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I'm not sure what you mean here. The new battery I'm buying has the 6yr warranty. They are going to install it today. The battery that's in the car now is the original one.
Sorry about being unclear. Let's say the new battery dies and needs to be replaced under warranty within 6 years. If they will take it out, and put the replacement in, I would be more than happy to spend $100 and have them install it, no matter which type it may be. (I am lazy if I have to pay for labor in the first place).
 

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Interesting points, InjuredAgain. My car has not been giving me the miles that it did before. 3 weeks ago it went from 70miles avg per charge, to less than 50. No change on my part. Smart of San Diego checked it and stated "all is fine". BS!!!!!

I then went and had the 12v battery checked (Smart did NOT check it!) and one of the cells is bad. I'm going to change the battery (hence this thread) to see if that could be the problem.

Make sense? Thoughts?

2014 ED
41K
Just hit four years 4/13. No BAP.
Pinan, it could be that the bad cell in your 12 volt battery is confusing the battery management system, causing it to try to continuously charge the 12 volt from the HV battery? Seeing as you are going to replace your 12 volt battery, you will soon know if this is the case.

Just wanted to say and give public thanks to MB DNA, who sent me links to information about how other electric vehicle brands, like the Leaf, seem to handle charging of the 12 volt. It was very educational and there are some complexities in how state of charge is managed in the 12 volt battery that never occurred to me since my experience has only been with gasoline engines. Those larger owner communities make it more likely that someone with the necessary skills will get curious and dig into why their 12 volt batteries also don't seem to last long. It's a lot of reading and since I'm heading out of town tomorrow on a long trip, I'll try to get through that and give my layman's summary of it.

But what MB DNA did get me curious about is how much parasitic draw there is in my vehicle just from sitting there. I'll measure the voltage before I leave and after my return, and will use the Sokoloff battery tester unit to get a report right before and just after. I hope that will shed some on how much my battery's charge degrades while I'm gone.
 

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Discussion Starter #23 (Edited)
Small update: The Delco (or any) group 47 are not an "exact fit", except maybe into the battery compartment. The battery itself is 2" longer, so the stock bracket will not hold the battery. I said no to that type. They have ordered me a battery that should fit AND be vented. I will update the thread with the info.

Btw. This particular shop only charges $10 to install.

Also. The stock (451 982 00 08) battery is NOT AGM.

Confirmed. All that you lose when removing the battery are radio presets and the time.
 

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Looks like that battery part number, 451 982 00 08, also fits some Mercedes. So that means it should be available from any Mercedes dealer. MSRP - $150, wholesale - $112.50. For that price, I'll likely just go to the Mercedes dealer and get one when the time comes. Love to know what manufacturer Mercedes uses for that battery - used to be Varta.

Len
2014 EV Coupe 15,000 miles
2014 EV Cabriolet 5,000 miles
 

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Pinan, it could be that the bad cell in your 12 volt battery is confusing the battery management system, causing it to try to continuously charge the 12 volt from the HV battery? Seeing as you are going to replace your 12 volt battery, you will soon know if this is the case.
I like this theory - especially in our smart ICE "CAN Bus world' where we know that a failing battery can stir up some rather serious gremlins! >:D

In his May 3, 2017 Q1 conference call, Elon stated that the Model Y will not use a CAN bus and instead use a new high speed bus. He said that while Model S used 3 km of wiring, and the Model 3 uses 1.5 km of wiring, the Model Y will use 100m.

He also said they will finally discard the legacy 12V power, which he derided as saying wasn't the right voltage for anything. May 3, 2017, Elon Musk just teased some tantalizing details about Tesla Model Y

Musk said he also plans to ditch the 12-volt battery architecture used in Tesla’s other vehicles, which could dramatically reduce the length of electric wiring needed and simplify the production process. Less wiring means more automation in the production process, and Musk has said he plans to introduce more robots into Tesla’s production line.

https://www.theverge.com/2017/5/3/15537612/elon-musk-teased-new-details-tesla-model-y
 

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I like this theory - especially in our smart ICE "CAN Bus world' where we know that a failing battery can stir up some rather serious gremlins! >:D
I thought about the info in the Leaf thread that you gave me the link to. In an ICE car, even if the alternator runs and runs and runs all the time, it's much more difficult to know because the reduction in fuel economy is kind of in the noise of tank to tank variation.

But in an EV, which tries to manage the 12 volt by keeping it at some specific SOC that is around 60-80% and not near 100%, there might be a lot of confusion as the HV battery pours power into the 12 volt via the BMS, but the BMS is getting mixed messages as you say. Some of the cells are exhibiting behavior showing they are at or beyond their desired SOC, and the shorted cell continues to gobble up power with low resistance, the opposite of what would happen if it were getting full. And the HV battery gets drained in the process.

