Vampire Drain Fix: How to solve in under a minute (indoor or outdoor)

[gultin]

My name is blah-blah-blah and I suffer from VD (Vampire Drain, not the other kind thankfully ), on my late-2022 Gen 1 R1T.

A few months ago I was facing 15-16 miles lost per day (despite Gear Guard being disabled and proximity set to Lock Only at home) at one point. The service center replaced both my 12V and that helped a bit but still didn't quite solve it fully. I was still seeing 8-10 miles lost per day. I then realized that Lock Only at home doesn't really mean Lock Only and that the frunk and gear tunnel doors are still proximity-sensitive.

So I then turned off proximity-based lock/unlock entirely and began only relying on my key fob (physical button presses) for lock/unlock as if I had teleported myself back to the 90s . With that, VD symptoms got much better but I was still losing 3-6 miles per day, even when ambient temperatures were in the 50s and 60s.

Having read numerous threads it was pretty apparent that periodic DC-to-DC conversion to charge the 12V was the primary issue causing VD. For instance:
https://rivianforums.com/forum/threads/gen-1-vampire-drain-possibly-solved-or-hacked.31506/

However, I couldn't bring myself to pry open panels, or hard wire stuff to my relatively new (at least in my mind ) truck. I was hoping there to be a plug-n-play option, given that Rivian clearly wasn't going to ever fix this issue for good.

I decided to try and stand on the shoulders of giants when I specifically noticed the below post from @Tim-in-CA :
https://www.rivianforums.com/forum/threads/trickle-charge-12-volt.36052/post-659940

The OBD port was clearly the plug-n-play option I was looking for!

However, I have a few wilderness camping trips coming up, where I'd like to have minimal to no loss due to a total lack of charging options and since a plugged in battery tender wouldn't work. So I began exploring solar options, particularly those where I could keep the panel inside the vehicle.

After debating a few options I settled on a 30W panel, given that multiple modern ICE vehicle owners were happy with a 20 W panel, and I assume Rivians had to be drawing quite a bit more out of their 12V systems during idle versus modern ICE vehicles.

With the below two solutions, I've been testing both at night (garaged) and during the day (parked outside) for the past 3-4 days in 50-60 degree ambient temperatures and I've noticed minimal to zero lost miles during idle periods. My windshield is tinted to pass through 70% of light, and the solar panel seems to be charging the 12V even during cloudy or partly sunny days.

Garaged/Indoor/Nighttime Solution:

3-amp Tender:
https://www.amazon.com/Deltran-Battery-Tender-Power-Plus/dp/B016S7NHWQ

+

OBD adapter:
https://www.amazon.com/Battery-Tender-081-0154-DL-Connector-Maintainers/dp/B007KJ2RZK

Camping/Outdoor/Daytime Solution:
30 Watt MPPT Solar Panel:
https://a.co/d/f2J3cSJ

+

OBD adapter:
https://www.amazon.com/Battery-Tender-081-0154-DL-Connector-Maintainers/dp/B007KJ2RZK

Money wasn't ever the primary object in all of this, but for the sake of completeness, the three parts above cost me around $170 and I expect them to pay themselves off in under a year.

Also, both the options above take under a minute to plug in and similarly long to take off, meaning that I'm able to use them similar to how I might've plugged in my truck. In fact, I'm now plugging in the battery tender instead of the EVSE (which I'd previously plug in every other day or so even though I didn't need to, just so I wouldn't "notice" the VD loss). Now I plan to plug in the 12V tender daily and use the EVSE when it is actually needed for the HV (say once a week).

Just to be clear, I'm not saying this is the best overall solution. I'm just saying that it is the most convenient I've found so far. I don't know what the long-term implications of this solution would be, but I imagine there might be some, so I'd be curious to hear any thoughts. Could I damage my OBD port due to the daily/repeated plug
-in and plug-out for instance? Will I be shortening the life of my 12V batteries? etc. Let me know!

Pictures (as otherwise it didn't happen ):

3-amp Tender:

OBD connector (this fits into the driver under-seat storage bin for quick access BTW):

30-watt solar panel that rests on the dash and tucks in neatly behind A pillar, with no additional mounting needed:

MPPT unit behind the solar panel, which shows how much charge the 12V has, and blinks when charging:

Sponsored

 

[mudito]

Amazing!

