I have a 2020 AMG GT-C (C190.380) and I'm wondering about the state of the lithium-ion battery before I embark on an extended trip. To be clear, this is the starting battery for the car -- it does not have a separate lithium-ion battery for the start-stop system.

At about 13,000 miles, the battery is original -- the clamps and retaining bolts are absolutely pristine.

The car doesn't show any symptoms of a failing battery at all, though I'm not sure what to look for since I've not had a car with a lithium-ion battery before. Starts right up, nothing is weak of flickering, headlights don't dim under load, and so on. No weird electrical gremlins or codes.

For a regular car, I'd just replace it before my trip -- it's 5 years old, so why not? But this battery costs at least $2000, so I'd rather not do a replacement until it's clearly necessary. (For that matter, what lifespan should I expect from the lithium-ion battery?)

Anyway: after not driving the car for about 24 hours, the battery reads 13.2 volts at the posts. There are lots of cool displays on the dashboard, but I don't see anything for battery voltage.

Is 13.2 volts resting considered charged? Any way to load test the battery, or any other way to evaluate its condition? I have a

(I posted to this forum because I think that lots of other models have the lithium-ion battery, so the answer is probably in common for them all ...)

Thanks!!1!

 

I can see why you don't want to rush at replacing your... $2000 battery.

Use an appropriate float battery CHARGER to prevent drain by parking then you'll be golden. I think CTEK has units geared for these newer cells.

(Use an appropriate battery TESTER if you don't trust the charger... Li-Ion have different threshold voltages than lead-acid AGM's)

 

Which tester would you recommend? I have a Foxwell BT-705 which works great but doesn't support lithium-ion batteries.

 

I dont recommend any battery tester... simply skip measuring low mileage battery - Instead float charge your battery to make sure it stays in best possible shape.

 

OP the LI battery in my 2015 S-65 is original and works perfectly.

*Mic-drop.

 

Lithium batteries are promoted as having 2 to 3 times the service life of conventional AGM batteries, but use and abuse always factor in to create exceptions. If you're planning travel and are uneasy about the possible need for exotic replacement items such as a lithium battery or a 23" odd dimension runflat performance tire, make a few phone calls, find some suppliers who stock the items, and ask if they express ship. Then add them to your speed dial. Good luck and happy motoring!