OPTIMA® Batteries High Performance D31M BLUETOP® Dual Purpose Deep Cycle and Starting Sealed AGM Boat and RV Battery, 900 CCA, Dual Terminal, Maintenance Free, Versatile Mounting

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.

I originally purchased these batteries 5 years ago for my old 5th wheel. I stored the rv at a campground in Arizona for 6 months and forgot and left the ceiling fan on. Of course the batteries eventually ran out of juice and were in a constant discharge for the whole time. When I returned, I put the rv on shore power and charged the batteries. I kept them in use for 2 more years for dry camping and solar charging, then transferred them to my new truck camper, where to this day, they are storing power from my solar panels and are still working as they should. They have been in service for a total of 5+ years so far. I have never been able to get regular plate batteries to last more than 3 years, definitely worth the difference in price if you need reliable power storage.

I bought this in September 2016. I went fishing in Dec 2017 and my battery was completely dead. It would not take a charge, and Amazon technical support for the battery would not help me and sent me to contact Optima directly. Optima refused to help me since I bought it on Amazon. I didn't get any support and a dead battery. I finally got it to take a charge after three days of recharging. Now it will take a charge; but, it will drain from 100% to 25% just sitting for one week. It's terrible. When I go out fully charged, it drops to 25% after about 3 hours of trolling. It lasted all day when it was new. I expected it to last all day. I certainly don't need a four-hour battery for my fishing trips. Without a dought, this is the worst battery support I have ever had to deal with, and it's the worst battery that I have ever purchased. I have been buying batteries for more than 40 years. I never had this problem with other brands. I even purchased their expensive charger, which did not help one bit. Do yourself a favor and buy something else somewhere else. There is no support for this product on Amazon and the product died in only 1 1/2 years.

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

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 love Optima batteries. They last long and hold a charge all winter. I got 8 years out of my last D34M. This year decided to replace with the D31M as I am upgrading my electronics so wanted more capacity with the higher current draw. NO HANDLE - My biggest disappointment is there is no handle on this battery. It weighs 60 pounds and I have to lower it into my battery compartment without the benefit of a handle, putting strain on hands and back. It slipped out of my hands and dropped as I was putting it in, fortunately nothing was broken. Now any time I need to remove the battery to get to my bilge pump I can look forward to dealing with this issue every time MINIMAL HARDWARE - The battery comes with only two nuts and no split-lock washers. I also purchased two LiFEPO4 batteries from Lossigy. They not only included a handle and hardware with split-lock washers, but included an extra set of hardware, plus they included two very thick gauge battery cables. This is a high-quality battery. For $430 you would think Optima could include a handle and plenty of hardware. Whoever it was at Optima that decided to save a few bucks in cost made a poor decision.

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