Customer reviews for Duracell Marine Deep Cycle Battery, Group Size 31 forGood choice to learn how to design a solar system.
I'm on year three with these batteries while running a part of my home electrical system. It is charged by 800 watts of solar panels. I chose these lead acid batteries for specific reasons: 1.) price; 2.) this was the first solar system that I designed, so I expected to have a learning curve; 3.) and, availability. First, let's be realistic; these are lead-acid batteries.If we were to design a lead/zinc battery that could mach the storage and cycles of lithium (or others), the cost would be astronomical. As it is, I calculated that the same storage capacity in lithium would cost five times or more as much as lead. All batteries have a life expectancy, and they all can meet a quick demise through human error. So we have a trade-off. The one-year warranty is a clue. However, the company must account for the people that strait-up ruin batteries. Most manufacturing defects should be found well before a year. And, I've used dozens of these batteries in other applications (cars, trucks, and tractors) and always get four year plus, but they do require maintenance. I have an applied science degree in controls technology. Before you build, design your system. My requirement was a system capable of running a flat screen with DVC (4 hours per day), a laptop (4 hours per day), one small refrigerator, and a microwave oven on high for 10 minutes a day. I got the appliance specs from the labels (the average refrigerator from google). The second specification was that the batteries could run the system for 48 hours from full charge down to no less than 70% with no sun. The last detail was that the maximum instantaneous draw would not exceed the 205 minute rating for the Duracell 31DCX. To match this, I then needed 31DCXs. With lead acid, battery maintenance is critical: Design your system to draw no more than 25 amps (300 Watts) per battery. Build in enough reserve. I have drawn mine below 90 percent no more than three times. A secondary problem is that lead-acid batteries a prone to sulfiding when left uncharged. Reference the following: % charge voltage 100 (full) 12.7 90 12.5 80 12.4 70 12.3 60 12.2 these can run a bit different in practice, mostly due to temperature. Again, many (most?) voltage controllers account for temperature. Some inverters shut down somewhere between 50 and 70 percent. It is best to put all batteries on line at the same time. Fully charge all batteries before hooking them up. Allow them to sit on slow charge for at least a day. Never hook up directly to a solar panel. Panels will put out way too much voltage. Use a voltage controller that has a flooded battery setting and a float setting. Note that these batteries are already filled, contrary to what some may state.Do not fill these to the top. assure the plates are covered. If you need to add to a new battery, do not use water. Use battery acid solution. Use distilled water to refill. With a controller, it is unlikely that you will need to fill often (I have never needed to add to mine). Have a de-sulfiding or battery conditioning charger on hand. Some charge controllers have this function built in. As I rarely run my system down below 90%, I can get by running a de-sulfiding protocol every 2 to 3 months. If you don't, your batteries will first begin charging and discharging quickly lowed by them not taking a full charge. They will appear dead. That being said, lithium batteries are worth considering. You still need to match them to your system. If you mess up, you've lost more money. However, they can also be more forgiving. For example, for the above system I would not run my refrigerator and microwave at the same time because it would be beyond my specifications, potentially reducing the life of the batter. Lithium is more resilient. I calculate that the cost of lead-acid starts to break even with lithium (and others) between 4 and 5 years. The lead option requires a lot more attention, but mine is a hobby.
Junk
These are terrible batteries. They come partially charged and very low on acid. I had to add a whole Qt of acid in it then put on charger. Let's see how long it lasts. I did not know about these batteries being low on acid. I have never had one of these batteries last more than 15 months. I suggest you load test your battery before your year of warranty is up and exchange it under warranty if questionable.
So Far, So Good
I purchased a pair of these batteries 3 years ago for my 24 volt trolling motor, which I use seasonally 6 months out of the year. The rest of the year the batteries are stored and disconnected from my onboard charger. As a previous reviewer commented, the batteries are a bit "thirsty" and need to be topped-off with distilled water periodically. I'm on my trolling motor almost continually, I recharge after every outing, and the batteries are always on my charger when not in use (with the exception of when they are stored for the 6 month off-season). I expected these deep cycles to last about 3 years, which they have. I'll be anxious to see if I can get a 4th . . . or maybe even a 5th out of them.
