I don't buy new cars. 2008 was the last time and that was for an Infiniti G35x for my wife.

 

It seems the app wants more than just location. Im worried about it watching me, meaning turning my phones camera on, turning the microphone on listening. Im not tech savy so have no idea what they can do. Im one of those people that puts tape over my laptop camera, I would never buy an Alexa knowing other people can listen inside my house. I have security cameras all outside my house but would never put one inside. paranoid or smart? i read the battery monitors terms of service and thinks its a little much.

 

Hooked up the battery monitor and it seems like an informative tool. Shows my battery was low on charge so have it charging now. I want to bring it to full then see what the monitor tells me. Ran the charging and starting tests, everything seems ok. Im curious how it knows how full the battery is charged. When I hooked up my charger it quickly went up to showing over 75% charged. Ill have to play around with it more. For battery temp it says to stick it directly down to the battery with the included double sided tape, but I dont want to leave it on forever, and what if i want to use it for another car or battery. Glad i dont have it connected to my regular phone, it wont stop sending notifications to my spare phone, its crazy.

 

I found it very interesting that the monitor appears to show me exactly what the battery charger is doing voltage wise. Shows it on a nice graph. For some reason the graph switches to full view and doesnt seem to allow me to take a screenshot so had to take a photo with my other phone. Wondering how it can determine difference between voltage and the state of charge.


graph of the state of charge.



Graph showing voltage while the charger is doing its thing.



Used some Velcro to hold the monitor down, 2 pieces on the battery on each side of the monitor, 1 piece on the top of the monitor then a long piece over the top keeping it from moving, or so in theory.


I think I found one of the reasons it wants so many permissions. Can track your trips on Google maps. Has a feature to track how much money you spent, also seems like records braking and acceleration???




Not sure what this does, im assuming lets you share all the info to other devices. Dont need that feature, just yet so ill leave everything off.

 

I just notice it looks like the date of the battery is stamped on the negative post while looking at the photo. I was looking all around for the date earlier outside.

 

Depends on how detailed the programming is. Short of a Chem 401 lesson on redox reactions, the voltage should be 12.6 V at 20C. Higher temperatures mean higher voltage. If voltage is less than what the temperature indicates it should be, the charge is low.

 

I have some very interesting readings. I completely charged up the battery yesterday to 100% and now around 2:30pm the next day the battery SOC was reading 93%. At first i thought it was due to the battery monitor since the thing is always on, i also noticed a blinking blue led light on the monitor. The monitor connects via bluetooth so i have to be standing right next to the car for it to connect with my phone and view the graphs. Heres what it shows:


Fully charged at around 5pm. I have no idea what that huge dip is. I still had the battery charger hooked up until around 9pm because it was still in pulsating green light mode indicating "maintenance mode" whatever that is. Shows the charge SOC goes down to 99%, im thinking because I locked the car up and the battery monitor is connected and running.



The SOC stays at 99% until around 6:30am, and continues to go down around every 30 minutes.



9am the SOC drops to 94%.



11am it drops to 93%.


Any ideas why the odd drop in charge? I was thinking maybe it has something to do with the sun coming up and/or it getting warmer. When I looked outside this morning the car windows were covered in dew. I say this because i know the car does things on its own, I know it opens and closes the door to the heater/ac vent up where the plastic box is above the battery. When I had that box off before that door was closed and then awhile later i look and its opened. Im also wondering if it has something to do with the headlight switch being in Auto, I only put it to auto more recently a month or two ago when the parking lights were coming on when I was parked at stores at night, usually it only happened once in awhile at home and turning the lights on and off would usually fix the issue for the night. I havent researched exactly what the car does while parked, figured id see if anyone does know. I think ill disconnect the battery monitor tonight then hook it back tomorrow and see how much the SOC drops. But if it were just from the battery monitor usage im thinking the drop would be consistant.

