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12v battery maintenance


FROSTYBALLS
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Extracted from the Toyota UK blog advice:

"If you have a 12V Battery trickle charger, or a solar panel charger, and are confident using them, then these are a good option to keep the Battery fully charged while the vehicle is stationary for a period of time."

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2 hours ago, 182_blue said:

Out of interest can you safely put a Ctek charger on the 2019 + Rav4 Hybrid?  (12v accessory voucher).

I'm not entirely sure what you meant by "12v accessory voucher" but the 12v accessory sockets are live only when the ignition is 'on' so an attempt to use a charger while the ignition is 'off' will not be effective.

22 minutes ago, 2bikes said:

According to the car care nut on YouTube

( he's a Toyota master tech) trickle charger should only be connected direct to 12v battery,bit of a pain as it's in boot area .

In the 4.5 there is a convenient jump start / trickle charge point under the bonnet which is much easier to access. I believe the same is true of the 4.4 hybrid.

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9 hours ago, philip42h said:

I'm not entirely sure what you meant by "12v accessory voucher" but the 12v accessory sockets are live only when the ignition is 'on' so an attempt to use a charger while the ignition is 'off' will not be effective.

In the 4.5 there is a convenient jump start / trickle charge point under the bonnet which is much easier to access. I believe the same is true of the 4.4 hybrid.

Yes I'm aware of that 😏it's just he doesn't recommend using those for trickle charging ,not sure why .

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1 hour ago, 2bikes said:

Yes I'm aware of that 😏it's just he doesn't recommend using those for trickle charging ,not sure why .

Ah, well as Frosty said:

12 hours ago, FROSTYBALLS said:

Extracted from the Toyota UK blog advice:

"If you have a 12V battery trickle charger, or a solar panel charger, and are confident using them, then these are a good option to keep the battery fully charged while the vehicle is stationary for a period of time."

The jump start point is clearly designed for, and man enough, for the job. All we are doing as part of the "jump start" procedure is toping-up the Battery sufficiently to get the electronics going. As you will know, there's no starter motor to turn over with the 12V system which is why the hybrid can get away with such a puny 12V Battery in the first place.

The owners manual states:

■ Before recharging:  When recharging, the 12-volt battery produces hydrogen gas which is flammable and explosive. Therefore, observe the following precautions before recharging:

  • If recharging with the 12-volt battery installed on the vehicle, be sure to disconnect the ground cable.
  • Make sure the power switch on the charger is off when connecting and disconnecting the charger cables to the 12-volt Battery.

There is clearly a risk of "over gassing" and a build-up of hydrogen in the boot area. But a good smart charger  will reduce any associated risk to a level that I am happy to live with. (The charging system built into in the car will charge the battery in-situ in any case).

I wouldn't use an old fashioned 'dumb' charger and certainly not leave one connected for any length of time ...

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When using the trickle charger you should also make sure that the charging current is less than 5A. This is normally stated on the top of your Battery pack (Panasonic OEM). Note that this is for the hybrid, I don't know if it is the same for non-hybrid.

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14 hours ago, philip42h said:

I'm not entirely sure what you meant by "12v accessory voucher" but the 12v accessory sockets are live only when the ignition is 'on' so an attempt to use a charger while the ignition is 'off' will not be effective.

In the 4.5 there is a convenient jump start / trickle charge point under the bonnet which is much easier to access. I believe the same is true of the 4.4 hybrid.

Sorry my phone preferred voucher to Charger !

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4 hours ago, philip42h said:

Ah, well as Frosty said:

The jump start point is clearly designed for, and man enough, for the job. All we are doing as part of the "jump start" procedure is toping-up the battery sufficiently to get the electronics going. As you will know, there's no starter motor to turn over with the 12V system which is why the hybrid can get away with such a puny 12V battery in the first place.

The owners manual states:

■ Before recharging:  When recharging, the 12-volt battery produces hydrogen gas which is flammable and explosive. Therefore, observe the following precautions before recharging:

  • If recharging with the 12-volt battery installed on the vehicle, be sure to disconnect the ground cable.
  • Make sure the power switch on the charger is off when connecting and disconnecting the charger cables to the 12-volt battery.

There is clearly a risk of "over gassing" and a build-up of hydrogen in the boot area. But a good smart charger  will reduce any associated risk to a level that I am happy to live with. (The charging system built into in the car will charge the battery in-situ in any case).

I wouldn't use an old fashioned 'dumb' charger and certainly not leave one connected for any length of time ...

I have a top of the range Ctek trickle charger that works on stop start cars etc, I forget the model number but I purchased it all year for my old car due to covid. 

