Lexus Link App with UX300e showing wrong charging info

[EddyBaby]

I can't see why driving the car would help charging the 12V Battery especially when there is no belt driven alternator. For the purpose of looking into the reasons for any problems with the 12V Battery, it would be good to know how and when the 12V Battery gets charged. I assumed it was when plugged into a home charger.

I have never had any problems with the 12v Battery and even used it to pump up my tyres for winter. It seems incredibly unlikely that a 12V lead/acid Battery would be drained by Bluetooth communications. I always leave the app on and left the car for 2weeks in January without problems.

 

[ColinBarber]

1 hour ago, EddyBaby said:

I can't see why driving the car would help charging the 12V battery especially when there is no belt driven alternator. For the purpose of looking into the reasons for any problems with the 12V battery, it would be good to know how and when the 12V battery gets charged. I assumed it was when plugged into a home charger.

The 12 v Battery gets charged by the vehicle's DC-DC converter from the main traction Battery when the vehicle is powered on. Hence if you are not driving your vehicle regularly (or at least turning it on but not going anywhere), it isn't charging the 12 v Battery. I assume it will also be charged when the main vehicle is being charged. But again if you aren't using the vehicle much then you aren't charging it frequently either.

The 300e operates in the same way as the 250h. The 12 v Battery powers the alarm, keyless entry system and a few minor systems whilst powered off which slowly drains the Battery. It will last over 2 weeks without problem, but you need to use the vehicle enough to put back that 2 week loss. What the 300e doesn't do is use the EV traction Battery to power the standby systems and nor does the vehicle power itself up and recharge the 12 v Battery if it is getting low, unlike some EVs.

[Kevin Williams]

An interesting post Colin. I will soon be buying a UX300e. Should I include in the deal, that a brand new, good quality 12v Battery is fitted... Or have one fitted when I have bought a UX300e...? I should then be ok for a few months, or longer...?

If I power up the UX300e for half an hour each week I don’t drive it. Will the 12v aux Battery stay well charged…? Thank you

[ColinBarber]

20 hours ago, Kevin Williams said:

An interesting post Colin. I will soon be buying a UX300e. Should I include in the deal, that a brand new, good quality 12v battery is fitted... Or have one fitted when I have bought a UX300e...? I should then be ok for a few months, or longer...?

If I power up the UX300e for half an hour each week I don’t drive it. Will the 12v aux battery stay well charged…? Thank you

A used 300e isn't going to be that old so I doubt a dealer would replace a good working Battery. They are only ever going to replace it with a direct replacement, whereas the only way to improve the situation would be to replace it with a higher capacity one (if something of higher capacity can physically fit).

Powering up for 30 mins (if you have a volt meter you would need to give an eye on it to make sure it does fully charge and if not just extend the time a little) will keep it charged and avoid any issues.

[Kevin Williams]

1 hour ago, ColinBarber said:

A used 300e isn't going to be that old so I doubt a dealer would replace a good working battery. They are only ever going to replace it with a direct replacement, whereas the only way to improve the situation would be to replace it with a higher capacity one (if something of higher capacity can physically fit).

Powering up for 30 mins (if you have a volt meter you would need to give an eye on it to make sure it does fully charge and if not just extend the time a little) will keep it charged and avoid any issues.

Thanks very much Colin. I will buy a volt meter...

[stepppy]

You could buy yourself a smart charger and save all the worry. I purchased the one below during the lockdown and it looked after the 12v Battery on my Prius really perfectly. Less than £30 is a bargain for peace of mind.

Maypole 7423A Battery Charger Auto Electronic 4A 12V https://amzn.eu/d/i4KrH4C

Still use it now if I’m not going to use the car for a couple of weeks.  My Battery is now over 5 years old and it’s still going working perfectly. 

I also have a small jump pack in my glove box, just it case I need it whilst I’m away from home.

 

[Kevin Williams]

23 hours ago, ColinBarber said:

A used 300e isn't going to be that old so I doubt a dealer would replace a good working battery. They are only ever going to replace it with a direct replacement, whereas the only way to improve the situation would be to replace it with a higher capacity one (if something of higher capacity can physically fit).

Powering up for 30 mins (if you have a volt meter you would need to give an eye on it to make sure it does fully charge and if not just extend the time a little) will keep it charged and avoid any issues.

Sorry Colin. One last question... Do you know how many volts need to be in the 12v aux Battery to put the UX300e into Ready mode...? Thank you

[ColinBarber]

33 minutes ago, Kevin Williams said:

Sorry Colin. One last question... Do you know how many volts need to be in the 12v aux battery to put the UX300e into Ready mode...? Thank you

Not sure. It will probably go into ready mode if the voltage is as low as 12.0 v but you would only have 30 to 40% charge at that point so you don't want it to go that low on a regular basis. Ideally you want to charge it at 12.4 v (if not before) and you want it to be at 12.8 v once you have charged it.

[Kevin Williams]

4 hours ago, ColinBarber said:

Not sure. It will probably go into ready mode if the voltage is as low as 12.0 v but you would only have 30 to 40% charge at that point so you don't want it to go that low on a regular basis. Ideally you want to charge it at 12.4 v (if not before) and you want it to be at 12.8 v once you have charged it.

Okidoki. Thanks very much Colin.