Highlander Hybrid Battery


#1

I was told by a dealer service manager to disconnect the battery cable if the car was going to be unused for two weeks to avoid the battery draining. I am concerned they just didn’t want to check for a drain.


#2

Why should they check for a drain? You haven’t mentioned any problems.

Two weeks is not long enough to drain a healthy battery in a healthy car. Still, not everyone’s car will pass such a test. Therefore it may be a sound idea to disconnect the battery before your trip.

If you are indeed having known problems with a discharged battery, provide the details.


#3

To clarify, the dealer is probably talking about the conventional 12-volt battery, not the hybrid battery pack. Modern cars, especially one with as much fancy stuff as your Highlander, have a lot of electronic devices that draw a little bit of current even when the ignition is off. It’s nowhere near enough to drain the battery during typical use, but if you’re letting the car sit for a while it will eventually drain the battery and leaving the battery discharged for a long period of time can damage it. This is true of any car, hybrid or not.

That said, I think it’s a little overkill for two weeks. If it was two months I’d say definitely do it, but over two weeks, it probably won’t even drain, let alone damage the battery.


#4

If the Highlander is like the Prius then yes, you should disconnect the auxiliary battery if not used in 2 weeks or more. The Prius aux battery is a small sealed lead acid battery. It’s smaller than a regular car battery because it normally does not have to start the engine.

See page 8 of this link:

http://www.autoshop101.com/forms/Hybrid03.pdf