Solar Battery Frenzy

We’re partying like rock stars at EVTV.

The jist of our mirth revolves around making LARGE batteries out of Tesla Model S Battery Modules and using AC coupling from grid-interactive inverters to harvest sunshine into the batteries.

This was widely reported as impossible. And it turns out it is not only possible, but very nearly inescapable. Indeed our primary issue of the moment is to get them to QUIT charging our batteries in controlled fashion

In this episode, we hardwire our Powersafe100 battery/inverter/charger system into our shop power distribution system. A kind of pricey and physically large power switch let’s us quickly switch between running on grid power to running entirely on the Powersafe100 with zero possibility of getting confused about all that or hooking them up to each other with potentially disastrous consequences.

The main thrust of all of this is to address the 97% of residential solar power installations that have no energy storage capability at all.  The model that has emerged is to use grid-interactive inverters, and increasingly microinverters, to convert the photovoltaic panel output directly into 240vac power.

These microinverters are not only a famously good idea, but we look for this to quickly morph into ACM’s – AC photovoltaic modules, where the microinverter becomes an integral part of the photovoltaic panel itself.  Within a year, mayhaps two, you will no longer have to wire up microinverters and panels.  The panels will simply put out 240vac instead of the DC voltages you may be accustomed to.

This will dramatically ease installation issues.  Solar panels will be just like wiring in an electric dryer or stove.  Using normal house wiring, you’ll connect them into a circuit breaker in an existing loads panel.  Perhaps a manual disconnect switch to comply with code requirements.

But as thousands of Californians learned the hard way during the recent storm of wildfires, having solar on your roof does not imply power to your smart phone. These installations are ENTIRELY inoperative on loss of grid power.  For the unschooled, it can be quite a shock to learn your perfectly operational $70,000 solar roof is TOTALLY useless if you lose grid power.

The issue of course is anti-islanding requirements that the utility companies have insisted on that prevent solar installations from making power when the grid goes down.  A 240vac 60Hz grid power signal MUST be present for the grid-interactive inverters to “synchronize” with in voltage, phase, and frequency. This is a totally fraudulent control scam by the utilities and entirely unnecessary.  We’ve had automatic disconnect switches to protect the grid for over 20 years, accomplishing every safety requirement BETTER than the UL1741 requirements for the grid-tie inverters.

But the next phase of utility grid deeply evil behavior is already underway.  That is to extend peak demand charges to residential customers as they have so profitably with their commercial and industrial accounts.  Make no mistake, this is driven SOLELY by greed.  They make more money using demand charges.  And the subscribers bill goes UP in ALL cases.

They have successfully done this in mandatory fashion in Massachusettes for residential customers beginning in January 2018 and it is oddly an “option” in Arizona and Colorado now.  But it is a forced option.  If you have a net metering agreement, you will find your were automatically signed up for it there.

And there is a nationwide epidemic of grid operator “consultants” advising them on how to unctiously phrase “the narrative” to public utility commissions and the public to achieve acceptance.

One of the most Machievellian elements of this is the preposterous claim that those with solar panels on their roof are stealing from the other subscribers by producing their own electric power.  This results in a “cross subsidy” where other ratepayers must pay more per kWh because the solar guys are using their fair share and helping to support the company.  They actually refer to people who have spent tens of thousands of dollars to help produce electricity in a sustainable and clean fashion as “free riders”.

Kind of causes just a little taste of vomit in the back of my throat.  What kind of person arises each AM to shave and charge off to make a living, effectively devoting their life to crap they know to be fraudulent and evil.  Stop for lunch, and then do more of it in the afternoon. 

In any event, peak demand charges work like this.  You pay a LOWER rate per kWh of electricity, but then an enormous rate based on your highest 15 minutes of use in the month.  So it’s like $15 per kW for any period of more than 15 minutes where  you use more than 5kW,  plus $10 per kw for distribution.  Then your regular monthly duties based on kWh.

In this way, those who use little in total kWh can be sacked for using the grid at all – effectively erasing any economic advantage from installing residential solar at all.

Make no mistake, these peak demand charges are coming to a theater near you.  Like your home.

I had warned of a future war with the grid utilities as early as 2009/2010.  Everyone laughed then.  The electric grid was “friend” to electric vehicles at that point, sponsoring pilot programs and so forth.  Well the war is on, and they are hoping enough of you are blissfully unaware long enough for it to be won before you know you’ve been had.

Ergo my vision of “selfish solar” where you use the grid rarely, and by slowly trickle charging batteries that then power the residence.  It is innately “peak shaving” in design and implementation.

Because of the immense variation in solar incidence, both by weather and by season, it is difficult and expensive to build a residential power system that can be entirely off grid.  And if you could, in most municipalities you would find it illegal to occupy the premises if you did so.

