user33

A bit off topic, but hopefully useful info ...
I was testing a script change in my RaceCapture unit prior to an upcoming track day and had the OEM battery charger attached to the GTR Pro.

Stupidly, I decided to leave the RaceCapture unit -- which connects to, and is powered by, the OBD port -- connected overnite. My thinking was "no worries, it consumes little power and the battery charger is on." Stupid me (and I do have enough knowledge about these things that I should have known better!). While the RaceCapture unit doesn't draw much power, the fact that it's doing OBD/PID requests for data means that multiple modules won't sleep (I'd guess at least ECU, a SAM, Head unit at a minimum). I now know that the total current draw was significantly more than the battery charger was delivering because I had a dead battery, the next day.

In fact, I suspect due to the "foreign device" (RaceCapture) being connected, the car didn't protect itself and shut everything down before the battery got below the low-voltage threshold that allows things to recover (if I was responsible for the code, I'd consider that a bug, but ...). The first thing I tried was the OEM charger's reset/recondition button ... no effect ... no charging ... oh crap! As it happens, I also have a NOCO GENIUS10 charger which can deliver more charge current than the OEM unit ... so I tried that charger. Still a no-go (oh-oh). The NOCO also has a battery reconditioner mode (likely equivalent to the OEM charger's reset-button mode), so I tried it ... no effect (now I'm getting very worried).

Having done a bit of "stuff" with Li batteries and spend a fair amount of time researching their behavior (ain't Mr. Google wonderful!), I have had good luck with other Li batteries (for tools) that had gotten fully discharged and were unable to be recharged by their appointed chargers. The way I've recovered them is to use a DC power supply to give them a sufficient charge voltage/current for a short time (minutes only, don't want to overheat the cells!) then revert to their proper charger.

Turns out that the NOCO has a "direct power supply" mode, so I used that on the GTR's battery for about 5 minutes then reverted to the NOCO's recondition mode ... and it started to charge ... yay! After about a half an hour -- because it was unclear whether the recondition mode was supposed to be used on Li batteries -- I switched to the normal Li charging mode. After a number of hours, the charger indicated that the battery was fully charged and the car's electronics were, once again, alive and behaving normally (though a Xentry scan shows a few codes that seem to be related to the power outage).

After that self-inflicted issue and recovery, the battery seems to be back to normal (whew), though I don't doubt it's life was decreased somewhat by my stupidity. Live 'n learn.

Surge

Does anyone know where the fuse is located for the cargo area 12V socket? Mine is not working. Oddly, the charger gives no error; but plugging even a very small power consumer into the socket does not work, even with the engine on. I’m thinking the fuse may be blown.
If so, this could lead to situation where the battery dies because the charger is not charging it.

Stenzel-Germany

Hi Surge,

Rear SAM (Behind left door in trunk)
Fuse Number: 39 (Look at center by the relais)
Value: 15A

15A = Color code: Blue

Best regards

Stenzel

user33

Hmmm, posted this yesterday but must have goofed, somehow ... this might help, also:
https://mbworld.org/forums/coupe-roa...ml#post8400088

Surge

Sure enough, the fuse was blown; hence why the 12v socket was not powering anything.

The real question is why was the “smart” charger not showing an error!? This means that our batteries may not be charging at all, if the fuse is blown, and we won’t know.

user33

I assume that the charger did not show the "light brigade" progression as it determined/escalated the battery's voltage/charge ... that would be the clue. Whenever I connect a charger, I look for some confirmation that it's operating (seemingly) correctly ... too often I've not pushed the plug in far enough or something similarly oops-ish. #;-)

Surge

You're right, it didn't. But the charger instructions are poorly written as they don't mention any of this. They actually mention an "error" state which is a flashing LED, which did not happen. They mention the reset procedure which briefly illuminates a charge state LED, which did happen.
So if you follow the instructions, you can think the battery is charging and have no confirmation that the fuse is actually blown and you are not charging the battery!

