What should I do to make it stronger?

The time I had it tested at AutoZone in October, they said it was 100% charged.

 

Just because it is 100% charged doesn't mean that it can hold that charge. It could have gotten charged to that 100% level as you were driving to the AutoZone, but, if the battery is starting to fail, it could lose most of that charge in the next 12-24 hours.

If that is happening, there is nothing you can do to "make it stronger". The only solution is to replace the battery.

 

What settings would be lost with a new battery?

 

They should not just being doing a charge only test. Did they do a load test???

 

If it is done right, you shouldn't lose any settings. Most shops and auto supply stores should be able temporarily connect your car to another battery/power source while the switch to the new battery is being done.

 

I don't remember what exactly I asked them anymore, since it was October. I wonder if I said "charge test" instead of "load test".

Or maybe I did say load test.

 

As I posted last fall my '14 ES350 also reloads the Nav if it sets for 3-4 weeks without being driven in these covid times. I conducted a little test last time which leads me to believe the problem is in the navigation system not the car battery. After the car has sat for 3 weeks, I switched the ignition ON without starting the engine and let the Nav reload (1-2 minutes) after it finished I switched the ignition OFF without starting the car. I then switched it back ON and the Nav did not reload a second time. Obviously the car battery would have been discharged slightly more the second time, so this leads me to think the problem is in the Nav not with the car battery. I do not know what the Nav system uses to hold the settings in memory (button battery, capacitor or something else) but that seems to be the root cause.
FWIW the car always starts fine and has no other problems which makes me think the battery and charging system is fine.

 

I've read discussions like this before, best post was by someone who works with batteries for a living.
He said he doesn't trust the circuitry on inexpensive battery tenders to not overcharge the battery.
So, with cars and mowers, and bikes in winter storage, he puts his battery tenders on timers, and only has them
charging for 2-4 hours a day, figuring that at 0.50 an amp or so, they literally can't overcharge the batteries.

FYI - Lowes & Target both sell a simple "appliance timer" for about $6. These are mechanical clock timers, so if your power were to go out, when it comes back on, no need to reset them. Just that they were charging from 2 -5 pm, now might be 4-7pm... Would you care? Sometimes high-tech is *not* what you want.
/

 

I got the message again yesterday.

Radio was on but car engine was off. I then turned the engine on.

I have a service appointment in a few weeks, so I'll ask for a load test then.

 

When I have my service appointment, if they charge for a battery test, should I have them do it?

On one hand, I can go to AutoZone, etc. and I think have it load tested for free. I did go in October but I don't remember if I asked for a "charge test" or "load test".

On the other hand, this has been an ongoing problem since October, and it would be nice to properly identify the problem and get a resolution to it.

 

Bump? Thoughts?

 

When I went to have my service done, they did a test on the battery, but couldn't find any issues.

They then wanted to do a diagnostic on the Navigation system, but said they can't do it on Saturdays, they're too busy.

They sad to come back M - F.

I don't think I'll come back just for this, so this issue will probably persist for another year, until my next appointment.

 

The System Loading message happened to me again yesterday.

Slight difference this time was that I had turned the car's 2nd level power on (push the start button twice).

Then I turned it off, then started the car.

In previous times, I had probably only turned the car's first level power on (push the start button once).

I think I am going to call Lexus and see if they can provide any assistance or suggestions.

I think also next time, after I turn the 1st or 2nd level power on, then off, I will try counting to 6, before turning the power back on.

 

Bump? Any advice?

 

Just a follow up on my earlier posts on this navigation system reloading problem, I recently replaced my '14 ES 350 battery with a new one which has more CCA capacity than the OEM battery. The nav system still reloads if the car is not driven for 2-3 weeks so I still believe the problem is with the navigation unit not the car battery. For me its just a minor annoyance having to re-enter the speed parameters and other things that default on the reload. Since this is the only issue I have seen on this car for the past 7 years I'm still quite happy with it.