A trickle charger will fry your battery. You need a tender, or maintainer that moniters the battery and only kicks on when it gets low. The trickle charger...just keeps giving it the juice and frys it.
Go on Ebay, do a search for "Battery Tender" and purchase yourself a great item for a great price. They even make ones that if you have multiple vehicles it will do more than one at a time. Battery Tender is the brand and I've used them for years on my cars when they are in storage for the winter and they work great. For winter storage I just run the cables up from the bottom of the car and attach to the battery so I can still close the hood and put the car cover on for the season.
I bought a CTEK battery charger. I really like it. It will work as a maintainer or charger. You can leave it attached and it will only charge as needed, shutting off when a full charge is reached.
The main reason I bought it vs a Battery Tender is that the CTEK has specific settings for they type of battery. It has a motorcycle setting that is really low amps (.8 amps) so it won't fry a small scooter or motorcycle battery. It has a regular setting for car batteries like in our GT500. It also has a setting for gel type batteries (Optima, etc) With the gel batteries it has the same amps as the regular car battery setting, but charges at a higher voltage. I've got an Optima in my race car, the regular battery in my GT500, and a Yamaha scooter I use as a pit bike with the race car. I can use the CTEK on all three.
These chargers also are oem acc for Porsche. Mercedes, Bentley and Aston Martin.