Does the hybrid battery also power AC etc?

[JayCee88]

My impression is that the hybrid Battery solely powers the electric motor. Hence if the engine is not running and you have heating and radio on, this will be powered solely by the 12V Battery. 
 

However I’ve seen posts elsewhere that says Toyota hybrid batteries also power other electric systems. Can anyone confirm?

[sportse]

I believe it's the other way round for the temperature - the petrol engine has to be running for you to have heating but the air conditioning is electric so will run without the petrol engine.

As long as the car is in ready mode, the 12V Battery is being charged by the hybrid one. This happens even when the petrol engine is off.

When the hybrid Battery charge drops to a certain level, the petrol engine will start up to recharge it a bit. This cycles as necessary depending on charge level.

[TonyHSD]

Hi, 

the Air conditioning of Toyota hybrid cars are powered directly from the high voltage Battery. This Battery also charges the small 12v Battery that feeds all other accessories like power steering, interior lights, infotainment, wipers, everything. It is close and connected system between 12v battery, the 200v battery and internal combustion engine. You need all 3 to work correctly to operate the car. 
 

[JayCee88]

Thanks all. I didn’t realise that the hybrid Battery will also charge the 12V Battery. This is a pretty good system which means the 12av Battery should not be in much risk of going flat.

I somehow managed to completely drain my 12V battery few weeks back. It was a cold morning mind, and I was not driving the car much bar short trips. Even then I managed to do most trips on EV mode, with seat heating and radio etc on. Perhaps the hybrid battery did not charge the 12V enough, even if it was at 70%+.

[Jas2001]

1 hour ago, TonyHSD said:

Hi, 

the Air conditioning of Toyota hybrid cars are powered directly from the high voltage battery. This battery also charges the small 12v battery that feeds all other accessories like power steering, interior lights, infotainment, wipers, everything. It is close and connected system between 12v battery, the 200v battery and internal combustion engine. You need all 3 to work correctly to operate the car.
 

When you say "the small 12v Battery that feeds all other accessories like power steering, interior lights, infotainment, wipers, everything", I presume you mean the 12V Battery will supply power to the accessories when car is not in Ready mode? I.e., the high voltage Battery will also power the accessories while in Ready mode.

[TonyHSD]

1 hour ago, Jas2001 said:

When you say "the small 12v battery that feeds all other accessories like power steering, interior lights, infotainment, wipers, everything", I presume you mean the 12V battery will supply power to the accessories when car is not in Ready mode? I.e., the high voltage battery will also power the accessories while in Ready mode.

The 12v Battery supply all car systems, in ready mode and when the car is off.
The 12v Battery locks and unlocks the car plus starts the high voltage Battery, the relays that disconnects the high voltage battery from the inverter.  
When the car is ON ( ready mode) all systems receive power from the 12v battery, the 12v battery recharge from the high voltage battery and the high voltage battery gets charged by the petrol engine.
All that electric power demand and supply happens via inverter converter that invert and convert electricity between all 3. All of these needs to function properly  so the car can operate. If any of the 3 is at fault the car will not be able to drive. 
If the car is not used for long time the high voltage battery can not recharge the small 12v battery and you can have flat battery and not able to start the car. Sometimes when the 12v battery is totalled and can not hold charge at all the car will not go into ready mode even with jump start. This is the sequence how Toyota hybrids starts normally. 
1. 12v battery 

2. 200v battery 

3. Petrol engine 

[AndrueC]

2 hours ago, JayCee88 said:

Thanks all. I didn’t realise that the hybrid battery will also charge the 12V battery. This is a pretty good system which means the 12av battery should not be in much risk of going flat.

Sadly not the case. Toyota saved some money on the earlier models by only fitting a smaller capacity 12v Battery having known that it wasn't carrying as much load as on a conventional ICE vehicle.

Unfortunately this means that the standby draw (power drawn even when off eg; alarm system) is a larger proportion of the battery's capacity. This in turn means that the 12v Battery can be drained relatively quickly if the vehicle is unused.

This was a particular problem during the Covid pandemic lock-downs and there are occasional reports of people finding the car to be dead after a couple of weeks in an airport carpark.

