Hi,

The battery on my RX is draining overnight. I need to jump start each morning before I go to office (11 mile drive). The battery is about 2 years old. The vehicle always had this problem but the battery used to drain in like 3-4 days earlier (past few months) if I don’t use the vehicle. Now it’s draining over night. I had the battery tested and they said the cells are fine.

I am no pro by any means but after watching a couple YouTube videos, I disconnected the negative terminal and when I measured the amperes using a multi meter across the negative terminal and the battery post, it showed 1.6A with everything in the car off. Then I kept removing each fuse in the hood (barring the 100A fuse and the couple long ones) but no luck. The meter still shows 1.6A

Are there any other checks that I could do, before I take it over to the dealership?

thanks!

 

what little I know; it still could be the battery or the alternator...

 

That's a pretty good drain. I'd say there's still something connected.
Otherwise, give it to the dealer.

 

Any aftermarket stuff? Dash Cam? Remote starter? Light kit?

 

Just to be sure, use your multi meter, measure across the battery terminals and start the car. Have
someone rev the engine and check that the VM kicks up to 14+ V. Simple check on the alternator/charge system.

I would take it to a good tech with a battery load system and check near or close to the full CCA and be sure the bat is aok.

 

Yes for Dash Cam (hard wired for parking mode about 3 years back but I disconnected the power supply to it before I measured the current leak).

Yes for Remote starter too. When the vehicle stopped supporting the inbuilt 3G remote starter, I installed an after market 5G starter. This was about 1.5 years back.

 

Will check this today. Thanks for the suggestion.

 

I would disconnect all aftermarket stuff and measure again

 

Agree. I think he's missing something.

 

There are legacy data communications modems under the hood of vehicles and they try to link
to systems that are no longer active! I received a note on that issue via my Subaru dealer. These devices per the dealer can be disconnected if low bat occurs at no charge. I would investigate this item with your local dealer. Service bulletins etc... One solution from Subaru and I quote" Your bat is to small, we have increased its capacity from 500 CCA to 750 CCA!"

 

1.6 amps is pretty significant for having the key off, imho.

 

Amp Hound 2


https://a.co/d/7VRpMT2

Uneed two items. The supplied fuse clamps are useless. Please also report ur diagnosis and findings.

 

Just to close the loop on this one, I gave the vehicle to Toyota dealership. They had it for 3 days and returned back to me stating there is no problem with the vehicle or the battery. (They had the after market dashcam disconnected so the vehicle started without problem the next day and the day after). As per them, the battery drain is because the hood was open when measuring the drain and as per them, opening the hood will pull some drain though they weren’t able to explain the substantial drain.

2 months fast forward, I kept having the same issues. Had advanced auto parts test my battery and they said it’s as good as dead. Went to Costco, purchased their AGM battery and never had an issue so far though the vehicle is not driven for more than 2 days.

Hope this helps.

thanks!

 

Hi. I bought a 2022 RX 350 new. I drove it home and left it sit in my garage for two weeks. Battery was dead when I tried to start it, so I boosted it. Then next day it was dead again (nothing running, fan off, etc.) I called Lexus roadside and they sent a CAA flatbed to bring my new car back to the dealer. Turns out it was simply a bad battery. That just happens. The dealer replaced it forthwith and I drove home a happy camper. It’s now October 2024 and no issues whatsoever.

 

I had the exact same issue with my wifes 2023 CRV. Took it back and same as you, bad battery. Perfect now.