UCIMBZ

How about that gradual charging scale on the charger? Did it progresses from low charge to charged in your case?

Surge

Nope, it didn't. I guess that's how you can tell. It's just not at all clear from the manual that these lights will illuminate. I had forgotten after just 1 year that this is how it should work! Had I not tried to inflate my tires using the rear socket, I would have no idea that the fuse is blown.

lgarcia

I have learned so much from reading this post. I found the tow hook, first aid kit, and tire inflator kit. No trickle charger.....I will order the Juice My Ride with Lithium mode, thanks!

Surge

Sure enough with the new fuse (15A #39) the “smart” charger now has a yellow LED illuminated corresponding to one of the battery charge levels, in addition to the green LED.
This is not at all clear in the owners’ manual for the charger! All this time I thought my batt was being charged when in fact it wasn’t!
When the battery is full, do you still have a yellow LED always illuminated?

user33

Although it may not be obvious to most people, this actually makes perfect sense in that there's no connection to anything when the fuse is out/blown so, technically, the charger is not connected and therefore wouldn't show any change. Yes, it helps if you're a computer/electronics geek (well, in this case, anyway). #;-)

garymac

When the battery is fully charged you’ll have two green lights on the charger. The top right LED will be green. On the left, below the reset button, the LED will also show green. By the way, the same lights and colors apply when charging the agm battery in the base GT.

user33

The green LED by the "circled 1" icon is just the "I'm powered on" indicator. If charging/maintenance mode is activated, the applicable yellow/green indicators will be lit, indicating the level of battery charge and mode of charging ... the last one (underneath the "full battery" icon) being green when it's transitioned to maintenance/"trickle" mode). It takes a bit of time for the charger's programming to figure out the full state so, for example, plugging into a car that has a well-charged battery, takes tens of seconds before the "light brigade" identifies the "current level of charge" (pun intended!).

It does appear that the instructions could/should be more thorough.

Surge

Indeed, you are right! Just when I thought I was somewhat smart-- DUH! Of course there will be no indication that something is wrong when there is no connection to the battery!

lgarcia

Received my Juice My Ride today and plugged it in already, the battery started charging from 60% at first, going on 80% by the time I took the pic. Thanks for this posting, I did not know about this topic and I am glad I came across this way to save the battery

user33

If you're interested in learning more about LiFePO4 batteries (like the one in the GTRs), this is one of the better articles I found:
https://www.solacity.com/how-to-keep...tteries-happy/

Although the article meant for batteries used in power-storage systems, much of it applies to our batteries. I first ran across it when searching to determine the voltage vs charge level for LiFePO4 batteries when I was adding additional parking-mode battery support for the dashcams in my GTR. I needed to know where to set the cut-in/out voltages in the Victron Energy Smart Battery Protect that I use to determine when the auxiliary dashcam batteries would be charged.

MikeGLS450

I have a NOCO. Says it’s good for Li. Can i use it or get the CTEK?

M~Factor

I think this would be one of very few times I'm glad that I have the base GT model. No lithium battery. Just a regular battery that I had to replace after 4 years. I failed to use the trickle charger over the winter. Cost to replace? $250 at Autozone.

user33

You might want to read the following post: #;-)
https://mbworld.org/forums/coupe-roa...ml#post8656449

LAsunset

Curious to know what's everyone's resting voltage, like in the morning before starting the car or sat over night etc. Mine sits around 13v to 13.25v. Wondering if normal for this Li.

Dave Backmarker

The answer will be, “it depends”. As voltage is the potential across cells, “resting” may not be the right word. Prior to starting, voltage will vary based on technology (e.g. lead acid versus li-ion) age of battery and the magnitude of parasitic draw on the battery. I doubt any of us want to disconnect the battery to measure the voltage. This would take a little doing and it would remove power from settings that are stored in volatile memory.

user33

This should help answer that: