The Gun Counter

Picked up a new battery for the truck, an AGM battery. Heard these are great newer technology and superior to flooded cells in every way.

True/false?

This one was a brand new, never used, not a mark on the terminals, and this year's production, but had been returned to a store. Store can't sell returned "used" batteries as new, so they mark them "Refurbished". Six month warranty, but only $29 instead of $129.

Use something similar at work for battery backup of our communications sites. They're a lead acid battery you don't have to screw with.

Kissing cousins are gel (Optima makes one for the automotive market I believe) and VRLA. All are so much less hassle than the old wet cells.

I'm familiar with them for radio power back up systems, not vehicles. One big advantage over standard vehicles is a low self-discharge rate, especially compared to standard batteries. Makes them especially suited for stand-by power applications for stuff not used very often, when you can't keep it on a trickle charge.

I have one in the Suburban. I did a bit of research before I bought it, though not exhaustive.

The way I understand them, they can discharge fully without damage, then recharge fully. Also, they're a bit like a deep cycle battery in that you can use them to listen to the radio for a long time without having to worry so much that they won't start the vehicle.

I got one for the Suburban because it's old enough that there's no dinger if you leave the headlights on. On moderately bright rainy days, I've been known to forget to turn the headlights off.

Since I got it, I've done that twice. Once, 4 hours later, it still started. Once I needed a jump, and the battery has shown no signs of trouble. I'm sold.

What you should not do with AGMs is equalize them, such as can be done to flooded cell batteries. Also, the peak charge and float voltage is generally slightly less; it's why the newer "smart" chargers have different settings for various battery types.

Dang acronym overlap...I was looking for Air to Ground Missile batteries.