I’m 84, and I traded my Toyota Matrix for a 2018 Subaru Forester, but I’ve had several problems with the battery draining to the point that the car wouldn’t start. I learned from a [British Columbia Automobile Association] BCAA mechanic, and eventually from the dealer, that the problem is that these new fully-loaded SUVs must be driven 10,000 kilometres a year in order to charge the computers that provide all that bling like rearview cameras and power tailgates that are so necessary for seniors and other drivers. The dealer said all modern SUVs share this problem. I live on an island; l never drive 10,000 kilometres a year! It was suggested that I must trickle-charge the battery when it is parked and that I “drive it around for half an hour or so.” I am on a walker. I cannot clutch my walker and charge the battery. And in a green age, why must I drive it around to keep the battery charged? I am very angry that nobody ever disclosed this. – Pat, Saturna, B.C.
It might seem shocking that you have to drive to charge your car’s battery, but it’s not new, experts say.
“The battery-life issue is not new – batteries have been sulphating since the creation of them,” said Josh Smythe, BCAA automotive manager Josh Smythe in an e-mail. “In newer vehicles, the demand for power is actually lower due to lower amperage requirements for accessories combined with intelligent battery circuits that avoid battery draining from sitting parked.”
Batteries produce electricity through an electro-chemical reaction – in most car batteries, electricity is produced as electrons flow from the lead oxide anode to the metallic lead cathode, through a solution of sulphuric acid.
That reaction keeps happening, but more slowly, when the battery isn't being used. That's why batteries lose their charges as they sit on a shelf.
If the battery is connected to your car, it drains even faster because your car sucks power even when parked – especially if it has an alarm system, on-board computers and memories for seat positions and radio and climate-control settings.
Things like backup cameras and power tailgates don’t drain the battery while parked unless you use them when the car isn’t running, Smythe says.
As you drive, your car’s alternator recharges the battery.
But if you have a lead acid battery, you’ve also got to worry about sulphating, even if there isn’t much drain from computers, Smythe says.
What’s sulphating? It’s when a layer of lead sulphate forms on the plates inside your battery.
An AGM battery will still sulphate if you don’t drive often enough. But it will take longer than it would with a traditional lead acid battery.
So how often do you have to drive to keep your battery charged enough to start the car? Subaru doesn’t recommend any specific mileage that you drive. It just says you have to start and run your car “periodically.”
“I’m not sure why someone told her she would have to drive 10,000 km – that is not true,” said Steve Elder, automotive instructor at British Columbia Institute of Technology (BCIT), in an e-mail.”In very general terms, probably running a vehicle once a week for half an hour or so would be enough to maintain the battery – but I don’t feel this is a prudent long-term strategy.”
Just idling isn’t enough; you actually have to drive to recharge the battery properly.
There are other ways you could keep your battery from dying without having to drive across Canada every year.
Get a new battery: Lead acid batteries can only be fully drained five times before they need replacement, Elder says. A new battery will be better at keeping a charge. Ideally, get the biggest battery that will fit in your car. An AGM battery won’t sulphate as quickly but could cost two or three times as much as a normal lead acid battery,
Install a battery maintainer: Elder suggests a battery maintainer that’s directly wired to your battery. That way, you don’t have to hook it up to the battery every time you park. It stays on the battery all the time and you just plug it into a wall outlet whenever the car has to sit than more for a few days.
“Unlike a trickle charger, a battery maintainer has an intelligent circuit and will cycle on or off as needed to maintain a full charge to the battery,” Smythe says.
If you don’t have access to a wall outlet, there are solar battery maintainers that sit on your car’s dash.
“This would need the car to be parked outside,” Elder says.
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