I love that it will save on energy bills as well as provide backup power during blackouts.
- Single-Family Residence
- , CO 80602
- Solar PV
- December 2022
- Size of System:
- 12 kW
- To generate electricity
- Gross Cost of System:
- Value of Tax Credits:
- Net Cost of System:
- Annual Savings:
- Own or Lease:
- Cash Purchase
What You Need to Know
Sol-Ark 12k EMP rated, with 60kWh EG4 LiFePower battery bank attached (48V). Uses 12kW of Q.Cell 400W panels with TIGO TS4-A-O module level optimizers and CCA. Critical loads panel, with TIGO CCA attached. External rapid shutdown (simultaneous) of TIGO CCA and Sol-Ark.
Rate shifting from more expensive On-Peak and Mid-Peak Time Of Use rates to less expensive Off-Peak times. Discharge from batteries and augment power during the expensive 3pm-7pm On-Peak time, and recharge from batteries in the evening or solar the next day.
No major maintenance. Enjoy monitoring to identify any issues or change parameters to better optimize for changing situation.
Primary motivator was to have "endless" backup power in event of extended grid-down outage, to keep food in freezers from spoiling and to be able to cook in the home. Backup generator could work for a few days, but requires fuel and is very noisy/smelly (zombie attractant). Secondary motivator was long-term energy costs (they keep increasing) and being less dependent on utility company.
Make sure you fully understand all the specifics of your particular installation, including from inverter manufacturer if you are doing any kind of customization for your system. Don't be quick to accept day-of-install changes without checking those with manufacturer - it could void warranty if outside their installation specs.
Experience with Installer:
Difficult to find an installer who would work with our "custom" batteries and inverter (i.e. not SolarEdge or major manufacturer). Needed to know more about my own setup than installer, to keep the installation from voiding warranty. But they worked with me and did a great job in the end.
Original plan was to have panels on East, West, and South faces. However, due to DC string designs, inverter max string wattage and VoC limitations, plan was changed to be just East/West arrays. This turned out to be a better plan, and more optimal than having some South-facing, due to the max output limitations (9kW max) of the inverter. Evens out the power curve throughout the day because the peak is shaved due to the limitations. So we have higher power in the morning on the East array, and in the evening on the West array, with less of a peak being shaved mid-day, which creates more power overall. This East/West configuration without South facing panels would NOT likely be optimal with micro-inverters. The Sol-Ark system's built-in rapid shutdown does not directly support the TIGO TS4-A-O optimizer system because that system requires the TIGO CCA module, which runs on 24VDC power (their kit comes with a converter from 120VAC to 24VDC). However, there are options for how to wire the external rapid shutdown to meet fire and electrical code updated requirements. You can wire an external rapid shutdown switch to the CCA module itself to initiate module-level shutdown, and/or you can power the CCA from the critical loads panel (a good idea in the event of utility blackout, so your modules are still producing) and rely on the inverter's shutdown to cut off power to the CCA on the critical loads panel, which will in turn shutdown the CCA and Optimizers at the PV module level. You can even get a double-pole shutdown switch and do both simultaneously (as our system is configured).
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