How Often Should I recondition Main Battery?
 

My car is now on its 3rd battery (replaced with a new battery just Tuesday).

I don't drive this car daily, maybe 2-3 times a week, and usually just short trips (<15 miles). So I assume my new battery will start to lose its capacity in a few months, or at least sooner than a car driven 30+ miles every day.

I bought a Stanley Battery charger and conditioner for Christmas...


https://images-na.ssl-images-amazon....TL._SX569_.jpg

With a new main battery like this, how often should I charge it (or recondition it) to keep it at peak performance? Once a month, every three months, etc? Same timeline for the Aux. Battery?

I assume I can leave either battery in the car and charge them while connected? TIA

if you drive that much you should be fine and maybe just bad luck on battery.
OR alternator is not putting out enough....
30miles should be enough as if engine gets up to temp enough time to charge battery

But you can hook up your charger when you park it and put in trickle mode.



Heck I let my truck sit for month at a time and still using same agm battery over 5 years old.
My E400 gets driven maybe 4-8 times a month and still good on 4 year old battery...

By 15 miles, I mean 15 miles round trip (at most). Often, my local trips are less than 4 miles one way (8 miles total). Sometimes I don't drive but once a week.

I drive twice a week to physical therapy for my knee replacements, but the gym is just one mile away.

I've owned this car a year now. A full tank of gas will last me 3 months between fillups...

I daily drive less than 15 miles too, less than 5k a year. Had probably use my Ctek around 4 or 5 times since I own the car. I have not seen the low battery message on the dash yet with the original 2015 batteries. Wonder when it will show up as the eco stop/go haven't activate for around a year. Don't have the ECO icon in yellow font on dash too.

If I remember correctly, MB don't want more than 14 or 14.4V on the car or else will damage electronics (some where in the manual). The recondition function stage (per my Ctek manual), is at 15.8V :eek:. I haven't try it yet in either battery. Probably can try on the aux since I usually take it out to charge (~5 lb vs the ~50 lb main battery that I'm not taking it out). Somewhere on the web said not to recon more than 1 or 2 times a year on a motorcycle/atv battery. Haven't been able to find the info on car batteries.

You can plug it in anytime you want if all your doing is float and pulse stages. Just make sure it will change to pulse stages as some cheap battery tender clone will continue to float and damage the battery.

We have our cars sitting up to 3 weeks at the time and they will fully recharge on first 3-4 miles.
It is regenerative recharge that is killing the batteries in newer cars and you have to live with it if you want to save fuel money.
If you really want to keep you battery topped off, buy $9 maintainer at Harbor Freight.
The Stanley gives lot of sale pitches in its description, but I don't see tech specifications for maintaining mode?

If yuo do drive that little each trip.... I suggest going a few miles extra to allow engine, tranny and differentials to get up to temp and work properly.
Especially for the engine.... else get quicker oil changes as it will turn acidic due to water and blow by never escaping engine.

In hindsight, the absence of any warning lights (ECO start/stop or low battery warning) did not mean the main battery was good in my case. More telling, my ECO start/stop had not worked in six months or so, same as you, With the new main battery, ECO now works when I stop at the intersection leaving my subdivision (300 yards from home) on a cold engine. I've read here that the AUX Battery poweres ECO Start/stop, but I've concluded not exclusively.

I bought the battery charger to use on my older cars, but now I'm thinking I should plan proactive use with the E350. All I have to do is put a reminder in my Outlook calendar. But how often, as I don't see doing this weekly?

The small AUX battery at the trunk is only to maintain electronics and your air cond blower fan and stereo when start stop eco function is at ENGINE OFF MODE. I dont like ECO mode, i disable it all the time .
The engine starter uses the big main battery to re-start the engine and take over from the small AUX battery when out of ECO mode.

I do not know if E350 charging system is the same as my E400 or its stand by electric load when parked at home un-used similar to E400. Assume it is the same because it is W212 chassis.

