OPTIMA® Batteries D31M BLUETOP® Boat and RV Dual Purpose Sealed AGM Battery

These batteries are Often advertised as maintenance free; But they DO Require a VERY MINIMUM Amount of Maintenance to keep 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 reviews on 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; before being recharged again. For these BLUE-TOP Optima Batteries State of charge is as follows: 100% = 13.18 volts 75% = 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-volts and 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 either 1.) 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

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.

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. Sincerely UGWU$4

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.

I purchased three of these very expensive batteries for use as my Chassis Battery Bank in my 40 foot Alfa SeeYa RV. They fit, provide the power and appear to be very well made. If they prove to be as good as they are touted, I will be looking into more of these for my two other onboard battery systems, House and Inverter banks. We will see how the first three perform. I will continue to report back over time and let you know how it goes. Optima also has a great customer service and was very helpful in my planning process and purchase. In addition, I also purchased the Optima D1200 Battery Charger and Performance Maintainer for keeping the batteries properly charged and maintained while in storage, a key to extending the life of any battery system.

Not the same quality since moving to the new factory. Better options out there

These are the best batteries on the market. I have four of them in my bass boat, three for the 36volt troll motor and one for the starter/house battery. I just replaced the first set after six years of use. This boat travels long distances and fishes many tournaments and fun fishing days. My Champion boat has a four bank professional level charger that gets plugged in as soon as possible. I can't over estimate the importance of using the right charger and using it correctly. These batteries have outlasted all the others I've tried over the years - three times longer than flooded cells. They have outlasted other glass mat types/brands by a year or two. I also outfitted my big offshore boat with eight of these - it's quite an investment but in the long run it's way cheaper and more reliable.

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.

I have been using Optima batteries for years in automotive, industrial, and marine applications. When it comes to lead acid/AGM, nothing can compare. I had two red tops in my 2003 Dodge diesel that were 13 years old before I had to replace them!

Great product but I didn’t notice they could not be returned. My mistake for not reading the fine print.