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usulio

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Seems like the cheapest battery option might just be another car battery, which might have enough capacity to help make it through the night without waking the HV. And you have a spare if your 12V dies while camping for some reason.
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Yossarian

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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.
Wouldn't the tint of the roof glass decrease the output of he solar panel pretty significantly? Perhaps a better solution might be a flexible solar panel in roughly the same size as the windshield itself which would not only charge the 12v battery but double as a sun shade for the vehicle.
 

CBRacerX

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Timely. I've been adding solar 12v battery maintenance to all my ICE cars that just sit around since I bought the R1T. I've jumped on your solution and will put in place.

Thanks!
 
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gultin

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Wouldn't the tint of the roof glass decrease the output of he solar panel pretty significantly? Perhaps a better solution might be a flexible solar panel in roughly the same size as the windshield itself which would not only charge the 12v battery but double as a sun shade for the vehicle.
I've been thinking about this too, a foldable panel that also serves as a windshield cover, a true win-win.
 

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smokeybear32

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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 :D. 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:
IMG_20250323_141917~2.jpg


OBD connector (this fits into the driver under-seat storage bin for quick access BTW):
IMG_20250322_143929.jpg


30-watt solar panel that rests on the dash and tucks in neatly behind A pillar, with no additional mounting needed:
IMG_20250322_123615~2.jpg


MPPT unit behind the solar panel, which shows how much charge the 12V has, and blinks when charging:
IMG_20250322_123335.jpg
I like the solar power solution for while you’re camping. But when you’re in your own garage… what’s the advantage to this over just plugging your truck in?
 

Riviot

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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?
They're 12v x 135amp so 1620watts per battery.
 

SSteveEV

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I like the solar power solution for while you’re camping. But when you’re in your own garage… what’s the advantage to this over just plugging your truck in?
In garage it is strictly an energy savings. If you plug in 12v via trickle charging the R1 sleeps longer and doesn't wake up all systems to power up the HV pack to top off the 12v battery. If you plug in normally it wakes everything up and burns more juice to top off the 12v.
So some electrical savings with the trickle (calculated in some other post linked earlier) to be had but both are good options for long term garage storage if worried about running low.
 

3wisemonkeyz

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I like the solar power solution for while you’re camping. But when you’re in your own garage… what’s the advantage to this over just plugging your truck in?
cause frequently waking your Riv up to charge the 12v all the time is a big drain on the battery - hence the VD. It’s highly inefficient.
 

SSteveEV

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Wouldn't the tint of the roof glass decrease the output of he solar panel pretty significantly? Perhaps a better solution might be a flexible solar panel in roughly the same size as the windshield itself which would not only charge the 12v battery but double as a sun shade for the vehicle.
Yes the tint would kill the effectiveness but I'd like something I can place and forget since I park outside 90% of the time and would have bought a truck without the glass roof if an option. (I am always annoyed that automakers decided this should be a popular trend instead of an opening smaller sunroof, but I act like a grumpy 110 yr old so that's on me)
I already have a sunshade for the roof and the dash for the summer but would buy an insulated panel for the roof in a heartbeat if it had a trickle solar panel built in. Dreams.

Best reading I found for roof tint impact:
https://www.rivianforums.com/forum/...n-efficiency-measured-first-mile-dallas.4506/

I thought there was another with different measurements for windshield and roof but couldn't find it.
 

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gultin

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I like the solar power solution for while you’re camping. But when you’re in your own garage… what’s the advantage to this over just plugging your truck in?
Primary reason was efficiency, as has also been answered by others above. In my experience, it's been significantly more efficient to directly charge the 12V as opposed to energy going first into the HV and then DC-DC converted to the 12V. An order of magnitude (like 10x) difference in power usage between the two cases for the same end result, from what I seem to recall reading on other threads. As an EV driver in a fully de-ICEd household, I've become anaphylactically allergic to any form of energy inefficiency :).
 
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gultin

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They're 12v x 135amp so 1620watts per battery.
The 12V systems can't be drawing 135 amps all the time, right? I assume you're referring to the maximum rating or something like CCA? My question was more along the lines of the actual/typical power usage when screens and HVAC are running. I'd have expected that to be something around a few hundred Watts. Knowing this may help folks make a more informed decision on the BT or solar panel size to pick.
 

Riviot

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The 12V systems can't be drawing 135 amps all the time, right? I assume you're referring to the maximum rating or something like CCA? My question was more along the lines of the actual/typical power usage when screens and HVAC are running. I'd have expected that to be something around a few hundred Watts. Knowing this may help folks make a more informed decision on the BT or solar panel size to pick.
Ah, that makes more sense. Correct, I referred to maximum.

I think in the DRiVE menu you can see it, I'll take a look.
 

hammick

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Dumb question, but does it work in reverse? Most people seem to use it for drawing power from 12v, not sending it.
99.9% sure it does not.
 

hammick

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TLDR: Latest update has changed how 12v battery is charged (at least on G2 R1S).

Gultin great work on your setup. Since the latest update our G2 R1S has been sending a constant voltage of 14.3 - 14.4 volts to the 12v battery. The amperage is minuscule as the battery is fully charged. I have tested this overnight and in the morning without waking the car it remains at this high voltage. Over the next few days I will let it sit unplugged with no tender and see if the VD has improved. I suspect they did this to eliminate the constant drain and recharge of the 12v battery to reduce warranty replacements.

Wondering if Rivian is doing the same with the G1 cars.

Easiest way to test this is to open driver's window and place your OBD2 adapter so you can reach in and put a multi-meter on it. Best to lock the car and wait 30 minutes so you know if's fully asleep. Make sure gear guard and live cam is off.

If Rivian is doing the same with G1 I can't think of a benefit of using a battery tender when the car is asleep.

Rivian R1T R1S Vampire Drain Fix: How to solve in under a minute (indoor or outdoor) IMG_0547
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