 

Maybe a case of TMI?
The parasitic drain can be up to 1 amp until the ECU puts the car to sleep. It takes longer if the door isn’t locked. After that, maybe 200 milliamp or so. But it’s still sitting there listening. Exactly what it does is probably in a training manual … somewhere. When you open a door or unlock the car, the drain is fairly high as the systems prepare for you to start the car. There’s a component in the pre-fuse block called the quiescent current relay that you found. If it sees the battery get to 80%, it will disconnect everything except the ECU and the starting circuit. The ECU and the battery sensor have to be involved in this. But you are not getting anywhere near there. But the cause of the failure to start from a few days ago still hasn’t been located. As much as I hate to say this, maybe it has to be in failure mode to diagnose it.

 

Im thinking maybe this battery monitor is just not accurate. reading and displaying voltage is one thing, fairly simple, but to figure out the SOC I read is more complicated and not sure an $11 monitor will be reliable. Im sure it is detecting the charge going down, but it could be overstating the numbers.

When I got in my car yesterday the SOC was 93%, i drove to a store abnd parked, the SOC said 95%, i shut off the car went in the store then came back out, started the car and the SOC now said 99%. i stopped at one more store then got home and when i shut the car off the SOC said 94%.

later in the day I went out to the car and the SOC said 93%, unlocked the doors and popped the trunk to get my air pump out. Left the trunk open while i proceeded to fill all 4 tires, all were low around 5psi. Did not take long, maybe 10 minutes max if that. When i got done, closed the trunk and locked the doors the SOC said 83%. So in less than 10 minutes with just the trunk open the charge goes down 10%?

maybe the monitor does need to learn the battery?

One thing i thought that was really cool to see was how my battery charger works. The monitor shows how the charger charges the battery.




The two red lines on the graph show from when I hooked up the battery charger to when I took it off. The yellow line shows when the battery monitor says the battery was 100% charged. Im not sure if the battery was fully charged and the charger was doing things in "maintenance" mode, or if the battery was in fact not fully charged and the monitor is just wrong.

Heres the corresponding graph showing the SOC for the same time frame.

 

Seems I had different results over this past night. SOC said 83% when I went in last night, looks like it dropped 3% between 7-8am, then stayed at 80% until I went out to the car.

I did switch the headlights back to "Off"" instead of Auto. It looks like between 7-8am the car woke up and did something. I do remember reading how cars perform evap tests while the car has been parked and turned off for awhile, saw this when I was replacing the purge valve in his Chevy truck.







So it did stop at 80%, unless its a coincidence?

I have to ask everyone, is your bluetooth in the car always on? Whenever I walk up to the car the monitor automatically connects, on my phone the bluetooth screen pops up and shows this monitor and it also shows my cars bluetooth to make calls by pairing my phone. so it seems the car stereo's bluetooth is always active.

 

I would love to know if it is normal for the car to "wake up" ill call it at around 6-7am and run things? Seems all night it stays off, but then in the morning something starts happening that is using the battery. Today the car was at 66% SOC when i went out to it. Im not saying the reading is correct, but it is at least going down. And i never went near the car while parked, so its not like it woke up detecting my key fob or anything. Or do all Mercedes do this?


Car was parked all night, I didnt go near it until almost 2pm.

 

Does the monitor give the battery voltage at that SOC? It should never go below 10.8 V or you risk not being able to start.

 

Yes, here is the corresponding graph showing voltage. There numbers on the bottom, 0,1,2,3,4 etc are the time. 0 is Midnight, 13 is 1pm. So far I have never seen an issue with low voltage, I just chekced and since its been hooked up voltage never went below 12v. The low dips are me starting the car, then quickly jumps to over 14v and the monitor shows the battery "charging". I drive around with the app open on my phone constantly looking at it just for fun. Usually stays above 14v while driving except when taking off from stop lights, then it drops in the 13's very shortly.



Right now im just searching to see if it is normal for the car to be using the battery so much. Im wondering if something is turning on that shouldnt be, like a module. Seems to be happening around 6am. i read somewhere that the car will turn the climate control on to dry out the vents to prevent moisture in there, not sure if that is even true though. I need to find someone else with a monitor to see if there car does the same thing.