But using remaindered lithium batteries from salvaged/wrecked EV’s, we could reduce the impact of grid rate manipulations.  The seam in the zone is battery storage.

As you can see above, it is only in the past 12 months that residential energy storage has had an awakening.  Indeed currently it is on par with large scale utility deployments of battery storage for the first time ever.

So at EVTV, it feels like a race against time to develop and demonstrate ways and means to survive and thrive in such a bizarre future where solar power on residences is actually under attack and every effort is being made to basically outlaw it one way or another.

While it has kind of reduced our videos and blog levels, I’m pleased to report that things are going well.  With very little in the way of manpower to do it, we are winning on several fronts at the same time.  The problem is we are drowning in projects all with the top priority.

Collin and I have suffered a serious breakthrough in talking to the MOdel 3 battery module BMS.  No, none of the chips on this device are commercially available – they are truly Tesla custom chips.  But we’re getting voltage readouts now and have done a shield design for our ESP32 controller to talk to it reliably and support more code development.  I’m believing that balancing and temperatures are achievable as well.

I purchased another wrecked Model 3 which should be delivered this week. Unlike the first, this one runs and drives.

I purchased it mainly because it was nearby in Nashville.  But incredibly it starts and drives, has key cards, and has just 746 miles on the odometer.

Richard thinks he can get it back on its feet.  And he made be right.  Had an interesting conversation this week with a body shop in North Carolina.  He had purchased a Model 3 for just $16k at auction.  

https://epc.teslamotors.com/#/catalogMore incredibly, Tesla now has a parts catalog online. https://epc.teslamotors.com/#/catalog.  And Dennis of North Body and Paint reports that he called Tesla and ordered some parts from it. They told him there was no telling how long it would take to get them.   But three days later he had them – including a hood that was offered on eBay at $750 but he got directly from Tesla at $450.

He also reported that all the testing and inspection to get a car back into the system is now GONE.  It’s not a problem and they no longer disable salvaged cars.  This is FANTASTIC news for those wanting to resurrect a Tesla.  I don’t suppose some wiring diagrams would be just too much to ask???

We are rather fully partnered with Sigineer Power.  We no longer need to call it the EVTV inverter/charger as they are not only accepting our changes, but migrating them into their full product line.  They have also agreed to produce an initial run of 96volt inverters that will relieve some of the I2R issues with the 48v systems, but more importantly accommodate the Model 3 modules.  It will have 3 voltage settings for batteries.

1. Four Tesla Model S Modules in series.
2. The 23 cell Model 3 module.
3. The 25 cell Model 3 module.

I’m also pleased to report that since this current episode was shot, we have replaced the 12kW inverter with the new 15kW model.  Notably, this model has a set of dry contacts allowing us to switch from 60 to 62.5 Hz for a few hundred milliseconds if the battery becomes full or the charging power level from the Solar Edge becomes excessive – more than 15kw.

We are offering this inverter at the same $2799 as Sigineer.  The difference is we have them in stock here in the U.S. and can ship the same day.

It is also interesting to note that we have converted our entire 13.8 kW TEST array, previously DC, to use the new Enphase IQ7X microinverters.  AND we have found that they work simultaneously on the same system with the five Solar Edge inverters.  No really conflict issues between them at all.  The 62.5Hz kicker takes them ALL – Solar Edge and Enphase – offline for five minutes.

Our Wiegmann enclosure is in and we have begun assembly of Powersafe 100.1 for Walter Crumbly.  This one will be much nicer.  Starting with cast iron 6-inch casters.

We have had a lot of very subtle and niggling software issues with the ESP32 controller, almost all due to using abandoned libraries for AWS_IOT.  I’m coming to the exact OPPOSITE view of our little buddy Damien Maguire.

Free and open source is increasingly becoming aligned with NEVER FINISHED and ABANDONED by KIDS in my mind.  Collin’s work excepted.  He’s been a stallion in hunting down little things in these libraries, which were never updated at all by the original authors, which we found astounding that they were ever working at all.  We begin in appreciation of such work and end cursing it.

Of course, I have a unique talent in being able to break things no one has ever broken before, apparently. But some of these have truly been hard to get a rope around.  Like losing our entire control system whenever we microwave chicken.  Or losing just current sensor reporting every day, at some point during the day with no apparent pattern or event triggering it.

The problem is you want your solar system to work day and night for weeks or months on end.  And little glitches like that are hard to test for and detect.

In any event, the wireless and IoT Cloud enabled ESP32 controller is nearing release.  Soon(ish) I hope.

Our Raspberry Pi 3B+ based display is just working famously.  But I really don’t know how to get this to the point where you can use your own MQTT broker and TSL1.2 security credentials.  We don’t even really have a file system for the ESP32.  But we’re working on it.

And so I’m feeling a little overwhelmed with targets of opportunity here.  On any given day we have more to do than we can quite say grace over.