Disconnecting battery for long storage

[Zvi]

I will be traveling and storing my Yaris Hybrid (2020) car. Is it enough to disconnect the 12V Battery when storing for more than 6 weeks or does the high voltage Battery need to be disconnected too?

[Mojo1010]

My guess is the HV Battery should be left alone. I would think the 12v Battery would still need a top up charge even disconnecting it. Maybe a good option is to get a trickle charger, if the car are garage then just plug the charge in the engine bay charge point. Someone with better knowledge may come along and give better info. 

[TonyHSD]

No, you should not disconnect the 12v Battery but instead you can attach smart charger either on plug or solar panels. Otherwise after 6 weeks you very likely will find your 12v Battery been completely dead., and new Battery will be needed. 

[Max_Headroom]

You could get one of these then you don't need to touch the Battery.

 

 

[Roy124]

12 minutes ago, Max_Headroom said:

You could get one of these then you don't need to touch the battery.

 

 

Max, not ideal for this situation.  The jumper is ideal for low voltage but of the Battery drops too low it might not work. 

I don't know enough to specify how low the 12v needs to be before it can't be jumped.  The best options are as above:

Battery charger if the car is in a garage 

Solar charger if in the open. 

[Max_Headroom]

What causes a fully charged 12v Battery to go so flat in 6 weeks it cannot be jumped with one of these?

[Jimota]

Interesting subject as I’m off to Australia for 6 weeks early next year.  As I’ve never owned a Toyota or indeed a hybrid vehicle, I’m not sure which is the best way to protect the Battery for an extended period.  I do own a portable jump starter but getting a little bit concerned about using it on a hybrid.

[Max_Headroom]

6 minutes ago, Jimota said:

 I do own a portable jump starter but getting a little bit concerned about using it on a hybrid.

You are not jump starting like an internal combustion engined car (ICE) you are powering the 12v system which allows the hybrid system to do its thing.

I am sure members will be able to explain that better  😉

[Jasper.]

I used my Noco jump starter on the Yaris without any issues..

[Jimota]

Thanks Max, still can’t get my head round some of the issues surrounding hybrid vehicles.  I’m in my mid 60s but I’ve never felt like a virgin for such a long time!

[Roy124]

2 hours ago, Max_Headroom said:

What causes a fully charged 12v battery to go so flat in 6 weeks it cannot be jumped with one of these?

Short answer it the same discharge that will cause it to loose a couple of volts over a couple of weeks.  Extend that power loss and you will eventually get. A sub optimal voltage before it eventually dies. 

That power drain may be a constant with the Battery condition being the variable. 

The reason jumping may fail is the Battery might be nadgered. 

Now in theory, your jumper pack may energise the system and the car may start.  If you  disconnect the jumper the car when the Battery is totally u/s the car may stop  - I don't know.  If you restart using the jumper pack will it keep the hybrid system online and in turn get charged - I don't know. 

[Roy124]

36 minutes ago, Jimota said:

Thanks Max, still can’t get my head round some of the issues surrounding hybrid vehicles.  I’m in my mid 60s but I’ve never felt like a virgin for such a long time!

It's a learning curve.  With the traditional alternator system you can get a situation where the current draw exceeds the alternator's ability to power the systems and the Battery drains even when running. 

The hybrid has no alternator and the HT Battery charges the 12v.  Can the 12v Battery run into deficit too?  I don't see why not. 

 

[Jimota]

Now I’m a super virgin.  I didn’t know that hybrids don’t have an alternator.  😍

[Bernard Foy]

9 minutes ago, Jimota said:

Now I’m a super virgin.  I didn’t know that hybrids don’t have an alternator.  😍

Every day is a school day James where hybrids are concerned 😟.

[Catlover]

22 minutes ago, Jimota said:

Now I’m a super virgin.  I didn’t know that hybrids don’t have an alternator.  😍

Toyota hybrids don’t have an alternator, not sure about other makes of hybrid.

