We live in Chicago in the summer, Florida in the winter. We have a 2005 Mustang that sits in the FL garage over the summer, for roughly six months, without being used. I know I should disconnect the battery terminals before I leave for the summer, or put it on a trickle charger, but I always seem to forget. Last winter when I arrived, the battery was completely dead. Thinking it was probably just old (I believe it was the original battery), I just bought a new one and installed it. Car worked fine all winter.
Yesterday I got to the house and opened the door to the car and could hear the tell-tale clicking of a drained battery trying to operate the accessories. I did not have time to do anything with it as I was leaving town for a week, so it’s still sitting there.
Anyway, six months seems like an awfully short time for the battery to completely drain, especially since the 2005 Sport Trac that sits in the driveway started right up. Am I correct in thinking there is something wrong with the electrical system to drain a relatively new battery in that period of time?
Assuming that this does seem wrong, any suggestions as to likely culprits for the drain? I’ll probably just take it to a local mechanic, but thought I’d ask here just to see what might come up.
I would say nothing is wrong. You have a very slight drain, just the fact that it still clicks indicates the drain is extremely light. Might just be the quality of the battery.
Obviously as you can see with your Explorer, this isn’t normal for every car. If you were handy with an electrical multimeter, you might be able to track down where exactly the parasitic drain is, although it may well turn out to be something you can’t disable and so it could be normal for this car.
You might want to get a quick-disconnect battery cable installed on the negative terminal. Maybe you’ll be less likely to forget if disconnecting the battery at the end of the season is a 2 second job, or if you do forget it’d be a reasonable thing to ask a neighbor to do.
Most modern cars will drain their battery in maybe 2 to 4 months, so dead after 6 months is perfectly normal. Get a battery tender from ye ol local auto parts store for when it sits. They don’t cost that much.
I don’t live in Chicago, but I am in Chicagoland (northwest suburbs.) I’m single, but I have a two-car garage in my condo. For years, my dad has stored his 2007 Mustang in my garage over the winter.
The first year - he directed me to drive it once or twice a month. Which I did. But I unfortunately dinged it (in the garage, not on the road) and he got paranoid. From now on, “Don’t touch it!” was his mantra. He even stopped leaving the keys.
This lead to a repeating (three years! Every year!) comedy. He’d come to pick it up in the spring. It wouldn’t start. I’d grab jumper cables - sometimes it would start with those, but the thing wouldn’t hold a charge if he stopped for food, drink or gas (~Belvidere Oasis, about midway from Chicagoland to Madison, WI)
I finally got sick of it and bought a battery-jumper on my own. Last winter it worked to get the thing started, but even driving 20 minutes wouldn’t charge the battery enough to where it would start.
Helpful fellow at an auto supply store told me - Only thing for long (in this case about 6 month) storage is a trickle charger. Doesn’t matter if the car or battery is still not that old. A car stored for months without running will need it. No way around it. A trickle charger does take a day or two to get the battery charged up again, but it does work. Worked last winter for me and my dad; I gave it it to him in case he decides to store his car elsewhere this winter.
Note that if you are going to disconnect the battery (rather than use a battery tender), some devices like radio and alarm systems can get rather unhappy about it. Check with your manufacturer’s recommendations for how to handle a disconnected battery with those devices.
Also note that some vehicles have specific recommendations related to the engine computer after disconnecting the battery. In order for the engine computer to properly adjust itself, you may need to vary your driving for the first X number of miles or whatever so that it can measure itself over a wider range of conditions. The vehicle’s manual should list any restrictions.
A Battery Tender is about $35, and it’s well spent. It’s a smart trickle charger, it’s simple to hook up (much easier than disconnecting and reconnecting a battery, and more effective), and it will save you a lot of headaches.
That still may not be a great solution. Car batteries can discharge just sitting even without any kind of drain. Auto parts stores (if they’re handling them properly) will only keep them on the shelf for three months, after which they’re returned to the plant for revitalizing. You may find the battery dead, or very low on charge, after six months even disconnected.
Using a proper trickle charger is likely to save you a significant amount of money, time, and aggravation.
Batteries do have an internal resistance which will cause the battery to drain. Here is an image however I do not know how accurate it is. Also, if that car has an alarm system or anything else like OnStar, that system is on and draining power regardless if you activate it or not.
A tender is the way to go, some even come with a pigtail that you connect to the battery and then to the tender when you leave. Very nice and convenient.
