How to Recondition/Service Your 12V Battery

JohnL

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I’m also getting the ‘electrical system drain’ warning on a daily basis. There is nothing plugged into the car, but I do have the ChargeSmartMA app that allows the electric company to throttle my charging if they need extra juice.

I’m thinking I should desulfate the battery to be sure that isn’t part of the problem. I have a CTEK MUS4.3 polar charger. In all the charging programs it starts with a 15.8 V desulfation cycle for up to 8h. @Mach-Lee I assume this charger is not appropriate due to the high voltage and I should get a charger specifically for AGM batteries?
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Shayne

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I’m also getting the ‘electrical system drain’ warning on a daily basis. There is nothing plugged into the car, but I do have the ChargeSmartMA app that allows the electric company to throttle my charging if they need extra juice.

I’m thinking I should desulfate the battery to be sure that isn’t part of the problem. I have a CTEK MUS4.3 polar charger. In all the charging programs it starts with a 15.8 V desulfation cycle for up to 8h. @Mach-Lee I assume this charger is not appropriate due to the high voltage and I should get a charger specifically for AGM batteries?
Seems to be a 4.3 amp charger and may error out on you due to power draw from the MME and it flagging it as a drain problem as my 4 amp did. You will need to keep an eye on that and reset it if it is just a one time thing. The best for me was a higher amp charger 15 amp it did not error out over extended periods of time. Mine is MotoMaster Eliminator Precision Series 15 - 1 A Battery Charger & Maintainer when it came on 40% off. Thinking no Canadian tire down there but for the specs it is a start.

Edit: It is an AGM battery
 
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Mach-Lee

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I’m also getting the ‘electrical system drain’ warning on a daily basis. There is nothing plugged into the car, but I do have the ChargeSmartMA app that allows the electric company to throttle my charging if they need extra juice.

I’m thinking I should desulfate the battery to be sure that isn’t part of the problem. I have a CTEK MUS4.3 polar charger. In all the charging programs it starts with a 15.8 V desulfation cycle for up to 8h. @Mach-Lee I assume this charger is not appropriate due to the high voltage and I should get a charger specifically for AGM batteries?
Correct, I would avoid using the desulfate setting. Charge with the regular car mode, that will work fine. Verify it stays in float mode (#7) for 24-48 hours. Avoid waking up the car during this time as much as possible.

I would also disable welcome lighting.
 

kennethjk

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Correct, I would avoid using the desulfate setting. Charge with the regular car mode, that will work fine. Verify it stays in float mode (#7) for 24-48 hours. Avoid waking up the car during this time as much as possible.

I would also disable welcome lighting.
Would a CTEK Multi US 7002 work?

thanks
 

Dzrhino

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Should I be concerned if we leave the car undriven for 3 weeks when we go on vacation?
 


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Should I be concerned if we leave the car undriven for 3 weeks when we go on vacation?
Nope, just remember to lock it :) wait, you can use FP to lock it from anywhere!!!
 

mkhuffman

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Should I be concerned if we leave the car undriven for 3 weeks when we go on vacation?
I would leave it at 60% charged and unplugged, and enjoy your vacation!
 

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Should I be concerned if we leave the car undriven for 3 weeks when we go on vacation?
We haven't heard of very many 12v battery failures lately.....certainly not as many as when these cars first hit the streets, so maybe the software has been improved to maintain that thing. Even so, I always leave my EVs plugged in and set routine departure times while I am away on vacation. That way the car wakes up, conditions the cabin and by default it will also charge the 12V if needed.

A departure time once per day, early in the morning is what I prefer. I don't know how necessary it is to do that though. Presumably the car is able to force dump some energy into the LVB if it gets low but I don't really trust that system. I would prefer a slower charge on a more frequent basis anyway and a departure time schedule should accomplish that.

If once a day seems excessive then every 2-4 days would easily cover your concerns as well.

Are you able to plug it in while you are away or are you leaving it at the airport or something?
 

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It'll be in our garage, and I can leave it plugged in. Didn't know if that was a good idea or not. No guidance from Ford on this kind of thing.
 