[Derek.w]

Dont disconnect 12 volt Battery use a ctek smart charger or depending on time of year and its location fit a solar charger.

[Jimota]

Yes, every day is indeed a school day.  I love learning new thing as I get older.  Mentioned the alternator thingy to my wife and she just looked like a rabbit caught in the headlights!

[bathtub tom]

1 minute ago, Jimota said:

Mentioned the alternator thingy to my wife and she just looked like a rabbit caught in the headlights!

I only recently found out you can get ironing boards with built-in seats: https://www.yorkshireprophire.co.uk/product/ironing-board/

Suggested to SWMBO I may buy her one for Christmas. I should be out of hospital for the New Year.

[MikeSh]

2 hours ago, Jimota said:

head round some of the issues surrounding hybrid vehicles.

Some (or all) of it isn't hybrids per se, it's all modern cars.

Back in the day you turned the ignition and the lights off and, unless you left the interior light on by mistake (yes, I have the tee-shirt), nothing drains the Battery and a few weeks parked up is no problem.

These days there are all sorts of electronics that are consuming a few mA or more (that's thousandths of an Amp) even when you think it's 'off' and over time that will drain the 12V Battery.

Drained enough it won't be able to power the car to begin operation. (On a conventional car that's turning the starter, on a hybrid or EV it's pulling in the big traction Battery contactor.)

Drained to totally dead - the battery may be toast (or the opposite of toast?). Lead-acid batteries don't like being completely dead - in simple terms it buggers up their chemistry. New battery time (people say they can be saved but it's usually not long lived - just buy a new one if you want a life not dominated by having to trickle charge it all the time).

[Trewithy]

10 hours ago, bathtub tom said:

I only recently found out you can get ironing boards with built-in seats

I only found out recently that toast is made from bread.

[Roy124]

To add to Mike's post, the alarm is one constant drain and disconnecting the Battery will disable your alarm. 

The car is also listening for a call from the mothership. I can lock the doors, flash the lights, turn on the heating, and find out where the parking company has parked it. 

As long as I have an Internet connection my car is listening for my commands. 

[Roy124]

3 minutes ago, Trewithy said:

I only found out recently that toast is made from bread.

Can you toast cake? 

[Trewithy]

11 minutes ago, Roy124 said:

Can you toast cake? 

I don't know, I'll have to ask my wife.

[Hybrid21]

15 hours ago, Jimota said:

Thanks Max, still can’t get my head round some of the issues surrounding hybrid vehicles.  I’m in my mid 60s but I’ve never felt like a virgin for such a long time!

A hybrid virgin James, I'm sure your not the only one 😃

[TonyHSD]

Let share something about batteries and chargers. 
My neighbour works abroad and often are away for months 6-10 at a time. They used have petrol manual corsa and they were changing Battery every two years because the obvious, lack of use. Last year before they got rid of the car they bought a large solar panel smart charger (20w or more). They attached to the windscreen and plugged in directly into the obd 2 port. The summer was hot and sunny, the smart charger worked well and even after many months of not using the car they were able to unlock and start first time. 
They decided to go full ev and bought a leaf first gen facelift.  The leaf has same function as my gf Hyundai, the traction Battery to maintain and charge the auxiliary 12v Battery while car have not been used. These cars has 3 large blue led’s built in top and middle of the dashboard to indicate traction battery charging or auxiliary battery charging while car been parked and locked, off charger too.
The Nissan been left over the summer and never seen the blue lights flashing = charging the 12v battery, which proof the solar charger did its job well., however recently I saw the blue lights flashing, it seems that lack of sun energy trigger the car valet function and the car started charging the 12v battery itself. My girlfriend’s car was doing exactly the same when I looked at hers, it seems these cars are smart indeed. Unfortunately Toyota hybrids has very small traction batteries and similar functions are impossible. 
For the op question, best to connect the battery to smart charger which will maintain it healthy and ready to go when they return, or at least a solar charger. 👍