Brand new battery drained overnight

[rjinaz]

About two weeks ago I replaced my battery with a new Optima H7 yellow top. Old one was throwing low voltage errors.

Yesterday morning I went out to start my truck and it was 100% dead. Black screens, nothing working.

I was able to jump start the truck and pulled low voltage DTC on just about every module, which makes sense. I decided to drive to the parts store to have the battery tested.
The battery tested fine, but they said my alternator was dead/not charging the battery.
I know the Powerboost trucks don't actually have a traditional alternator, so not sure how to read that.

After having jump started it that one time and driven it around a bit, the truck seems to be acting normal. Haven't needed to jump start it ever since. No more low voltage DTC.

This morning, I changed the battery SOC to 95% and drove about 10-12 miles. No issues at all.


One thing I do recall is the night the battery died, I forgot to remove my Bluetooth ODB reader from the port.
Could that thing really drain a battery that low overnight?

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[EL5_Zero]

I doubt the OBD reader itself killed the battery. However, maybe having it plugged in signaled multiple modules to power up and stay on.

 

[HammaMan]

No, the BT won't kill the batt unless it's keeping modules awake. When the truck is running, put the HVAC on level 5 or higher and take a voltage reading on the main batt. If it's above 14v the charging system is okay and it's likely modules not sleeping. Do you have any modules not responding?

 

[rjinaz]

No, the BT won't kill the batt unless it's keeping modules awake. When the truck is running, put the HVAC on level 5 or higher and take a voltage reading on the main batt. If it's above 14v the charging system is okay and it's likely modules not sleeping. Do you have any modules not responding?

Everything is working fine now. No DTC this morning when I adjusted the SOC to 95%.
Driver seat module had a response error on startup, but it is working.

 

[HammaMan]

Again, double check your voltage while running to verify you're charging. Fan level 5 forces the system into 14.2v. We just saw someone whose isolator failed essentially making the under-hood disconnected from the truck.

Fan level 5, key in truck, driver's door closed

 

[m_bt54]

Did you reset the BMS when you changed the battery? If not I would charge it up disconnected from the truck then reset it.

 

[rjinaz]

Only reading 12.9 V at the battery when engine is running, and fan set to 7.
Correction... peaked 13.6 V after it ran for a minute.

 

[rjinaz]

Did you reset the BMS when you changed the battery? If not I would charge it up disconnected from the truck then reset it.

BMS was reset.

 

[HammaMan]

Okay so charging system is working okay, might have been the OBD device keeping modules awake. The truck dieing entirely has nothing to do with the BMS, systems weren't sleeping.

 

[powerboatr]

No, the BT won't kill the batt unless it's keeping modules awake. When the truck is running, put the HVAC on level 5 or higher and take a voltage reading on the main batt. If it's above 14v the charging system is okay and it's likely modules not sleeping. Do you have any modules not responding?

That is the best, easiest way to see what's what.
I have used your plan a few times

 

[rjinaz]

It never went above 13.6v.
Batt voltage with the truck off was 12.2v.

I did drop it at the dealership this morning to have them give it a once over.
It's all under warranty anyway and they gave me a loaner to drive.

 

[VRFlyer]

I doubt the OBD reader itself killed the battery. However, maybe having it plugged in signaled multiple modules to power up and stay on.

It happened to me with my 2014 EB, I completely forgot to unplug it for approx 12hrs when I remembered, and during mid-winter on top of that. It was a fun event trying to start the truck with every light and failure you can think of being displayed on the cluster as they cycled through.

 

[m_bt54]

It never went above 13.6v.
Batt voltage with the truck off was 12.2v.

I did drop it at the dealership this morning to have them give it a once over.
It's all under warranty anyway and they gave me a loaner to drive.

if they are anything like my dealership they will squawk about it being an aftermarket battery and not a motorcraft

 

[rjinaz]

if they are anything like my dealership they will squawk about it being an aftermarket battery and not a motorcraft

I’ve had the same service advisor for years. He never gives me any grief over aftermarket mods.

 

[Sojourner]

I doubt the OBD reader itself killed the battery. However, maybe having it plugged in signaled multiple modules to power up and stay on.

Based on my same experience (on a 2012 F-150) it's almost certainly this.

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