Battery dead after 10 days of no use

Shouldn't go dead after 10 days. If battery is healthy and there are no additional devices running (like webcam, etc) it should be good for 20 days.

The advice that Toyota have given us (the country is in lock-down) is to run the car for 20 minutes every 4 days. It doesn't rotate the tires, but does take care of batteries, oil pooling, and water/condensation. I think that every 4 days is too much - once a week should be fine.

It's not ideal, but under the circumstance, it is reasonable preventative maintenance

 

primes have had a lot of bad batteries. sitting 10 days shouldn't be a problem, so it was probably weak to begin with.
get a load test at an auto parts store, and if it's good, charge it up and keep an eye on it.

if it's bad, replace it. check if it's under warranty

 

12V battery QC isn't the best, although when you consider the zillions of batteries being produced, the % of early failure is still rather low.

Modern cars are exceptionally complex (duh!). Parasitic draw can come from anywhere, and you'll drive yourself nuts trying to find it.

I've been using BatteryTenderPlus on ALL my 12V batteries for 15 years. Easy to pigtail onto the 12V, bundle the cord out of the way, and you've got easy access for a periodic charge (assuming you've got a driveway/garage).

Terminology: Battery tender type chargers, after fully charging the battery, go to a "float" charge. This is NOT the same as a "trickle" charge, which would remain constant and possibly overcharge the battery.

bisco's advice is good.

 

Over the years we have found out that some are delivered with aged 12-volt batteries. The dealer will show off the hybrid multiple times without actually driving it. That duration taken to explain features ends up deeply discharging the accessory battery, shortening its life... which puts you in a surprise situation upon discovery. It's really unfortunate.

 

Get yourself a Ctek MXS 5 or MXS 3.8 battery conditioner. You can leave these on and they will keep the battery up to full charge without overcharging it.

 

As will a LOT of other brands of fully automatic tender type small chargers.
No need to look for a specific brand.

 

^^^+1...

 

I'm sure this happens to the specific VIN's / cars used in dealership showrooms.

Back when I sold Hondas, we did not disconnect batteries for in-showroom cars. Within days of being put into the showroom, the batteries would be dead from people moving the seat controls, or just from sitting since the batteries weren't strong to begin with (having sat out on the lot for weeks between test drives).

-----

The OP also lives in what I believe is a 'hot' state. Batteries last a lot shorter lives in hot states. Here, two years is about the norm between aftermarket battery purchases.