AGM Deep Cycle batteries

[Gone Fishin]

So I am in need of a new battery or two for my trolling motor. I have been comparing the different types and trying to decide what to buy. If I buy an AGM battery I can probably only get one. If I buy a standard deep cycle battery I can probably afford 2. I am trying to keep my trolling motor from consistently dying when I am fishing. Anybody have any thoughts?

[T Dot]

have you looked into optima, its sorta a median between the two.

[Anglinarcher]

There are really only three types of deep cycle batteries, about four sizes, and a hundred names all telling you that they have the best.

The most important thing you can do is to upgrade your battery charger to a three stage, and if possible, one designed for the type of battery(s) you use. The new chargers make a huge difference in how long a battery last, and how well it holds its duty cycle. A Gel Cell actually should be charged and maintained at a slightly different voltage then a Lead-Acid or a AGM. The big thing is that you may find your battery last long enough when it is new, but if it is not charged correctly, it will loose its ability to hold a charge for the day pretty fast.

The battery sizes range from a group 24 (smallest) to something in the group 30 something. I use a group 27, weighs about 62 lbs, AGM, or Gel Ceil, and they last forever. But, lasting for a day? That depends on your usage and how many amphours your battery is rated for.

Look at the batteries and buy one that has the largest amphour ratting, or whatever rating that battery uses. For example, you want a battery that will push the desired amps for the longest period of time. This is the amount of power that is available in that battery. A group 24 battery will never match a group 27 battery, and a 27 will never match the bigger batteries.

Now, Lead-Acid verses any of the others. If the amphours rating is the same, the batteries will last the same amount of time, no matter what the type. The real advantage is that Lead-Acid batteries are cheap, well cheaper anyway; but they require constant maintenance. Fail to add water, distilled water, and the battery looses duty cycle. Gel Cell batteries are maintenance free, last for years if properly taken care of, and tend to be a little lighter in weight from what I can tell. AGM (Absorbed Glass Matt) batteries are maintenance free, last for years if properly taken care of, and tend to be a little more vibration resistant that the other batteries. Vibration, say on a bass boat pounding the big waves getting to the hot spot, can crack a plate on the others (mostly on the Lead-Acid).

So, what one for you? If you have the right charger, and if the amphour rating is sufficient, and if maintenance is not an issue for you, then the Lead-Acid will probably work just fine. Nevertheless, you will probably toss the battery in about two or three years.

If you have the right charger, and if the amphour rating is sufficient, and if you do not want to maintain your battery but still want it to last for years, than a Gel Cell or AGM is probably better.

The choice I'm afraid is a very personal one.