Two batteries dead one after another.

[Oneand0]

I tried to post this twice, sorry if it’s a repeat.

I went beach camping this weekend and had a 14 month old Costco battery (pictured)

drain completely. Had a new one brought to me on Sunday and it got me home fine with two stops on the way. Left Monday on business trip, to come back home just now on Thursday to find new battery also dead.

Any ideas on what to check on my own before taking it in. I’m not mechanical, so any ideas welcome. Thanks

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[CitrusBronco]

If you installed anything electrical start with them.
Watch a couple videos on tracking down electrical drains and pickup a meter and start looking.

 

[UncleBrad]

This is my single biggest gripe about my Bronco: there is no overhead in the electrical system. There is the constant scanning for bluetooth clients. updates, entry attempts. There is the in-vehicle hotspot (which is stupid expensive) and always on (regardless of whether it shows as available on a client). Stuff like the automatically cracking of windows upon entry, priming the injectors, etc all contribute. You can't turn this stuff off!

If you want your own hotspot, that's about all the Bronco can handle. Add on a refrigerator for a road trip, radio equipment (like a digipeater) and you're hosed. After a while, the software "learns" to scale back usage while the vehicle is "off" - but that it not good enough. And I have the stripped down Big Bend (which was the "base" in 2024)!

I've already been locked out, and carry a Milwaukee jumpbox now wherever I go.

This is one of the reasons why I bought my old 1988 Jeep YJ. I have absolute control. I can design what I need and implement it without the nannies, fear of loosing warranty, violating some "terms and conditions" etc. And it was $40K less than the Bronco sitting the garage.

 

[huey]

gotta be a drain....i'm 44k miles and just over 3 years old. stock battery. If you don't have any electrical mods might be dealer visit time...or at the very least a shop that you trust can chase down electrical gremlins

good luck

 

[mmasters]

Having been thorough this, check the negative post on the battery, there is a shunt that is know to go bad. Was $24 part, that made all the problems go away.

 

[UncleBrad]

gotta be a drain....i'm 44k miles and just over 3 years old. stock battery. If you don't have any electrical mods might be dealer visit time...or at the very least a shop that you trust can chase down electrical gremlins

good luck

What if it's not gremlins? What if we're talking about capacity limits inherent in the design? This vehicle has lots of ways to extract 12VDC (and in higher trims, AC inverters). Even so, a family trip involving tablets, smart phones, start-stop "feature" in crowded cities, RV refrigerators, camping lighting and heating etc. demonstrably exceed those design limits. When we start adding what we need, along with all the gimmicks that are 24/7 marketed to us, we hit a wall - and the battery itself (already over-sized and expensive) is the first to cry "Uncle!". And dealerships cannot fix bad decisions made on conference room markerboards.

 

[Hemisfear]

What if it's not gremlins? What if we're talking about capacity limits inherent in the design? This vehicle has lots of ways to extract 12VDC (and in higher trims, AC inverters). Even so, a family trip involving tablets, smart phones, start-stop "feature" in crowded cities, RV refrigerators, camping lighting and heating etc. demonstrably exceed those design limits. When we start adding what we need, along with all the gimmicks that are 24/7 marketed to us, we hit a wall - and the battery itself (already over-sized and expensive) is the first to cry "Uncle!". And dealerships cannot fix bad decisions made on conference room markerboards.

If's and but's, candy and nuts...
'21 2Dr Badsquatch Lux 2.7L with tons of electrical additions, original battery and no issues, other than the loose grounding of the fuse box, which was a bit of a inconvenience...but light years better and more dependable than either of my previous YJ's, Jeeps are tractors compared to Bronco!

 

[Lcubed]

I tried to post this twice, sorry if it’s a repeat.

I went beach camping this weekend and had a 14 month old Costco battery (pictured)

drain completely. Had a new one brought to me on Sunday and it got me home fine with two stops on the way. Left Monday on business trip, to come back home just now on Thursday to find new battery also dead.

Any ideas on what to check on my own before taking it in. I’m not mechanical, so any ideas welcome. Thanks

did you reset the BMS after installing the new battery?

 

[UncleBrad]

If's and but's, candy and nuts...
'21 2Dr Badsquatch Lux 2.7L with tons of electrical additions, original battery and no issues, other than the loose grounding of the fuse box, which was a bit of a inconvenience...but light years better and more dependable than either of my previous YJ's, Jeeps are tractors compared to Bronco!

