12v battery issues, anyone got a Jump pack?

[Dala]

1 hour ago, philip42h said:

....If you drive for more than 1 hour per week the car will stand for correspondingly less and the battery should become fully charged over time....

By using the car in any way (to stay in "ready" mode or driving ), you will never charge the car Battery to full capacity !

57 minutes ago, TonyHSD said:

... up to its full charge which is from as low as 12.2v up to 13v....

a mistake or the idea that 12.2V is a fully charged car Battery?

[philip42h]

4 minutes ago, Dala said:

By using the car in any way (to stay in "ready" mode or driving ), you will never charge the car battery to full capacity !

Why not?

The car is equipped with a smart charger - the DC-DC converter - that charges the auxiliary Battery from the traction Battery when in Ready mode. The engine will run as required to maintain the state of charge of the traction Battery.

This will charge the auxiliary battery to the 'design' capacity ... and that's all we want.

While it may be possible to disconnect the battery from the car and 'fully' charge it to something in excess of 12.6 volts (or whatever) it won't stay that way for very long. When reconnected to the car it will revert to being maintained by the DC-DC converter at the 'design' capacity.

[Dala]

3 minutes ago, philip42h said:

... 'design' capacity ... 

??

[TonyHSD]

46 minutes ago, Dala said:

By using the car in any way (to stay in "ready" mode or driving ), you will never charge the car battery to full capacity !

a mistake or the idea that 12.2V is a fully charged car battery?

12.2v is low Battery after 5-7 days of inactivity but then 40min in ready mode and the Battery goes up to 13v, switching off the car and measure again after few minutes it stays around 12.9v. Then the car left without use for another week and the Battery slowly discharges as usual but remains over 12v and I repeat the ready mode because I didn’t want to bother with cables and chargers and all was good. This is how my car survived the lock downs and my holidays of up to 5 weeks. 

[Dala]

19 minutes ago, TonyHSD said:

12.2v is low battery after 5-7 days of inactivity but then 40min in ready mode and the battery goes up to 13v, switching off the car and measure again after few minutes it stays around 12.9v. Then the car left without use for another week and the battery slowly discharges as usual but remains over 12v and I repeat the ready mode because I didn’t want to bother with cables and chargers and all was good. This is how my car survived the lock downs and my holidays of up to 5 weeks. 

Tony, do you have a chart ? How long do your car batteries hold voltage?

[TonyHSD]

2 hours ago, Dala said:

Tony, do you have a chart ? How long do your car batteries hold voltage?

Remember we have discussed this in different posts in Auris forum. 
Back in May I have stopped driving for 5 weeks and I did not touched the car for 13 days in row, then the Battery was down to 12.15v shown on multimeter after unlocking and removing everything from the boot to get access.
I connected to the smart charger and left for 3.5hrs, then I have stopped charging and continued the next day until Battery showed full at 12.9v. 
I left the car for 7 more days and then I started it for a first time in 20 days  but I didn’t take any measurements. Kept in ready mode for around 30min. 
After another 5 days  of inactivity I started the car again and the voltage was shown on Carista app as 11.7v at the moment of pressing the start button, the brake booster was pressuring the system. Then the voltage went up to 14.43v as shown on t(e app. I thought not to bother using the charger anymore and only keep in ready mode.
I am confident leaving it for up to a week without use. Been left up to 4 weeks previously without any problems, but now it is very old and I am afraid of leaving it for much longer. 👍

 

 

 

[TonyHSD]

Forgot to mention something interesting. 
Before I removed everything from the boot I did one final test.
I unlocked the car and measured the Battery showing 12.36v after 5-6 days without use. Started the car and set in ready mode for 40 min and then switched off and measured again it showed 12.9v. This is why I decided not to use the smart charger anymore. , it was no need for me. 

[Roker]

On 8/6/2023 at 2:21 PM, Roy124 said:

Zen, correct on all counts.

The dealer should certainly check that battery.  A jumper pack is a cheap insurance aid.   Breakdown cover is fine but could be frustrating if you wait an hour or more for some you could do on minutes.

This would work:

https://www.amazon.co.uk/Portable-Flashlight-Automatic-Emergency-FitAutomotive/dp/B0BN8KMB9Y/ref=mp_s_a_1_14

Or this: https://www.ebay.co.uk/itm/185920789446

That's an example, not a recommendation. 

Why do we need high capacity charges when we are just starting the computer and not cranking the engine xs

[Roy124]

1 minute ago, Roker said:

Why do we need high capacity charges when we are just starting the computer and not cranking the engine xs

Quite, hence a simple jumper pack.

