Can solar car chargers work without having the key to the car turned to accessory?

I am thinking of installing a solar trickle charger in my car. Most of them have a cigarette lighter plug-in for easy installation. But I am not sure they will actually charge the battery. I cannot get power to the cigarette lighter plug-ins without having the key turned to "accessory". If I were to plug in a solar charger, I am afraid that it would not work, simply because no complete circuit to the battery exists while the key is not in the ignition. There are chargers that connect to the battery using alligator clips. But these mean running a separate line to the battery. Is there a solution to this seemingly simple problem?

Public Comments

1. If your cigarette lighter works when the key if off, then yes, the solar charger will work. That will confirm you have popwer to the lighter when the key is off, thus the necessary connection to the battery.