My Ford has had a problem with intermittent starting for a few years now. Short version: when it starts getting colder, my vehicle sometimes struggles to start, but it does this intermittently. It is not the battery as we have now bought a stronger better battery with good warrantee and it tests just fine. Vehicle would sometimes just be "dead", but if I wait a few minutes, I would sometimes get it to start up again, other times I have to use my starter pack. Sometimes it would drag when trying to start and if I wait a few minutes, it will start again. My son is at a loss as what could be causing this. Any ideas?

 

No crank no start or crank but no start?
What do you mean when you say "Vehicle would sometimes just be "dead"", what is dead? No power everywhere including dome light or what?
What is a starter pack, is it like portable jump starter? If it doesn't start and when you use the jump starter I assume, does it start 100% of the time?
How often do you or your son drives the vehicle is it daily or weekly?

 

1. When I say "dead", I mean no crank at all, but domes lights are on. The battery is not dead.
2. Yes. Portable jump starter and yes, it starts it immediately.
3. Daily driver, but we have found that when not driven for a few days, it struggles to start.

When we then go have the battery checked, it checks out OK.

 

I suggest you to get a battery monitor like this: so you can check the health of your battery in real time on your phone.
How to hook it up? Most European cars have their battery in the trunk, and is a + and - posts in engine compartment for easy access, dedicated jump start posts. And then on some cars because the battery is not easily reachable there can also be dedicated jump start posts as well. If your Escape has dedicated jump start posts you need to connect this battery monitor to the jump start posts, so it doesn't interfere with the factory BMS (battery monitoring system).
How to use it?


You see the 100% shown above that's called SoC (State of Charge). Do not let the SoC to drop below 50% at any time. If you see 51% and you have no plan to drive the vehicle, you should hook up a battery charger like Noco Genius 10 (not genius 5).
Below is the cranking voltage at 9.75v and is showing OK in green. If you see the bar in red but it's above 9v that's acceptable as well. On the Setup screen (no pic shown here), you can disable all notifications. This little battery monitor device is a must have for any cars on the planet. It will remind you when you need to drive it or charge it.


Just because you have a new and you think it's better (AGM perhaps?) battery with good warranty but if you only drive it twice a week and short trips, your SoC can still drop to below 50%.
Since you said you can jump start it and it starts that way 100% of the time I suggest you to clean all the reachable battery terminals using Equate 91% isopropyl alcohol spray type (you can get it at Walmart) with wire brush and have you son do the same thing at the starter solenoid as well. And of course, inspect all the battery cables as well. After cleaning tighten the battery terminals to 6nm torque specs, not just snug and also don't overtighten the terminals.

 

I will give this info to my son. He has a mechanical background, so he has exhaused all avenues from his side. He takes really good care of the Ford for me.
We are replacing the batteries every year. The only reason this one has not been replaced is because it is only a few months old and it keeps on checking out ok.. I drive 20 miles to work and same back everyday on the highway here in Wichita, KS, so the car is is always driven.

 

Remember SoC keep it above 50% at all time, then even the cheapest battery from Autozone/Walmart should last 5 years or longer, and of course top off with distilled water every 3 months if it's a flooded type.

 

Next time it will not start, turn on the headlamps and go to start it.. If the headlights go dim or out, poor connections between battery and cable connection at the battery
When you connect the jumper you bypass those connections. Let us know what you get if further suggestion is required, thanks.

Something we need to know, has anyone checked the charging system for proper function ?

The need to keep replacing batteries may not be a battery problem at all.