[philip42h]

38 minutes ago, Roy124 said:

40 minutes ago, Roker said:

Why do we need high capacity charges when we are just starting the computer and not cranking the engine xs

Quite, hence a simple jumper pack.

As Roy says, we don't need a high-capacity jumper pack - a modest one will do.

But while we don't need to "crank the engine" we do have to do more than "just start the computer". The key drain on the system before we get into Ready mode is running the brake boost motor to ensure we have hydraulic pressure before the car will start. That's the strange whirring we can hear as we open the driver's door to get in!

[Roy124]

Regarding the DC-DC design capacity,  indeed.  However the voltage to which it will charge and maintain the Battery voltage seems to be lower than the voltage that the smart charger will give.

The difference will be in the time for it to discharge to, say, 12v.

[philip42h]

50 minutes ago, Roy124 said:

Regarding the DC-DC design capacity,  indeed.  However the voltage to which it will charge and maintain the battery voltage seems to be lower than the voltage that the smart charger will give.

The difference will be in the time for it to discharge to, say, 12v.

True ... but what do you understand these voltages to be?

In the example Tony gives:

6 hours ago, TonyHSD said:

... 40min in ready mode and the battery goes up to 13v, switching off the car and measure again after few minutes it stays around 12.9v. 

13V sounds like a normal 'float' voltage output by a smart charger (the DC-DC converter) to maintain the charge state of a fully charged Battery. 12.9V sounds like a pretty good figure for a fully charged AGM or GEL Battery. As I understand the OEM batteries in our cars tend to be standard flooded cell batteries - mine is certainly - and you'd be looking at a fully charged resting voltage of closer to 12.6V in that case. Don't forget these batteries remain connected and in use all the time so there's little chance of getting an additional 'surface' voltage to play with.

So, in this example the DC-DC converter seems to be doing pretty much as well as any smart charger might be expected to.

As you say, if you are planning to leave the car standing for a longer period of time, make sure that it is fully charged before to leave it. And if you want to extend the viable standing time, fit a higher capacity Battery.

[Roy124]

Philip I forget the figures I had as I haven't checked recently but the charger floats at a higher level than the DC-DC achieves and iirc the rested voltage off charge is about 0.2v higher when it had the smart charger.

If I remember I will do a check over the next weekend. 

 

[CruxisCore]

If you spend 50-100 on a jump booster and drag it along, might as well pay 20 extra and get one that is able to start your neighbours ICE car as well.

[Roker]

On 8/6/2023 at 2:21 PM, Roy124 said:

Zen, correct on all counts.

The dealer should certainly check that battery.  A jumper pack is a cheap insurance aid.   Breakdown cover is fine but could be frustrating if you wait an hour or more for some you could do on minutes.

This would work:

https://www.amazon.co.uk/Portable-Flashlight-Automatic-Emergency-FitAutomotive/dp/B0BN8KMB9Y/ref=mp_s_a_1_14

Or this: https://www.ebay.co.uk/itm/185920789446

That's an example, not a recommendation. 

Why do we need high capacity charges when we are just starting the computer and not cranking the engine xs

[Roker]

Could we just use ordinary batteries instead of Lithium this would eliminate potential fires having the lithium flying around in the boot

[UncleZen]

On 8/17/2023 at 5:12 PM, philip42h said:

The key drain on the system before we get into Ready mode is running the brake boost motor to ensure we have hydraulic pressure before the car will start. That's the strange whirring we can hear as we open the driver's door to get in!

I get this whirring sound when I sit on the seat, not when I open the door, I'm pretty sure about that. 

[Roy124]

Uncle Zen, I agree, same with the YX.  It may be a change as I think the Corolla dud it on door opening.

[TonyHSD]

Is it when you seat on drivers seat or when you step on the brake ?  

It seems Toyota has changed the settings then, most other hybrids like Auris, Prius, Corolla once you open drivers door the brake booster starts and this is highest 12v energy drain before the car starts. So if your car is off and you are constantly playing around opening and closing the drivers door in other hybrids you can easily drain your small 12v Battery. 
What else is draining your batteries on top of the DCM and connected services. 
Brake booster, Auto parking brake, auto folding mirrors, coming home lights , interior lights settings, keyless entry. Added cameras. 
Some of these can be switched back to manual control and only use when necessary, this will reduce a bit the 12v energy consumption and extend the life of your Battery. 
 

[UncleZen]

4 hours ago, TonyHSD said:

Is it when you seat on drivers seat or when you step on the brake ?  

For me it's when I sit on the seat.