Dead Battery - Can not get it to start

[jrollo7]

2 things here ,1- don't let your bronco sit that long before starting it, the ecm is active all the time. This situation is happening a lot on several different forums, guys let their vehicles sit for a number of days then drive it a short time, 10-20 min. then let it sit for several days. After they have done this several times the batt runs out of power.

2- Not knowing how you connected your batt. charger, here is the proper way to charge a batt that has a batt. management system. Charger red or positive to the positive batt. post, then negative to a ground point on the vehicle. Do not put the negative clamp on the negative batt post. The charge has to go through the batt management system so your computer can see that the batt. is being charged.

Surprisingly very few people are aware of this, as a retired mechanic I didn't know about it until about a yr. ago

Excellent advice/information.

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[tclem3314]

Battery tender installed from day 1, not a single battery issue. I plug it in when not driving, it only gets driven 2-3 times a week. Great investment!

 

[Brian_B]

Battery tender installed from day 1, not a single battery issue. I plug it in when not driving, it only gets driven 2-3 times a week. Great investment!

That's a nice install there.

 

[KRAKEN]

My bronco is not a daily driver and after taking note of the battery issues I picked up a NOCO GENIUS5. I am not installing it in the Bronco, but got an adapter to wire to the battery so it can just be plugged in the adapter connector and forgo the clamps.

 

[Greg2060]

My bronco is not a daily driver and after taking note of the battery issues I picked up a NOCO GENIUS5. I am not installing it in the Bronco, but got an adapter to wire to the battery so it can just be plugged in the adapter connector and forgo the clamps.

I'm planning on doing the same thing. Does it matter which of the posts on the positive side you attach to?

 

[Severum17]

2024 Mine has a bolt on the left fender with a cable that goes to that whole negative mess. Is that a good spot to hook up?

 

[mdfilip]

That's fine. Any good ground other than the negative post. It just needs to be on the backside of the BMS sensor

Isn't that the same as being on the battery post? it's less than a 1/2" away. Where exactly is the "backside of the BMS Sensor"?

 

[Ducati1098]

Isn't that the same as being on the battery post? it's less than a 1/2" away. Where exactly is the "backside of the BMS Sensor"?

No, it’s not the same. The BMS sensor is literally between the post and the spot the picture showed. The backside of the BMS is anywhere prior the sensor itself.
If you just put it on the post, you’re bypassing the sensor.

 

[mdfilip]

Udate.... I got it charged and started the day I made the post. Called the dealer they said to bring it in and they will test the battery and do an initialization to fix my drivers window that stopped working after the battery died. I was still under the 3/36000 until April and they tested and said it was borderline weak and decided to change the battery for me under warranty now as after April my for ESP would not cover it.

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