 

I forgot I threw the charger on it. It actually charged the battery to 100% pretty quickly, even the charger showed the charging complete quickly when it usually stays on "maintenance mode" for over an hour alone. The red lines are when I hooked it up then disconnected it. Then after i went driving around.

 

Heres the full graphs for the whole day. Red lines are with the battery charger hooked up. Yellow lines i was driving around, parked the car around 8pm. Charge goes way down for some reason while parked.





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The state of charge and the voltage are tracking. 75% SOC @ 12.5 V checks with what I read on the Century battery site. So it looks like the monitor is telling the story. But I don’t know what the story is.

 

I'm sure there are a lot of things going on when the car is off: Theft monitoring, "listening" for the key fob, receiving/transmitting signals to the Mercedes satellite in the sky (back when mbrace worked on older cars).

Which makes me wonder, because mbrace was discontinued for older cars because the cellular provider no longer supported the technology, were those features deactivated (which I doubt) or are they still listening for a signal that will never come? Kinda sad.

 

Funny you mention mbrace, I was just reading an article about Mercedes doing away with the Mercedes Me something to do with 3g. When I signed up with Mercedes online a screen popped up saying my car had a subscription for the mbrace or Mercedes Me. I wondered what it even was and says something about remote start from a phone.

I do know the bluetooth in my car always seems to be on. When I walk up to it with my phone open the bluetooth screen pops up and shows it pairing automatically with the car to make phone calls.

As far as the SOC and voltage dropping after i parked the car last night I wonder if it was the climate control fan kicking on. When i was driving home the windows fogged up so i had the auto defrost on for a few minutes, then I clicked it off, but looked back down and the ac was still on. Wonder if it is true that the fan kicks on after parking the car to dry out the vents of moisture to prevent mold.

Ill try and repeat what I did then listen for the fan afterwards. Looks like it happened 1hr after parking the car.

 

Sorry, can’t resist.

Sort of like the Star Trek movie where the old Voyager space probe comes back looking for its maker with a big friend and decides to sterilize the planet when it keeps sending RTS and no one remembers that the Hayes communication protocol reply is DSR.

 

I should have read the Operators Manual sooner. It states in the climate control section that the blower runs 1hr after locking the vehicle after the a/c has been used. This lines up perfectly with the graph above. Im thinking everything is working fine, battery, alternator, starter, its just me not driving enough to charge up the battery to 100% every day. Red battery light has yet to come back on, so maybe it was the battery being at a very low charge at the time. The great thing I found was the battery monitor does not affect the battery charge at all, so I will leave it hooked up all the time.

 

Well so far the red battery light has not come back on since which is great. Now im still wondering why the car is using the battery while its off and parked. Im also wondering if the battery is "healthy" or if its not and the reason why its being drained. i went ahead and just ordered another battery tester, this one shows the CCA which im curious to see. Was only $19 after discount. I have a Konnwei OBD reader and it works very well though its very basic and just reads and erases codes. Should be here Monday. i have another year on the warranty for this battery so if it isnt healthy id like to get a new one.

 

Received the Konnwei battery tester today and played around with it. I decided to throw the battery charger on the battery so it was fully charged prior to testing, which i now think was not needed. When i first hooked the tester up I noticed my other battery monitor was not showing the exact same voltage, which i find off since i would assume they should be the same. Im beginning to think the Ancel BM200 monitor isnt that reliable.


Battery voltage readings are close, but not the same.



When setting up the Konnwei tester to test the battery it has you pick which type of battery it is and then how its rated, I picked AGM flat panel and then CCA. Then you choose the amp size of the battery, my battery says 700A.Then a screen pops up saying to turn the cars lights on for 10 seconds then turn off to relieve any surface charge. For the 1st test I did NOT do this. here's what I got:





I saw the 84% 593A and was bummed, i got the battery about a year ago and I didnt even notice until recently the battery is stamped 21 on the post so i think thats when it was manufactured. I was thinking the dealer suckered me with a worn out battery. So then I decided to test it again and the screen popped up again to turn the headlights on then off so thats what I did. this time I got a much better result. I tested it one more time after that and got the same result.




