12v battery maintenance, issues, etc.

[jthspace]

11 hours ago, HarryW2024 said:

Agree, however if you went on holiday for say 3 weeks which system would better guaranteed to start on your return……

Agreed, but I've got a lithium booster pack in the glove box just in case 😎

Come January it will be parked up for 46 days whilst we sun ourselves 🛳️; solar panels in operation so we'll see what happens..........

[hind]

Booster pack, yes, but as you wrote - just in case (of emergency power failure), not as a workaround tool for the bad design 😉 If you need to use it, you Battery already got hit hard with the low voltage. IMO the cutoff mechanism which disconnects the 12v Battery (almost) completely is better as it prevents the unevitable damage with a price of the inconvenience to unlock the car with a physical key. 

[Chas G]

My Yaris Cross self charging plug in hybrid shows 12.6 volts in accessory mode and changes to 14.4 volts as soon as I put it in ready mode.

The voltage then drops to 13 volts after about 1/2 mile of driving.

Wouldn't it be better if the charging system just bunged 14.4 volts up the pipe like an alternator would do and keep the 12 volt Battery fully charged?

After every journey when i get home the accessory mode voltage is always less than when I started out.

Ps. Every hybrid/mild hybrid car I have looked at eg Honda Civic and Jazz, Hyundai CX30, Ford ecoboom etc all suffer from the same 12 volt Battery issue to some extent.

With some hybrid cars when the 12v gives up the ghost, the car will still not start with a jump pack or new Battery until the monitoring system has been reset.

[Cyker]

Yeah I think they should nick that idea from Hyundai too - It's not very elegant, but it's simple and easy to use and will stop you getting stranded and having to faff about with jump leads just as you need to get somewhere in a hurry. It would also prevent the 12v from being discharged to 0% (Which is, if not a death sentence, is at least a fairly severe maiming, for lead acid batteries!).

Honestly they need to do something instead of just ignoring the problem - They already went through a lot of pain with the same problem back in the day with the Auris hybrid, and I always thought it was a bit of a weird blindspot in Toyota's normal 'continuous improvement' mantra.

[hind]

Yeah that continues improvement happens, just in production cost and the profit per car 😉

[RickyC]

23 hours ago, hind said:

Booster pack, yes, but as you wrote - just in case (of emergency power failure), not as a workaround tool for the bad design 😉 If you need to use it, you battery already got hit hard with the low voltage. IMO the cutoff mechanism which disconnects the 12v battery (almost) completely is better as it prevents the unevitable damage with a price of the inconvenience to unlock the car with a physical key. 

It's not a simple problem of opening the car with remote or with phisical key.  There are a lot of modules that are 12V Battery backupped. If you cut 12V with a relay, you risk to lose some data and settings. 

Maybe it could be useful to have an option to disable connected services and remote after one day or something like that reducing power consumption.

The way HV Battery is used in Kia/Hundai and Toyota cars is very different.   A Hundai hybrid car can start also with a totally flat HV Battery, a Toyota can't.  So, security issues apart, is too risky to connect HV battery to DC/DC converter with parked car on a Toyota.

[hind]

8 minutes ago, RickyC said:

If you cut 12V with a relay, you risk to lose some data and settings. 

If you let the voltage drop to critically low level you will loose them anyway. What is worse, you might enter the brown-out condition which might leave the various microcontrollers in the unstable, undefined state. There are specialized mechanisms to cope with the brown-outs. So cutting the voltage to 0V is much safer for the stability of the electronics than leaving them in semi-alive state with voltages of around 8-9V

11 minutes ago, RickyC said:

Maybe it could be useful to have an option to disable connected services and remote after one day or something like that reducing power consumption.

So I wan't be able to run remote heater in winter because the car was sitting outside for the weekend? 🙂 Anything time-related won't work with a Battery which SOC might vary. Again, something like "long term parking mode" enabled from the car would be much better option here. 

 

[Dala]

14 minutes ago, RickyC said:

...If you cut 12V with a relay, you risk to lose some data and settings...

Even with an empty Battery

[Mikw]

Alright peeps, going to have to leave my Yaris Hybrid Hybrid for 8 days in a garage in September.

Do you think the 12v Battery will "hold out" that long?

Car is four years old and without issues so far.

[jthspace]

14 minutes ago, Mikw said:

Alright peeps, going to have to leave my Yaris Hybrid Hybrid for 8 days in a garage in September.

Do you think the 12v battery will "hold out" that long?

Car is four years old and without issues so far.

I would say "yes"

Start a poll? 🤣

[Mikw]

20 minutes ago, jthspace said:

I would say "yes"

Start a poll? 🤣

I have no idea how to start a poll but i like your optimism!

I have a life pattern that suits a car, a couple of journies a week of about an hour, longest it's been left before has been 6 days without use.

8 days is something i'm worried about.