My W212 E400 will consume 0.4 amps constantly during stand by parked un-used. This is a 19.2 amps hour gone per 2 days. This is a very high stand-by load, but it has to feed them electronics and keyless GO.
I will charge it once per 2 days when I do not use it. Using the Ctek 5 amps charger.
If you do the same, your new battery will last 4 years easy if your city is not crazy hot every day of the year 365 days like a tropical country.

What you need to watch out is these :
01. Cleaning the car with the door open and the interior and under door lights ON, this is about 7 amps. Say 2 hours car cleaning and then parked it. You loose 14 amps already. Park the car another 2 days and more loss.

02. On the battery negative post ( at least on mine ) , there is a charging chip made by Hyundai. Small black plastic thingy A0009052902
https://www.ebay.co.uk/itm/Mercedes-...-/122808317066
For my E400 the charging perimeter of the alternator + the charging chip is for AGM, hence it is 14.7 volts to 13.8 Volts , depending state charge of the battery.

AGM , at least the Varta brand who supplied my MB part no A001 982 81 08, is designed for 14.8 volts charging at bulk mode. See PDF attachment.
Most common flooded lead acid can't take 14.7 volts, usually they want 14.4 - 14.5 volts, see the PDF for Varta flooded battery charging needs.
For my configuration, if I use common lead acid, the battery wont last long as it is being overcharged by 0.2 to 0.3 volts and this is BAD for battery.

Don't recondition your AGM battery, Varta does not recommend it.
Reconditioning a battery is okey with lead acid battery where it has filler caps to refill loss battery water, but don't do it even once a month please.
Every 6 months okey when battery is used for deep cycle purpose, but don't use it at all if battery is well charged most of the time.

Try to see how is your charger charging profile.
How many amps at the start, 30 - 60 minutes after and its top off charge at say 4 hours of charging.
Slow small amps charge at 10% of battery rating is better than fast bulk charge.
Max charging limit stay under 20% of battery rating for non AGM, which is about 18 amps for a typical 90 Ah battery we use.
AGM can take higher charge at 25 - 35% of battery rating, but slower is better, less heat.

The worst/longest charging duration is 95% to 100% full charge, it is what it is due to the battery chemistry.
If your charger charging profile is good, this last 5% may take 2-3 hours but at very low amps of 0.5 to 2 amps. This is called the acceptance charge.

Charging is best done when your car battery is at room temperature, hopefully 20-30C max.
Your charger and my Ctek charger does not have battery temperature sensor, so it can't compensate battery temperature to its charging profile, so stick to room temperature.

Hope your battery can last longer....:)

S-Prihadi

I believe you need to address the .4amp parasitic load. It should be no where near this high. Something is draining your battery and needs to be identified and repaired.

I initially thought so too, that this is a possible parasitic load, part of it, not the entire 0.4 amps. I wish there is a similar car to test instead of needing to pull fuses.
I just measured it again with high accuracy low amperage unit, it is 0.31 amp.

This car from door locked to lowest stand by load at 0.31 amps need 3 minutes. After door locked, it is 3.46 >>> 2.27 amps first for 3 minutes.
This is why I am kind lazy to pull fuses to test , the door switch is why.

This old WIS data too bad does not yet have Keyless GO suggested load.
https://www.benzworld.org/forums/att...tery-drain.pdf

When I have time I will pull fuses to breakdown the Keyless GO own load.

Thanks for the "trigger":cheers:

I do a lot of short trips but there are longer drives mixed in too. When I replaced the original battery that died a slow death in less than 4 years, I charged the replacement battery with the ctek every 6 weeks but even with that it only lasted 3 years. I started to think my charging may have introduced too much heat. So now I've gone to an on demand model. Every 6 weeks or so (when I'm checking fluid levels), I check the battery voltage. If it is less than 12.4v or anytime I notice the car takes a little longer to start than normal, then I will put the charger on. Unfortunately, the W212 fuel sipping alternator doesn't output at high enough levels all the time.

