

#105

Post by jaggederest »

pedalpete wrote: post #58

I love the design, but I wonder about the "selling feature". How many people regularly experience power outages (ok, if you're American relying on Canadian electricity, you might have a right to be concerned). I'm surprised you're not touting the "save on your power bill" benefits. Could this not store power when rates are low, and use the battery when rates are higher, while maintaining a balanced minimum storage am…

> How many people regularly experience power outages

Anecdotally in a major city it was rare I would not have a power outage several times a year. In a more rural location now, it's rare I have a month without a power outage, some very extended.

We have a backup generator and it has saved our frozen foods at least a dozen times over the last few years. Installing a backup generator costs about $10k for a whole house permanently installed unit, so it's not a small cost, and the running and maintenance costs are not zero ($5 an hour when running, $100+ a year for parts and consumables)

Re: Show HN: We built a Plug-in Home Battery for the 99.7% of us without Powerwalls

#106

Post by luis_cho »

vasco wrote: post #96

Pila means cock (as in dick) in Portuguese and this whole post and website are hilarious. Dick energy. I'm holding off tears. Definitely wouldn't recommend plugging in your pila into any outlet.

One time set-up: 1- Plug Pila in :D

Re: Show HN: We built a Plug-in Home Battery for the 99.7% of us without Powerwalls

#107

Post by thousand_nights »

pedalpete wrote: post #58

I love the design, but I wonder about the "selling feature". How many people regularly experience power outages (ok, if you're American relying on Canadian electricity, you might have a right to be concerned). I'm surprised you're not touting the "save on your power bill" benefits. Could this not store power when rates are low, and use the battery when rates are higher, while maintaining a balanced minimum storage am…

yeah it looks like a fancy tech gadget marketed to people in developed countries where you have like one power cut every 2 years

Re: Show HN: We built a Plug-in Home Battery for the 99.7% of us without Powerwalls

#108

Post by robomartin »

I have two questions:

How are you funded?

Hardware products are capital intensive. The cost of inventory alone can be a killer. The problem with buying a product like this is that an underfunded company can go "poof" inside of a year by quickly getting over its skis and gasping for air (money). And, of course, warranties are only as good as the life of the company.

How much/how was it tested?

Managing power can be dangerous. I get that your experience telegraphs that you are more than qualified for the task. However, established companies invest a non trivial amount of money into products in order to, among other things, ensure they are safe when manufactured and deployed at scale. Heavy abuse with environmental chambers, EMC emissions and susceptibility, as well as corner cases (fridge compressor over-current event, SMPS on a computer exceeding startup currents, etc.) are examples of this. This kind of testing isn't trivial, can take a long time and cost a lot of money. BTW, just going through UL, CE, TUV, etc. testing isn't equivalent to a solid testing program.

EDIT: Sorry, one more question.

What's the power-in/power-out efficiency?

Not through the inverter, but in the power-in -> charge-battery -> battery-power-out cycle.

This alone could negate savings. If each side is ~80%, the plug-to-plug (through the battery) efficiency is only 64%, which means you consume much more energy to deliver the same outcome.

Re: Show HN: We built a Plug-in Home Battery for the 99.7% of us without Powerwalls

#110

Post by Nextgrid »

pandemicsyn wrote: post #44

> no bidirectional power, no integration with solar or smart home systems, and no ability to manage home energy dynamically. They tend to be boxy, ruggedized, meant to be moved around, not seamlessly integrated into your living space. On top of that, many use e-mobility battery chemistries, which are great for delivering high power on demand but wear out faster when cycled daily for home energy use. I already use an…

> Is the main difference between an Ecoflow and this basically the form factor?

The form factor and the potential rugpull in the future when this turns into a subscription and/or a "virtual power plant" where you get the homeowners to pay for the device while the manufacturers sells the aggregated capacity to source/sink power to the highest bidder and keeps the profits. There's a reason these have built-in cellular; you don't put that in (and pay the ongoing data charges) without one.

This thing is too "nice" and polished for its price point, so profits will have to come from somewhere down the line (because they're definitely not making any on the actual device sales).

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