Ideal Battery

Anyone have suggestions on ideal battery for boat lift? I have an oil hydraulic lift. Pump is powered by 12v battery. Battery is recharged by solar panel. I currently use Interstate Deep Cycle Marine battery but seem to be blowing through them pretty quick - after 6 months they seem to have trouble holding a charge at high enough voltage. Do you think something like Optima Blue Top would be a good alternative - would it make a difference? Would also take suggestions or best or at least better practices on maintaining the battery for the lift.

my buddy has 2 optima blue tops in his boat. seem to work well.

look into wheel chair batts or golf carts.

it sounds as if you solar charger may be the problem. If its not producing enough amperage and the batterys get slowly run down they will not last. Optimas are an AGM battery and dont do well with trickle low amperage charging. They seem to like a quick high amp charge better. If a battery is properly charged they sould give you several good years of service. http://batterystuff.com/ has alot of good info on battery maintence

i'm not the brightest on batteries, but my dad has a solar trickle charger on his deep cycle trolling motor battery and we hardly ever have to charge it, probably just twice a year and we use it often, so maybe look into a deep cycle battery such as one for a trolling motor.

If the battery is failing after 6 months then something is seriously wrong!

If we are talking about lifting the boat once a day, twice a weekend type of thing then I just can't imagin that the battery would be drawn down any significant amount. The battery you are using should do fine, last three to five years.

Like KG said, I suspect the solar charger, but I suspect that it might be over charging instead of under charging.

How big is the solar charger? If it bigger than 5 watts and is unregulated then that could be the problem. My suggestion is to add a solar charge controller, something like this:
http://www.affordable-solar.com/989.html

Do you check the water level in the battery often? A battery on a constant charge can boil away the water fairly quickly. You should keep a jug of distilled water on hand and make sure that the level never drops below the top of the plates.

If keeping the water level full is a problem then the Optima battery would be a good option. While they don't need to have water added they are rather sensitive to over charging so I would not leave one connected to solar charger without a controller.

Here's a little reading for you, batteries 101:

http://www.phrannie.org/battery.html

thanks for the suggestions. i'm learning more about batteries than i ever wanted to know but none the less pretty interesting. I'll let everyone know what the problem and solutions end up being. More thoughts and suggestions are welcome in meantime.