Phantom / Vampire Drain Solution Works! Using 12v Battery Tender

[NY_Rob]

I used the NOCO dual bank 10 amp (5 amps per bank) charger which I connected directly to the dual batts in my R1T. It had no problem charging both batts to full.
The details are in this thread if anyone's interested..

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[SPITmadFIRE]

If it's never going green your battery is never getting full. 1 amp is only 12 watts, although over 24 hours that is 288 Wh....I want to say I think mine was closer to using 400Wh a day but I'm not sure. Yeah will be curious how 3amp charger changes your results. Even 2 amp charger might be enough.

lucky you, without the battery tender my vehicle was using on the order of 2.8-3kwh a day

 

[Aardvark]

Long Term Test Update 4/11/2025:
I had my Gen 1 R1S parked in my garage for 13 consecutive days while traveling. Gear Guard was "Off at Home" and I did not use Shipping Mode. My 1 amp NOCO battery tender was plugged into the OBDII port. Temperatures were in the 50s (deg F). I remotely checked the status only 1 time.
I lost 9% (11.9 KWh) over this period. This averages to 0.69% per day, or 0.92 KWh per day.
While this is far below some of the horror stories on the forum of 2 to 4% per day, I have to say that I was disappointed. With the battery tender connected, I was hoping for something around 0.1% per day.
I am still baffled as to why my NOCO charger/tender never goes green, indicating a fully charged battery. It was still red after 13 days connected to a sleeping vehicle. Even though others on the forum have had good luck with similar 1 amp tenders, I may still invest in a 3 amp unit and see if I get different results.
It's also possible that my tender is working exactly as designed, and something in my vehicle is causing 12 V battery drain in excess of 1 amp.
More to follow....

Update 4/13/2025
I couldn't find a 3 amp charger/tender from a reputable brand that had the features I was looking for. So I went with the 2 amp NOCO Genius 2. That did the trick. Within 5 minutes I was in the green showing a fully charged battery snd maintence mode was starting.

 

[Aag12]

Is everyone really routing an extension chord through the window?

I read the majority of this post and surprised people are going through the extra steps of plugging/replugging.

Is shipping mode a halfway solution to this all?

 

[DayTripping]

If using the battery tender through the OBD port, does it charge both batteries if you have a dual battery setup? I though I read somewhere that it just did one but I can't find the reference now.

 

[DayTripping]

Is everyone really routing an extension chord through the window?

I read the majority of this post and surprised people are going through the extra steps of plugging/replugging.

Is shipping mode a halfway solution to this all?

I run the battery tender cord out along the lower door driver's seal and keep the charger in the truck on the backseat floor. Easy to plug and unplug, getting in and out of the truck. I am charging through the OBD port.

While this approach hasn't stopped the drain, it has slowed it. I think the most recent updates might have also had an effect.

Originally, when I got the truck last year, Electrafi was saying I was losing 2.5-3.3 kWh a day. It has has sat on the street for the last few days, and it is about 1.2-1.4 kWh. When plugged in I am about .4 -.9 kWh. Some days when plugged in I might not see any at all.

That is why I asked the question, if it is a dual battery setup, does it charge both batteries through the OBD port if a battery tender is hooked up there.

 

[Aag12]

I run the battery tender cord out along the lower door driver's seal and keep the charger in the truck on the backseat floor. Easy to plug and unplug, getting in and out of the truck. I am charging through the OBD port.

While this approach hasn't stopped the drain, it has slowed it. I think the most recent updates might have also had an effect.

Originally, when I got the truck last year, Electrafi was saying I was losing 2.5-3.3 kWh a day. It has has sat on the street for the last few days, and it is about 1.2-1.4 kWh. When plugged in I am about .4 -.9 kWh. Some days when plugged in I might not see any at all.

That is why I asked the question, if it is a dual battery setup, does it charge both batteries through the OBD port if a battery tender is hooked up there.

Thanks very helpful. What amp tender did you get? Seems like people say you need >1 amp

 

[mudito]

Is shipping mode a halfway solution to this all?

In my experience (you can find my posts reporting about this around here), shipping mode will HEAVILY reduce VD but not eliminate it. With Shipping mode, my R1T was "almost" on-par with my wife tesla but still waking up for a recharge every ~26hrs.

Still, having a battery tender not only will help with VD but also with the overall health of the 12v AGM battery so in the long-run (if you keep your R1T Garaged every so often), your batteries are going to last longer.

