Hi there, I have a 2010 Prius that still has its original 12V battery. We don't drive the car very often, roughly 3-4 times per week; sometimes that just means a 10 minute drive down to the supermarket and back, but other times it's a 45 minute drive to another city. Quite often, when I try to start the car after it's been sitting for a day or two, it will either struggle to start up, or it won't at all and I'll need a jump. This has happened off and on over the last two years, but every time we have the battery tested, we're told that it's in great shape and that there's absolutely no need to replace it. Last time, the Toyota rep told us that it's simply because we don't drive the car often enough; that these cars "like to be driven". Most recently, I drove the car to another city about an hour away and back, then didn't touch it for the whole next day. The day after that, it struggled to start up and I had to press the ignition a few times to get it to fully come online. It just doesn't seem right to me that our battery could be totally fine, but it can't hold a charge based on our use. I assume that it just needs to be replaced, but I'm worried that I'll shell out the money only to have the issue continue. Any ideas? Thanks, Jordon
welcome! coupla things: it is getting on in years, and would be a good idea to replace it. if yo'd rather not spend the money, get a smart charger and leave it connected when parked. here's the thing, these batteries are small and weak. and there's a constant drain on them when the car is off. so even if you buy a new one, with your driving pattern, you should still trickle charge it regularly.
To go further on Bisco's post, you don't really want a "trickle charger" as there may be limited control of the charging. You want a battery tender. There are several makes to consider, but all of them are designed to keep the 12V battery healthy over extended times of no use. They usually come with cabling and connectors that allow you to just plug the unit into the car. They all require a 115VAC outlet near the car, so you have that to consider. They can be had for as little as $25. I use a "Battery Tender" unit. They started business building these devices for ATV and motorcycle use. They work well for the Prius battery. Connection can be made in the fuse box under the hood or at the battery in the hatch area. You can get one at Canadian Tire, or you can get a "Genius Charger" but they are more expensive. Oh, and do replace your 12V battery, it's too old to be reliable. It's expensive (in the $250 area), but you do need to replace it. You can get a replacement from the dealer or from Canadian Tire (I paid $170 for their "Ultra AGM" unit). Good time to shop for one, as they probably have them on sale for the "Black Friday" event.
Another case of over-thinking what should be obvious. At 7 years old, you probably would be due for a new 12V battery anyway. Then given your "harsh" driving schedule, as it pertains to the battery, there should be no doubt that you need a new one. If it won't hold a charge, it is NOT "totally fine". Get a new one. Charge it up fully before it's first use. Consider using a battery tender if circumstances permit.
We're very similar driving scenario. As mentioned above, a 2010 car, don't even hesitate: time for a new battery. Canadian Tire has a Motomaster (rebadged Exide I believe) that's dimensionally identical, has the correct vent port. I recently bought a replacement battery for our son's Civic at the North Van CT, had to run it down to them, stuck near Lonsdale Pier. The counter guy was happy to check their battery with their electronic battery test, it was in perfect shape. The Motomaster is around $230, likely you best bet. Dealership price for the battery only, is at least $270 (that's where it was, around two years back). I replaced ours with an Optima Yellow Top through SaskBattery, in Sept 2015, but will likely be trying the Motomaster next time around. MotoMaster Eliminator Ultra AGM Automotive Batteries | Canadian Tire (4 showing in stock at Main St, North Van location) Here's how our garage queen looks these days: Maybe check yours with a digital multimeter: see what voltage reads, with the car off and after sitting overnight, and post here.
