A California homeowner had been puzzled by solar electricity going to the grid before their battery was full.
Here's what to know
On Reddit, the homeowner said they had selected self-consumption for their system and was on Pacific Gas and Electric's NEM 3 plan. Their battery was at 92% when they noticed electricity being exported.
By their understanding, the program was supposed to export energy to PG&E "only after my battery is 100% charged."
"Am I right so far?" they asked. "If so, why am I exporting even though the battery is only 92% charged?"
Solar electricity can reach the grid before a battery is full if the panels generate more power than the battery can accept, commenters in the Reddit thread explained. They said batteries begin charging more slowly at around 90% capacity to protect their cells.
More background
For homeowners exploring energy storage options or comparing equipment, EnergySage offers a resource for researching battery products and comparing competitive installation estimates — useful groundwork when deciding how storage should serve a household.
EnergySage partners with electrification company Qmerit to help homeowners secure the best available battery-storage pricing.
Storing solar electricity can help lower electricity costs by keeping power available for use at home. A battery configured for backup can also supply electricity during an outage, extending its benefits beyond managing exports.
Crushed by your bills? See instant solar savings from vetted installers in just a few clicks With energy prices through the roof, there's never been a better time to go solar — and EasyHome can help you find the best prices from the best installers in your area. EasyHome takes the guesswork and headaches out of energy upgrades by showing you estimated savings from a network of vetted local partners. To get started, just enter your ZIP and share a few details about your home — seeing your estimate is really that easy. |
Storage can also support greater energy independence, including off-grid use when a system is designed for that purpose.
What can be done?
Commenters also discussed how charging works near 90% capacity. They said an Enphase update keeps battery charge levels around that point.
Despite the initial confusion, the homeowner saw a potential financial benefit to sending surplus electricity to the grid.
"I don't really mind this, because my understanding is that under NEM 3 I get a premium for exporting during the months of August and September," they wrote. "Did I enable a setting that's responsible for this? Is this simply the way things work under NEM 3?"
For shoppers who are looking for a simpler backup option, Pila offers a plug-and-play battery alternative at a substantially lower price point than whole-home backup systems.
Where can I learn more?
Battery settings and export rules help determine where solar electricity goes and how much homeowners save.
• A California Powerwall owner saw solar exports at 88% while using Savings mode.
• A California homeowner received a negative PG&E bill thanks to August battery exports.
• A California shopper questioned a five-year battery agreement while weighing NEM 3 rules.
• California's solar export credit cuts pushed new buyers toward batteries costing more than $14,000.
Get TCD's free newsletters for easy tips, smart advice, and a chance to earn $5,000 toward home upgrades. To see more stories like this one, change your Google preferences here.