Although the 12v Battery doesn't do anything to start the engine it does have to power a relay to connect the traction battery to start the system. If the 12v battery is dead the car is as well. Even the central locking might not work.

I think that later models have a more normal capacity battery fitted.

[sportse]

Yes, the later models seem to have a more normal sized Battery. My 23 icon has a 45ah one rather than the very small ones you used to get initially. 
 

during lockdown in my auris I’d put it into ready mode for an hour a week, that kept the 12v Battery charged up even though I wasn’t driving much. 
 

the portable jump packs aren’t much use as the clamps that come with them are close together - you can’t reach the two spots it tells you to in the manual for a jump start. 

[Don Mac]

4 hours ago, Jas2001 said:

When you say "the small 12v battery that feeds all other accessories like power steering, interior lights, infotainment, wipers, everything", I presume you mean the 12V battery will supply power to the accessories when car is not in Ready mode? I.e., the high voltage battery will also power the accessories while in Ready mode.

To clarify (apologies Tony) - the car has two electrical systems, low and high voltage.

The low (12V) voltage systems are connected to and always powered by the 12V Battery.

The high voltage parts (air conditioning compressor and the motor generators) are connected to the high voltage (traction / hybrid) Battery.

The inverter (power control unit) links the high voltage system to the low voltage, allowing power to be supplied to the 12V Battery from the high voltage side.

As Tony says the 12V system turns the high voltage system on and off. When the car is "off" the high voltage battery is disconnected. When the car is running the engine can supply power to the high voltage battery via the motor generators, but not directly to the 12V battery.

[Cyker]

16 minutes ago, sportse said:

the portable jump packs aren’t much use as the clamps that come with them are close together - you can’t reach the two spots it tells you to in the manual for a jump start. 

Just be aware you don't need to connect it to where it says - You'll need to attach to the positive pole, but the negative can be connected to any handy bit of exposed metal bodywork.

The reason they show you the location in the manual is to minimize the chance of sparks near the Battery, but with 99% of portable jumpstarters there is no risk of sparks as they aren't live when you connect them (Whereas if you're e.g. using another car to jumpstart, it will be live and very sparky!)

 

[Jas2001]

48 minutes ago, Don Mac said:

The low (12V) voltage systems are connected to and always powered by the 12V battery.

I'm questioning this aspect since if the 12V Battery is supplying power to the accessories and therefore after a while itself needs charging, how can it simultaneously power the accessories whilst also being charged.

[AndrueC]

9 minutes ago, Jas2001 said:

I'm questioning this aspect since if the 12V battery is supplying power to the accessories and therefore after a while itself needs charging, how can it simultaneously power the accessories whilst also being charged.

I assume it's the same as for a conventional ICE except that the traction Battery does what the alternator does.

Given the power it has available I'd assume that the traction Battery would power the items and (if needed) top up the Battery.

[Jas2001]

33 minutes ago, AndrueC said:

I assume it's the same as for a conventional ICE except that the traction battery does what the alternator does.

Given the power it has available I'd assume that the traction battery would power the items and (if needed) top up the battery.

But then what if the traction Battery needs charging 😉.

[Don Mac]

9 minutes ago, AndrueC said:

I assume it's the same as for a conventional ICE except that the traction battery does what the alternator does.

Given the power it has available I'd assume that the traction battery would power the items and (if needed) top up the battery.

Like Andrue says, the 12V system runs the same way as a conventional ICE but you have power being fed in via the invertor rather than an alternator.

When the engine is running ("on" for the hybrid) the supplied power is sufficient to keep everything working and charge the 12V Battery. The 12V Battery stays connected to the circuit all of the time whilst the alternator/inverter is connected across its terminals. Yes, you could argue that the 12V Battery has stopped supplying power.

Sorry if I confused things by oversimplifying them.

A fully correct description of what goes on would be

               a) more complicated  (I should probably be saying 'voltage' rather than 'power' for instance)

               b) beyond what I'm sure I know (the way that the inverter supplies 12V power may be a lot smarter than an alternator)

 

[Don Mac]

9 minutes ago, Jas2001 said:

But then what if the traction battery needs charging 😉.

