12v battery maintenance, issues, etc.

[Minimac]

6 hours ago, philip42h said:

It's really not a problem - as Ernie suggests, it is a feature of hybrids and EVs having more complex electrical systems and smaller auxiliary batteries. The vast majority of us drive around very happily without worrying about it at all. That said, it does help to be aware of it and avoid obvious pitfalls - like using Accessory mode for an extended period or leaving the car standing for many weeks. Anyone using their car for more than an hour per week / doing more than 2000 - 3000 miles pa won't need to think about it.

Did you leave the car in Accessory mode (to listen to the radio for example)? If not, it does sound as though your car may need a new auxiliary battery ...

 

Hi, thanks for this insight, could you enlighten me on accessory mode, being a new owner of a hybrid I'm not sure what this means. Thanks 

[philip42h]

17 minutes ago, Minimac said:

Hi, thanks for this insight, could you enlighten me on accessory mode, being a new owner of a hybrid I'm not sure what this means. Thanks 

It's all in the manual, and I'm pretty sure that it is in this thread too but ...

• When you get into the car, you put your foot on the brake pedal and press the Start button to put the car into Ready mode. At this point the traction Battery is 'engaged' and you can put the car into gear and set off. In Ready mode the 12V auxiliary Battery is automatically charged as necessary from the traction Battery - everything is good!
• If you get into the car, but do not put your foot on the brake pedal and press the Start button the car is put into Accessory mode. This is equivalent to the first position (the accessory position) of the ignition key in a dinosaur car - the 12V system becomes active, but the 'ignition' is not on and the engine can't run. In Accessory mode you can open and close the windows, listen to the radio, run the aircon to keep cool etc. and flatten the 12V auxiliary battery in a matter of (tens of) minutes depending on what you turn on.

The simple 'solution' is to use Ready mode rather than Accessory mode for pretty much everything. Accessory mode is OK if you forgot to close a window and now need to, and I'll use it for long enough to preset a destination in the sat nav, but otherwise always use Ready mode.

[Minimac]

17 hours ago, philip42h said:

It's all in the manual, and I'm pretty sure that it is in this thread too but ...

• When you get into the car, you put your foot on the brake pedal and press the Start button to put the car into Ready mode. At this point the traction battery is 'engaged' and you can put the car into gear and set off. In Ready mode the 12V auxiliary battery is automatically charged as necessary from the traction battery - everything is good!
• If you get into the car, but do not put your foot on the brake pedal and press the Start button the car is put into Accessory mode. This is equivalent to the first position (the accessory position) of the ignition key in a dinosaur car - the 12V system becomes active, but the 'ignition' is not on and the engine can't run. In Accessory mode you can open and close the windows, listen to the radio, run the aircon to keep cool etc. and flatten the 12V auxiliary battery in a matter of (tens of) minutes depending on what you turn on.

The simple 'solution' is to use Ready mode rather than Accessory mode for pretty much everything. Accessory mode is OK if you forgot to close a window and now need to, and I'll use it for long enough to preset a destination in the sat nav, but otherwise always use Ready mode.

Thanks, that's really helpful and clear, so using electric seat change with engine in accessory mode will deplete 12v Battery more quickly,might be our issue.

[philip42h]

1 hour ago, Minimac said:

Thanks, that's really helpful and clear, so using electric seat change with engine in accessory mode will deplete 12v battery more quickly,might be our issue.

Quite possibly ...

You can use the electric seat adjustment to restore a saved position before you get into the car and while the system is otherwise Off. One repositioning of the seat shouldn't have a significant impact on the auxiliary Battery or the car's ability to get into Ready mode.

Putting the car into Accessory mode will start the A/C fans etc.. If you then spend 20 minutes setting up his and hers seat positions, checking that you can switch between them and adjusting them 'cos they weren't quite right, you might well have a negative impact on the auxiliary Battery. Only you will know what you actually did. 😉

If you have simply run down the Battery, charging it up and not making the same mistake again will sort the issue for you - the car will be totally reliable going forward. 🙂

If the battery was already on its last legs due to actions by the previous owner or a long time standing before you bought it, the battery will be 'shot' and need replacing. You may be able to persuade the selling dealer to do this for you. Equally, the 12V auxiliary battery is a consumable item (though the lifetime should be >5 years rather than <2 years) and you could simply replace it yourself - in the grand scheme of things a 12V battery isn't that expensive ...

[Terry10]

2 hours ago, philip42h said:

Quite possibly ...

You can use the electric seat adjustment to restore a saved position before you get into the car and while the system is otherwise Off. One repositioning of the seat shouldn't have a significant impact on the auxiliary battery or the car's ability to get into Ready mode.