Stay away from this battery
I bought this battery April 14th of 2019. Mfg date was February of 2019. I used the battery for my trolling motor one time that summer. The rest of the time the battery kept on a maintainer until this year. My trolling motor showed full charge but no power. Had it tested at two auto parts store and was told it had dead cells. Sams club confirmed this but of course it has a 12 month replacement warranty. The same club person told me these batteries have a lot of this issue and not to purchase another one. Don’t waste your money on this trash. There is no savings buying from Sam’s for this size battery. Just get a reputable battery from somewhere else. If you are set on buying one make sure to get yourself a load tester and check it monthly to ensure if or when it goes down you know. Mine still shows a 12v charge but is gone.
Find Something Else
Remember when the name Duracell indicated quality and long life? Not anymore. I bought this battery in august of 2019 and the date of manufacture was July of 2019. Installed it in my backup sump with a battery maintainer. Now it is the end of October 2020 and it will no longer hold a charge, not low on charge, just zero electricity. Wrote Duracell and have not heard back from them. I get it was cheap but 15 months with never being used?????
NOT GOOD
BOUGHT BATTERY 6/23/18 FOR REPLACEMENT OF RV BATTERY THAT FAILED WORKED WELL FOR FIRST YEAR . IN BETWEEN USES STAYED ON BATTERY MAINTAINER , NOW DEAD AND WON'T CHARGE . I'LL TRY A DIFFERENT BRAND BATTERY FROM DIFFERENT COMPANY AND SEE IF I HAVE BETTER OUTCOME.
Terrible for trolling motors
I purchased these batteries about 2 years ago for my jon boat. I ran 2 of them together for my newer model 24v Minn kota trolling motor that has a digital maximizer. They performed great the first year then things started going down hill. Unfortunately they only lasted 2 seasons of bass fishing here in Pennsylvania. I took very good care of these batteries all things considered. I have a pro mariner onboard charger which conditions and charges the batteries that is plugged in 24/7. I also made sure to take the batteries out of the boat in October both years to sit in a temp controlled environment during the winter while still plugged in to the pro mariner conditioner/charger. I did everything by the book and these pieces of junk still didn’t last 2 seasons! And to boot, there were several days after being on the water for about 6 hours they were noticeably drained already and my trolling motor would lose power so I can’t say these are up to par with the claimed amp hour rating. I was just out this past weekend and was nearly stranded because the batteries are now absolutely toast and have no life left when it seemed like they did the previous trip. I’m very disappointed because the cheaper everstart group 29 deep cycles from Walmart perform better than these. I am talking specifically about the group 31 Duracell deep cycles in this review. Great price but poor quality. I have a group 24 Duracell deep cycle as my cranking battery that also runs a 12v tiller trolling motor for extra power and it has been working flawlessly for 3 years now. I would stay away from these group 31s choose another brand. For some reason it seems like the group 24 has way less issues.
12 month warrenty matches the 14 month life
Bought 3 hoping to get 3 years out of them. One will only charge if I blast is with a boost charger after I plug in the onboard charger. Then the other two will be completely charged and my failing batter will take another 100% proportionate amount of time to charge. Hate to replace the one assuming the other two are going to fail soon.
Working great in my RV
I replaced a group 24 battery that came with my RV. I had about 2.5 years on it but wanted a larger battery so we could dry camp without running the generator so much. This battery has been working great. I had to get a larger battery box and beef-up the battery holder to accommodate the heavier battery. I wish the battery was fresher, it's already 3 months old but it's all Sams had and I didn't want to wait for new stock. All cells had to be refilled with distilled water, they were low, but not critically. After that, I put it on a charger overnight, leaving the caps loose, and by morning it was at 13.7 volts. Good to go.
Keeps failing
I just don't understand. I purchased 3 of these a few years ago. Luckily I kept the receipts because all 3 failed around 10 months. The replacements failed around 10 months also. So I am on my 3rd set of these. They all didn't fail at the same time. But they were a couple of weeks apart. These are properly maintained used on a boat with onboard charger. I mean I guess I'll keep using them and getting free replacements every 10 months but it is just such a pain. If anything last longer than a year I will be replacing with something different for sure.