Gen 1 Vampire Drain (Possibly) Solved (or Hacked)

[JerseyGreens]

I wonder if replacing the 12V battery with one that has higher capacity would help? It seems to me the root cause is all the system activity that is draining the 12V battery, which requires the HVB to keep it from dying. A battery that has a slower drop in SoC might make a measurable difference in VD.

Just a thought.

I wonder if anyone following this thread has installed one of these:

https://www.ohmmu.com/product-page/12v-lithium-battery-for-r1t-r1s

If so, curious if it changed their VD.

I'm with @Tim-in-CA - this VD is literally taking away my excess solar production and it's frustrating.

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[Yossarian]

In an earlier post in this thread, I mused about how beneficial it would be for someone at Rivian to be aware of the observations, comments and experiments that have been documented.

I've read that Wassym Bensamid, Rivian's software development VP, monitors FB (or was it Twitter/X?) and encourages folks to send information and comments his way via social media. Since I have essentially no social media presence, I wonder if folks on this forum who do would consider trying to make Wassym aware of this important discussion via X, FB or whatever channel is appropriate?

It may well be that, as others in this thred have speculated, Rivian is content to have gotten parasitic drain in most of its vehicles down close to 1% per day (though I frankly don't know if this is accurate - the rate, not the speculation.) But it can't hurt to try and get Rivian's attention on the subject and perhaps inspire them to do a bit more.

 

[biker1284]

No expert here but YouTube suggested this video for me.

Fisker users are using an OBD2 battery tender:



Seems like this would be super easy? Wonder if it'd work on Rivian too.

 

[Yossarian]

I would think that if Rivian uses a standard OBD2 port, an adapter like the Battery Tender would work. I'm sure that folks much more knowledgeable will chime in with something more definitieve.

It still seems to me that the way to go is to cut the ac-powered charger out of the picture. In my fever dream, this means using solar-power (a few flexible PV panels and controller) in conjunction with a small LiFePO4 battery, connected via an SAE pigtail directly to the Rivian 12v battery system.

What I'm not smart enough to figure out is how much PV output is needed and how arge the aux battery needs to be to keep the Rivian 12v battery happy during hours of no sun. If 100w of charging, a 20 Ah controller, and a 20 Ah battery are sufficient, the total system cost would be pretty modest, probably under $250.

 

[jplblue]

I would think that if Rivian uses a standard OBD2 port, an adapter like the Battery Tender would work. I'm sure that folks much more knowledgeable will chime in with something more definitieve.

It still seems to me that the way to go is to cut the ac-powered charger out of the picture. In my fever dream, this means using solar-power (a few flexible PV panels and controller) in conjunction with a small LiFePO4 battery, connected via an SAE pigtail directly to the Rivian 12v battery system.

What I'm not smart enough to figure out is how much PV output is needed and how arge the aux battery needs to be to keep the Rivian 12v battery happy during hours of no sun. If 100w of charging, a 20 Ah controller, and a 20 Ah battery are sufficient, the total system cost would be pretty modest, probably under $250.

If charging via OBD2 port works, couldn't those of us with a 12v cigarette port under the dash use that to charge a battery while the car is running, and then use that battery to charge the 12v while the car is sleeping? Should be simple to make a self-contained unit -- and I don't think solar would be necessary.

Questions are (1) does charging via OBD2 work; and (2) does it charge both 12v batteries (for those of us with 2).

 

[josh0]

I would think that if Rivian uses a standard OBD2 port, an adapter like the Battery Tender would work. I'm sure that folks much more knowledgeable will chime in with something more definitieve.

It still seems to me that the way to go is to cut the ac-powered charger out of the picture. In my fever dream, this means using solar-power (a few flexible PV panels and controller) in conjunction with a small LiFePO4 battery, connected via an SAE pigtail directly to the Rivian 12v battery system.

What I'm not smart enough to figure out is how much PV output is needed and how arge the aux battery needs to be to keep the Rivian 12v battery happy during hours of no sun. If 100w of charging, a 20 Ah controller, and a 20 Ah battery are sufficient, the total system cost would be pretty modest, probably under $250.

I’m planning on setting up a hood-mounted solar panel to test this, but won’t be able to do it until November or December. However, I don’t know that a second battery will be necessary. If the solar panel ensures a 100% SoC on the 12V battery at the end of the day, will it drain enough overnight to require a charge before the sun comes up and solar charging resumes?

