Toyota: advice on 12v battery maintenance

[AEG]

On 1/31/2022 at 4:23 PM, Dala said:

12V for AGM?

I measured when the car was not running:
day 1: (second day): 12.4V - 12.5V
Day 2: 12.2V-12.4V
Day 3: 12.1V-12.2V
Day 4: 12.0 V - 12.1 V
Day 5: 11.9V - 12.0V
Day 6: 11.8V
day 7: 11.7V 

Isn't it possible that the car battery is being discharged by the Toyota MYT satellite system? 

I have the corolla 2022,   2.0 Hybrid.  Which suffers the same large voltage drop if left for a week uncharged.  Why is this ?  Well if I measure the Battery discharge current with the car locked and the alarm system on, the car system draws 0.6 Amp/hr.  So after a week it is not surprising the Battery is almost flat.  So what is draining the Battery ?

After looking into this a little deeper I found the alarm system is the main power consumer.  I proved this to be true by by switching off the movement sensor ( next to the mirror), and measured the discharge current again.  This had dropped to 0.065A. (65mAh). So I am clear, as to what is draining my 12v 45Ah battery down.

Obviously leaving the alarm system off is a risk, unless your car is securely locked away in a garage .     

     

[Roy124]

@AEG good thank you, though my Corolla sat in the garage unlocked during Covid and still suffered drain and flat Battery. 

[peter radford]

CAN YOU FIT A BIGGER Battery TO A TOYOTA YARIS CROSS FOR THE 12V SYSTEM

[Roy124]

On 2/22/2024 at 4:11 PM, peter radford said:

CAN YOU FIT A BIGGER BATTERY TO A TOYOTA YARIS CROSS FOR THE 12V SYSTEM

Yes

[Gren]

You could also fit a powered 12v socket directly to the Battery, like this poster did...

I fitted one to my car, quite an easy job, it provides a permanently-live socket that I can plug my trickle charger into (Noco, with the 12v socket adaptor)

 

[Auris Geezer]

Out of interest sake, what do you do when you park up at Manchester Airport to jet off to sunnier climes for a fortnight?

[Roy124]

1 hour ago, Auris Geezer said:

Out of interest sake, what do you do when you park up at Manchester Airport to jet off to sunnier climes for a fortnight?

In case you use a covered car park get a jumper pack.

If you know you will have a sky view rely on the jumper pack or get a solar charger.

Or rely on a breakdown service.

[Auris Geezer]

That's not ideal is it?  So what is it that actually runs the 12v Battery down please?

[Roy124]

12 hours ago, Auris Geezer said:

 

Trev, that was slightly tongue in cheek as it happens .but is not as frequent as you might suspect from this forum.  If it was 10% of all Toyota Hybrids per flight, or even 0.1%,it would hit the national press.

As for your question,  the answer would appear to be a combination of many things.  The Alarm system and possibly a dashcam; the remote key system listening for an unlock command; the Data Communication Module,  having uploaded the last trip data remains active should you want to check the status, heat the car, or flash the hazard warners.

Then you have normal voltage loss, common to all batteries. 

Clearly a small Battery, 35AHr, has a much lower starting capacity than a higher capacity one capable of driving a starter motor. 

[Hadrian1]

During lockdown the 12v Battery on my Lexus IS300h failed, it just wouldn't hold a charge. I managed to get a genuine Toyota Battery to replace it.  It was 6yrs old, which was about right I'm told.

When changing one of these batteries don't forget to disconnect the Battery vent tube.

[flamarro]

Hello to all of you

I've read all of your comments about this "thing"  with the 12V batery

I don't have my Yaris cross yet ( end of June probably ) but I want to be aware of what to do.

So, my car will ride 2-3 times a week, 10 minutes or less, twice a day on work days.
Longer rides at the weekends, sometimes. Sometimes not
A big ride, twice a year.

I think when I have the car it will be different, but now is more or less this way with my 10 Year old 2008.

So with this use, it is probably that I will have troubles with my 12V batery, slowly lowering it's capacity, right? Or don't even think about that, because it is enough?

Things to get
Voltage meter to connect to the cigarette lighter. Once I detect that being lower than 12.1V, need recharge

Ways of doing it
Turn on the car to ready, and leave it for an hour, maybe once every two weeks, if I didn't take it to a walk at the weekend.

Get a noco or a cetek charger to charge the batery.
A problem to me is that this chargers are to be connected to a electric source, and my car will be parked in the streets, no power supply.
Is there a Battery charger with battery's itself? Is Noco booster a solution? That way I'll have a device that can help other people too, if needed to start their cars, hybrid or not. So many times that it would have been useful, without the need to park side by side and connect the two battery's. But it's expensive.

Thanks in advance

 

[Espiga]

Hi What is the best solar charger for a 22 yaris. Caught out for the second time after leaving car ar airport for a few weeks. Mydealer was absolutely of no value didn't seem to acknowledge a problem.

 

[IanML]

I have a AA brand one from Amazon £31.90.  Works well to maintain charge, but you can't use it to recharge a low Battery - that really needs a mains charger.

[GalloB]

I have a very simple Aygo now with no fancy Battery or stop start, but with my previous cars with stop start, it would always stop working after a few weeks as I only do a few short journeys a week. I bought an intelligent Battery charger from Halfords and used to put it on overnight once a month. That seemed to do the trick. 

Think it's this one:

https://www.halfords.com/motoring/battery-maintenance/battery-chargers/halfords-smart-battery-charger-8a-496254.html

I charged the Battery in the Aygo once the first time I got it as it had been sitting around at the dealer for a month or so before I bought it and was three years old but not sure if I need to keep doing the monthly charges on this little nugget, or if a short Tesco run once a week is enough to keep it ticking along.

 

[Big_D]

This is the one I have

[dannyboy413]

I also have one of those. When I had the Yaris Cross, which had a 35amp Battery, I used to plug the charger in to the car via the OBD port, on the 3 or 4 times I came across to the UK and never had a problem on my return. I have used it once in the C-HR when I left it for five days, but got the impression on my return to the car that it had not been necessary - the C-HR has a 45 amp Battery. However, the main reason for this post is to answer the comment from @IanML . I am presuming you are correct Ian when you say it can not charge a low Battery, (12v?), but I use the solar charger for charging the battery on my electric start lawnmower and that charges fine. However, the battery is just one of those little ones - I am not even sure what the voltage/amps are.