Will a solar maintainer prevent a dead battery?

Yes, for batteries in good condition. A 5W solar panel compensates for the 20-50mA parasitic draw that slowly drains parked car batteries. It won't save an old battery that's already failing.

Can I leave a solar maintainer connected permanently?

Yes, that's the intended use. Quality maintainers with overcharge protection are designed for permanent connection. Check the panel and connections seasonally for weather damage.

Best Solar Battery Maintainers 2026