[Dala]

26 minutes ago, Mikw said:

...going to have to leave my Yaris Hybrid Hybrid for 8 days in a garage in September...Do you think the 12v battery will "hold out" that long?...

fully charge the car Battery before leaving and it shouldn't be a problem - if the Battery is OK

The question is : how much will the car Battery voltage be dropped.

If the voltage is below 12.06 V after 8 days, the car battery is already somewhat damaged.

If the voltage is below 11.58 V after 8 days, the car battery is already permanently damaged.

 

[jthspace]

19 minutes ago, Mikw said:

I have no idea how to start a poll but i like your optimism!

I have a life pattern that suits a car, a couple of journies a week of about an hour, longest it's been left before has been 6 days without use.

8 days is something i'm worried about.

Before I changed my Battery to a Yuasa it was 2 years old but i did not know it's history so changed it "just in case"

I had left the car for a week and it was perfectly OK - before I changed the Battery - so just speaking from personal experience.

[dash]

1 hour ago, jthspace said:

 

Start a poll? 🤣

Have a look here for some insight … 

 

[Jeff43]

Just to clarify..is it totally safe to leave a solar charger (I have the AA one) permanently plugged into the OBD port for a week or so when I go on holiday?

[TonyHSD]

3 minutes ago, Jeff43 said:

Just to clarify..is it totally safe to leave a solar charger (I have the AA one) permanently plugged into the OBD port for a week or so when I go on holiday?

Yes, should be totally safe to leave in plugged in for years. 
I known someone who usually goes abroad for 3-6 months or more and they plug in a solar charger into the obd 2 port. It’s not an AA but larger one I believe 20w and this panel remains plugged for months up to 9 months at a time. Never had any problems. 
What I noticed on their previous car that was equipped with inbuilt trickle charger that uses power from the traction Battery to recharge the 12v Battery during the autumn clouds the car started to trickle charge the 12v Battery even though the solar panel was still plugged in. All that means one thing - solar chargers only able to help in sunny days. 👍

[Dala]

22 minutes ago, TonyHSD said:

... solar chargers only able to help in sunny days...

I have the opposite opinion - in bad weather are sufficient to maintain voltage

Everything is related to the height of the sun above the horizon

 

many users have this AA panel 4,8W laid down, but in spring and Fall is necessary tilted position

 

I would modify your opinion : ... weak solar chargers only able to help in summer...20W-40W solar panel is recommended for spring and fall (in Europe)

[Cowgirl]

2 hours ago, Jeff43 said:

Just to clarify..is it totally safe to leave a solar charger (I have the AA one) permanently plugged into the OBD port for a week or so when I go on holiday?

I leave mine plugged in at the airport with no issues

[Jeff43]

Any recommendations for a 20W+ solar charger (OBD powered) that I can use from October to March? I do tilt the AA one into the sun but it seems from comments here that I don't need to in summer. The parked car is in the early sunshine until midday only and then it gets some shade. Ten weeks' ownership of my new Yaris Cross and no issues so far.

[Dala]

1 hour ago, Jeff43 said:

Any recommendations for a 20W+ solar charger (OBD powered) that I can use from October to March? I do tilt the AA one into the sun but it seems from comments here that I don't need to in summer. The parked car is in the early sunshine until midday only and then it gets some shade. Ten weeks' ownership of my new Yaris Cross and no issues so far.

https://optimate1.com/product/tm522d2ck/

https://www.youtube.com/watch?v=5sTk1l6HFLE

https://www.youtube.com/watch?v=MHR3z1NZp2U

I was afraid to attach the panel to the glass. I use a furniture leg.

This is what a 45 W panel looks like

 

[Graham47]

2 hours ago, Jeff43 said:

Ten weeks' ownership of my new Yaris Cross and no issues so far.

Unless your usage will change significantly in Oct to Mar., why do you feel the need ?

[Jeff43]

This July/August have been manic. On the M25, M20 and M11 a few times, plus lots of local South Circular trips. Very atypical of my January schedule. By the way, a good plan to charge up the 12v Battery via Ready mode is to join the queue for the Dartford tunnel northbound at 8.30 on a weekday morning!

[Mikw]

7 hours ago, Jeff43 said:

This July/August have been manic. On the M25, M20 and M11 a few times, plus lots of local South Circular trips. Very atypical of my January schedule. By the way, a good plan to charge up the 12v battery via Ready mode is to join the queue for the Dartford tunnel northbound at 8.30 on a weekday morning!

Yep! Another one is to hope for a tailback before leaving it for 6 days in a hotel car park at Heathrow. Last time i did that (after getting stuck for 2 hours in very slow moving traffic the night before my flight) i was actually quite happy that my 12v would be alright for when i got back from my holiday.

[Countryside]

This has opened a new craze join tailbacks around the country 👍

[Derek.w]

This is my solar charging for Aug2 to 16 voltage drops to around 12.5 volts overnight then recharges some deys in low light it stays around 12.7 to 13 volts range.