A $20,000 set of Enphase Encharge home batteries that are supposed to charge from our solar panels died so hard when our grid power went out, we were left without water and power. And we needed *grid power* to restart the stone-cold-dead Enphase batteries.
Enphase Encharge home batteries left us without water and power
Enphase batteries should not be eligible for reliability subsidies until a fatal flaw is fixed
The ~infallible~ system
In November 2020 we installed a 13 kW (AC) with 44 solar panels along with a 20 kWh of Enphase Enpower backup batteries. We live in rural Gold Country California on 10 acres of land. We are on well water which needs electricity for the pump, and when we lose power, we also lose water.
The allure of the home backup batteries was three fold for us:
- We would never lose power to our well and house as long as the sun was shining.
- We could get the cost of the house batteries, approximately $20,000, reimbursed though the Self Generation Incentive Program.
- Compared to buying a propane-fired backup generator which requires expensive-routine maintenance and propane to run, we would have “free” energy along with no maintenance costs.
Below is a simple photo diagram of the batteries and microgrid system. We can power 100 amps of backup loads, which includes our heat pump HVAC system, refrigeration, stove, many of our main-living area loads, our internet and networking, and most importantly, our well pump.
When the grid power goes down, the microgrid controller almost seamlessly switches over to the batteries and solar. We can easily switch over to the microgrid for testing simply by pulling the 200 amp main breaker for the utility (PG&E) meter. During a power outage, we can power our house from both the batteries and solar panels during the day. When the sun goes down, you obviously only have the batteries.
Off-grid failure
On August 19, 2021, our rural neighborhood suffered a PG&E power failure around 11 pm. Our battery had been drained down to 30%, as it’s scheduled to do to offset our peak-electricity pricing from 4–9 pm. You can see in the Enlighten app below that everything continued to mostly work fine after the outage around 11 pm. And the 100 amps of backup circuits continue to run.
Apparently the microgrid controller did cause a brownout of sorts when the grid power was cut, as my networking equipment on the backup circuit crashed and our internet was taken offline. This is a new problem, as our internet networking was recently moved to the Encharge backup circuit. My mistake was removing the uninterrupted power supply from the networking equipment; I assumed the power coming off the Enphase microgrid controller was clean enough to prevent the networking equipment from crashing.
Encharge drove itself off a cliff
Although the Enphase system appeared to handle the backup situation ok, what happened next is quite disturbing. Around 1 am and about two hours into the power outage I woke up and noticed our air purifier, which is on a backup circuit, was not running. This clued me into the power outage.
As mentioned previously, the switchover to the microgrid crashed our networking equipment. After a dark trip to the networking dungeon and rebooting everything, I checked the Enlighten app. I found about only 16% of battery charge left. There was no way we were going to make it through the night. We needed to shed some load, ASAP.
At night, we only run our mini-split heat pumps in two of our bedrooms. I immediately shut these heat pumps off from the HVAC app. But the fridge, freezer, and dishwasher were still chipping away at the remaining 15%. I went back to sleep, falsely believing everything would be ok in the morning when the sun started charging the batteries.
Encharge killed itself by continually restarting with 3% charge
Around 5:15 am, the Encharge batteries reached 3% of remaining charge and switched themselves off for “good”. Things probably would have worked out fine if the batteries actually remained off until the sun was up. But the microgrid kept trying to restart over itself and over again!
The Enphase microgrid controller kept trying to come back on, each time reaching a foregone conclusion; the system should shutdown immediately because there was no charge to be had from the solar and the batteries were in a critical state. I know the system was trying to restart because I woke up several times to blinking lights on our HVAC system in our bedroom. Then the HVAC lights would go blank, i.e. the power went off again, and then come back on a bit later. The remaining 3% of battery power, which is needed for the batteries to start charging again from the sun, was squandered trying to restart a system with no power for charging.
