Trying to find the electrical draw that drains the battery...

[Kern Dog]

One bad cell is all it takes. The vendor should do a direct replacement. How old is it?

It had a 11/19 sticker on it.
I just came back from the store. I returned the battery and bought a conventional one. It will be simpler to charge should the need arise. The old one had 750 CCAs, this one has 800. I've heard Cold Cranking Amps for years but all I know is that more is better. Years ago I thought the rough guideline was to double the engine size to pick the right battery. I have a 493 but I don't know of a 1000 CCA battery.

 

[Sixpactogo]

With that mini starter, you have plenty of CCA. Good luck with the new battery. I went with the AGM battery in my trunk also because of the fumes issue. Mine has not caused any problems in three years. Keeping my fingers crossed though since it is my first experience with one of them.
7 months old battery should have 100% replacement. Did they test it for a dead cell?

 

[RJRENTON]

With that mini starter, you have plenty of CCA. Good luck with the new battery. I went with the AGM battery in my trunk also because of the fumes issue. Mine has not caused any problems in three years. Keeping my fingers crossed though since it is my first experience with one of them.
7 months old battery should have 100% replacement. Did they test it for a dead cell?

I believe because of the AGM construction, individual cells cannot be tested for voltage only the overall terminal voltage and the battery's load test. With "old" lead acid storage batteries (not maintenance free type as those are usually sealed), individual cells could have the specific gravity of the electrolyte tested and if one (or more) cell had a low specific gravity, the low cell was begining to sulfate and the battery wss a candidate for replacement.
An AGM battery, because of the internal construction and chemistry, have a lower internal resistance which usually yields more CCA or CA available but a slightly lower terminal voltage. Typically a lead acid storage battery has both lead (+), lead dioxide (-) as the plate material and sulfuric acid as the electrolyte. The chemistry yields ~ 2.5 volts/cell x 6 cells = ~ 13.5 terminal volts. More plates per cell yields more amps produced overall not more voltage, as voltage is a function of the chemistry.
BOB RENTON

 

[bearman]

Don't forget that the Ford solenoid also pulls 1.5 amps at every engagement and will pull a battery down pretty quickly. Hot starts the amp pull could be higher. Then you run it into the mopar starter relay which pulls another amp off the top of the cranking. Just thinking out loud

 

[Kern Dog]

Ford solenoid also pulls 1.5 amps at every engagement. The Mopar starter relay which pulls another amp off the top of the cranking.

Really? I did not know that.
What I noticed is the huge drop after trying to start when the starter cranks slow. The AGM would start at 12.6 or better but after less that 10 seconds of cranking, the voltage would momentarily drop to the mid 11s. It would slowly come back up but it seemed to me that a healthy battery shouldn't discharge so much.
It is a curious thing though: The faster the starter cranks, the more likely the engine will start causing LESS draw on the battery. The less voltage at the battery before even turning the key, the less power to the starter, the slower the cranking, the lesser chance that it will start and run.
Turns out this new battery is rated higher than I thought:

It started fine several times after installing this new battery.
Also, the voltage number when idling was in the mid to high 14s with the AGM. With the regular NAPA battery and this new one, it dropped to the 13.6-13.8 range. This makes me wonder if the AGM did have some defect to it.
I keep expecting the starter to drag every time I hit the key. I'm still curious if the problem will reappear.

 

[Kern Dog]

With that mini starter, you have plenty of CCA. Good luck with the new battery. I went with the AGM battery in my trunk also because of the fumes issue. Mine has not caused any problems in three years. Keeping my fingers crossed though since it is my first experience with one of them.
7 months old battery should have 100% replacement. Did they test it for a dead cell?

They did not test it when I was there. Maybe when it is shipped back they might, who knows.

 

[bearman]

What is your voltage at the main power at the ign key.

 

[Kern Dog]

The large post on the starter relay is within a tenth of a point of the voltage at the battery .

 

[Photon440]

It had a 11/19 sticker on it.
I just came back from the store. I returned the battery and bought a conventional one. It will be simpler to charge should the need arise. The old one had 750 CCAs, this one has 800. I've heard Cold Cranking Amps for years but all I know is that more is better. Years ago I thought the rough guideline was to double the engine size to pick the right battery. I have a 493 but I don't know of a 1000 CCA battery.

If your trunk is big enough, large CCA batteries are easy to find. This Northstar marine battery has 1450 CCA and is a deep cycle. It's also $700 and made in the USA.

 

[Kern Dog]

I'll put four back there and be able to do wheelies!

 

[bearman]

150.00 group 31 950 cca. I use them in heavy equipment.

 

[bearman]

Duralast battery

 

[hammond472]

I have seen a lot of new or nearly new batteries that were bad lately especially AGM batteries. It makes electronics diagnostics on new cars a nightmare if you don't catch it. Nothing like chasing CAN network issues etc. for days only to find the battery is the cause. Not load testing is the equivalent of not checking the fuse before you rip the entire car apart. I have been down that road. Now I won't even diagnose electrical before I load tested any more. I have a feeling that planned obsolescence has been applied to battery longevity. Just remembered that AGM batteries don't handle full discharge well. Also if you over charge them the cells overheat, dry out and the battery is done. They need to be charged with a special AGM charger and if not used regularly they need to be on a trickle charger. If it is a good quality battery and taken care of properly expect a good 7 years of service.

 

[Kern Dog]

Thank you.
I found it odd that it would test okay but then wimp out after a few seconds of cranking. If it did start, once it was slightly warmed up, it started real easy. Maybe that was due to the surface charge from the short run time? Also, the running voltage with the AGM was the upper 14s where it is supposed to be 13.7 or so, right? As if the battery was like a glass under a faucet and where the glass had a hole in the bottom. It was taking a LOT of charge but not keeping it.

 

[Rusty 72]

I've been following your post because I have a similar weird starting issue. One day acts dead, another day fires right up, some days starts slow and if I keep cranking it just comes back to life?

Today I noticed that I got a little careless with my wiring orientation on the starter relay. The main post on the relay had 3 wires coming off it and one of them was making contact with the ignition wire (not sure if that's the actual name) for the starter. I am not sure why this wasn't causing the starter to just keep cranking but it wasn't. I moved them all over so none where coming close to any others and voila the car cranked normally and fired right up after sitting for 3 days.

Just thought I'd throw this out there.

 

[Kern Dog]

Since I changed the battery, the dang car just cranks up and starts fast like a new car.
S C O R E !

 

[kiwigtx]

Since I changed the battery, the dang car just cranks up and starts fast like a new car.
S C O R E !

Dead cell in the old battery.

 

[Builderguy]

Great news!!!!!!!!!!