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2 hours ago, 182_blue said:

I have a top of the range Ctek trickle charger that works on stop start cars etc, I forget the model number but I purchased it all year for my old car due to covid. 

Probably CTEK MSX 5, though there are some other models, but I highly recommend that one.

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  • 2 weeks later...

I have hard wired a CETEK connector to the Battery under the boot floor, the connector is accessible now in the boot, so now just have to plug in the CETEK when needed.

I have been using this since March without problems.

Paul

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Just had an email through from our dealer, Motorline Toyota Worcester, see below. I've spoken to them this morning and they're recommending the solar charger of which they have two types for £27 and £40 (forget capacities of these). The person I spoke to said he thought they could be connected via the cigar lighter socket. I'm going in on Monday morning to see what they have and how they recommend they are connected.

 

With most of us staying at home and being encouraged to park our cars if we can, you may be concerned about the level of charge in your batteries during long periods without use.

At Toyota, we like to give you total peace of mind. So we recommend buying a 12V Battery trickle charger or a solar panel charger to ensure your Battery remains fully charged at all times.

 

 
 
 
 
Which trickle charger is best for you?
 
 
 
 
 
Solar Powered
Solar-powered trickle chargers 
Solar-powered trickle chargers charge at a rate that's equal to the self-discharge rate, so they’ll keep your batteries charged at the proper level. They won’t charge a completely dead Battery, though.
 
 
 
 
Smart Battery
Smart battery trickle chargers 
As well as discharging, analysing, conditioning and performing cycle tests on your batteries, smart trickle chargers typically charge your battery in the same amount of time as a rapid charger.
 
 
 
   
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  • 3 months later...

I’m taking delivery of my new Rav4 Hybrid this week so hopefully won’t need a charger for some time.

My current car is a Jaguar XE R-Sport with the Battery under the spare wheel in the boot,  so I bought a CTEK MSX 5.0 and fitted a remote charging socket / condition indicator in the boot so the charger can be easily plugged in.

CTEK Technical Department we’re very helpful regarding connecting the charging socket, in the case of the Jaguar it was “Red” wire directly onto the Battery positive terminal and the “Black” wire to a earth point on the car (not directly onto the battery).

 

AC58CD87-AB82-4137-84B8-E74EC3632754.jpeg

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I too have the CTEK 5, a week ago I connected the wife’s Auris Battery via the terminals under the bonnet, should take it through to December then I will give it another charge ready for the bad months. My Prius will also get a charge then as well. Brilliant piece of kit.

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This is something I’m going to have to consider buying.  I’d have thought that when connected to the mains to charge the traction Battery the DC to DC converter would be powered to fully charge the 12 AGM Battery, sadly this is not the case.  If I use the MyT app to monitor the charge I get a warning to say that doing so requires the car to be “awake” and this might discharge the Battery.  There are numerous other warnings that will similarly discharge the battery, e.g., making setting changes.

Interestingly, when tethered to the mains, it’s happy to run the car in “room mode” (so you could sleep in it) or to pre condition the and climate control the car, defrost the windows but not to trickle charge the AGM battery?

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2 hours ago, Rigsby said:

a CTEK MSX 5.0 and fitted a remote charging socket / condition indicator in the boot so the charger can be easily plugged in

AC58CD87-AB82-4137-84B8-E74EC3632754.jpeg

I presume this it the connector with green, Amber, red lights. I found it would register green only for an hour or 2 before going amber and then red in a day or two.  I sent it back.  Was I premature as the Battery was subsequently changed as faulty. 

How long did yours stay green? 

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On 6/7/2021 at 10:33 AM, Catlover said:

Hi Alan, your little grandson has just made Toyota Owners Club forum redundant - any problems you have in the future just ask him 😀

👍

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1 minute ago, Rigsby said:

👍

 

21 hours ago, Roy124 said:

I presume this it the connector with green, Amber, red lights. I found it would register green only for an hour or 2 before going amber and then red in a day or two.  I sent it back.  Was I premature as the battery was subsequently changed as faulty. 

How long did yours stay green? 

My Jag’s Battery is nearly 4 years old so probably not in peak condition but stays green for a day or two following a charge, doing mainly short trips at the moment so not getting a good chance of a charge.

Stop / Start doesn’t work for weeks then all of a sudden starts working again.

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  • 6 months later...
On 2/5/2021 at 10:30 PM, philip42h said:

I'm not entirely sure what you meant by "12v accessory voucher" but the 12v accessory sockets are live only when the ignition is 'on' so an attempt to use a charger while the ignition is 'off' will not be effective.