Putting the car into Accessory mode will start the A/C fans etc.. If you then spend 20 minutes setting up his and hers seat positions, checking that you can switch between them and adjusting them 'cos they weren't quite right, you might well have a negative impact on the auxiliary battery. Only you will know what you actually did. 😉

If you have simply run down the battery, charging it up and not making the same mistake again will sort the issue for you - the car will be totally reliable going forward. 🙂

If the battery was already on its last legs due to actions by the previous owner or a long time standing before you bought it, the battery will be 'shot' and need replacing. You may be able to persuade the selling dealer to do this for you. Equally, the 12V auxiliary battery is a consumable item (though the lifetime should be >5 years rather than <2 years) and you could simply replace it yourself - in the grand scheme of things a 12V battery isn't that expensive ...

Anybody know if you can literally change the Battery yourself?? I thought that I read somewhere that you had to keep power to the car whilst you disconnected the terminals and put the new one in. The risk is loosing information in the car, therefore needing a trip to the dealer.

Terry

[Cyker]

The 12v Battery? Yeah you can change it yourself - It's no different than any other car.

It'll forget some settings but they can easily be put back in or re-learned.

[forkingabout]

9 minutes ago, Cyker said:

The 12v battery? Yeah you can change it yourself - It's no different than any other car.

It'll forget some settings but they can easily be put back in or re-learned.

Toyota is pretty easy & just needs a few systems to reinitialise which is covered in the owners manual. 

Some modern vehicles need the Battery disconnected / reconnected following the correct procedure to shut down & boot up the body computer safely else you can end up with a recovery wagon trip to the main dealer - just look on a Peugeot forum 😅

[Cyker]

Yeah, and some are worse than that - A lot of BMWs now require the 12v Battery to be coded to the car with a diagnostic tool or the infotainment goes into a sortof limp mode!  And people still buy these cars! 

Toyotas tend to be the easiest cars to do DIY on as they are designed with that in mind to a certain extent, which is why commonly accessed things tend to be at the top and not buried inside the engine bay, and they often have little hatches to e.g. change the oil filter and drain the oil, without needing to remove the whole undertray.

I love the little details like that.

Most other marques, less so...

 

[forkingabout]

2 minutes ago, Cyker said:

Toyotas tend to be the easiest cars to do DIY on as they are designed with that in mind to a certain extent, which is why commonly accessed things tend to be at the top and not buried inside the engine bay, and they often have little hatches to e.g. change the oil filter and drain the oil, without needing to remove the whole undertray.

The built in service features like rear pad replacement mode, maintenance mode to run the engine etc will all come in useful for future DIY owners. 

IIRC there is a built in service mode for bleeding the electronic coolant valve as well. 

 

[Dala]

15 minutes ago, forkingabout said:

Toyota is pretty easy & just needs a few systems to reinitialise which is covered in the owners manual. 

Some modern vehicles need the battery disconnected / reconnected following the correct procedure to shut down & boot up the body computer safely else you can end up with a recovery wagon trip to the main dealer - just look on a Peugeot forum 😅

Isn't it enough to back up the voltage ?

[forkingabout]

1 minute ago, Dala said:

Isn't it enough to back up the voltage ?

 

For Peugeot its just as easy to follow the correct procedure to shut down / reboot the vehicle systems correctly. 

[PAISLEY1903]

Anyone got a link to a solar trickle charger they have purchased. 

Just want to get one for wife's car when we're away on long road trips in mine. 

[Griff_4988]

I bought this one from Amazon a few months ago.

[PAISLEY1903]

2 hours ago, Griff_4988 said:

I bought this one from Amazon a few months ago.

Thank you. Did you buy the 7.5 or 9 one. 

Do you just leave it sitting inside on your dash if away on holiday for few weeks. 

[Griff_4988]

I bought the 7.5W one, but haven’t actually used it yet as we haven’t been away and left the car for long enough to make it worth using. With a previous car (and an old panel), I used to just leave it laying on top of the dashboard when in use.

I also bought an OBD to Solar Panel Charging Cable available at the time from Halfords, although they don’t seem to list it now.

Although this is an easy way to connect a solar panel directly to the Toyota’s 12V Battery BE AWARE THAT THE POLARITY OF THIS CABLE IS INCOMPATIBLE WITH THAT OF THE SOLAR PANEL and you will need one of these SAE to SAE reverse polarity changers in between.

[PAISLEY1903]

55 minutes ago, Griff_4988 said:

I bought the 7.5W one, but haven’t actually used it yet as we haven’t been away and left the car for long enough to make it worth using. With a previous car (and an old panel), I used to just leave it laying on top of the dashboard when in use.

I also bought an OBD to Solar Panel Charging Cable available at the time from Halfords, although they don’t seem to list it now.

Although this is an easy way to connect a solar panel directly to the Toyota’s 12V battery BE AWARE THAT THE POLARITY OF THIS CABLE IS INCOMPATIBLE WITH THAT OF THE SOLAR PANEL and you will need one of these SAE to SAE reverse polarity changers in between.

