RC300h "house" Battery not charging?

[Cardog]

After my last service my RC300h would not start.  I took it back to the dealer (Jacksons IoM UK) and whined bitterly. They investigated(?) & said it was my fault - I was doing something wrong ... i.e. not locking the car properly when leaving it in my locked garage, or going to post a letter without locking the car when I would be 5' away for 10 secs!

After more of my whining they agreed to replace the Battery at Lexus's cost.   Eventually ... (cos of Covid) ...  they replaced? it. (or sed they did.)

The problem is still there.

The car will start when I put it overnight on my super sofisticated Battery charger, but after a few days won't start.

I haven't changed my driving habits, the car worked faultlessly untill that last service. I think they did something during that service to make the car stop charging the "house" Battery.  I don't want, or expect to have to connect my charger every week - this is not a Plug in EV !!

Jacksons IoM are starting to treat me like a pain inna butt ....  I want my car back to the super reliable Hybred it was ......

Any advice??    Thanks people.

 

 

[ColinBarber]

Not sure what the dealer could have done to trigger the change. You cannot disable charging the Battery.

How often are you using the vehicle? If you fully charge the Battery (on AGM mode) then you should expect to be able to leave the vehicle for two weeks and be able to start it (it would then need at least a couple of hours to recharge it again though).

[Herbie]

4 hours ago, Cardog said:

I think they did something during that service to make the car stop charging the "house" battery.  I don't want, or expect to have to connect my charger every week - this is not a Plug in EV !!

 

Simple way to make sure the Battery is being charged (if, by "house" you mean the 12V battery) is to measure the voltage at the Battery terminals, which should be as per the chart below. Put the car into READY mode and measure again - it should now show about 14.5V if the charging system is working correctly.

 

[08ISF]

Have you checked is something draining power while the car is locked? I have had  starting problems in conventional cars where the boot light or the interior light was on all the time and eventually drained the Battery sufficiently to prevent starting. The Battery in Lexus hybrids is not very big so it wouldn't take much to reduce it to the point where the car wouldn't start. The boot light is a suspect, it is possible I think to move the switch to the point where it doesn't go off when the boot is closed. Try switching it off altogether and see if it makes a difference.

[Linas.P]

very hard to say ... but are you confident your Battery charger actually charges the Battery (could it be that some settings are wrong and it discharges it?)... and secondly are you sure dealer replaced the Battery i.e. maybe they just charged it and put it back in?

I would say if Battery is in good order, then even after 1 month of car being locked it should still be fine to go.

[Cardog]

Thanks very much for these thoughts. I'll try them all & hopefully fix the problem. Ta guys.

[Alpha]

Did you solve this?  I had a similar problem after fitting a new dashcam, I'd not wired it in correctly, but after re-doing the wiring it's fine now.

[Zotto]

Another suggestion is keeping your remote key far away from car, as when in proximity the system is engaged and some current flows from 12 V Battery, discharging it.