 

[Aag12]

In my experience (you can find my posts reporting about this around here), shipping mode will HEAVILY reduce VD but not eliminate it. With Shipping mode, my R1T was "almost" on-par with my wife tesla but still waking up for a recharge every ~26hrs.

Still, having a battery tender not only will help with VD but also with the overall health of the 12v AGM battery so in the long-run (if you keep your R1T Garaged every so often), your batteries are going to last longer.

Thanks! Very helpful. My 12v was just replaced under warranty and will be out of warranty by the time this new one will probably die so weighing a tender vs my wife's ire of me plugging in something else when we park the car

 

[DayTripping]

Thanks! Very helpful. My 12v was just replaced under warranty and will be out of warranty by the time this new one will probably die so weighing a tender vs my wife's ire of me plugging in something else when we park the car

It just becomes a habit and I have both cords next to each other so very simple to do.

Here is the tender I am using. I'd say at least a 2 amp and I don't think the OBD port can handle more than 3 amps, so I just bought a 3 amp. The batteries are pretty small anyway. What a stupid design. Buy it from your online vendor of choice. Amazon and Walmart have them cheaper.

https://www.batterytender.com/produ...7mVlhfQ5RVrMIQjwBUBJcO9aTXNTuCwi_kp-coAaXdh-R

 

[Aardvark]

Is everyone really routing an extension chord through the window?

I read the majority of this post and surprised people are going through the extra steps of plugging/replugging.

Is shipping mode a halfway solution to this all?

That's what I'm doing. When I park for the final time each day, I plug in the tender through the passenger window.

 

[mudito]

Thanks! Very helpful. My 12v was just replaced under warranty and will be out of warranty by the time this new one will probably die so weighing a tender vs my wife's ire of me plugging in something else when we park the car

https://www.rivianforums.com/forum/threads/trick-for-maintaining-health-of-the-12v-battery.37720/

That's my "trick" that I do every now and then. I don't do OBD, I have a direct wire setup (explained in the post) and my R1T sleeps peacefully for 14-16 hours every day without waking up. I need to stress that a good battery tender does more than just charge but also reconditions the battery. That's KEY to me

 

[bigsky]

My R1S still loses 2-3 miles per day with a battery tender via OBD port, BUT, the tender has reduced vampire drain significantly.
Without battery tender, and my R1S in storage, first two charging sessions were 20 and 19 days apart (drain 50% to 20%, charge back to 50%).
Plugged in tender a while ago. Now third charging session, with the tender charging, my R1S went from 50% to 20% SOC in 81 days!
A 326% charging reduction in terms of days between charges. The tender does do the job.

 

[James Worden]

Wow, even with a 13-14W, 1A 12VDC battery tender, the R1-T still sucks up that much energy?!? Crazy. If you need a 3A, 39W battery tender to keep the truck from having vampire loss, the tender alone could be using over 1kW per day (A 2A, 26W tender would use 0.7kWh/day)! Rivian really needs to fix this, at least I sure hope they do. I really wish I could just disconnect the batteries for when I won't use it for 2-4 weeks at a time so it doesn't suck away power for no value or reason. I wish I had known the Ford Lightning had such a super low vampire drain. I recommend anyone who doesn't like the giant vampire drain of Rivian but instead a Ford. I love everything else about the R1-T, but vampire drain spoils my love for it.

 

[DayTripping]

Wow, even with a 13-14W, 1A 12VDC battery tender, the R1-T still sucks up that much energy?!? Crazy. If you need a 3A, 39W battery tender to keep the truck from having vampire loss, the tender alone could be using over 1kW per day (A 2A, 26W tender would use 0.7kWh/day)! Rivian really needs to fix this, at least I sure hope they do. I really wish I could just disconnect the batteries for when I won't use it for 2-4 weeks at a time so it doesn't suck away power for no value or reason. I wish I had known the Ford Lightning had such a super low vampire drain. I recommend anyone who doesn't like the giant vampire drain of Rivian but instead a Ford. I love everything else about the R1-T, but vampire drain spoils my love for it.

Well, it won't draw that much power all the time. It still is a pretty stupid design and something I hate about my truck. Not in my top spot, but top 3. Number one is the GD wind noise at 75 & up. Second is how crappy Driver+ is on the G1 trucks. At least Comma.Ai can take care of #2 on my list.

With the battery tender, at least I don't lose the few percent I might need from the battery pack directly.

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