@db4690 Yes you are right I was only responding to your post, read it again, with an answer to your post. The boat battery is still on a maintainer, as we speak, no need to make a 500 mile trip today to do something different than I have done in the last 20 years. And please notice I was only answering your question as who it was directed to and included who suggested it, It was not you, did not mean to imply it was @db4960
@Barkeydog
Try the same time (8) months in Maine…li still do the same thing with my boat batteries. But, a car battery for two months ? That’s OP’s situation. That’s pretty easy.
I agree with @circuitsmith. A healthy battery is fine for up to about 6 months. And, cold temps extend the life of a battery. It’s warm temps that shorten it’s life. Ideal conditions for storage are a “cool dry place”…not warm and just like recomended by the “traveling Willburys”. Freezing is a factor only in batteries with insufficient acid levels.
Or VERY cold temps.
I agree in general it’s bad practice to leave it, chargers in general, unattended and plug in that long. If you use a solar charger, I could change my mind.
@dagosa - the battery tenders are designed exactly for this job. Many motorcycle riders routinely use them for the long winters, no problem. And my healthy (brand new) battery isn’t good for more than 3 months. There are a few loads on the system on new cars (built in security systems, in particular) that seem to cause problems.
If you park your car for any extended period of time you need this little unit to keep the battery charged. Plug it in and you’re all set! 1.25 Amp battery charger designed to fully charge and maintain a battery at a proper storage voltage without the damaging effects caused by trickle chargers. The new BTP micro-chip technology applies the correct peak charge, then automatically maintains the battery at the perfect float voltage which virtually eliminates battery destroying sulfation! Temperature compensation ensures optimal charge voltage even in extreme weather conditions. Powder coated aluminum chassis. Spark Proof! Reverse polarity protection ensures safety. Built in 72 hour timer will protect a marginal battery from over charging.
@texases
No one, especially me doubts that battery tenders work. I have one on my house gen as I look at these differently. There is no house power when I ask it to start. . I have just not found a need for one when you disconnect a fully charged battery for two months. I don’t even find a use for them leaving my boat batteries in my garage all winter…ldisconnected. Now, if you want to milk an old battery or leave it connected, fine, pay the electric company and hope there is no problem.
you might want to look at a " Battery Tender"
From what i gather reading these comments a battery maintainer aka: float charger is just used for when the battery gets charged then take it off because it might burn down my shop if I leave it on there for any extended amount of time after the battery gets fully charged. If that’s the case the why do I even need a battery maintainer on my porsche or volkswagen beetle if I’m just going over seas for 3 months vacation?
I do not know that you need a battery maintainer for 3 months, every car is different. We have 6 water pumps at work that are kept on a battery maintainer until needed so the battery will be good to start them. Never had a problem. A charger can overcharge a battery, and fry it. A maintainer should not overcharge a battery and fry it. I do not mind posts from 2013 getting revived.
A battery maintainer/tender will hold the battery at 13.5V or so, which is okay to hold indefinitely.
But any electrical appliance has some chance to malfunction. Using a UL listed device pretty much insures the malfunction won’t be catastrophic.
A basic “dumb” trickle charger can raise the battery voltage to 15V or more; and left unattended for days or months can “boil” a battery dry.
Back before the era of “smart” chargers you could plug a trickle charger into a household timer set to come on an hour a day and get along that way.
My lawn tractor sits in an unheated shed in the back yordfrom early november to late april and even thought the temperature near Buffalo regularly drop into the low teens and sometimes below zero, it has never frozen. The first two years of a new battery it will stary the tractor after that I jump it with my car the first time I cut my grass. I could run a cord out to the shrd and put a charger on it but it is easier to just jump it.