battery damaged? low cranking voltage 9.49v despite full charge

[STW]

Cranking voltage varies between 9.3V and 9.5V, start by start. Despite being at full charge.
Battery Tracker shows consistent low cranking voltage and gives this warning below.

I guess this means I need to replace this (13 month old) original battery?

Charging from alternator is good. The ESS Aux battery has been disconnected for a couple weeks, and the Main battery stays on a tender every night since a couple weeks ago when I discovered both my Main and Aux wouldn't hold a charge. Noco 10 Repair function brought them back so both now hold a charge, but I've left Aux disconnected and don't use ESS, though it seems to work fine too, with main only. They probably suffered that parasitic death-dance the Main/Aux ESS system seems prey to.

I assumed there would be some permanent damage and I'm guessing this consistently Low Cranking Voltage is a sign of that damage?

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[smokeythecat]

I had an OEM battery go bad on me about 6 months after I bought my Jeep. The dealer replaced at no cost to me.

If you charge the battery and then test the voltage after removing the charger you might see that the voltage immediately starts dropping. Not by huge steps but rapidly and constantly.

 

[STW]

I had an OEM battery go bad on me about 6 months after I bought my Jeep. The dealer replaced at no cost to me.

If you charge the battery and then test the voltage after removing the charger you might see that the voltage immediately starts dropping. Not by huge steps but rapidly and constantly.

I'm using the Battery Tracker and it shows voltage does not drop much when I unplug the charger. It drops from about 12.81v on the charger to 12.79v off the charger after 10 minutes.

This tells me it holds a charge ok, but just cannot give a healthy 11+volts of cranking voltage.

That's my guess anyway.

https://antigravitybatteries.com/products/accessories/battery/chargers/bluetooth-tracker-lead-acid/

 

[smokeythecat]

This tells me it holds a charge ok, but just cannot give a healthy 11+volts of cranking voltage.

Ah, OK. I think in my case there was a cell inside that was shorted out. I have no idea how lead acid batteries are constructed inside, but it behaves as if you lost a parallel circuit. You would read 12v no problem but it would drain fast once you put a load on it.

At any rate, good luck!

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