Power Wall Pricing

[jaydee325]

Enphase

 

[cqaigy2]

Thanks for the write up Peter.

Not gonna lie, the powerwall looks pretty cool, but ning's type of system is more like something that would interest me. I looked at something like Snobdds shows, the Bluetti and there are a bunch of similar systems out there, even some homemade ones. It doesn't pencil out for me, but i wouldn't be ad versed to something a bit quieter, for when the power goes out.

 

[ponytug]

Thanks for the write up Peter.

Not gonna lie, the powerwall looks pretty cool, but ning's type of system is more like something that would interest me. I looked at something like Snobdds shows, the Bluetti and there are a bunch of similar systems out there, even some homemade ones. It doesn't pencil out for me, but i wouldn't be ad versed to something a bit quieter, for when the power goes out.

I hear you. (Sorry, couldn't resist.)

I think what ning has done is really impressive. Locally, solar and batteries seem to have become something of a third rail with inspectors, which makes it even harder. Did I say how impressed I am with what ning has done? :thumbsup::thumbsup:

I thought long and hard about the Enphase batteries. I like the modular design, the battery chemistry, and the plan to be generator integrated. Unfortunately for me, they were much more expensive due to the ins and outs of the incentives. They don't currently have very many hours on the systems relatively speaking. (That old MTBF thing) If they had been the same price I would have considered them, but they weren't in my budget by a lot. So whatever my generator integration turns out to be, it is almost guaranteed not to be anywhere near as nice.

I have Enphase micro inverters on my solar which I love, and they just work, but the initial Enphase microinverters had a decidedly rocky start from the reliability perspective and I wasn't willing to pay more for an Enphase battery with less of a track record than the Tesla Powerwalls.

At the end of the day, I think that the batteries are a utility, or should be. How often do you stand around and watch your utility meter spin or change numbers? Exactly. Battery backup should be boring, something that you never really think about for a couple of decades.

The trend seems pretty clear that as more electric vehicles are recycled, there will be many more options for repurposed vehicle batteries, adding to the options for household battery backup. All of which will help lower the cost, and with more users, the weak links will get fixed until it is just power.

There certainly seem to be lots of places that could be considering batteries for reliability reasons these days...

Stay safe!

All the best,

Peter

 

[user.69169]

Comes to mind dis game been bein played since around 83 when wellhead gas and co-gen got real popular and Herb Tarlocks ran wild. Lot of Co-gen & peak shaving plants went in, and users were happy till electric bill came next month with unused capacity in place charge. Den price of #2 diesel went over 85¢ a gallon and sales potential went down drain.

Lithium battery is wonderful, BUT anybody find plane splashed down in Everglades yet? Local AHJ all nervous cause dey read articles about battery bunker fire 2-3 years back. Nobody knew how to stop fire, solid concrete bunker self destructed and fire kept burning. Pretty much all batterys like steam locomotives, self destructing over time. What de plan fer used batterys?

 

[ponytug]

Well, lithium batteries are quite valuable and there are many companies that recycle them. There are lots of companies that repair and recycle battery packs, ranging from hand tools to computers to cars. The market is already there. For lithium battery fires, I believe that the routine is to kill the grid power and use water.

Cogen still works, but it depends on where you are and what you are using for fuel, and what you can do with the non-electrical energy. A large school near us uses cogen to generate their power and uses the heat to run absorption chillers that cool water for AC and heat water for hot water uses. In the first version of it, they had an underground cavern for making the ice in for chilled water. Around here, commercial power runs $0.20-$0.50/kWh, so cogen economics tends to pencil out easily, except for the pollution control bits. So the projects tend to be big, rather than small.

I wouldn't recommend shooting your own battery pack, or propane tank, oil tank, or steam locomotive...there are lots of things with large amounts of stored energy in them that I would recommend not messing with, but that doesn't mean that they aren't useful. Since I want to live a long time, I have found it useful to assume that anything with stored energy is loaded; gas tanks, batteries, capacitors, welders, guns...not surprises that I like.

