Battery Sourcing
 

Just a sanity check.....

My car has been cranking a bit slowly so I checked cold voltage, car off, for the main battery, scanner showed 11.6v. Charge rate is ok at 14.8v when the car is running, so I'm thinking that this 5 yr old AGM battery is probably fading. I'll look at replacing it, I'm thinking with a Duralast AGM Group 49/H8, $194 w/core. I also saw posts about where batteries were purchased, but I'm thinking there are only a few actual mfg, with the batteries re-branded to different stores.

As preventive maintenance, I'm also planning to replace the original aux battery (left side of dash). No battery malfunction message but it's about 8 yrs old and not expensive. I've looked at other posts about where this battery was purchased from, but it varies. I can get an oem branded battery for $40-$50, but I also see folks that have bought them for much less. However, on some of those posts, they have had issues with the alternatives. I don't have an issue getting the oem branded battery but is there a general consensus I may have missed about sourcing the aux battery?

For main battery hard to beat Bosch sold at PepBoys. They have internet pricing, so order on line with free replacement, but I did not let them touch my car.
I don't believe in preventive parts swap. With today's unsetlet quality, chances are that new battery will die sooner than older would.
so IMHO now is good time to "invest" in battery tester like latest gizmo under name sonar.

thanks Kajtek, I'll check the Bosch out. I'm in same mindset - I will change the battery out myself.
I understand reasoning on the aux battery, maybe I'll leave it alone until an actual issue as it's easy enough to change out.

EDIT - Picked Bosch Group 49 @ Pepboys. $175 w/ internet discount, 4yr warranty. thanks again.

5 years is pretty good depending on the climate in your area. Since moving to Florida I have yet to have a battery last more than 3 years. So the Bosch with 4 year warranty was great for me. Already on my second one.

I think I got my aux battery off Amazon. Just a cheap 3rd party option. No issues. But I waiting until I got the message. No real advantage to doing both at the same time.

You should be more specific with MY as technology changed and I am not sure if everything changed with facelift on W212.
Early cars had small battery mounted in the dash for transmission lock and steering back-up.
Later models have ECO restarting and mid-size battery in trunk for that. somewhere at that time come energy recouping option, who saves environment and fuel money, but with the cost of faster battery killing.
I think I heard about only 1 owner who having smart charging managed 5 years on factory battery.
Most of them go in 3.

Both OP and I have 2011's so it's the small battery in dash.

Yes, small battery in dash, no ECO.
The main battery in my car (underhood, passenger side) had been replaced by dealer before I bought the car, showed up on the vehicle maintenance records. Its actually just under 5 yrs old.
I agree getting 4-5 years out of a battery these days is pretty good, especially a vehicle with lots of electrical churning away like these cars.

I got my aux battery from Amazon, the proper, german Nanny approved OEM version for 47$. I wouldn't go with anything else since I've read complaints about proper fitment with the offbrand cheapos. One thing to look for is corrosion on your aux battery terminals, mine had quite a bit of crud on the negative one.
I might go for that pepboys offering since mine has moments when it's taking a few turns to start the engine. I've also been keeping it on life support for the past year (CTEK every couple months) so it might need to be retired. What's the A rating (or CCA) on the pepboys Bosch?

CCA=850, I added the link below.
Note though that higher price shown includes $18 core charge and $69 installation, neither of which I included. Prefer to install it myself and taking old one back.
Bosch Battery

I've gotten the auxiliary battery malfunction message... It showed up once a while back and hasn't come up again... Is this something I should be worried about? Should I look into replacements? Messaged popped up, I OKed it, and hasn't showed up since.

Thanks
T

That's 1000 CA ?
I bought wet model of Bosch just weeks ago and solar tester shows 1260 CA on 1000 rated battery. 96 months prorated warranty.

I would have gotten the same Champion AGM battery at Pepboys. It has a $40 rebate good til January 27th. Makes it much cheaper than the Bosch battery. Also Champion is made by JCI and Bosch is Exide. JCI made the OEM Varta battery and Exide doesn't have as good a rep as JCI.

https://slickdeals.net/f/12599818-ch...s-4yr-warranty

http://img.rewardpromo.com/1/7175/20240.pdf

Ah, missed that, thanks. Out of curiosity I'm going to stop by and ask them about the Champion. I need to return the old battery anyway.
Kajtek, CA = 1020 on this battery.

EDIT - I'll be danged, it was very easy to return the Bosch and get the Champion instead. I stuck my old battery back in the car and just carried the Bosch in. I got a full credit for it and then just bought the Champion "online" while I was in the store. It will be there tomorrow for pickup. They were very easy to work with. $40 MIR is now onroute to Pepboys rebate center. Happy ending!

S550e, if you're getting the aux battery malfunction indicator, it's probably going to return soon. I would think its time to replace that aux battery. In my case I decided to wait after advice here until I saw the indicator rather than replace it now. Note comments about location (either under dash or in trunk) before selecting a replacement.

That's a great deal on an AGM battery. I think the Bosch had the rebate when I got mine.

My aux battery indicator would pop up every 1-2 weeks but eventually started coming on each time I started the car. I suppose the car knew the voltage was getting low and started to give an occasional warning but eventually the voltage dropped low enough to get the message every time. This thread has the best info on replacing the smaller dash aux battery.

Incidentally, I tried charging my original aux battery using my ctek first. It worked at first but the message started to appear again after about 5 months. Another recharge and the message came a month later. Then I ordered a replacement for $13 going on 7 months ago and all is well.

Glad you were able to swap it out. I figured it was too late for you but thought that the info might help someone else out.

Thanks again, I really appreciate it.

All done, replaced the battery this morning.
Pushed the hood up to the 90 degree open position and isolated the positive lead while I was doing the replacement. Also ensured negative side vent was connected and positive side vent was plugged.
That H8 size filled up the space in there, replaced the smaller size MB branded battery.
No memory settings seemed to be lost, radio, clock, etc. stayed the same. The only change was the "mileage since reset" went to zero (new start) which didn't matter that much to me.
Car engine spins noticeably faster as well.
http://pic20.picturetrail.com:80/VOL.../414120919.jpg

Wait a minute? You hear your engine spinning?
All my MB start on instant, maybe not of the 1st but on 2nd cylinder. If you engine take longer, it might be due for tuneup. :)

Lol, no sir, it's immediate start, just spins up fast.
No dealer trip needed! ;)

Just called my local PepBoys in Las Vegas, NV. The Champion AGM batteries have the $40 rebate until 02/24/19. It also comes with a 4 year free replacement warranty.

WTF I just bought the Champion at PB last night when my wife's car wouldn't start, didn't say anything about a rebate. Wasn't cheap but I needed it RIGHT NOW. Guess I'll stop on the way home and ask, does anyone have an online link or anything with info on the rebate?

FYI for tracking purposes, this was the original factory battery I replaced, car has a build date of 09/13, one of the first facelift cars. 5-1/2 years, not too bad. Although I'm surprised it was fine all last week when it was -10, -15 but decides to go TU when it's 60 and sunny....not that I'm complaining....

Thanks,
Darel

Disregard the above request, found the link online, although it's saying "receipt not found" when i enter the info. Maybe it takes a day or two to go through.

Darel, the online reg was fiddly for me, so I printed out the rebate form and mailed it in. Received an email a few days later that it was being processed.

Got it to go through just a few minutes ago. Thanks!

I had good luck with Dura Last series from AutoZone. The Volvo XC90 I had was one of the AGM series and worked great. I think it was in there for about two years prior to my purchase but still good battery. If I have to replace any batteries soon I will most likely save up and get the D/L AGM.