Potential Faulty Battery?

Hey everyone! Currently working on the electrical setup on my first ever build and have hit a road block.
Current installation: 2 100ah battleborn batteries/Renogy 500A shunt & monitor/Renogy 60A DC to DC charger/Renogy 2000W pure sine wave inverter & charger.
Current problem: both the inverter and dc charger do the same relative cycle when charging the batteries so I was leaning to something being wrong with the batteries but here it goes… when plugged into shore power and when the ignition switch on both the inverter and dc immediately begin to charge. However, after a few minutes both will suddenly stop charging once the batteries hit a voltage of 14.4 but the batteries aren’t even close to full according to the battery monitor. I’m sure I’ll need to provide more information to further help but I needed a starting point. Any help??

Did you set your battery monitor up correct? Typically you need to be sure the batteries are at 100% and tell the battery monitor that is the case.

Wait till you believe everything is 100% charged. Disconnect everything from the batteries and then wait a while. At least 2 hours, but really the longer the better. You should then meter the batteries after that time period to determine if the voltage is equal to what it should be at 100% charge. somewhere between 12.6 and 12.8 depending on your
battery type.

I believe I set the monitor up correctly… I have two 100ah Battleborn batteries setup in parallel. The positive on battery #1 runs to a 200A fuse then into the Victorian lynx distributor. The negative on battery #2 runs to b- on the shunt and the p- on the shunt runs to the lynx. Then the b+ on the shunt runs to the positive on battery #1.

When I originally hooked the shunt/monitor up it read that the batteries were at 13.2V with 0ah so the battery percentage said 0. After wiring and connecting the dc to dc charger and inverter I decided to try each one to see if it’d charge and that’s when I noticed it would charge briefly then kick off once the monitor read 14.4v. But the ah only got up to about 12% (12ah). So I’m confused as to why both stop charging when even though the voltage is at 14.4 the ah barely went up from the charge? Maybe I didn’t have quite the understanding of how the chargers worked but I thought the voltage was supposed to be regulated so that the batteries could then take on more amps to the battery bank. Sorry if this is all extremely basic I just thought I had a good grasp and am now just baffled lol.

It really sounds to me like your battery monitor is just setup wrong. You have to ensure everything is full and charged. It would not have worked from 0 unless you batteries were completely dead when you started. The monitor can’t just determine what the ah is. You have to tell it and it has to figure it out based on input and output. It’s not smart enough to just be hooked up and determine the batteries current capacity. You have to:

  • Have batteries at 100%.
  • Tell monitor how many amps you have (200).
  • Let monitor know your batteries are full.

Again the only real way to test the batteries is to do what I said above by charging them to what you believe is 100%, disconnecting everything and later metering them.

The other option is to remove the batteries and take them somewhere to be load tested like an auto shop.

14.4 is a standard charging voltage. 12.6 - 12.8 is full capacity. It it drops below 12 at any point (with nothing running) then the batteries are likely shot.

Yup… just a dumb moment by me :sweat_smile:
I never “told” the monitor that the batteries were at full capacity… thank you for the help and dealing with my incompetence!