If your mustang is not your daily driver and you let it sit for a few days in between driving it, is this considered deep cycling for the battery? If not then what is deep cycling??

 

As I said in the other thread.

Deep Cycling is when you fully drain then fully charge a battery.

doing it rarely isn't to bad, but doing it offten is.
Some with crazy stereo systems get deep cycle batteries because they can drain the batteries fast when the alternator isn't at full speed.

 

Driving your car daily or once every month does not deep cycle your battery. As long as the engine is running, your battery is charging with a healthy alternator. The engine uses the battery for starting only and then it runs off the alternator. In applications like my boat which has a trolling motor, the deep cycle batteries are used all day with a heavy drain from the trolling motor and other electronics with no charging until I get home. Some days I nearly drain them completely. THAT is deep cycling.

 

so you guys dont think what I am doing is deep cycling? Its not me thats killing the red tops?

 

I have a red top. i think it keeps a good charge for about three weeks with no driving. I now keep a trickle charger on it as i dont drive it much during winter months..

 

If you're killing ANY battery with your car and not trying to power a major metropolis with it, then you need to have the alternator load tested. The charging system on these S197's are barely marginal at best and the alternators are a chronic problem.

 

As the other guys said, Deep cycling a battery is when it's discharged to it's maximum charge loss, usually that's 10.8v. And if it isn't designed as 'deep cycle' battery it will die real quick.

Deep cycle batteries have heavy lead plates designed to hold the charge longer, ie using a trolling motor,

Standard batteries are "dead" at 10.8v, They will loose roughly 5% (more if the battery has some age on it) of its rated capacity each time it's discharged below that.

If you're batteries are dying from sitting for a couple weeks, it's because you have some parasitic drain,

Easy way to check it is wil an amp meter, Standard drain should be less than 50milli-amps.

 

well i have a accuplus scanner that checks the alternator and diodes and I checked the alternator diodes and it said it was fine still

 

No offense, but from the statements in your original post, I'm not sure how adept you may be at testing the alternator and if an accuplus scanner is the right tool for the job. Take the car to an Autozone or any other auto parts store that'll test it at no charge.

 

^^This^^. I had a 2010 that was a weekend play toy. Kept it for a while until I had to get rid of it for other reasons. Never had a problem with it. it saw about 50 - 100 miles a weekend and a couple of trips to the beach. It would go for about 2 or 3 weeks at a time without cranking. No problems at all. I will also add this for Ford. All Ford's IMHO have barely adequate alternators unless you have a Super Duty.