Looking for a good way to maintain the charge on the battery of a car that is driven infrequently-about once a week or two weeks.
My first thought was a solar charger but the car is parked on the north side of a building and doesn’t get much direct sunlight. Should we put a plugin trickle charger in the car and leave it plugged in all the time while it’s parked? Does the charger still use power when the battery is charged? Harmful to the car or charger? Better solution?
Thanks. It’s my daughter’s car and I’ll see how old the battery is when she gets it boosted and gets here. Still, I wonder about modern cars that use all kinds of power when they’re “turned off”. Today is the first time it hasn’t started and it’s about -33C outside.
Just came in from plugging our car in for errands later today. It’s chilly.
There’ve been long threads here about how it’s the heat that kills batteries, but in my experience, they always die on days like today. If I get three years from a battery, that’s good; four is great. Can you check to see how old it is? When CAA installs one, it usually puts a label with the date on it.
Wasn’t there a thread not too long ago where one or more posters were arguing that it’s heat, not cold, that reduces the life of a car battery? (Cold makes the car harder to start but doesn’t actually harm the battery.)
That matches what I know. I use to know a lot about battery maintenance but that was a long time ago.
In New Jersey, a battery should easily hold 2 weeks without driving anytime of year and still start the car. But in very cold places, it just gets a lot tougher to start the car.
I never had one do that but NJ. What Thudlow is referring to is sulfation. The lead plates build up a crystallization that prevent the battery from getting a full charge.
OK, so while the cold prevents the battery from getting and maintaining a full charge it generally doesn’t cause the battery to degrade. Though if the case cracks from the cold, that is a whole other thing.
Over-heating and very hot weather will cause battery fluid to evaporate which is bad. It can cause overcharging that leads to sulfation. It can cause corrosion to the lead plates which shortens battery life and reduces max charge.
Unless the alternator is not 100%. Connections etc. The stuff you don’t think to check until it’s subzero by a lot.
My work car sits a week or two sometimes but until now we haven’t been subzero F. My truck is just much nicer to drive in these conditions.
How long is it driven when it is driven? That would be a factor. It may be prime conditions for gradually depleting the battery then one day it doesn’t start. Also it would stress the alternator as it tried to charge a losing battle. So yes if you want to do a battery tender, no harm no foul. Solar charger would require mounting to an always live circuit of the car, so may or may not be as simple as plug in to the car cig. outlet.
There is a different product generically called a “battery tender” sold exactly for this purpose. They tend to be smaller than chargers but otherwise look the same. Their design intent is to stay connected to the battery all the time, or, if it’s a vehicle, connected all the time the vehicle isn’t driving. They apply more or less current depending on the battery voltage and the temperature, to keep the battery ready. However, they don’t have much current capability, and would take a long time to charge a dead battery.
I kept one on my old tractor for many years, and now on the new one. I keep one on my battery-start 10 kW backup generator. I also got another one to put on my car but haven’t yet gotten around to figuring out how to do it conveniently, as you need someplace to run the wire out of the vehicle where you can reach it, and of course some way to do the same on the house and box side.