Trickle charger is nothing but a car battery charger and you can leave the charger in the battery for a long period of time and you can recharge the battery whenever you want. If this happens so then the charge will be slowly added to the battery from the trickle charger. There are also many opinions coming in for how long the charger can be left on a battery and what will happen if the battery has been charging continuously. Let us see about them in detail in the following paragraphs.