If you have your own trickle charger, safely charging your own dead car battery is a simple matter. Stockbyte / Getty

I think I remember hearing somewhere that if your battery goes dead, you should put it on a trickle charger instead of just driving it around. What is a trickle charger, exactly, and is that really a good idea? If it is what it sounds like, then it sounds counter-intuitive to charge the battery slowly instead of just driving it around, or even using a charger that can charge quickly. Wouldn’t faster be better? So what I’m wondering is what is a trickle charger, and do I really need one?

Answer:

The term “trickle charger” technically just refers to a battery charger that charges at a very low amperage, but the situation is a little more complicated than that. A lot of battery chargers are capable of putting out a variety of different amperages, to charge a battery slowly or quickly as the need arises, and some are also designed to be left connected long-term without overcharging. When you hear people talk about trickle chargers, that’s typically referring to.

For general use, any battery charger, or trickle charger, that puts out between about 1 and 3 amps will do, and you don’t really need one with float mode monitoring unless you want to be able to leave it connected for some reason.

As to why you should charge your battery instead of just driving it around, there are really two issues. One is that your alternator can only put out a limited amount of amperage, so your battery is likely to still be low on a charge if you just drive to work or run some errands.

The other issue is that alternators aren’t designed to charge totally dead batteries.

Trickle Chargers Versus Normal Car Battery Chargers

There are two main ratings you’ll see attached to car battery chargers: amperage output and voltage. To charge a typical car battery, you need a 12V charger, but many car battery chargers have 6, 12 and even 24V modes.

The main thing that defines any given charger as a trickle charger is that it will either have a low amperage option, or it will only be capable of putting out a low charging amperage. Most trickle chargers put out somewhere between 1 and about 3 amps, but there is no hard and fast rule on that.