In the 4.5 there is a convenient jump start / trickle charge point under the bonnet which is much easier to access. I believe the same is true of the 4.4 hybrid.

jump start / trickle charge point worked for me do not fancy sitting in car for an hour to charge the Battery every week i do not use car

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  • 3 months later...
  • 5 months later...

I know there have been other posts concerning the 12 volt Battery but here’s another as I consider this item to be the achilles heel of an otherwise excellent car.
My car had its first annual service on 8 September and on the 11th we drove 700km to a Spanish destination. Obviously in HV most of the time. Left it for three days (the first night of which the front windows were accidentally left open but discovered and rectified in the morning - would the 12v Battery have been affected by this?). No problem then driving it to next destination about 50km away. Three days later the car (unused again for three days) died on me shortly after I tried to put a new address into nav system - without having put the car into Ready, I should add. Car completely dead. Won’t mention all the pain involved but eventually the breakdown guy arrived and jump started it from under the bonnet (which I admit I didn’t know could be done, thinking he would have to go to boot for 12v Battery - but have since learned a bit more by properly studying the manual.) I then drove to the nearest Toyota dealer who recharged the 12v battery, stating it had been too low.
On the way home we got stuck in a monstrous traffic jam in the late evening on the A43 near Grenoble, and hardly moved for an hour, but with lights on, worried that the car might die as the traction battery was at what I call the Hybrid setting (30% ?), and the ICE wouldn’t run, being mostly stationary, unless I  put it onto the Charge setting. Fortunately we managed to get off the motorway and get home safely.
Questions:
1  is there a simple way to monitor the 12v battery health? On the US forum some people suggest a simple voltmeter to plug into the 12v socket (aka cigar lighter!). Would this give a useful reading?
2  what parts of the car are directly powered by the 12v battery once we are under way? Could the lights have failed in an enforced nighttime stoppage? Or would the ICE kick in to charge the traction battery to then trickle charge the 12v battery? Dare we use the heaters or AC in that sort of situation? (We didn't)
3  More generally, if, as in my case, most car trips are around town and solely in EV, should we routinely charge the 12v battery by (as I understand) leaving the car in Ready for 20 minutes to let the traction battery charge the 12v battery? If so, how often? Or does the act of charging the traction battery do that sufficiently anyway? There seems to be some ambivalence in the posts I have read on the forums.

I find the lack of any warnings concerning 12 v battery on the dashboard to be a real negative!  Sorry to go on about this but my faith in the car has been shaken.

 

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The 12v auxiliary Battery is charged from the traction Battery when the car is in Ready mode. The PHEV is able to use power provided from the mains for this; both PHEV and HEV will run the ICE if necessary to tip-up the traction Battery so that it can top-up the 12v auxiliary battery. As long as the auxiliary battery is healthy, and the car is used reasonably regularly, there is no issue with this system at all. Toyota guidance is that 60 minutes in Ready mode per week is sufficient - personally I suspect that is way more than sufficient.

All the car's normal 12v systems are powered from the 12v auxiliary battery - just as they would be in a conventional ICE powered car. Provided that the car is in Ready mode the 12v auxiliary battery will be topped-up as necessary to maintain this situation 'indefinitely'.

So there a few things to avoid / note:

  • Don't leave the car in Accessory mode (or in Ignition on mode) for any length of time to listen to the radio or whatever - this will drain the 12v auxiliary battery without allowing it to be topped up from the traction battery.
  • Don't leave the lights on, the door open, or the interior lights on - though the interior lights will go out quite quickly to save you from bother.
  • Be aware that the security and remote access systems remain active (obviously) when the car is off and locked. If the keys are frequently moved and close to the car drain would be higher than if the keys are stored well away from the car.

A voltmeter in the accessory socket will provide a voltage reading when the car is not Off - the accessory socket is not powered when the car is Off. Once you are in Ready mode it should show at least 12v because the auxiliary battery is being charged.

Looking at the distances you have driven over the period in question, the auxiliary battery should have been fully charged - even if the garage had done something pretty dumb during the service. What seems most likely is that you, or a family member, used the 12v accessory services / mode for an extended period during your stay?

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Thanks for the reply. Maybe my trying to input the destination address when not in Ready mode did the dastardly deed, but nothing else I am aware of!

One more question: you write "As long as the auxiliary Battery is healthy, and the car is used reasonably regularly, there is no issue with this system at all. Toyota guidance is that 60 minutes in Ready mode per week is sufficient". Well, I use the car almost every day, in EV mode when charged as it usually is. Does the reference to "60 minutes in Ready mode per week" refer to being stationery and letting the traction Battery charge the 12v Battery, or does it mean, you need to drive the car at least 60 mins per week, when by definition it is Ready? That's a dumb question perhaps, but I need to be clear.

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