Cheers will probably go straight from Battery.  Avoid any issues! 

[Renquist]

I'm looking to buy a new Battery for my 2019 hybrid, I'm not with the car so I can't measure it myself but could someone give me the correct dimensions that I need to get please? 
I'm looking for an AGM one but it seems to be dependant on the size of the Battery, I could measure the one in my PHEV but I'm not sure if its the same one.

[ernieb]

I thought the 12v Battery in my ‘21 PHEV was an AGM, lots of references to it being an AGM. However, it is nit.

[Hadrian1]

This subject has probably been covered, but rather than trawl through 10 pages maybe someone can give some advice  ?

My 2020 Rav4 Hybrid wouldn't start this morning as the 12v Battery was nigh on dead.  I did get everything to light up using a booster pack but it still wouldnt start. Using a meter I find the Battery is down to 5.4v, and doesn't seem to want to take a charge. So it looks like a new Battery is needed, problem being, if I get a new battery how do I change it if I cant open the tail gate ?
I am presently charging up another booster pack to see if that will let me open the tail gate.  If it doesn't what next ?

[philip42h]

4 hours ago, Renquist said:

I'm looking to buy a new battery for my 2019 hybrid, I'm not with the car so I can't measure it myself but could someone give me the correct dimensions that I need to get please? 
I'm looking for an AGM one but it seems to be dependant on the size of the battery, I could measure the one in my PHEV but I'm not sure if its the same one.

Go to the website of a reputable Battery supplier, like Yuasa: https://www.yuasa.co.uk/

Select Battery Finder, and lookup via your registration number, make and model, or VIN ...

[Heidfirst]

1 hour ago, Hadrian1 said:

This subject has probably been covered, but rather than trawl through 10 pages maybe someone can give some advice  ?

My 2020 Rav4 Hybrid wouldn't start this morning as the 12v battery was nigh on dead.  I did get everything to light up using a booster pack but it still wouldnt start. Using a meter I find the battery is down to 5.4v, and doesn't seem to want to take a charge. So it looks like a new battery is needed, problem being, if I get a new battery how do I change it if I cant open the tail gate ?
I am presently charging up another booster pack to see if that will let me open the tail gate.  If it doesn't what next ?

Can you not get to it via the back seats? You should be able to open the driver's door manually using the physical key blade in the fob.

[robo1]

You can open the back door manually according to the manual. Sorry first page at bottom

[Heidfirst]

but you are going to need to access that via the back seats as per my earlier post. If you've done that you might as well just plug into the Battery whilst you are there ... 😉

[Hadrian1]

Thanks for the replies and advice.

I already had the drivers door open when the Battery finally gave up.  I managed to eventually get enough volts

into the Battery to open the tailgate. It took quite a long time for the charger to start working and give me some

power, which enabled me to also start the engine. Until I had some power the back door wouldn't open.

I would be reluctant to try and manually open the tailgate, at the risk of damaging the electric struts, which are

very expensive to replace.

Although the Battery is I assume the one that was originally was supplied with the car, I would have expected it to

last more than 4 years.  Although I had to change the battery in my previous Lexus hybrid during lockdown when

it was 6 years old.  Maybe it's because I don't use it a lot,  This time being 5 days since we last used the Rav4.

We've only had the car about 5 months, so it might be covered by the warranty.

 

[Thermal]

I had my 12V Battery replaced under warranty after 3 years.
At irregular intervals, I could not activate the hybrid system to "Ready" state, even after trying 5 or 6 times.
Sometimes the entertainment display showed "Starting..." and nothing further, even after waiting for minutes.
Pressing the START button then shut the system down again.
Then, with the 5th, 6th or 7th try, the system finally entered Ready Mode.
This happened both Summer and Winter time.
It reminded me of the embarrassing moments in my cars from 40+ years ago when the distributor got wet on a misty morning... ☹
Strange thing was, that this sometimes also happened after >100 Km trips, switching the car off and after 5 minutes trying to restart to park the car... And sat there again for 10 minutes pressing the start button 50 times.
Also, the car got me stranded a couple of times, far from home.
Winter time, freezing weather and the 12V Battery went down to 11 Volt (measured) after 3 days.
Knowing now that the 12V Battery was a weak point of the car, I was prepared and always have a NoCo GB40 Booster in the in pocket behind the passenger seat. (Not in the boot!)

Before the 3 year warranty ran out, I finally convinced the dealer to replace the 12V battery.
Occasionally, the hybrid system still takes 15 to 20 seconds to "half wake up", and requires a second Start pressed to Ready state, but it is a vast improvement.  Possibly, the dealer not only replaced the battery, but  also applied a  firmware  upgrade for the DC to DC converter or some other battery management computer. I could not get that confirmed.
Never any DTC's were stored to document this problem.

Other than that, it’s a very nice and reliable car!