Speculation again, but as you say, this may be an unexpected circumstance that brings up gremlins.
 

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I doubt that the ED is only keeping the 12V battery at a 80% SOC. Lead acid batteries need to be charged to 100% or they degrade fairly rapidly. I'm sure the Smart charges the 12V battery like any charger does - constant current to 13.5 volts then maintains it a 13.5 volts or so. I'll check the voltage on mine (via the "cigarette lighter connector) to see if it does that.
 

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I doubt that the ED is only keeping the 12V battery at a 80% SOC. Lead acid batteries need to be charged to 100% or they degrade fairly rapidly. I'm sure the Smart charges the 12V battery like any charger does - constant current to 13.5 volts then maintains it a 13.5 volts or so. I'll check the voltage on mine (via the "cigarette lighter connector) to see if it does that.
Yinzer, with hopes that it is okay with MB DNA, here is the link to the Leaf discussion:

LEAF's 12V battery behaviors - and why they go bad - My Nissan Leaf Forum

I've relied on the voltage/SOC chart from this source:

Measuring State-of-charge - Battery University

and I believe the battery in my ED sits at about 12.7 or 12.8 volts after not being charged or used for a day or so. The chart indicates this can be anywhere from 70-95% full. The battery in my Corvette, which often sits for a week or two between drives, always measures over 13 volts.

I'm hoping to measure the voltage tomorrow morning prior to leaving on a 17 day trip, and then measure it again after returning home. Unless one of my kids drives the ED, I'm hoping to see if there is any parasitic discharge/utilization during that time, hoping it might be another piece of the puzzle as to why the 12 volt battery seems not to last long despite what seems to be a fairly easy life.
 

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Checked the article and I agree. If the charger is only trying to maintain the the battery at 13.0 volts, it is not going to be close to fully charged.

It is strange that the designers of an EV, would no know how the care and feeding of an ordinary lead-acid battery.

edit: I just checked my ED (via the "cigarette lighter") when switched on and got 13.9 volts. Is there an easy check point for the voltage switched off?

And I dont think it has been established that the ED has a premature 12V battery failure problem.
 

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Discussion Starter #31
Adding to the drama; I unplugged my car this morning and got a "Brake Malf - Shop" warning. Turned car off then on again, drove around, no issues, warning gone.

Gremlins from the 12v battery? I hope so. Jeesh!

The shop received the battery today. I'm on my way to it installed.
 

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Discussion Starter #32
Updating this post so all info is in one place. I'll add to OP if possible as well.

Stock Battery: 451 982 00 08 (this is NOT an AGM battery).

Exact size replacement: ACDelco Professional LN1PS. $156 OTD (out the door).

The LN1PS fits perfectly. However; It is only vented on the right side so they had to install a longer vent tube. No problem.

Installing the battery does not require a battery tender (or whatever) to keep memory, as ALL you will lose is the clock time. Radio presets are NOT lost, at least on stock radio.

*Note that Group 47 battery's (posted in other threads) will NOT allow the hold down bracket to fit. Note the top battery in below pic.

I truly hope this post helps others in the future, as locating this information anywhere was next to impossible.
 

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Good info Pinan - thanks for posting. Is there a manufacturer name on the original battery? Varta maybe?

Len
2014 EV Coupe 15,000 miles
2014 EV Cabriolet 5,000 miles
 

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I kept having HV battery issues, a few times the car would not start and give me 'go to shop' warnings. I seen somewhere online that a bad 12v battery could cause weird issues and warnings. I couldn't find a replacement at any local auto part stores here in Utah for some reason, finally found on at Costco, an Interstate Batteries H5(47) for $105 USD. I installed it myself like any other ICE 12v battery, no need for any special method or extra percussion's. This battery was a little bigger and a snug fit and also had to bend the 90 degree tab on the hold down bar so it would fit over the battery, which was easy with some pillars and hammer.
 

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I think I would like to change my battery out with an AGM. Wouldn't changing it to an AGM remove the issue with the vent tube length?
Can anyone tell me which AGM battery I can use? I would like purchase the smallest I can get away with. That way it'll be a little lighter and less weight in the car.

Thanks in advance for any suggestions.
 

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I think I would like to change my battery out with an AGM. Wouldn't changing it to an AGM remove the issue with the vent tube length?
Can anyone tell me which AGM battery I can use? I would like purchase the smallest I can get away with. That way it'll be a little lighter and less weight in the car.

Thanks in advance for any suggestions.
What year is yours? Seems like a 453 as delivery was in 2018?

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