NEED HELP ASAP !!! My car doesn't start without jumpers. Was parked for more than 60 days and I need to know if i can charge the 2015 prius c auxiliary battery under the seat with a regular shop battery charger??? Thanks
If you can jump start the car, but the battery needs to be jumped every time you park the car after driving it, your 12 volt auxiliary battery isn't holding a charge and will need to be replaced. Leaving the car parked for 60 days can ruin a lead acid battery, especially if the battery was already a few years old. You can charge the battery but it won't restore it to health.
You can test the battery, not just the voltage but its viability, with an electronic load tester. I’m not sure of the generic name for this sort of tester; there’s various ones available. Solar BA9 is a current one. I have an older BA5, so familiar with that line: you connect its clamps directly to battery posts, enter some stats (battery type and rated CCA), then start test. In a split second it lets you know as-tested CCA and gives a verdict: pass, pass-but-recharge or fail. that said, yours likely will need replacement. But these are handy gizmos. In the interim, if you can get the whole car, or even just the ailing battery, to an automotive retailer selling batteries, they’ll often have pro-level testers of this ilk, and be willing to test yours for free. Check with them before going in.