Kamuelaflyer

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It'll be in our garage, and I can leave it plugged in. Didn't know if that was a good idea or not. No guidance from Ford on this kind of thing.
I had mine in the garage for 5 weeks when I had knee replacement surgery. I set it to to charge to 60% and set a departure time for 3 days a week. Probably mega overkill. Your car will be fine.
 

mkhuffman

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It'll be in our garage, and I can leave it plugged in. Didn't know if that was a good idea or not. No guidance from Ford on this kind of thing.
The only reason I would not leave it plugged in is the possibility of thunderstorms. We get a lot in our area this time of year, and while I have not heard of a MME getting damaged by lightening, it would worry me to leave it like that when I am not at home to unplug it when a storm comes.

Ford does have recommendations for long term storage. 3 weeks is about when you start to think about following their recommendation, which I believe is 60% charge and disconnecting the LVB. I definitely would not disconnect the LVB unless it will be sitting for months. It should be more than fine for 3 weeks at 60% HVB charge.
 

dbsb3233

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The Mach-E charging system only charges the 12V to 90% SoC, so leaving the car on is not a suitable means of fully charging the battery (DC/DC does not continually charge at a high enough voltage). Some form of external charging is required to get it all the way to 100% and completely cure any sulfation issues. Again, external charging is only necessary if you are getting repeated low battery errors/issues, not everyone needs to do this.

Also, the point of fully charging is to restore lost capacity, not just to raise the SoC. Voltage only tells part of the story, so checking it is not the final determinant of whether or not you need external charging, or whether it was successful. A low capacity battery might show 12.8V but sill need charging if issues are ongoing. The proper way is to do a capacity test, but this requires special lab equipment. Most folks will just have to adopt a “wait and see” approach after charging to determine if their battery issues are solved, or if they need to take the next step of having the battery replaced.
While not completely curing the issue, it should still be enough to help get us by for a while though, right? I've read about half the thread now for guidance. I've had my FE since Feb-2021 with no battery problems, but all of a sudden started getting the "12V Battery Fault Service Soon" message a few times in the last week (just flashed for 3 seconds when starting the car, maybe 1 in 20 starts). And got the "Stop Safely Now" message once when the car would only go into Accessory Mode (but on 3rd attempt it fully started and was fine).

I keep a little cigarette lighter volt meter in the armrest plug. After the car is turned off, it usually drops to the 12.3-12.6 range. When running, it's usually 14.3-14.7 (I assume that's the maintenance charge from the HVB).

We leave on a 2000 mile trip tomorrow and these messages all started in the last 3 days, so I'm just trying to give it enough boost to get through that trip safely, then I'll deal with the long-term when we get back. I started the car in the garage last night, turned off headlights/radio/climate, turned off the 30-minute shutoff, and left the fob in the car. Meter showed the usual 14.4 when I left it. Checked this morning and it's showing 13.5.

Does that likely mean the maintenance charge (14.4) shut off after the battery reached 90%? And that my actual battery is at 13.5 now?

I do have an OBD2 reader with Carscanner, and tried taking sample readings throughout this. None of them have been very low. 12v battery SOCs have shown 75%, 77%, 89%, and 96%. But I think those were all with the car ON.
 

JimmyMachE

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I do have an OBD2 reader with Carscanner, and tried taking sample readings throughout this. None of them have been very low. 12v battery SOCs have shown 75%, 77%, 89%, and 96%. But I think those were all with the car ON.
13.5V is "neutral", the battery is neither charged, nor discharged. It means the battery was deemed fully charged (90% SOC or more).

Check the Standby drain / Quiescent average in Car Scanner.
 

dbsb3233

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13.5V is "neutral", the battery is neither charged, nor discharged. It means the battery was deemed fully charged (90% SOC or more).

Check the Standby drain / Quiescent average in Car Scanner.
Quiescent is usually showing 27ma.

20221016_095924.jpg
 

JimmyMachE

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27 mA quiescent average is good. Some vehicles on forum have 50mA or more.

I would monitor the 12V SOC - is it in any way related to "12V Battery Fault Service Soon"?

And I always remove the obd2 dongle after use.
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