In regards to reconditioning, most charger manuals I've seen recommend once a year because that it really cooking your battery with voltage. I've never bother with it because you should pull the battery from the car. Really any charging over 14.7v or so is not recommended while connected to the car. Check your charger manual to see what the output voltage is. I actually returned a different battery charger before I got my ctek because its regular charging mode used 15.3v.

Fisch, you are in Florida it is quite a hot city some years of the month.
Dang, DFWdude is in Texas... hot too, my apology..... we all 3 are in hot ambient cities and by geography I will have the shortest battery life for being
in a tropical country 365 days hot all year round, coolest temperature 26C at night at best in rainy season.

Historically for most cars in my country and also my cars, non AGM, except those with cooler located main battery at the trunk/boot ( which I never own ) ,
2 to 2.5 years is the best we get for daily drive driven 4-5 times a week.This is 20 years data.
Battery quality gets better today but the traffic jam got worse and worse. I guess that evens it out as far as battery life span based on hot engine bay of a car in the bumper to bumper traffic,
assumed healthy alternator.

On my boat, outboard powered, the same battery can last 4 years ( Delkor Calcium ) and 6 years for AGM ( USA brand, I forgot the name ) due to no hot engine bay and cruise speed at 4,500 RPM for at least 90 minutes non stop, where alternator pumps good power at this higher RPM. NOTE : This boat is 365 days 24/7 on shore power and battery charger when not in use. This is a 15 years data since 2004.

Varta AGM is only on my E400, my other cars and boat uses either common Yuasa with filler cap or kinda sealed Delkor Calcium https://www.delkor.com.au/en-au/prod...cium-batteries
My E400 , original new battery came with the car. June 2014. Replaced by 1st owner on 28 March 2016. 19 months. Original MB by Varta both of them.
I bought the E400 used on May 2018 and replaced the battery on 15th July 2018, not because it is dead but it is no more full capacity. Varta Silver Dynamic AGM, same size as MB one. 2 years 5 months of use.
This 3rd battery I want to see if it can last 4 years, but I must track down the parasitic load as suggested by Sunnyslope48:thankyou: as MB recommended 100mA or 0.1 amp as max standy-by load.

I got the attached info from the net. Which open up my eyes on the CAN bus behaviour and SAM module of the car and its sleeping and waking up nature and handshake too, so it is better to use Millivolts reading of voltage drop and not pulling fuses if I can't access the wire to use clamp amp meter.
"The fuse box is your friend, but not for the reasons
technicians have traditionally believed. While pulling fuses
and watching for the current draw to disappear worked
well for the cars of yesteryear, that procedure will not help
you given the advanced electronics of today’s Mercedes-
Benz vehicles. Doing so will only confuse the modules,
circuits, relays, and the CAN itself, all of which operate off
of battery power."


This is a well documented troubleshooting by someone capable. It is a very good read because it involves an earlier repair which needed SAM coding as a 2nd issue , on top of the real battery drain culprit.
https://www.benzworld.org/forums/w21...em-ever-2.html



@DFWdude
Perhaps you try to check your parasitic drain too.
If the said 3 batteries are for your 2016 E350, and driven albeit short run <15 miles but 2-3 times a week, based on MB 0.1 amps normal drain, you probably have more than my 0.31 amps drain.


Safe drive everyone. I shall report ( on a new thread ) when I get to find my battery drain real culprit.

.

Wow, thanks for all the data points. I've found the 'less than 3 year battery' issue applies to our Honda too. That car takes a non-AGM battery and those typically last 2.5-3 years also. For the Honda, Advance Auto has batteries with an added S in the part number and a description "This battery is only available in select Florida and Puerto Rico locations." We got one of those from Advance for the Honda and after 2.5 years it died while on a March roadtrip to Tennessee. We drove from 80 degrees F to 32 and the next morning it wouldn't start and tested bad. In warmer climates, the battery chemistry cooks and can produce more amps but shortens the life. Take a cooked battery to a colder climate, the chemistry slows and it doesn't have enough amps. Well we got Advance to replace that battery under the 3 year warranty at a local Tennessee store but the ones they carry did not have the S designation. Well that non-S battery only lasted a year (or one Florida summer). By the following March it was dead.

