Can’t figure out what is going on...Blue Sea ML-ACR/Northstar fail (1 Viewer)

[Shoredreamer]

Looking for a little help or any idea why and what is happening here. ‘93 FZJ80, dual batteries (start/house) joined by a Blue Sea ML-ACR. Truck runs great, zero electrical issues beside this quirk. Cant figure it out.


Issue:
-So I park the truck, turn off the engine but leave the key in the ON position.
-The radio is playing, fan is blowing on low, dash is lit up, all normal.
-Voltmeter at the shift console, running direct to both batteries reads full 12.8
-Blue Sea ACR switch is lit, meaning both batteries are joined.....then

Due to radio playing and key in ignition, starting battery voltage drops below 12.75. This causes the ACR to separate the 2 batteries.

At that instant, I hear the magnetic latch disconnect on the ACR and my starting battery (Northstar X2 27F) reads below 11 volts the radio shuts off, fan turns off and most of the lights on the dash go dark or turn dim. I then try to start the truck and after a couple turns, the truck starts and from then on the battery functions again perfectly normal as if nothing happened. This happened twice today, once a couple days ago and once a few months back. Each time it happened in the same sequence, same conditions.

Any insight to what is going on? I’m heading out for a week to Utah to get super remote with the family and it’s not too comforting seeing my starting battery flatline like this. Thanks

 

[od4x4]

Have you tested the battery? It sounds like it may just be weak... how long does it take to disconnect?

What is the voltage on the house battery after disconnect? I suspect that it it is floating your main battery and that the main battery might just be bad. I had something similar happen with an old dual battery system I had but it was the other way around. After I replaced the second battery, everything went back to working fine again.

 

[Shoredreamer]

I had the battery tested at Batteries Plus where I got the X2 and it came back good. The batteries separate whenever either one falls below 12.75 volts, which usually happens between 1-4 hrs after I turn off the truck if I have nothing pulling power; or within 30 seconds to a couple minutes if I have something runn8ng fridge or radio, lights etc. my house battery is great, shows normal resting voltage after shutoff. Thanks, I’ll likely just reach out to Batteries Plus again and Blue Sea. Super odd

 

[od4x4]

Definitely test that battery... sounds like it is weak.

Another thought. Disconnect the batteries before turning the ignition off and then check the voltage immediately and after 30 min with nothing on. If you are seeing it drop then that will pretty much confirm the battery... if not then I will be interested in what you find out.

 

[MANUCHAO]

-So I park the truck, turn off the engine but leave the key in the ON position.
-The radio is playing, fan is blowing on low, dash is lit up, all normal.

I have to ask why do this...? Just curious......
How much draw are those three items pulling ?
Your Main Battery should have one job only......
I really consider having the radio run from the Aux battery......

Have you checked what charge your alternator is giving out to each battery while there are separated ?
I'll concur with the rest that the Battery seems to be the weak link....
Good luck and let us know what happens.....

 

[Shoredreamer]

Bad battery. It happened again today and I couldn’t start the truck so I had it tested at Batteries Plus on their tester and it was showing 12.03 volts and only 400 CCA. I haven’t heard of any problems with the X2 (Northstar) Batteries yet. My alternator is in spec and I run a Battery minder AGM charger every month or two. My house battery is a Deka AGM and it got us home and has been solid. I’ll be trading the new warrantied X2 for a Duracell (Deka) AGM.

 

[od4x4]

Yup... that’s what everything was pointing to.

The problem with batteries is that they don’t always fail completely and even a reduced capacity battery should be able to start your car so you may not notice until it gets bad,

Glad you found it and that you had that second battery to get you home!

 

[bluesquirrel]

@Shoredreamer
How long did you have your Northstar before it died?

 

[Shoredreamer]

Had the Northstar (X2 Power from Batteries Plus) for about 16 months. It comes with a 5 year warranty. Initially was stoked about it but pretty shocked that it failed because they have a good rep. I will say the customer service from Batteries Plus was very good though. I also charged the Northstar when I had it in the truck with an AGM smart charger from BatteryMinder every month or two.

 

[bluesquirrel]

Damn. That sucks. I hope that's not typical.
I have plans for two of their group 31 batteries for my hundy