Now the Konnwei was saying 98% 688A. But then i noticed the state of charge says 99% at 12.59V while the Ancel is saying 92% SOC at 12.55V. I have no idea what this means, either ones right and ones wrong or they are both wrong, who knows. Ill play around with them more. Im at least thinking the battery is good.

Also while I was under the hood with the cover over the battery off i noticed the door to the climate control was operating along with other various noises the car was making without the key in the ignition.






I also found that there is some type of gauge or viewing port on the battery that had been covered by the sticker. I was looking online at Mercedes batteries and noticed mine wasn't visible. not sure how it works, i seem to remember previous cars had some type of port like this and they were glowing green which meant the battery was good.

 

Both Ancel and Konwei are highly rated devices. Maybe the differences are one calculating what the other is measuring?
That window under the sticker is just an electrolyte level monitor. Your recollection is correct. This one just uses a different optical trick. Many maintenance free batteries have one or the other. If it says “bad” the electrolyte has boiled off and the battery is bad. A “good” indication means the electrolyte is still there, but the battery can still be bad.
I’m kind of a Neanderthal when it comes to battery testing: I don’t trust rapid testers. My electrical system tester (which is about the size of a toaster oven) takes about 2 minutes to test a battery. But in all honesty, turning the key and listening to the starter works about 90% of the time.

 

I know nothing about batteries and how to test them. Seems the more i research the more im confused, information overload. I basically wanted to see why that red battery light was coming on, was it the battery, the alternator, or something else with the car. Now that I have been using the battery monitors it does seem the car is pulling power when the key is not in. just unlocking the car and opening the door i am seeing and hearing things turning on and off and operating, like that door in the fire wall going to the climate control vents. Im also thinking in the morning when the sun is coming up it is doing something similar, I can see condensation on the windshield and then dry areas like the defrost is turning on clearing it.

I went out just now to use the battery monitor, battery tester and my multimeter.


All 3 devices give slightly different voltage readings. Thankfully they are very close, so i can say they are reading properly for the most part.



tester tells me to turn the headlights on and off so I did.


I know the battery is an AGM, wasnt sure if its flat or spiral but im thinking flat.


I have no idea what these choices are. My battery says "700A" on it, so I chose CCA. I know what that means.


I typed in the 700 since thats whats on the battery. It stays at this setting everytime its turned on which is a good feature.



Heres what it read.


Im happy with the CCA results. The state of charge were different, but a lot i think. But the thing is when i was seeing these 2 numbers for voltage i noticed the car was making all kinds of noise, like switches turning on and off, also that door was opening and closeing. because i had just turned the key to on and fiddled withthe headlights directly prior to testing. So the car was obviously pulling power, so im thinking the test results would be skewed. i think i would have to disconnect the battery and then test to give the most accurate readings.


Im still happy i got the Ancel BM200 monitor. I think its good in my situation to be able to view the voltage as im starting the car, i can see if the voltage jumps up which indicates the alternator is working. I dont think the state of charge is accurate but i could be wrong. I think the voltage is accurate though, and it seems to be good for viewing the graph and see what the voltage was doing while the car was parked.

I find it odd that I had just fully charged the battery yesterday, i did not drive the car, and now the monitors are telling me the battery is 60%-74% charged. Just me unlocking the car, turning the key on, turning the headlights on for 10 seconds then turning the car off the state of charge dropped from 78% to 74%. I just want to document my findings in case someone else is dealing with similar issues. Ive gone out to the car and some days the monitor says the battery is at 60% state of charge, and i didnt even drive the thing. If i parked it for a week the battery would be dead based on the readings.

 

I need to start paying more attention. I just realized I had the Konnwei battery tester set to the incorrect standard, i had it set to CCA when the battery clearly says 700 A (EN). I thought it stood for English. Wonder if the battery will test better or worse with this setting. Im not having much faith in these testers other than giving ball park voltage readings in real time and if the battery is good or bad. I think they are basing the SOC off voltage readings.