The 12 volt battery in the rear is used for all 12 volt accessories including the ones that you mention. The high voltage traction battery is used for:

• electric propulsion
• ICE engine starting
• controlling transmission gear ratio
• air conditioning compressor
• charging the 12 volt battery
• 120 volt power outlet (if equipped)

 

Thanks. That's what I thought but just wanted to confirm. That little battery at the back can have quite the load.

 

When the car is running, the DC-DC converter will be directly providing 12V powering the car’s accessories.

 

Thank you all for the responses. I am reassured about what I assumed. The reason I ask was because we do a lot of camping and I disable the power doors and interior lights. I think I'm doing right thing because we don't move the van for many days.

 

Also the radio, found out the hard way by listening to the radio for 8 minutes and the car wouldn't start. Carry a backup battery just in case.

 

Better yet a portable radio that runs on double AAs plus backup spotify on mobile!!

 

I usually upgrade all my batteries to AGM in all my vehicles for emergency purposes.
I'll see what options there are are once my sienna gets here next week. I might even consider removing my spare tire and throw a large battery/invertor setup there.

The battery in the back makes it alot easier to wire an invertor setup and even add in a solar panel.

 

I usually upgrade all my batteries to AGM in all my vehicles for emergency purposes.
I'll see what options there are are once my sienna gets here next week. I might even consider removing my spare tire and throw a large battery/invertor setup there.

The battery in the back makes it alot easier to wire an invertor setup and even add in a solar panel.

AGM ?

 

Just search for other hybrid models that use the H5 battery. ie highlander hybrid. Seems to work. $180.
There was a major AGM shortage last year so not sure if supply has caught up.

https://costco.interstatebatteries.com/home/results?key=auto&ZipCode=77064&l=77064&Program=100500&choice1=2039195&choice2=2040374&choice3=2040399&choice4=2040400&choice5=2040401&Country=US

 

Thanks, very helpful.

Do you know, the gen4 Sienna OE battery, is it also an AGM battery?