Oh no... battery or BMS trouble?

[Packer Bill]

And... the new AGM battery the dealer installed did not fix the issue. After sitting for four days, the Maverick went into battery-saving mode, with no exterior or interior lights not coming on when I unlocked the truck.

May I ask which brand of battery you purchased? Also did the mechanic reset the BMS and allow 8 hours for the BMS to relearn the new battery?

Sponsored

 

[desmobob]

May I ask which brand of battery you purchased? Also did the mechanic reset the BMS and allow 8 hours for the BMS to relearn the new battery?

The dealership installed a new Motorcraft brand AGM battery at no cost to me. I have no idea if they did a BMS reset. I'll do one tomorrow. I did one previous to my visit to the dealer (actually, a few) and it didn't help.

 

[Packer Bill]

The dealership installed a new Motorcraft brand AGM battery at no cost to me. I have no idea if they did a BMS reset. I'll do one tomorrow. I did one previous to my visit to the dealer (actually, a few) and it didn't help.

I also want to mention that sometimes a newly installed battery is not always fully charged.

 

[desmobob]

I also want to mention that sometimes a newly installed battery is not always fully charged.

I drove a total of more than two hours since the battery was replaced and before the Maverick sat for a few days, so I'm assuming it was fully charged. I forgot to do the BMS reset today... I'll try to remember to do it tomorrow!

 

[MakinDoForNow]

I drove a total of more than two hours since the battery was replaced and before the Maverick sat for a few days, so I'm assuming it was fully charged. I forgot to do the BMS reset today... I'll try to remember to do it tomorrow!

If your new battery is 80% charged it might be that the BMS learns that as the fully charged voltage.

 

[skinnyboy]

If your new battery is 80% charged it might be that the BMS learns that as the fully charged voltage.

I was wondering if that scenario is causing a lot of the battery issues owners are having. Seems ridiculous, but perhaps the BMS was programmed that way.

After having the no dome light symptom for a few days, then a completely dead battery, I was going to swap it for a new one on the assumption that it was a crappy battery and had been written off by the deep discharge. Got an East Penn battery while charging the original, but found it had been on the shelf for a long time, so returned it. It was made in Europe, not the US as expected, so no surprise it was old, once shipping and being shelf stock were factored in.

Fully charged the old battery out of the vehicle, did the battery sensor and BMS reset, and installed the Fordpass app. to warn if the voltage dropped overnight. No issues for weeks, so uninstalled the app. Trickle charge every couple of weeks just to be sure, but don't believe it's necessary.

Going forward, on any vehicle with a BMS, I would fully charge the battery with the negative cable disconnected then perform the reset procedure.

Cheers.

 

[Packer Bill]

Going forward, on any vehicle with a BMS, I would fully charge the battery with the negative cable disconnected then perform the reset procedure.

You can also connect to a bare metal ground nearby.

 

[skinnyboy]

You can also connect to a bare metal ground nearby.

My thought was having the negative cable (and therefore BMS) disconnected for an "initial" charge was that when the battery was reconnected the vehicle would wake up with a fully charged battery, and the charging algorithm would then (hopefully) maintain the battery at 80% of that state.

Cheers.

Sponsored