It's time for a new battery. Put your volt meter on the battery as someone else tries to start the car. If it drops below 10 it's time to be replaced. "Cranking Amps" is the measurement you're looking for.

I don't use a multimeter much and forgot that measure. Clip the meter wires to the battery and prop the face on the windshield. Got it! Thank you and welcome to DU!

Hi, thanks for the welcome!
I went camping and freighted the storage area and managed to turn on a very dim dome light. Didn't trust the battery would make it through the approaching winter and replaced it when the cranking amps dropped below 9

AI recommends 9.6, you mentioned 10.

I've run the car with the 16 year battery installed 3 times today for about 15 minutes each. Interestingly the voltage is going up and now stabilized around 12.2. The CCA reading was 8.6 this morning, 8.8 at 2 pm and now 9.0 after dinner. I will leave it until tomorrow am.

I'm really not trying to avoid buying a new battery, I have one all priced up, my concern being this is apparently a quality unit, and I'm very curious to see where the CCA levels out.

The other battery, the 4 year one, simply would not hold a charge. It would no longer charge above 12.1, and most alarmingly when it was on the lawn mower charger the charging voltage wouldn't go above 12.4 and then it would drop back immediately. Tiime was it could charge at 13.4. Something really bad about that battery.

Here's what GOOGLE AI had to say about CCA recovery:

CCA (Cold Cranking Amps) represents a battery's ability to deliver a burst of energy to start an engine, particularly in cold temperatures
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Here's how CCA can be affected by a discharged battery and the potential for recovery:

CCA decline with discharge and age: As a battery ages and undergoes charge/discharge cycles, its CCA rating naturally diminishes. Deep discharges can accelerate this process and negatively impact overall battery performance, including CCA.
Stratification and Low Charge: A common cause of low CCA readings is stratification, which can result from a low charge or infrequent use. Stratification is a condition where the electrolyte separates into layers of varying density, leading to an artificially low CCA reading.
Reversibility of Stratification: In many cases, stratification is reversible. Fully charging a battery after resting it can help restore the electrolyte to a more uniform density and improve CCA performance.
Impact of Deep Discharges: While some deeply discharged batteries can be recovered, they rarely return to their full capacity or performance. Repeated deep discharges can lead to sulfation, where lead sulfate crystals harden on the battery plates, reducing the battery's ability to hold a charge and deliver power. If the sulfation becomes permanent, the battery may not be recoverable.
Importance of Proper Charging: Using a charger designed for lead-acid batteries and ensuring a full recharge after discharge is crucial for maintaining optimal CCA and battery life. Avoid prolonged deep discharges and ensure regular battery maintenance, including keeping terminals clean and free from corrosion, to help preserve CCA performance.

In essence, recharging a discharged battery can help recover its CCA, especially if the discharge wasn't excessively deep and the primary issue is stratification. However, if deep discharges have occurred, the recovery may be limited, and the battery's overall capacity and lifespan may be reduced.

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So maybe I did the battery some good by shaking it vigorously left and right, tilted too. I think I'm going to get one of these $20 everything battery and charge units ... maintainer, charger, diagnoses, desulfate and more.

and it MOSTLY just fires up once a week for generator self-test. Seems to be the norm the days, though it's a small sample size.


Being chemical, there must be a complex formula for life vs temp, time, load etc. That's why we measure under load. Easier.

The 4 year old battery is clocking its best readings in years. 12.5 volts, and 10.7 on the CCA test.

The 16 year old battery is clocking at 12.62 volts, and 9.7 on the CCA test.

I've ruled out parasitic draw ... the draw is 7.6 milliamps, which is negligible.

However, these batteries seem susceptible to draw down when connected to that 7.6ma draw overnight. I'm thinking that actually running these batteries for a good road test will get the deep CCA recharged.

The only thing that I changed was to clean the Battery Ground and reconnect with a film of dielectric grease. Must do this on the older car as well. And as I said I shook them vigorously side to side, and tilted 45 degrees in each direction. Online AI tells me that will help with sulfation, but on newer batteries that aren't made as strongly, it could crack the lead plates. So there's confirmation that they don't make them like they used to.

I was ready to replace them both. Had it all cued up online then decided to test.