Optima Red Top Bad?

I'm trying to start my 340 Duster a fairly major engine combo change and EFI conversion. After several failed attempts I've started looking at things outside of the EFI settings. The car has a Optima red top that I noticed was dated 11/11 (time flies when on jack stands). The car sat dormant for several years and I rarely put a battery tender on it, but voltage always seemed to be 12+ when I checked. I have been using a tender as I've started to wrap up the EFI install.

Yesterday I had the battery load tested at Advance Auto. At 76°F and 12.3-12.4V the battery showed 635CA when it is rated for 800CA. I trickle charged it back up last night and 12 hours after removing the charger it is back around 12.3V. Is this a sign of a weakened, but not dead battery? I plan to pull one out of my cummins to try starting the Duster with tomorrow.

Take the battery out of the car, turn it upside down for 24 hours. Now charge it upside down. I've seen this revive MANY AGM/gell cell batteries!!!

That is very interesting considering they have no liquid or loose pieces inside.

Do you have a regular charger that can charge at 6-10 amps? If so put it on that overnight and see what it looks like after, should be 13+ right off the charger. Tenders are good for maintaining a charged battery but are not very good at charging dead ones.

Advance auto likely didn't load test the battery, most places use a digital tester these days and those can be accurate but also can just spit out BS, they don't actually load the battery which is what you need. However at 12.3 volts the battery is significantly
discharged and a CCA of 635 isn't horrible. Fully charged at rest you should see 12.7-13.00 for voltage and that will have a big effect on CCA.

Check your voltage while cranking, that will tell the story of what your EFI is seeing.

Hey man. I don't have a big charger, but I'll see if I cant find one to borrow. I started down this road because it looked like my voltage was dropping off pretty fast in tunerstudio while cranking.

I'll try that other battery and may shoot you a message this weekend.

After a long charge let the battery sit 2 hours.
Rested voltage should be over 12.5 volts.

Today’s light weight lead plates seldom last longer than 7 years.
50% of modern batteries do not last 5 years.

I have been impressed with this charger/maintainer/pulser:

https://www.amazon.com/Pulsetech-Xt...8-1&keywords=desulfating+charger#Ask

https://www.pulsetech.net/xc100-p-xtreme-charge-12v-battery-maintenance-charger-desulfator.html

I wish it had a 85% LED between 75 and 100%

It claims to judge the battery condition by “charge acceptance” rather than voltage.

Batteries take a long time to go from 75 to 100% on this charger.
Starts charging batteries using 50 watts of power.
From 75% it is down to 8 watts and at 100% 3 watts.

I read similar information before asking here. After trickle charging over night and letting it sit for 8-10hrs it ends up around 12.35V. I repeated this test twice.

Ask friends if they have a pulse charger you could borrow for a week.
It usually takes several days for the pulses to de-sulfate the crystals that allegedly form.

12.37 is only a 70% charge. i think you need to go battery shopping.

My favorite automatic charger I have used to date is the one Optima sells. My yellow top is 9 years old and it puts in work with EFI, two fuel pumps, two fans, electric water pump and cooling between rounds at the track. I try to put the charger on it once a month when I can.

That being said all automatic chargers are kind of junk, they all shut off too early. But with an AGM its kind of necessary to use the right charger to prevent damage.

This one?

https://www.jegs.com/i/Optima+Batte...uQDKEAQYAiABEgKv1fD_BwE&gclsrc=aw.ds

Yep, they make a larger one also but that is the one I have. I once left the key on for 2 weeks and drained my battery totally dead, that charger brought it back up and it has been fine. Most chargers wouldn't have even acknowledged a battery was hooked up when they are that dead.

Red top in my Satellite is now 12years old . . .still going strong ! Although, when parked, I do leave battery maintainer on it, as rest of my cars . . . .

No prob with mine, but they live on a battery tender when parked between races.