Boat Lift Battery

[Canterbury]

Hi Everyone,

A battery question for those with a boat lift. Not looking for a mfg recommendation per se, but your experience and how yours is setup.

I have a Sunstream with a 12V battery to operate. Recharge with a 100W solar panel that gets direct summer sun for probably 4 hours in the morning and then varying levels thereafter. The lift is only used maybe 5 or 6 times per month though could be several times in a day. In winter, battery is placed on a trickle charger.

The battery is a Duralast deep cycle and was replaced 2 years ago. I dont have the specifics but a Group 27 rings a bell. Went to use the lift this weekend and the pump was acting all kinds of funny, strange noises, wouldnt work at all to lift, only to lower. Charged the battery and still wouldnt do anything. Took one of the batteries out of the Cobalt and instantly worked, though this was a "starting" battery vs the deep cycle.

QUESTIONS:
- Mfg says a Deep Cycle is the recommended battery, but only 2 years out of a new one?
- Why wouldnt a starting battery be a better option? I have 2 starting batteries in the Cobalt, one was new this summer and the other is 7 years old. Switch back and forth to keep fresh and play tunes at the sand bar.
- Ideas?

Thank you kindly.

[jhnmdahl]

I'm curious what happens if you take the original lift battery and put it on a charger for a day. It sounds like you've got the right setup, and the battery should be fine.

[bruceb58]

A starter battery is designed to start the boat with maximum current capability but is not as good if the battery is more deeply discharged than that.

Personally, I would buy a lithium battery for a boat lift. It will probably last you the rest of your life in a boat lift. How much current does the lift draw when operating?

[Canterbury]

Thanks for the replys. The lift is the Legacy 6,000 capable and I cant find the current draw. The Lithium battery would be nice but about $ 1,000, YIKES. I was thinking an AGM battery but have to do some research on the compatibility with the solar panel and charging rates. I saw that the AGM's have specific requirements.

[jhnmdahl]

In the FAQ on the SunLift Legacy page, they say that a group 27 deep cycle battery is typically expected to last 2-3 seasons. Sounds like this may not be atypical, despite feeling like it didn't last long. Could always see if you can find a group 31 battery to replace it with and hope to extend it one more year...

[bruceb58]

Thanks for the replys. The lift is the Legacy 6,000 capable and I cant find the current draw. The Lithium battery would be nice but about $ 1,000, YIKES. I was thinking an AGM battery but have to do some research on the compatibility with the solar panel and charging rates. I saw that the AGM's have specific requirements.

Why do you think a lithium battery would cost $1000.

[Canterbury]

Did a quick search for a Group 27 AGM battery and this was in the $ 300 range vs $ 125 for the Lead Acid. One of the pop-ups showed a lithium for $950 or so. I just did another quick search and Bass Pro Shops had a Lithium for $ 600.

[bruceb58]

https://www.litime.com/collections/12v-batteries

Buy one of the 100AH ones.

In particular, this one because it has bluetooth and cold weather protection. You may need a different charger or solar charger but they are inexpensive.

https://www.litime.com/products/12v-100 ... 8342387932