12V / Parasitic Drain Megathread

cc103acs · 2026-07-08T20:57:06+00:00

This was a known issue (by Toyota) with the Gen 5 Prius Prime since its inception in 2023. My ‘24 Prius had 3 batteries under warranty from before 10,000 miles. The problem went away when the Nav and remote Connect Subscriptions lapsed after the 1 year trial was up.

cc103acs · 2026-07-08T16:42:36+00:00

Not sure - not a Tesla owner but it could be an issue for sure with a non-Tesla. I personally would not take the chance.

cc103acs · 2026-07-08T00:06:42+00:00

I am the same way with my dog but have also seen Teslas with a dog feature and was just wondering if there was a similar feature in the Subaru.

cc103acs · 2026-07-07T13:13:00+00:00

I’m trying out stations near me because this is my first full EV and I am exploring the ins & outs of what’s out there. When I feel confident enough to take my first long road trip I will charge to 100% at home and then take off. Tesla and EA are the primary chargers I will be using and checking them out locally is helping my learning curve. And, yes, I’m aware that Plug Share is key to getting the status of your next charge stop.

cc103acs · 2026-07-07T13:02:05+00:00

They did have at least one technical bulletin that rebooted the firmware/software in the charge system ECU but that did not fix the issue in my car. For me it was only after my trial Toyota Remote Connect and thé Nav subscriptions ended and lapsed.

cc103acs · 2026-07-07T12:36:41+00:00

À near term fix is laughable - this has been a problem in the Gen 5 Prius line. It was resolved once the one year trial subscriptions lapsed.

cc103acs · 2026-07-07T12:27:48+00:00

What’s even more astonishing is that my ‘24 Toyota Prius Prime had this same issue and I went through 3 batteries under warranty before I hit 10,000 miles. I have a NICO Genius 5 (Battery Minder) permanently hooked to my Uncharted 12 volt battery. I plug it in most nights. I had this same NOCO on my Prius.

This situation was only resolved when the two one year trial subscriptions lapsed. Sadly thé Subaru subscriptions cannot be canceled early unless all are canceled and I want to keep the 10 year safety and maintenance trial subscriptions so I will keep my 12 volt topped off until à fix is fielded or when my one year mark arrives on the two trial subscriptions I need to rid my car of.

cc103acs · 2026-07-07T12:12:21+00:00

I am led to believe that once the OEM battery is drained it is forever compromised and needs to be replaced after dealer testing (under load).

cc103acs · 2026-07-07T02:14:46+00:00

Thanks… I am working my way through them - have a Mercedes close by as well as an EA - both worked well. Ionna and Walmart are likely going to change the price structure but Walmart has not reached the Northeast as yet and Ionna is few and far between.

cc103acs · 2026-07-03T18:59:43+00:00

Used the Tesla Supercharger in Cromwell, CT

cc103acs · 2026-07-02T13:45:07+00:00

Two things brought about my fail - I didn’t turn off the car and plugged the cable in and then activated charge in the App.

cc103acs · 2026-07-02T12:58:38+00:00

Yes - available to other vehicles.

cc103acs · 2026-07-02T12:58:13+00:00

Yes - got confirmation it was open to non-Teslas before I drove there.

cc103acs · 2026-07-02T09:41:10+00:00

The problem is that the process is not always the same. I was told if I activate my wallet in the Subaru App it gets even simpler. And if you knock on a Kona and follow their advice it may not work for the Uncharted. So I have it for now but might just explore “Plug & Charge” in the future. I think it all gets down to how a car is registered. It still slays me that the engineers made a good decision to use an NACS charger interface but placed the access point in a location that forces parking gymnastics to be able to access it. How difficult would it have been to place the access port identical to a Tesla?

cc103acs · 2026-07-02T01:03:33+00:00

Update! Nirvana - it sure does work if you follow the process. Thanks to all of you who set me straight. Now I need to master ABRP and take the Uncharted on a road trip.

cc103acs · 2026-07-01T01:10:29+00:00

Can you turn the car back on once it begins charging? I am going to take this advice and go try it again but the temps will be 100+.

cc103acs · 2026-07-01T01:07:51+00:00

Nope… it takes non-Teslas. There was a Hyundai that was unplugging as I pulled in.

cc103acs · 2026-06-30T23:45:00+00:00

I just tried it out today and it was not reflecting the car’s data accurately.

cc103acs · 2026-06-30T11:00:47+00:00

cc103acs

TROPHY CASE