All the best,

Peter

 

[beowulf]

We have had solar for a couple of years. If our power goes out we have a generator for the critical issues (fridge, freezer) and it also works well for tv and satellite. I installed a generator thru-the-wall kit to make it all convenient. What we will not have, however, is water as we are on a well. I have sketched out a couple of ways to configure power to the well with the generator but am still a bit nervous about the surges and such. So, because of the well issue I talked at length with a power wall vendor at a home show. He said the wall would not work with a well pump due to the start up draw - it could run the pump but could not start it. Anyway, I don't know if that is true, but, hey, he was trying to sell power walls.

 

[user.69169]

Phrase "have a well" keep poppin up in dese discussions. Really insufficient to gain information needed to make decision on backup power.

I got 2 wells, one 42 foot and one 3 foot called sump pump. Sump pump harder to start den 42 foot level capacitor start pump 3 times horsepower. Sump pump real hog because not capacitor start.

Power wall interesting concept, looks like 3 piece system of power in either solar or PoCo, battery & inverter. All pretty simple. Lookin at available literature looks like Tesla writers and editors spent whole lot more time hiding information den providing. Pretty normal fer hustlers, generally causes me to walk away.
Questions like what is voltage of battery going to inverter, and what is efficiency of inverter, and what is efficiency of delivery PoCo to outlet should be available. Don't smell right to my nose. Too much Tesla name, too little beef.

 

[user.69169]

Pony, trust me, battery fire wid lithium battery is gateway to He!!. Disconnect incoming power means nothing cause battery still providing power to itself in meltdown. Battery in meltdown lot like Acetylene, provides all it needs to sustain fire. Water becomes steam fast and some of fire becomes steam atomized. Gonna burn till runs out of fuel and burn hot enough to disassemble concrete like exothermic bar does.

Only thing can be done is back off and use monitors to protect surrounding.

 

[ning]

We have had solar for a couple of years. If our power goes out we have a generator for the critical issues (fridge, freezer) and it also works well for tv and satellite. I installed a generator thru-the-wall kit to make it all convenient. What we will not have, however, is water as we are on a well. I have sketched out a couple of ways to configure power to the well with the generator but am still a bit nervous about the surges and such. So, because of the well issue I talked at length with a power wall vendor at a home show. He said the wall would not work with a well pump due to the start up draw - it could run the pump but could not start it. Anyway, I don't know if that is true, but, hey, he was trying to sell power walls.

Before the battery system, I used a 3.5kW generator to power two fridges, a freezer, and our well.

It worked fine as long as the well didn't start up hahaha

Basically when the well starts, the generator breaker would pop, and I'd disconnect the fridges and freezer and then let the well run (and go flush any toilets that were let go with just #1) for a bit, then I'd start one fridge, then another, then the freezer... because all of these pull extra to start up.

The PW2 has a peak discharge rate of 7kW and 5kW continuous. I'm sure that would run my pump (¾hp) considering my 3.5kW generator manages (mostly).

The PW1 only has 3.3kW discharge (both peak and continuous) so I doubt one of those would run a ¾hp pump; maybe a ½hp?

 

[ning]

Attached is a diagram of yesterday's production & use in my system. The day was partly cloudy, and being still winter-ish, the solar day isn't as long as it will be later in the year (and the sun isn't at as good of an incident angle to the array).

Key -
Blue: solar production (always positive)
Black: grid power (above the axis = importing from grid, below = exporting)
Green: battery (above = discharge, below = charge) I'm pretty sure the app has a bug because the "charge" is always a lot more than the "discharge", more than makes sense for storage losses.
Orange: home use (always negative)

The system is set for "savings mode" so it will use batteries for house loads during "peak pricing" and then charge them off-peak. (It's set to only allow discharge to 40% right now.)

You can see the 220v hot tub fire up at about 5pm.