OPTIMABatteries High Performance D31M BlueTop Dual Purpose Deep Cycle and Starting Sealed AGM Boat and RV Battery, 900 CCA, Dual Terminal, Maintenance Free, Versitile Mounting

I purchased two of these batteries for my boat - one in early 2009 and the other in late 2010. I alternate using these batteries for starting the boat. I also use them for my down riggers when salmon fishing and trolling with a 9.9 HP kicker motor. After over 14 years, both batteries still start the boat with no issue. Plus, I can fish for at least four hours on one battery & still start the boat on that battery. Before I started using these two Optima batteries, a pair group 27 name brand non-AGM batteries only lasted 3 years.

These batteries are Often advertised as maintenance free;But they DO Require a VERY MINIMUM Amount of Maintenance tokeep them up to Snuff; for when the Boat (or) RV Usage season returns each year.Optima are Great Batteries;I have a feeling that most of the people giving bad reviewson this battery Do Not have an understanding of the design of 12-volt batteries.most 12-volt batteries are NEVER EVER Suppose to go under 50% charge; beforebeing recharged again.For these BLUE-TOP Optima BatteriesState of charge is as follows:100% = 13.18 volts75% = 12.69 volts ( down to 75 percent they may be recharged 750 times)50% = 12.28 volts ( down to 50 percent they may be recharged 600 times)Lastly THESE Particular 12-volt batteries are NEVER EVER suppose to go under 12.00-voltsand WHEN (and) if these Blue Top Batteries ever go down to 11.72-volts they MAY ONLY last for 450 or less charging cycles.THAT IS WHY:During the OFF-Season when these batteries are NOT Being used; they either1.) Need to be charged at the least 2 times over the winter with either Battery Tender Charger Part No. 021-0128 (or)2.) Or put the 15-watt battery tender solar panel with built-in charge controller on these batteries. which is Battery Tender Part No: 021-1165

Good battery, but Amazon doesn't know how to ship these!I purchased two of these batteries from Amazon, but they ended up shipping me a total of five due to shipping damage caused by inadequate shipping materials. This 60lb battery was typically shipped with zero protection, just the cardboard box. The 'large plastic bubbles' you see in lots of Amazon packages was used once, but not surprisingly, they popped and were deflated by the time the battery arrived. Brown paper was used a couple times...it was flattened easily and offered zero protection. Twice, styrofoam end caps were used (only one piece per box), though it was a styrofoam piece designed for a smaller battery...this worked enough for me to accept the products at least. Of the five shipments, the three 'rejects' had cracked plastic at the bottom of the cells...the first, I didn't notice until charging and a little acid leaked out. Once I knew what to look for, it was easy to spot. Amazon was very cooperative with the returns, but it was such a waste to see three of these batteries head straight to recycling when a little care and intelligence could have prevented that.If you're feeling lucky and you order one of these, be sure to check the plastic very carefully for cracks (it'll be easy to spot if you're looking for it)! Pay special attention to the plastic at the bottom of each cell.

Purchased 09/16/2022, NEW, to replace an old Dual Marine NON-AGM Battery that was 6yrs old. Did hours of reading and research and reviews before we made the decision to purchase this Blue Top AGM Battery from Optima. We weren't able to get the boat in the water in 2023 due to my FNL having medical issues, so we kept it on a battery tender and then April of 2024 we put in the boat, 2012 Hurricane SunSport 202 w/Evinrude E-Tec 200HP OB and it ran great all spring and Summer. We pull the boat out approximately 4 weeks ago and noticed battery was week and it says it has a dead cell and won't charge completely. Will not purchase another battery from Optima and will go back to a traditional marine battery with much greater life expectancy. Spending more money for what would seem to be the "best" AGM battery for our application turned out to not be the case. Thanks, Optima, for a subpar performing product.SincerelyUGWU$4

Optima batteries are one of the best on the market. I am very impressed by their longevity and high power delivery. I have had a yellow top Optima in my 4wd truck for 9 years now and it is as strong as the day I installed it. Other great features of Optima batteries are the facts that you never have to add water, they can be mounted in most any position and the terminals never corrode.This purchase was a second blue top D31M. I use two of these batteries in parallel to power a 2000 watt inverter. I tested it by placing a 1500 watt load on the inverter which drew 137.5 amps from the two batteries in parallel. They were able to sustain this load for 27 minutes. That is like cranking a 6 cylinder engine for half an hour. I previously used marine deep-cycle flooded-cell batteries for my inverter but they would only last about two years and I constantly had to check and add water as well as clean corrosion from the terminals. The bottom line is even though you pay more initially to buy an Optima battery the long life and power delivery quality actually make it cheaper than other batteries when you divide the cost by the number of years of service.

The battery was @75% when it arrived. It did charge to 100% and I’ve cycled it a couple of times now so it’s working as advertised. I have every reason to believe it’s going to be good. If I did it again though, I would buy locally. Why? Box was damaged, battery was missing a post cap and there was no other packaging. The battery appears new but packaging indicated it had been opened. Also, how would I get warranty?

This thing is huge. Works so amazingly good a bought another one. That one is red, and started my car with bad alternator like it was nothing.