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Odd battery problem any suggestions?

Cory S

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Duly noted. I thought I had read that somewhere in the forum. Thanks.
I’m sure you have, but most of those claims usually have abnormal issues causing the excess draw or tired batteries with noticeable reduced capacity.
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Postal Bob

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Key is usually in the bedroom, which is above the garage, and maybe 20’ from the car, which I leave unlocked.
That's your problem right there. If you don't lock your car, it's always in ready mode searching for a signal from the key fob. And your key fob may be close enough that the car is sensing it, and putting itself in ready mode, thereby constantly drawing power.
Simple solution-Lock your car every time! And if possible, move the key fob further away. But locking your car should solve most of the power drawing from your battery
 

TEAsGrabber

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That's your problem right there. If you don't lock your car, it's always in ready mode searching for a signal from the key fob. And your key fob may be close enough that the car is sensing it, and putting itself in ready mode, thereby constantly drawing power.
Simple solution-Lock your car every time! And if possible, move the key fob further away. But locking your car should solve most of the power drawing from your battery
Respectfully....as I have no clue, BUT.....I bought my MACh1 in November of 2022. It sits in my garage daily unlocked and the fob is in the sunglass compartment. I don't daily my car and sometimes it sits for days without being driven. Starts every time ? I did the same thing with my Mercedes prior and had zero issues.
 

Cory S

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Respectfully....as I have no clue, BUT.....I bought my MACh1 in November of 2022. It sits in my garage daily unlocked and the fob is in the sunglass compartment. I don't daily my car and sometimes it sits for days without being driven. Starts every time ? I did the same thing with my Mercedes prior and had zero issues.
Days vs. 14+ days could mean a considerable difference.
If the battery can’t crank the engine after only 3-5 days, it’s entire different problem than Keyfobs.
 

TEAsGrabber

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Days vs. 14+ days could mean a considerable difference.
If the battery can’t crank the engine after only 3-5 days, it’s entire different problem than Keyfobs.
Weird.....cause I was away from home last month for 12 days in Arizona. I still had a full battery. My radar detector gives me a battery voltage readout on start-up. Maybe I got a good batch of batteries from Ford????
 

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Cory S

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Weird.....cause I was away from home last month for 12 days in Arizona. I still had a full battery. My radar detector gives me a battery voltage readout on start-up. Maybe I got a good batch of batteries from Ford????
Very possible. Realistically, if there were enough problems with battery drainage in less than 2-3 weeks with Keyfobs left in the car or close by, Ford would have made sure this warning was clear and advertised as an important not to do practice.
 
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I’m glad this sparked an interesting discussion 😀 I looked into battery replacement but the ones that fit seem to only offer a marginal upgrade. The OEM battery is only $138, and is the cheapest flooded type. The enhanced flooded type upgrade for $209 has only 10 more CCA and a few more minutes reserve. Unless my battery is actually defective or damaged it doesn’t seem like it needs replacing, and I gave it a charge with a new Genius5 charger so I’m starting from full. I’ve changed my ways and now lock the car always and keep the fobs on the other end of the house. No troubles so far, but since it was intermittent it will probably take several weeks before I feel confident that’s the cause. And of course i always have my little jump box handy, and will check voltage with my multimeter if it happens again and see just how low it gets, and if it might need replacement after all. Thanks to all for the responses, if I have anything interesting to share I’ll update.
 

Cory S

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I’m glad this sparked an interesting discussion 😀 I looked into battery replacement but the ones that fit seem to only offer a marginal upgrade. The OEM battery is only $138.
You don’t need any upgrade really. Don’t get stuck on CCA ratings either. You can start your engine with a 220CCA battery. CCA was based on 1970’s testing in -20°F Minnesota winter on carbureted vehicles that may take 5-10 seconds to even fire up and run.

Reserve time is only important if you are drawing from the battery for extended periods during key on/engine off time.

I ran a motorcycle battery for a couple years on one of my 1.8L beaters (1996 Saturn SL1) as a test. As long as it doesn’t need to crank for more than a second or two, it works fine.
 

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Trunk light staying on? I watched a friend go through this(66 Impala). 2 batteries and an alternator later he climbed in the trunk and shut the lid. Light stayed on.

I was tempted not to let him out but I thought better of it.
 
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Updating after almost 2 months keeping the car locked and the fob usually (sometimes I forget) far away on the other end of the house. No more battery troubles to report. I’ve also noticed that the car will in fact make some noises if I approach with the doors unlocked, and it does seem plausible to me that with the fob at the edge of detection range it might go through this wake up cycle multiple times drawing down the battery. So, for what it’s worth, always keeping it locked seems to work.

I’ll theorize that if the fob is left inside the car, in close proximity to the interior antenna, which I think is in the center console, the car does not do this. It does of course sense when the key is removed while the engine is on because it gives you 2 beeps of the horn to let you know. So maybe that is why the person who leaves the fob in the glove box does not have problems.

At any rate, still enjoying the car and hoping this might help someone else. Thanks again for all the excellent feedback 😀
 

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Postal Bob

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Updating after almost 2 months keeping the car locked and the fob usually (sometimes I forget) far away on the other end of the house. No more battery troubles to report. I’ve also noticed that the car will in fact make some noises if I approach with the doors unlocked, and it does seem plausible to me that with the fob at the edge of detection range it might go through this wake up cycle multiple times drawing down the battery. So, for what it’s worth, always keeping it locked seems to work.

I’ll theorize that if the fob is left inside the car, in close proximity to the interior antenna, which I think is in the center console, the car does not do this. It does of course sense when the key is removed while the engine is on because it gives you 2 beeps of the horn to let you know. So maybe that is why the person who leaves the fob in the glove box does not have problems.

At any rate, still enjoying the car and hoping this might help someone else. Thanks again for all the excellent feedback 😀
I believe that's exactly what I said was the problem in post #17. This is one of the big reasons why these cars are constantly experiencing a dead battery condition.
But it's not just these cars, but any car with a key fob and push button start.
 

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I did that to myself once. I never really tested any distances or anything like that, but the center console is correct. Stay away from that thing. I left my fob IN the cup holder one time and learned my lesson on that, LOL. Luckily though, AntiGravity batteries have an internal safety circuit that will disconnect it internally to save itself from discharge and damage. I learned how to reset the battery and was up and running. And yes, when that internal circuit kicks in to protect itself, the car appears as if the battery is 100% completely dead. It’ll show zero voltage until you do the reset.
 

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I leave mine unlocked in the garage at all times. I do keep mine on a tender most of the time, I only take mine out usually every couple weeks. But when I do drive, I usually go for a hundred miles or more road trip. No issues so far.
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