Do cars really need spec’d CCA

[ssamaroo01]

I have two vehicles in need of batteries. The first is a 2012 Escape that's requires a 96R with 590CCA. The second is a 2008 Focus that requires a 96R with 500CCA. The current battery in the Escape is original and was installed on the build date of 11/11 from the door jam sticker. I had installed a new Motorcraft MaxTough battery on the Focus in April of 2012. I bought a new Motorcraft MaxTough battery for the Escape because my wife drives that to get out two babies under 2 years old to doctors appointments and such. So we need that vehicle to be reliable. The Focus is parked up until the weather warms up because we need to replace the shift solenoids. After a week of not driving the Focus, the battery ran down to 2.1 volts.

My question is, since the battery coming out of the Escape is still decent, can I put that 590CCA battery into the Focus that requires 500CCA to just be able to start it up now and then and do the repairs before I buy another battery? The shift solenoids are $300 for all 6 and I just a new battery. A second new battery is an expense that I don't want to incur right now. Btw, during New York winters, it is common to have warm days in the 40s-50s range that would allow me to work on the shift solenoids.

 

[knerml]

I would consider the 500CCA as a minimum.

 

[HangFire]

If I read the question correctly, yes you can put the (Escape) 590CCA battery safely into the Focus which requires only 500CCA.

Also the other way around, if the battery is in good shape, and the car isn't killing the battery, you won't miss the 90CCA, at least not until the battery is at End of Life.

However if the Focus has a short or parasitic draw that runs down batteries in one week to 2.1V, "reliably" is going to be the problem. You need to fix the problem there, or keep the battery disconnected until used.

For all unused vehicles, charging the battery externally at least once a month is necessary for good battery health. Wet cell batteries that sit in a discharged state degrade chemically, and do not have as long a useful life as a wet cell battery kept fully charged.

One more thing, for vehicles that sit a lot, Reserve Capacity is more important than CCA. CCA ratings are most important in very cold weather, and/or for large, high compression engines.

 

[Chris142]

Today's cars have tons of electronics. Many stay on even when the car is off. You can always use a battery with more CCA than required but don't go with less.

 

[The_Jeff]

What others said. If your battery voltage sags enough that your starter turns slowly, that is not good for the starter. Healthy batteries, and plenty of cranking amps, keep the voltage from sagging.

You are lucky to have two vehicles that take the same group battery.

I would disconnect the focus battery when stored to save it. You might have other parasitic draw issues, but if the battery runs flat, it could freeze.

 

[redhat]

Yes, and for replacement I always like to source the highest CCA I can find for that group size (within reason for price concerns).

This is a mediocre comparison at best, but think of CCA as the available electronic strength a battery has. Your vehicle may require 500 cold cranking amps and this battery can (in theory and in good working order) supply 590CCA.

 

[E150GT]

I look for minimum CCA but maximum reserve capacity in a battery.

 

[spasm3]

Originally Posted by E150GT
I look for minimum CCA but maximum reserve capacity in a battery.



I do as well. I look for the minimum CCA that meets my vehicle specs, with the largest physical size that will fit.

 

[JHZR2]

Originally Posted by ssamaroo01
After a week of not driving the Focus, the battery ran down to 2.1 volts.



In general you want a reasonably high CCA rating, higher than the manual for sure, and beyond that, the best mix of CCA and reserve capacity (RC) that you can find. But were not talking about a daily driver here, right? Rather reusing an old battery in a non-essential car that just needs something until the time comes to put a legitimate new battery in...

If its true that it dropped to 2.1V after sitting for only a week, its likely that you have a short circuit somewhere in the car, or a bad diode in the alternator.

So putting ANY battery back on will just destroy the next one fast. If youre going to connect it up, start it immediately and take it to be diagnosed, great. Anything else, I would NOT connect the battery up.

Instead I would hold onto it, Id put it on a float charger in your garage, and leave it until you need it. This will keep the battery in best possible shape, and ready for when it is time.

No way would I buy a new battery that isnt needed for the focus, until you have everything else figured out. So I think your idea is spot on!

Just one other thought - most ATs are electronically controlled, and a bad battery/charging system can cause havoc. You sure the AT is actually in need of repair, and it isnt a bad alternator or electrical system???

 

[spasm3]

Originally Posted by JHZR2

Just one other thought - most ATs are electronically controlled, and a bad battery/charging system can cause havoc. You sure the AT is actually in need of repair, and it isnt a bad alternator or electrical system???




JHZR2 has a good point here. Rare but possible indeed. I had a saturn with an auto trans. started acting up and staring out from a stop in 3rd gear. Trans shop replaced the valve body to no avail. Turned out the alternator was somehow putting out about 17-18 volts.

Replaced the alternator and the trans was fixed!

