The battery I use for my trolling motor and depth finder (electric only boat) isn't holding a charge nearly as long as it used to.  I used to be able to use the one battery all day.  Now I have to switch to another battery after using this one for just a few hours.

A buddy suggested putting an aspirin in each side of the battery to get it going again?  Anyone heard of this or maybe a real additive that can get my battery to work again, or is it just time to buy another battery?

I just bought this battery last year, I thought it would last longer than one season.

Aspirin is not going to do anything for it.

There are a couple of causes of your problem.

The first is just the battery went bad, that does happen to even brand new batteries.

Second, you ruined the battery by not properly maintaining it. This could have been from not fully charging it within 12/24 hours after use. Charging it at too low/too high of a charge rate. Not keeping it charged when not in use for more than a month. Running it down too far before recharging it. Not keeping the proper battery water level

Over charging, charging a too high a rate starts cooking the battery, and letting the cells get dry all cause the plates to deteriate.

Charging one at too low of a charge rate causes one to stratify, acid and water seperate, letting acid eat up lower half of plates.

Letting one sit discharged lets the plates sulphate so they can not pass electrons.

About the only one there is any hope of salvaging the battery is sulphation. You can get a 1 amp BatteryMinder Plus maintainer/conditioner and connect it to the battery. After a few weeks you will start seeing an improvement and after six to eight weeks the battery will be back to full capacity. They are a wise investment anyway because you can charge the battery and then put the BatteryMinder on it and forget it until the next time you're ready to go.

Another thing that shortens a batteries life are cheap chargers, like those automatic things everbody sells and seem to use.   You should never charge a battery at more than 14.6 volts and those cheap chargers can be hitting over 16 volts.  A good three stage or four stage microproccesor charger are well worth the few extra bucks.