>> Jeeps are tractors compared to Bronco!


When the tractor fires up and gets you where you need to go, I'll take the tractor. No BMS. No battery drain when the tractor is off. No start/stop, no touch-sensitive door entry, etc. If the battery is drained, you left the lights on. And no: I'm not a "Luddite". I know my way around hardware and software. Nevertheless, I'm not inclined to build or buy a cable and software, plug in a laptop and figure out why the battery died. I KNOW why: I left the damned lights on.

Another thing: I don't want Ford to know that I left the lights on. Am I buying a new battery because Ford needed to know that I needed a new battery - and why?

 

[Oneand0]

did you reset the BMS after installing the new battery?

Lots of awesome ideas here. Thanks to all. No I did not. I will charge the battery back up and reset it.

 

[Baja Bronco]

If you installed anything electrical start with them.
Watch a couple videos on tracking down electrical drains and pickup a meter and start looking.

Agree. What electrical devices did you add? Something is hot, battery, especially new won’t drain that fast.

 

[Brian_B]

Could be battery is fine but Bronco just thinks its low - the classic “Did you reset the BMS”

Not a certainty mind you, but a good check to make before jumping into a deep troubleshooting rabbit hole.

 

[Oneand0]

Tried to reattach the battery after charging all day and over night and all it does is blast the horn. Nothing else happens no attempt to give power to anything. Just like someone is laying on the horn. Trying to find where the horn is so I can troubleshoot.

 

[Hemisfear]

>> Jeeps are tractors compared to Bronco!


When the tractor fires up and gets you where you need to go, I'll take the tractor. No BMS. No battery drain when the tractor is off. No start/stop, no touch-sensitive door entry, etc. If the battery is drained, you left the lights on. And no: I'm not a "Luddite". I know my way around hardware and software. Nevertheless, I'm not inclined to build or buy a cable and software, plug in a laptop and figure out why the battery died. I KNOW why: I left the damned lights on.

Another thing: I don't want Ford to know that I left the lights on. Am I buying a new battery because Ford needed to know that I needed a new battery - and why?

When it comes to farm impliments, to each their own! lol
My 2 YJ's were under engineered pieces of crap!

 

[UncleBrad]

When it comes to farm impliments, to each their own! lol
My 2 YJ's were under engineered pieces of crap!

>> My 2 YJ's were under engineered pieces of crap!

I also have had two of them. They surely have their problems! But, for sure, they are not over-engineered - that is the issue at hand here! Though they are primitive as stone knives and bearskins to most today, their simplicity frees the owner from having to deal with all the unnecessary (and often unreasonable) complexity I find in my 6G Bronco. Sure, the YJ leaf-spring suspension is that of the 19th-century buckboard, but if I want to replace the rear brakes, I don't need the dealer to unlock the (electric) emergency brakes for me. If the windshield gets busted by flying gravel from a nearby truck, I can easily change it out myself AND not have to have the nanny sensors re-calibrated. The ancient YJ came with an actual oil pressure gauge. I don't even get that in my Bronco, which was a staggering $40K more! What gauges the YJ does have are all analog and easy to read - no menus or screens. Parts are cheap and readily available, with loads of available documentation. Aftermarket support is mature and massive.

Sure, you get wet driving them and can't hear the radio over the racket. You feel every crack and crown in the road. They are raw and authentic, short-wheelbase, 2-door, light-weight, manual transmission, scrappy little boogers that go over or through wherever you point them. In the beginning, wasn't that the whole point? Heck, my YJ doesn' t even have door locks.

I maintain that much of my 6G Bronco is decidedly over-engineered. Even so, I love mine, and at my age it will likely be my last new vehicle purchase. I'll take it on the longer drives and vacations. I pamper it. It is a 2-door manual, which is the primary criteria, and is as stripped as I can get it. It's a blast to drive, and folks I meet love to talk about it. But is it simple? No.

For the going-to-town vehicle, I'll fire up the ancient YJ. It runs on cheap gas. I can fix it myself. Taxes, tags and insurance are next to nothing. It doesn't yelp at me about not having my seat belts fastened or check if somebody is in the back seat. It stays on until I turn it off, and when I turn it off it really is off. Lastly: I'm not alone in this. The cost of good examples of the CJ and YJ series are exploding now, because people want them.

You see: their charm is in their simplicity; what you are calling their "under engineering." I can do another essay on the "piece of crap" accusation if you like...

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