 

[schlosrat]

Thanks for sharing your write up, and the off-grid solution for camping especially! Well done!

 

[usulio]

Awesome. For camping, could this charge a small battery during the day that keeps the 12V topped at night? Assuming no HVAC etc

 

[gultin]

Awesome. For camping, could this charge a small battery during the day that keeps the 12V topped at night? Assuming no HVAC etc

I see an SAE to USB-C adapter that could open up a world of possibilities:
https://a.co/d/1wZfk0r

 

[Riviot]

I see an SAE to USB-C adapter that could open up a world of possibilities:
https://a.co/d/1wZfk0r

Dumb question, but does it work in reverse? Most people seem to use it for drawing power from 12v, not sending it.

 

[HapticWagon]

wow I think you are on to something. I was wondering why I was having so much vampire drain all the sudden. first I thought it was the latest 2025.06 update, but I did also turn on proximity-based lock/unlock. I will probably turn that off again. Thanks for the heads up!

 

[gultin]

Dumb question, but does it work in reverse? Most people seem to use it for drawing power from 12v, not sending it.

I haven't researched battery powered trickle chargers, but I don't see why not. If a solar panel can do it, so can a (big enough) battery .

 

[Sempervirens]

Thanks, I like the simplicity of this solution. What do you do if camping - while there is no sun aka night.

We camped over the weekend and lose 20mi per day, a mix of VD and endless in and out of the vehicle as a giant bear box.

I am totally up to use a giant USB battery; I have a 42000mAh I would love to plugin to a tender, but imagine the output 18watts? isn't enough.

 

[gultin]

Thanks, I like the simplicity of this solution. What do you do if camping - while there is no sun aka night.

We camped over the weekend and lose 20mi per day, a mix of VD and endless in and out of the vehicle as a giant bear box.

I am totally up to use a giant USB battery; I have a 42000mAh I would love to plugin to a tender, but imagine the output 18watts? isn't enough.

My solar panel is rated for 30W, but it seemed to keep the 12V topped up during a mostly cloudy day, through a tinted windshield. So I imagine 18 watts might be more than enough, especially at night, when the vehicle is expected to be mostly left alone. If I can cut VD even by a half during long camping trips I'd consider that a huge win, especially when there isn't even a wall plug anywhere nearby.

 

[Riviot]

Thanks, I like the simplicity of this solution. What do you do if camping - while there is no sun aka night.

We camped over the weekend and lose 20mi per day, a mix of VD and endless in and out of the vehicle as a giant bear box.

I am totally up to use a giant USB battery; I have a 42000mAh I would love to plugin to a tender, but imagine the output 18watts? isn't enough.

18watt should be able to do 12v at 1.5amps, same as the baby trickle charger I had for my motorcycle battery. It's better than nothing!

42000mAh at the standard 3.7V for those battery bricks would give 155Wh, or about half a day worth of VD.

9/13/2024 Edit:
I have discovered that the draw from the 12V battery charger is about 0.3 kWh/day.

 

[Sempervirens]

Before I jump in;

I see some commentary on the 2amp version working, what's the reason for going 3a?

Heck BT has 800mAh versions

 

[gultin]

Before I jump in;

I see some commentary on the 2amp version working, what's the reason for going 3a?

Heck BT has 800mAh versions

I went with the 3A just to buy myself enough headroom. The 30W solar panel is effectively a 2.5A charger under ideal conditions, so I figured a plugged in wall charger ought to have at least that much. I'm not sure when I'll use any of that extra capacity though, may be in cases where I need to be getting in and out of the truck frequently, while I still have access to a wall outlet.

 

[gultin]

Out of curiosity, does anyone have numbers for what the typical power draw (in Watts) is out of the 12V for various scenarios such as while it is idle or when HVAC /screens are running, with and without Gear Guard etc etc?

 

[SSteveEV]

Bonus points for anyone that does a write up about how to semi permanently mount that (or other) solar panel to the inside of our glass ceilings.

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