mpg decreased a lot after "stay at home"

How many miles have you driven after the "stay at home" period?

 

Yep - short trips don't equate to good economy. It'll come good once the Pandemic is over.

 

I'd take a page from Douglas Adams and "Don't Panic!".
43 MPG isn't good for a Prius, but sitting for a month and short trips.
I'd just not worry until your next fill up. See what happens once you start driving more regularly. Hand calculate MPG for entire tanks for a while.
See whether the MPG improves, stays the same, or worsens.

 

Couple of things: 1) when cars sit, tires lose air pressure and flat spot. This increases MPG. 2) When the 12V battery sits, it loses volts and needs more recharge from the hybrid battery. I'm not saying this accounts for a 10 MPG drop in your displayed economy, but it will change it some. Don't panic over a single day's MPG. Only worry about it after a complete fill-up (Miles Driven / Gallons Used). Daily MPG estimates by the computer can vary widely.

 

hmm...sooo...more than one tank.

Have you checked tire PSI? Are you certain that your driving pattern is similar to before the "stay at home"? Ambient temps are warm enough that MPG should be optimum.

 

The biggest issue with the stay at home is the battery draining. I am having the same issue. However, when you drive it for > 10 miles it should start to get back into the average. Check tires and battery state. I use Dr. Prius App and the OBD2 wireless dongle

 

I wouldn't trust that they've put the correct PSI in the tires. It's always best to check it yourself, cold tires, in the morning. The general consensus around here is the doorjamb PSI is the MINIMUM, mostly for comfort, and most here put 4-6 pounds more in the tires, for better MPG. You might want to try that.

As for your battery, a comment like "still plenty of life left" sounds vague enough for me to think they didn't even check it.

Sorry to sound skeptical, but if you can, post your tire PSI numbers here, and then we can go from there.

 

Strange how low the voltage and CCA are.

 

I don't like those battery numbers, either, but I'm no expert. If this was a "load" test, I don't think that voltage should dip below 12v.

Hopefully, an electrical expert will post a response.

(personally, I don't like the inconvenience of a failed 12V battery, and I always replace them proactively. In this case, I'd replace it now)

 

CCA should be as close to 295 CCA as possible or higher ( I know it doesn't matter for starting a Prius but could point towards a batteries health. As for Voltage, when your at 12V your battery is around 50 percent charged, so your around 45 percent or so. My battery will stay around 12.4V in between driving 2 times a week in quarantine

 

Do you have a trickle/ float charger? And a multimeter