So now I always make sure the replacement batteries I buy have at least a 3 year replacement warranty. That way I might get a free replacement and essentially get 5-6 years out of one purchase.

The only battery I've had in Florida that last longer was the conventional battery in a Prius. That was still working when I sold it after 8 years but that isn't a fair comparison since that battery isn't located under the hood (they put it near the spare under the hatch floor) and the Prius doesn't use that conventional battery for starting - it uses the hybrid battery. The conventional battery is only used for accessory mode.

something to think about.

How all these issues with starting batteries in Combustion engines...

Now think if you owned a battery powered car and how temp & age effects battery power and life....

I've lived in N.Texas for 21 years now. Never had a problem with traditional batteries lasting at least 5 years in 8 different vehicles owned during that time (Ford Probe GT, Chrysler minivan, 2001 Mercedes C320, two Dodge Neons, Honda CRV, Hyundai Elantra and a Hyundai Sonata).

I have a Bipolar garage for two of these... housing a $64K MB E350 and a $21K Hyundai Sonata, purchased new in Dec 2013. It's on it's original battery, and I swear I heard it chuckle Tuesday morning when I parked the E350 (with its new battery) into the garage next to it.

I've read the manual for this Stanley battery charger. It doesn't say whether it can be used on an AGM battery. Can it? The charger is a 15V type, and its output voltage is 12V, not 14V+

IIRC the manuals typically say on the spec page what the max voltage is for the charging program(s). At least that's how I weeded them out several years ago. The 12v just refers to that it works with 12v output batteries and not larger or smaller ones. If the spec page on paper or on their website doesn't say, you could also use a multimeter to check the volts while it is charging. You'd have to check at various intervals if it is a step charger.

Below is an example of a page from a ctek manual
https://cimg1.ibsrv.net/gimg/www.mbw...58191dbcef.jpg

This is probably a different discussion. The batteries in an electric car is housed in the pan of the chassis, not in an engine compartment. So they shouldn't accumulate much heat, like an AGM battery, which is not recommended in the hot engine bay of a combustion engine :nix::eek::nix:. https://batteryuniversity.com/learn/..._glass_mat_agm

I think electric cars also use battery coolant or something like that but the heat profile without combustion is very different. But I really don't know what I'm talking about.

The stanley does not have AGM profile I read the manual and it has to have AGM selector switch if it can do AGM, so it will charge 14.4 volts there about as bulk charge.
No worry, it wont damage AGM ( assumed Varta ), but it wont be able to fully charged to 100%. But it is good enough.
All you need to do is when battery is near full, make sure it will charge under 3 amps as final acceptance charge or top-up charge.

BTW, I went to see US weather historical data, Texas, Dallas. By average Texas based on 1 year is much cooler than my country. Lucky you.
89 - 92F is my typical day time temp. At night it is 80-83F. All year round. Your temperature average is nice and cool other than June - Sept.
https://www.weather.gov/fwd/dmotemp

Same here. I had no battery warning lights. ECO start/stop rarely activated. Then all of a sudden one morning, my battery was completely dead. This happened about 3 weeks ago.

Dealer determined early battery failure, and replaced for free. 2016 model year with original battery.

And now the ECO works all the time, at almost every stop.

ECO is used for calibration + More !!
 

couple hands on observations...

I too hate the stupid ECO (engine stall at every wheel stop = starter killer) but it is used to calibrate the battery health under load. And that drain information in turn is used by the charging circuit (courtesy of Bosch design) to charge the main AGM. The goal being is to always keep the main battery *undercharged* so it can be topped off during regenerative braking (yes on regular V6/V8 gas Eng, Not hybrid) - So if you never let "ECO" do a Stop... the alternator will be controlled to conservatively way undercharge main AGM will minimal voltage. BTW normal alternator charge voltage goes up to 14.9V as often as computer think it's needed.