 

[Linctex]

I always install the largest CCA that will fit in that spot.

It often only takes 150-200 amps to crank and engine - which almost every 1-2 year of battery can "muster up"

But when your battery is 8 years old, the smaller of the two (500 vs 650) may not be able to give that much - where the larger of the two often still can.

 

[Uphill_Both_Ways]

For cold cranking amps skip to 2:30. Then comes reserve capacity.

 

[The_Jeff]

Originally Posted by Linctex

But when your battery is 8 years old, the smaller of the two (500 vs 650) may not be able to give that much - where the larger of the two often still can.


The flipside is that a well-built, lower CCA battery has thicker plates that are less likely to fracture. A high-CCA one has thin plates where things can go wrong.

Sadly, in the North, a low-cca battery is often a shoddily made economy model with less lead. Can't win!

For OP I would buy a battery with at least 590 CCA to allow versatility between both vehicles in case he trades or junks one of them.

 

[PeterPolyol]

Originally Posted by eljefino
Originally Posted by Linctex

But when your battery is 8 years old, the smaller of the two (500 vs 650) may not be able to give that much - where the larger of the two often still can.


The flipside is that a well-built, lower CCA battery has thicker plates that are less likely to fracture. A high-CCA one has thin plates where things can go wrong.

Sadly, in the North, a low-cca battery is often a shoddily made economy model with less lead. Can't win!

For OP I would buy a battery with at least 590 CCA to allow versatility between both vehicles in case he trades or junks one of them.


Very good point about the CCAs and plate thickness.

 

[dogememe]

Originally Posted by PeterPolyol
Originally Posted by eljefino
Originally Posted by Linctex

But when your battery is 8 years old, the smaller of the two (500 vs 650) may not be able to give that much - where the larger of the two often still can.


The flipside is that a well-built, lower CCA battery has thicker plates that are less likely to fracture. A high-CCA one has thin plates where things can go wrong.

Sadly, in the North, a low-cca battery is often a shoddily made economy model with less lead. Can't win!

For OP I would buy a battery with at least 590 CCA to allow versatility between both vehicles in case he trades or junks one of them.


Very good point about the CCAs and plate thickness.


Yes,this is why I always recommend the physically biggest battery that will fit. They tend to last longer. Around here CCA doesn't really matter. A good balance of CCA and RC beats a ton of CCA with little RC.

 

[PeterPolyol]

Totally, Big CCA and low RC is a huge warning flag!

 

[bbhero]

One thing to keep in mind here.... CCA measued at 0°F.... OEMs are thinking about coldest conditions likely to be seen... Has temp dropped obviously CCA drop has well. However, the need from the car or truck for amperage to start the vehicle goes up... It is a inverse relationship.
Example... My car specs a 550 CCA battery at 0°F. Let's say I take my car to Fairfax Vermont. Temp there -25°F in the am, car outside all night, no block heater used... Given that circumstance my car would still start ok given the battery is in good working order. Though it may barely be able to get the job done. But it would be able to do it.
Say another cat uses a lower rated CCA battery like 400 CCA rated. Same exact environment I am in. Temp around -25°F... Car outside all night and no block heater. That car does not start...
Another reason in places up where it get way way cold... Better to run the largest physical battery that will fit with the highest CCA... Therefore if I lived in Fairfax Vermont I would run a group 24f battery rated at 725 CCA and 120 minutes of reserve capacity... With that battery I would have no problem starting even if it was a bit colder than in my example above. In other words... Go big or go nowhere

 

[ssamaroo01]

Thanks for all the advice. I replaced the battery in the Escape and the old Escape battery is now in the Focus. I'm taking the old Focus battery in for a refund core charge. I also checked the alternator voltage when I got the Focus running and it was about 14.2V at idle. Because the alternator voltage was okay, I am leaning toward replacing the shift solenoids. The transmission is a 4F27E and I've changed the fluid about a year and a half ago. The fluid is nice and pink using the blot test. The car isn't used much. Maybe 3-5k a year. The last time I changed the fluid, I dropped the pan and cleaned the magnet. Not much was on the magnet and the fluid was clean. No signs of clutch material or metal shavings. The issue I am having with the transmission is that it takes a long time to shift gears. I would have to push it to 3500-4000 rpm to get it to shift into 4th gear. This was my daily driver from 2009-15 so I'm very familiar with how it should drive. Bought it with 36k and now has 156k. My mom drives it around town now. My idea was to buy all 6 solenoids and replacing only the ones that are bad. I was thinking about measuring the resistance on a new one and comparing it to the resistance on the old ones. If the resistance is off, I will replace them and return the parts that I do not need. I don't like leaving a car in pieces while I wait for parts plus I do not know what good resistance values for these solenoids are.