We can figure this out without needing solar, too. Just need to get a proper battery monitor on the 12V battery and watch the charge level to determine how fast it drains and at what SoC the charging process kicks in and drains the HV battery. That will also tell us how big of a battery we would need, if at all, to prevent that from happening overnight.

 

[NY_Rob]

^ interesting project guys! I'll be watching this thread for the results.

I can't tell you how nice it is to not use your Rivian for 2 days and get in it to see the same exact range you had when you exited 2 days ago

 

[Jakelake]

I had a 2005 VW diesel Jetta that came with a small solar panel, about 12X12 inches, that I would place in the rear window of the car and plug it into a cigarette lighter located in the rear trunk. The diesel had a huge battery and needed all of it to get started. I only used it when I parked at the airport for long periods of time, like greater than a week. I never had a battery problem but neither did I know how much power the panel produced. Not sure how much panel it would take to keep the Rivian battery charged but it would seem to be an easy solution to keep the 12 volt topped off if parked outside. That assumes there are no complications associated with the Rivian electrical system receiving a charge from a small panel. I'm guessing only the Rivian engineers could figure that out.

 

[NY_Rob]

The official "solution" to curtail VD in Rivian vehicles would be for Rivian to build solar cells into the glass roof like Fisker did On the Ocean One.
Since Rivian seems unable to simply "turn everything off" in it's vehicles, we need to accept the fact that they simply can't do it. With that in mind, the closest thing to a zero range loss solution is to keep the 12V batt(s) full charged 24/7 so the vehicle doesn't need to wake it's multiple systems just to charge the 12V batt(s) from the 400v battery 10+ times/day.

 

[HyperionMark]

What's the easiest way to know if you have two 12V vs one?

 

[NY_Rob]

What's the easiest way to know if you have two 12V vs one?

I think the cutover date was around March 2023 builds IIRC. Other than that, just lift the hood and remove (no tools needed) the cover between the frunk and windshield. It's the same procedure you'll have to perform when changing the cabin air filter.

 

[HyperionMark]

I think the cutover date was around March 2023 builds IIRC. Other than that, just lift the hood and remove (no tools needed) the cover between the frunk and windshield. It's the same procedure you'll have to perform when changing the cabin air filter.

So in theory, should we be seeing a little bigger VD on pre March23 builds than after? (due to charging and balancing two batteries instead of one)

 

[NY_Rob]

So in theory, should we be seeing a little bigger VD on pre March23 builds than after? (due to charging and balancing two batteries instead of one)

Very possibly!

The only difference for me was I had to order the dual bank NOCO trickle charger since my Jan 2023 vehicle has two 12V batts unfortunately.

 

[ascientist]

I'm a few days into keeping the 12V battery topped off with a trickle charger. I'm tracking the consumption from the trickle charger as well as normal loss reordered on the Rivian. After 3 days the Rivian finally showed 1 kwh loss. Adding in the consumption of the 12v charger I averaged 0.7 kwh per day. I'm going to continue to monitor and suspect it's actually a bit lower over a longer average, but that's already much better than the 2.33 kwh/day I was consistently losing prior. I sleep better at night knowing the waste had been dramatically reduced.

I'm using a 4A charger connected via a magnetic quick connect attached with double sided tape at the bottom left of the front windshield.

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[mudito]

Got a couple experiments running today...gotta love a good 3 day weekend!

2A load on a fully charged Ohmmu, with GoPro watching the voltage and time. Will be comparing this with the Rivian's AGM battery after swapping to get a feel of the actual capacity difference between the two. The Ohmmu folks are a bit cagy about 'capacity' and prefer to speak "Reserve Capacity", which does make some sense but makes it hard to compare. All we care about is can we delay voltage dropping to the point that the HV>12v recharger kicks on.

Also! Camp battery running through battery tender plugged into the OBD port. This is quite possibly an awesome solution if all works as expected...I can feed the camp battery from the Rivian when it's outlets are on or via solar if we are camping in one spot for a while, and it can keep the 12v battery tended without the HV>12v recharger ever lifting a finger. Unless of course I need to steal the camp battery from it's usual buckled-into-the-back-seat home to power our tent heater and/or electric fridge (in the truck bed), at which point it would be lovely if the Ohmmu has the reserve capacity to keep the computers off for at least overnight.

Hey! I'm curious of your results... Now that my R1T is sitting dead in my garage, I have time to read about this stuff

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