We know that lead batteries hate to be undercharged because they sulfate to their death. So that in part explains why this one is way oversized to begin with. It sulfates like crap being kept CONSISTENTLY undercharged on purpose: "save energy"!

When you use your favorite CTEK to perform what it does best, the computer goes nuts as soon as it realises the AGM is "abnormally" well charged. It puts the AGM under an abusive 100A (HUNDRED Amps) load until the voltage drops back down to Bosch low charge target. Imagine the rosting effects of: 100A x 12.5V = 1,250 Watts.... - Long story short: the more you CTEK pamper your AGM, the more it will have to be abused to get to a low charge level.

Couple more relating info:

There is a software bug in the battery/alternator control software that makes the "charging system" reach the ballpark of 11V discharge WHILE DRIVING... nothing in this car likes working under-volted: not the electric steering, not the direct fuel injectors, not the spark coils... (Sorry I cant find the TSB for that fix/update)

The Rear AUX trunk AGM is monitored as well and normaly "fully charged" every driving cycle. I believe this one more or less gets charged to a normal target level through 14.9V spikes

For the curious drivers: pop the "secret menu" on your display to show both BATT Volts & Amps before using steering wheel controls.

NOTE the main AGM is NOT inside the hot engine compartment! It has its own rubber sealed compartment to keep the heat separated from the battery & wipers section...

Never have seen 11 V in the car. Since I drive car having DPF with ScanGauge and have 4-display and I put voltage on 1 of them. When ECO stops the engine the gauge shows 12.3V, that after few seconds might go to 12.1 but have not seen it lower.
Also when heat suppose to shorten battery life, it turns a myth in real life.
We had 1998 ML320, where battery was directly in engine compartment with only some sheet metal brackets.
Used in No California, the car was towing quite a bit and frequent Las Vegas with 115F temperatures, so the battery have seen high 100'F quite often. .
So Spanish-made Varta lasted for 13 years with such abuse.

Where did you get this info?
Source?

Curious is all like to read more.

BMW ( non-hybrid ) I read uses its alternator to do regenerative braking. http://www.bmw.com.kh/asia/en/insigh...y_regeneration
Surely it is logical to allow the battery + alternator algorithm to keep some allowance to not fully charged the battery in anticipation of regenerative braking.... up to a point.
Assume MB does the same like BMW, but I doubt these cars charging algorithm it is that straight forward or that simple as in keep battery always undercharged.
It has to be sort of adaptive where "always undercharged" is not always happening or being the system single goal, it has to be smarter than that.

Someday I need to video the Volt + Amp data while driving to see if indeed MB charge the battery during braking and if at good cruise speed and how low is the charging amps.
It will kinda difficult to know if the lowered charging rate at cruise speed is due to power savings or a battery state of charge deemed full.
The simple test would be after the drive, open the hood, wait 24 hours to cool down and for the computers to sleep and measure battery voltage and normal battery amperage drain to make sure the
computers/CAN/SAM are really sleeping. AGM battery we can't measure its acid specific gravity, so voltage is the only way.


Yes, agree that the battery location in W212 is not as hot as some cars where battery does not get its own "compartment " and some is behind the radiator, I like MB W212 battery location.
Nevertheless it is still very hot when in bumper to bumper traffic.
At speed it will do well in cooling the battery.

Something else to note.
The secret menu for battery voltage and amps.
Its amps reading is not GROSS alternator output , but NET charging or discharging to/from the battery. Just in case if someone wants to verify if our 200* amps ( *on mine, Valeo ) alternator is pumping out enough.

.

OK, my head is starting to hurt and my eyes are starting to glass over. :bow:

I guess I just want to know if there is any benefit to occasionally charging these two batteries, and how often?

What I've read so far suggests that I can't hurt anything if I charge lightly (ie. 2-hours, or 4-hours) once every 3 months or so, or 6 months. I don't know.