© 2025 THE COOL DOWN COMPANY. All Rights Reserved. Do not sell or share my personal information. Reach us at hello@thecooldown.com.
“Why didn’t our Powerwall charge to 100% overnight during the super off peak so we wouldn’t have to draw energy from the grid?”
Photo Credit: iStock
A California homeowner expected a newly installed Tesla Powerwall to slash morning grid use right away. Instead, the battery appeared to charge in ways that felt backward, drawing power from the grid at the wrong times and prioritizing the battery over solar power.
In a post on Reddit, the new owner said the system had just been installed and was tied to an SDG&E time-of-use plan with super off-peak periods from 10 a.m. to 2 p.m. and from midnight to 6 a.m. Even so, the battery wasn’t acting the way they thought it would.
“Why didn’t our Powerwall charge to 100% overnight during the super off peak so we wouldn’t have to draw energy from the grid this a.m. before our PV started production?” the original poster asked. They also noticed that even though the system generates enough power to supply the whole house, it was instead using that solar energy to charge the battery while “pulling power from the grid using the non super off peak rate.”
Replies suggested the behavior can be normal at first while Powerwall’s TOU/Savings mode is still learning. Commenters also said the backup reserve and the utility-rate setup can affect whether the battery fills overnight with cheaper grid electricity or keeps space available for solar later in the day.
One Redditor pointed out that it “depends on the mode you’ve got it in.” 
“If you set time based control it’ll charge up off-peak with enough juice to get you through the day,” they explained, “It isn’t always all the way if it sees you have a sunny day, for instance.” They said that in the first week, the system learns how much energy the household uses and how much is generated.  
If you’re weighing a battery of your own, it may be worth exploring EnergySage’s free tools to compare home battery storage options and get competitive installation estimates. EnergySage has teamed up with the electrification brand Qmerit to guarantee you get the best price on home battery storage solutions.
For homeowners considering backup options beyond a whole-home system, Pila is another company offering excellent battery backup options. Its plug-and-play batteries are priced at a fraction of the cost of a whole-home backup system.
FROM OUR PARTNER
Want to go solar but not sure who to trust? EnergySage has your back with free and transparent quotes from fully vetted providers in your area.
To get started, just answer a few questions about your home — no phone number required. Within a day or two, EnergySage will email you the best options for your needs, and their expert advisers can help you compare quotes and pick a winner.
Solar panels can save you more than $50k over their 25-year lifespan, and EnergySage can help you save as much as $10k on installation. Which begs the question — isn’t that worth an email or two?
Battery storage saves the most money only when the settings match your utility’s rate schedule. In a time-of-use market like California, the gap between super off-peak and higher daytime rates can make a real dent in monthly bills if your battery charges and discharges at the right times. 
Battery storage has recently been soaring in popularity, with one report finding that falling battery storage costs are fueling annual installations by about 80%.
Battery storage can protect your home during outages, save you money on energy, and help you go off-grid. It can keep essentials running when the grid fails and help homeowners avoid buying as much electricity during expensive peak windows.
“Set it and forget it” is not always realistic during the first few days after installation. A battery may need time to learn household demand patterns, solar production, and rate signals before it starts optimizing automatically.
If you’re new to battery storage, check three things: your utility rate plan in the app, whether TOU/Savings mode is selected, and your backup reserve percentage. A high reserve can stop the battery from draining overnight, while a mismatched rate schedule can lead to charging decisions that seem counterintuitive.
Ask your installer about the system’s commissioning and learning period. Data collection can change how the battery handles cheap overnight power versus midday solar production.
For buyers still comparing options, getting multiple quotes can help you see if a full-home battery, a smaller backup setup, or a portable plug-in unit makes the most sense for your budget and outage needs.
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.
© 2025 THE COOL DOWN COMPANY. All Rights Reserved. Do not sell or share my personal information. Reach us at hello@thecooldown.com.

source