I think my old Mercedes battery lasted 7+ years before it stopped holding a charge and the cheapest replacement I could find locally was at the Mercedes dealer, something like $214 after handing over my old battery for the $30 core charge back. I was told it has a 2yr warranty. When I was at Walmart after that I noticed they sell batteries and had an H7 replacement for $170 I think, never even thought to look there but will from now on. I don't put many miles on my Mercedes so I use a Noco Genius 5 charger on it once a week or so. I recently bought a wireless Bluetooth battery monitor for the battery and seems the car wakes up at 6am everyday and does something to drain the battery, very strange
I bought the Ancel BM200. Its on Amazon, eBay, but I got it for the lowest price on AliExpress for something like $11 at the time. Ships from overseas but I received it in a little over 1 week. Ill also add there are others on Amazon, different brands. I do like this Ancel because it was inexpensive, I didnt even have to register with my name because I used it on an earlier device, and I drive around with my phone open and can view what the battery and alternator is doing by seeing voltage. But look around and see if theres another you like better.
I wrote all about it in my thread about how I was getting the red battery warning light coming on. i will say that the Ancel BM200 app wanted a lot of permissions to my phone, so instead i installed the app on one of my old cell phones with an earlier android os and was able to use the app without even registering my email nevermind give it permissions. Here's the thread.
I also just ordered a Konwwei battery tester because the Ancel does not show battery health/CCA. I should be getting that tomorrow to start using.
Heres a screenshot of that monitor graph, seems around morning time 6am the car wakes up and it using power. Im on a mission to figure out what is going on, if its normal.
Heres some advice i wish I had known when I bought my battery around 1yr ago. Look at the date it was made, my Mercedes battery has it stamped on the negative battery post. I didn't even realize until recently that it says something like 03 21, so it was sitting on a shelf over 1yr before I bought it.
Also my Mercedes battery is labeled 700 A (EN). I originally thought that meant English, but now realize its a testing standard, like CCA is. From my research that just means if you battery is an EN then you need a higher CCA rating if the batteries youre looking at are listed in CCA. This comes in handy if using a battery tester, the results are different depending if you choose CCA vs EN. The state of health shows differently.
They have an Everstart H7 80ah battery at Walmart with 850CCA for $179 that I would not have an issue buying if I needed a replacement. That has a 4yr warranty. Mercedes battery at the dealer runs around $214 after core return and only has 2yr warranty.
I dont drive the mercedes many miles so i got the Noco genius 5 charger and I put it on the battery at least once a month. I originally bought the Noco genius 1 which did work great but it just took way too long, had to leave it hooked up overnight. the Genius 5 will charge and do its things in around 3hrs. I noticed with that it will charge it to full pretty quickly, its just spent the rest of the time "conditioning" whatever that is.
And im constantly updating my thread I posted above. Both battery monitors are showing that my battery is going from full to 50% in two days just sitting there not even using it. I think my next step is to get out the multimeter and test every fuse for voltage drop with the key not in the ignition to see what is pulling power.
Slideshow: A one-of-one U.S.-spec Mercedes-Benz SLR McLaren Roadster became even rarer after a factory-backed transformation at McLaren's headquarters.
