Battery voltage reading 9.0-10.0v at idle - new battery?

[eclou]

I have a 2018 80k miles, MPT 93PRX tune, 3 accessory terminals used for lights all grounded to battery. Just changed batteries a month ago, last battery lasted only 14 months. No stereo mods. Tried to flash a tune using the NGage and the tuner said voltage too low. I set the gauge to read voltage and was shocked to see 10-12v when running and 9-10v at idle/engine off. Truck appears to run normally. I just drove to Colorado and back from Houston. It started up in the cold without any issues. Any ideas?

 

[smurfslayer]

#WeTooLow

Did you buy the truck used and/or do you know the truck history?
Asking because “last battery only lasted 14 months. replaced battery a month ago...

That doesn’t add up.
When the battery was changed, did you/they reset the battery management system? Not that this by itself would account for a battery that low in a month but still.

Are you connecting your lights using relays? If so, any chance the relays are faulty? I had <cough> "weather proof” relay on my rear facing lights under the bumper. One night I thought “hey, Terry sure has bright porch lights illuminating his back yard. Must be deer foraging.” Next night, same thing. “I guess Terry got motion sensing lights”. Only he didn’t. my lights were getting hot power to the relay, and the relay got soaked, and wouldn’t shut off. I was able to disconnect, pulled the relay and it was soaked, connections corroded. I’d only been through one day of rain with about a 20 minute drive. So my weather proof relays were like Hotel California; they let water in, but it couldn’t get out.

Else, I’d say you’ve got a parasitic drain going on.

 

[eclou]

#WeTooLow

Did you buy the truck used and/or do you know the truck history?
Asking because “last battery only lasted 14 months. replaced battery a month ago...

That doesn’t add up.
When the battery was changed, did you/they reset the battery management system? Not that this by itself would account for a battery that low in a month but still.

Are you connecting your lights using relays? If so, any chance the relays are faulty? I had <cough> "weather proof” relay on my rear facing lights under the bumper. One night I thought “hey, Terry sure has bright porch lights illuminating his back yard. Must be deer foraging.” Next night, same thing. “I guess Terry got motion sensing lights”. Only he didn’t. my lights were getting hot power to the relay, and the relay got soaked, and wouldn’t shut off. I was able to disconnect, pulled the relay and it was soaked, connections corroded. I’d only been through one day of rain with about a 20 minute drive. So my weather proof relays were like Hotel California; they let water in, but it couldn’t get out.

Else, I’d say you’ve got a parasitic drain going on.

The truck was bought new I am the original owner and installed all the crap myself.

Yes the front lights all have have relays wired to the factory upfitter switches.
Factory battery lasted 2 years. Second battery only lasted 14 months but I live in hot Houston weather.

Reset the battery management system? I've never heard of that. I will look that up thanks

 

[eclou]

OK did the BMS procedure and now the voltages sits around 13.0 volts. Much better

 

[smurfslayer]

cool! keep an eye on it and let’s hope for the best.