Morning light
When I awoke around 7 am, the lights on each of the six batteries were blinking yellow in “sleep mode”. Eventually the blinking yellow lights on the six batteries began turning off one-by-one until everything was completely dead. Things seemed grim. No grid power, the sun was up and supposed to be charging the batteries, and the ice cream was melting in the freezer. Even though the sky was smokey from wildfire smoke, the system was receiving several kW of solar power and and the microgrid charger still couldn’t restart itself.
The well goes dry
The worst part of our situation, and the exact reason we’re getting a ~$20,000 Self Generation Incentive Program rebate for “Equity Resiliency” for 20 kWh of backup batteries, is to power our well. Our well uses roughly 6–7 amps at 240 volts (1.4 kW) when it’s running.
The well-pump load is intermittent, thanks to two pressure vessels that “store” the water pressure. But it is a significant-intermittent load. You get one toilet flush for free when the power goes out from the water in the tank. Then you need to find some more water to flush with. We have 90 gallons of emergency water just for this purpose… but the Enphase Encharge batteries were supposed to remove the need to schlep water around the house and pour it into the toilets.
Enphase Support
I could, and maybe should, write an entire article about Enphase Support. Our solar system installer emailed me on the morning of the power outage to let me know my batteries were critically low on charge. I happened to bicycle to the end of my driveway, where I got cellular-internet connectivity to see an email from my installer about the issue.
Our solar installer jumped onto the Enphase chat and waited for over two hours to get a response. The response? We can’t help you. You have to call a special support phone number. When the installer called that number, it was busy and we had to wait for a callback. Meanwhile… the ice cream was still melting.
Enphase support did absolutely nothing
When we finally got a call back from Enphase, their response basically resembled the sarcastic guy from IT support that asks, “Have you tried rebooting your computer?” By now it was 11 am and we’d been without grid power for 12 hours. But there had been plenty of solar power to charge the house batteries for three hours.
With my installer on the line, the Enphase tech support had me turn off some of the circuit breakers in the microgrid controller… and simply wait for something to happen. There was absolutely nothing that could be done to bring out dead batteries back except pray the system recovered when the grid came back on.
Our installer raised the obvious question to the Enphase tech. “Why can’t you configure the batteries to not kill themselves by leaving a bigger cushion of reserve when the batteries power off, currently set at 3%?” our installer asked. This is especially relevant if the batteries cannot be restarted after a complete discharge without the electrical grid, which as we know now, is apparently the case. Enphase had no response or no plan to remedy this issue, according to the technician we spoke to on the phone.
Left for dead by Enphase support
Enphase has indirectly received millions of California ratepayer dollars via the SGIP incentive. But after this experience, it’s not clear the Encharge batteries are a reliable backup power system. If this was a public safety power shutoff (PSPS), rather than just an unplanned outage, we could have been left for days without power despite having a 13 kW solar system on our roof and 20 kWh of batteries in the garage. Enphase offered no assistance to us in our time of need. We wasted several hours just trying to get a hold of support during a time of limited connectivity.
Our worst case scenario, in my mind, is now:
- Loosing grid power right after we discharge our home batteries in the evening to offset peak-pricing electricity rates (this happened nearly perfectly during this incident)
- Having limited ability to recharge our battery during the day due to wildfire smoke (this also happened during this incident but the Enphase system was dead… so somewhat moot)
- Having an extended power outage in 100 °F+ temperatures and not being able to cool the house (we got lucky as it was relatively cool when the grid failed this time)
What is even worse is that some California utility customers are receiving these home-battery backup systems to run medical devices. This is not currently our situation but imagine if we had counted on this backup power to run a critical medical device?
Bricked microgrid
What I didn’t anticipate was a completely bricked microgrid in our house. A bricked microgrid is completely worthless. You can’t even talk to it to see what’s going on or what is wrong. As Enphase Support said, you just have to see what happens when the grid power turns back on.
I do sincerely hope that Enphase can come up with a software fix for this pretty obvious problem of system over-depletion. But if Enphase cannot show that its system is reliable, it is questionable whether Enphase systems should continue to be eligible for Self Generation Incentive Program funding from California ratepayers. Especially when people are relying on these backup batteries to power their medical devices and water wells.