That's easy, the engine fires up and turns the motor generators (with or without moving the car...)

[Jas2001]

10 minutes ago, Don Mac said:

That's easy, the engine fires up and turns the motor genera

Yeah I had kind of figured this out but was just really making the point there is no risk of the 12V Battery becoming flat while the car is in Ready mode even with the accessories all turned on.

[TonyHSD]

24 minutes ago, Jas2001 said:

Yeah I had kind of figured this out but was just really making the point there is no risk of the 12V battery becoming flat while the car is in Ready mode even with the accessories all turned on.

No risk in ready mode.
Only if you in acc or ON mode, these are respectively no foot on brake one push of start button sets the car in acc mode and double push sets in ON mode. When the car is in acc mode you can listen radio, or charge your phone , if you leave the car like that for 30 min there will be warning message on screen and the car will turn off itself to preserve your 12v Battery. Same if you leave interior lights on for longer. But if you repeat that you may run into trouble. 

[Pannett]

This is a fascinating thread and there are some most interesting comments. Because the Corolla has a 12 volt socket under the armrest, I have a voltmeter plugged in to check the Battery condition. This is partly because our previous car, an Octavia PHEV, occasionally and mysteriously lost enough 12 volt Battery charge overnight to prevent anything working until the Battery was recharged. I have no worries about the Corolla (so far!) but the habit persists.

[JayCee88]

On 3/18/2024 at 6:09 PM, AndrueC said:

Sadly not the case. Toyota saved some money on the earlier models by only fitting a smaller capacity 12v battery having known that it wasn't carrying as much load as on a conventional ICE vehicle.

Unfortunately this means that the standby draw (power drawn even when off eg; alarm system) is a larger proportion of the battery's capacity. This in turn means that the 12v battery can be drained relatively quickly if the vehicle is unused.

This was a particular problem during the Covid pandemic lock-downs and there are occasional reports of people finding the car to be dead after a couple of weeks in an airport carpark.

Although the 12v battery doesn't do anything to start the engine it does have to power a relay to connect the traction battery to start the system. If the 12v battery is dead the car is as well. Even the central locking might not work.

I think that later models have a more normal capacity battery fitted.

Interesting. Thank you for the clarification. My car is 2022 model so I guess I have the lower capacity Battery. Is it worth upgrading the Battery?

Further question, when my car is stopped, ignition on (Ready mode) and gear is in Park the engine switches off. During this time if I have AC/heating (including seat heating) and radio on, does the 12V Battery provide 100% power?

[TonyHSD]

31 minutes ago, JayCee88 said:

Interesting. Thank you for the clarification. My car is 2022 model so I guess I have the lower capacity battery. Is it worth upgrading the battery?

Further question, when my car is stopped, ignition on (Ready mode) and gear is in Park the engine switches off. During this time if I have AC/heating (including seat heating) and radio on, does the 12V battery provide 100% power?

On anything else except the air conditioning compressor the 12v Battery provides power. And the 12v Battery recharges from the high voltage Battery.   
Engine only will run when the high voltage battery gets low or extra heat is required for the cabin. 

[Roy124]

On 3/18/2024 at 10:40 PM, Jas2001 said:

Yeah I had kind of figured this out but was just really making the point there is no risk of the 12V battery becoming flat while the car is in Ready mode even with the accessories all turned on.

In theory, yes.  As reiterated below, the ICE will top up the HV when it has been topping up the 12v while it has been running the system. 

Where this might fail in practise is if the load is maximised and the HV to LV does not match the demand. There may then be a drop in 12v capacity.  On normal use your max demand will reduce (wipers off or AC fan slower etc).

If however the car is put in Accessory mode from this reduced state you might have a problem.  I think something like that when mine was in the tyre bay.  The voltage when back hone was 11.99v.  In other words the 20 minute journey home had not restored the Battery.

PS

After a 48hr charge then 2x90minute journeys the voltage was 12.64v.

[Roy124]

Notwithstanding my post above,  had I not checked,  and  not used the charger, I don't think I would have had a problem.   The car would have carried on as normal.