Sponsored

12V battery troubles

Milermore

Well-Known Member
Joined
Oct 24, 2022
Threads
1
Messages
163
Reaction score
178
Location
Oregon
Vehicles
R1S
is the 12v battery problem a "suddenly it doesn't work" problem or are there hints that can be observed as it begins to lose charge?
Such as in an ICE you'd see trouble cranking when starting the motor before you get all the way dead battery.
Maybe dimmed or flickering lights? Multiple attempts needed to unlock doors? etc... just pulling guesses from the air here.
Sponsored

 

PappaBolt

Well-Known Member
First Name
Don
Joined
Aug 20, 2022
Threads
36
Messages
951
Reaction score
1,354
Location
Bainbridge Island, WA
Vehicles
R1S, Corvette, 911
Occupation
Tech
Clubs
 
Yep, you could in theory run until the NOCO dies. I don't have my Rivian yet, but for this and a few other reasons, I just ordered a NOCO from Amazon. They have some great CyberMonday discounts running right now.
Where would one store the NOCO so it’s accessible in the event of a locked cabin and flat 12v’s?
 

Zoidz

Well-Known Member
First Name
Gil
Joined
Feb 28, 2021
Threads
105
Messages
3,122
Reaction score
6,867
Location
PA
Vehicles
23 R1S Adv, Avalanche, BMWs-X3,330cic,K1200RS bike
Occupation
Engineer
Where would one store the NOCO so it’s accessible in the event of a locked cabin and flat 12v’s?
In the frunk. There is a mechanical way to get into the frunk in an emergency. Certainly not convenient, but doable.

Also, some of these dead battery issues have been reported to happen overnight at home, so it does not necessarily need to be on-board.
 

CharonPDX

Well-Known Member
First Name
Charon
Joined
Jul 12, 2021
Threads
20
Messages
1,061
Reaction score
1,505
Location
Cascadia
Vehicles
R1T LE, Mach-E, Arcimoto FUV, Repl: F-250/Model S
Occupation
InfoSec Geek
Clubs
 
Post-Mortem Update on Bricked 12v Battery caused (Per Rivian) by file corruption issues caused by its own recent update to the vehicle"
Oh, crap. I got a "Service 12V battery system immediately" warning while driving yesterday. I rebooted the car, and it went away; I assumed it was a one time fluke. If I get it again, I'm immediately opening a service ticket.
 

Sponsored

BrianNakata

Well-Known Member
First Name
Brian
Joined
May 2, 2022
Threads
5
Messages
67
Reaction score
125
Location
Portland, OR
Vehicles
2022 Rivian R1T, 2016 Shelby GT350
Occupation
Software Engineering Manager
I use the Lithium version of this on one of my cars that has a lightweight LiFePo battery as it's a dry weather only vehicle so stays on a float charger all the time: Bluetooth Battery Tracker.

You simply connect it to a battery and it monitors it continuously. You connect to it via a free phone app via Bluetooth and you can connect up to five of these to the phone. Seems like you could get two and connect them to the primary and secondary 12V batteries and monitor them whenever you want by firing up the app on your phone. There's then no need to dismantle the cowling to put a DMM on them to measure their voltage.

The company did tell me that if you use more than one for multiple batteries, those batteries cannot be connected in serial or parallel.

Does anyone know if the two 12V batteries are connected together in some way? I would think that they are using an isolator so that both charge but only one is used at a time.

Brian
 

ironpig

Well-Known Member
Joined
Nov 19, 2021
Threads
7
Messages
1,959
Reaction score
3,342
Location
Los Angeles, CA
Vehicles
2022 R1T LE, 2015 4Runner, 1975 FJ55 Land Cruiser
(2) New dashboard digital guage that will show the current status of 12V battery (primary and secnodary) given how critical their state of charge is for people who drive this vehicle. Keep in mind it is not a redunant set up but hemispherical. The left side of the truck relies on the primary and the right half the secondary. That is bad and especially problematic when I am blind about their charge status.

IMG_3651.jpeg
IMG_3608.jpeg
Definitely should be able to monitor the health of those batteries on screen. We should push for that.

These smaller batteries are always an issue. My wife has had a series of Prius and they use the small 12v batteries in the trunk. I just replaced another one because it died after the car sat for a month. In my anecdotal experience, these batteries never revive after a full draining the way better standard size 12V batteries seem to be able to do.
 

mini2nut

Well-Known Member
Joined
Feb 4, 2022
Threads
43
Messages
1,606
Reaction score
1,925
Location
SoCal
Vehicles
Rivian R1T, Model Y
I wish Rivian would ditch the dual batteries and go with a single lithium 12v battery like Tesla has done.

The voltage of a 12v battery is a good way to determine the state of charge. Here's a handy table with the breakdown:

State of Charge Voltage

100% 12.7 - 13.2

75% 12.4

50% 12.2

25% 12.0

Discharged 0 - 11.9

If your battery is:

Reading 0 volts, chances are the battery experienced a short circuit

Cannot reach higher than 10.5 volts when being charged, then the battery has a dead cell

Fully charged (according to the battery charger) but the voltage is 12.4 or less, the battery is sulfated
 
Last edited:

Supraman16

Well-Known Member
Joined
Apr 26, 2022
Threads
8
Messages
65
Reaction score
77
Location
California
Vehicles
Supra TT, Lexus ISF, Forester XT, Odyssey
Occupation
Professional
Just had my 12V batteries replaced due to random errors popping up. First if was motor fault error, then power steering, then finally the 12V Batteries. All these errors were only intermittent, resulted in no noticeable issues driving the truck. I thought it was a software issue but it turned out that one of the 12V batteries was starting to go bad. The Service Center replaced both batteries. Here's hoping that was the fix.
 

mountainman

Member
Joined
Oct 23, 2023
Threads
1
Messages
17
Reaction score
17
Location
Colorado
Vehicles
Rivian R1S
I purchase an OBDII->USB adapter to power my radar detector (https://www.amazon.com/dp/B0C3V6XQZQ?psc=1&ref=ppx_yo2ov_dt_b_product_details). It monitors the voltage and will not power the RD if voltage is <=11.6V. Good way to visually confirm proper voltage of the primary 12V and if the RD doesn't power up I know there might be an issue with the battery.

I also purchased low profile Torx T20 and T25 (https://www.amazon.com/gp/product/B09PTBK1WP/ref=ppx_yo_dt_b_asin_title_o01_s00?ie=UTF8&psc=1) to secure inside the hitch panel and replaced the screws for the panel with thumbscrews from open source EV. I put a Noco GB70 in the frunk so can charge either 12V battery if they die.
Sponsored

 
 




Top