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Keeping the battery charged by running the engine without driving

I won’t be able to drive for about 4 months after a knee injury. Can I keep the battery charged by running the engine periodically? If yes, then how often and for how long?

My transmission is manual (stick) so getting someone I trust to drive it, who has the time, and is willing, is harder than I expected!

That’s bad for many parts of your engine. It would be better to pick up a battery tender (which is pretty cheap) and use that.

a relatively new battery should hold it’s charge for 4 months…reduce your insurance for that period of time.

Not in a relatively new car. There are several electronic modules in cars now that never power down. In general, the design goal seems to be for the battery to be able to withstand one month.
I too vote battery tender. Sports Academy sells some good ones (boating section).

Supplemential information, Do not view your cars charging system as a battery charger, if you break away from the mindset that it is you will on the path of better decisions regarding storing your car

Additional supplemental information. The old advice was to disconnect the battery during storage. With modern computerized cars this is bad advice, see this link. I also vote for the battery tender.

And, if this car will be sitting undriven for 4 months, you might want to add a bottle of fuel stabilizer to your gas tank, and drive it a bit to get the stabilizer all the way to the engine before parking it. I have read that current gasoline blends containing ethanol deteriorate faster than gasoline without ethanol.

A good battery, if fully charged with the cables disconnected will usually rest for 4 months without discharging.

I also recommend a battery tender. I would also consider checking with your insurance company and eliminate the collision (If you are not driving it, it can’t collide with another car.

The battery should not simply be disconnected, see here.

Just in case you’re wondering what a Battery Tender looks like. The original Battery Tender is a little expensive, but can be left hooked up to the battery for the entire time. I use mine about once a month on one of my older cars to keep the battery topped off. Check out the original Battery Tender or Battery Tender Jr. here.

You could also purchase a less expensive trickle charger. In my opinion, the Battery Tender is worth the extra cost. It’s still cheaper than a new battery.|GRP2005____

Ed B.

If the car is parked outside use a solar battery charger. Provides just enough juice to keep the battery up.

I have used this one
on some farm equipment for a few years with no problems at all. I am sure there are others in this price range that are good too.

Yes, you can keep the battery charged by running the engine for about 20 minutes once a week. That’ll also keep the engine’s internal parts lubed and wet as they should be.

Would it be the method you would choose? or would it be the method you would choose if you had no other choice? or would it be better or worse than doing nothing?

It’s the method I would choose if I were under the OP’s circumstances. It requires zero technical knowledge, no stressing of the knee, and no equipment investment, and it’ll do the job.

besides, it’s a direct answer to the OP’s question.

This is a one-time four month period where the car will not be driven. MB is spot-on with his advice. Just start the car for 20 minutes once per week or two weeks. I wouldn’t add fuel stabilizer or do anything else.

Next time you are in a Thrift Store, look around in the electrical department for a 12-14 VDC plug-in transformer that has a capacity of 1 amp or more…They are fairly common and can be had for a buck or two…snip the connector off, split the wires and install a couple of medium size alligator clips. You now have a $2 battery maintainer…Check the polarity, use black and red clips, a little common sense…Disconnecting a battery seldom causes any problems…Some theft protected radios need a code to work after power is restored…

Myself, I would just park the car, I know that at times doing nothing is the hardest thing to do. There is no issue with fuel “going bad” in 4 mths and don’t worry about internal engine components losing their protective oil covering at 4 mths. You could (if you are the handy type) perform a parasitic draw test and see just how much current your system draws after everything has timed-out, this will let you know if you should be concerned with your battery losing its charge. I would open the hood and look things over once a week, just to see if any animals move in

All theses parameters that a vehicle looses when the battery is disconnected are quickly re-learned as soon as the car is put back in service. Disconnecting a cars battery is not a life altering event. I can deal with whatever pops up due to a battery disconnect, it is when the customer keeps driving with the oil can symbol illuminated or the temp. gague in the red that causes real problems.

I’m not sure if Tiia14 is reading the posts?

My 2 cents is the battery should last a long time before it won’t be able to start the car. One month, no problem; 2 months should be OK, 3 months starting to get iffy, and 4 months about a 50/50 shot it will start the car.

The unknown is how much current the car’s electronics use while the car just sits? My T’bird ('04) will run down the battery in 2 months. My other cars last much longer.

If you don’t have one, I’d recommend you get a “jump start” box. Sold by all auto parts stores, Sears, Walmart, Target, etc. Figure it will be $30 to 50. Then you have a quick fix if you go to start the car and the battery isn’t able to do it without some help.

I use my jumper about 2-3 times a year either on the boat, or the T’bird, or if I leave the lights on by mistake. They come in handy. I think you’ll be fine, but a jumper gives you a simple backup just in case.

I vote for the battery tender. Starting the car every once in a while will do it good.