MK Deep Cycle 12 Volt E27-SLD-G Backup Sump Pump Battery Review

Today we’re going to review the MK Deep Cycle 12 Volt E27-SLD-G backup sump battery. However, before we do, it’s worth quickly reviewing why you’d want one to begin with. To put it mildly, no sump pump is foolproof, and AC sump pumps, no mater how good, have one crucial dependence: alternating current (i.e., electricity).

Even if you’ve got the best sump pump on the market, it’s not going to pump an ounce of water if you lose power in the middle of a rain storm. And in our experience, this is when you’re most likely to lose power (especially if you have a finished basement and are out of town; it’s practically guaranteed at that point). As a result, you need a backup sump pump, whether DC-based or water-based.

The best DC sump pump is the Wayne WSM3300, while a cheaper but good alternative is the Wayne ESP25. However, whatever DC system you invest in will need–you guessed it–a DC power source (i.e., a battery). Just as not all batteries are equal when it comes to powering things as large as cars or as small as TV remotes, you also don’t want to take a gamble with a cheap sump pump backup battery; you’re literally putting everything in your basement at stake.

Fortunately, there are a number of good models out there that won’t cost an arm and a leg. Let’s look at the MK Deep Cycle 12 Volt E27-SLD-G backup sump battery and see how it works in a variety of DC backup sump pumps. If you’re ready to buy and just want to know if you can rely on it, then yes you can, and you can buy it here.

Key Features of the MK E27-SLD-G Battery (60 Second Summary)

The MK E27-SLD-G is a deep cycle battery suited for backup sump pump and marine applications. It has a nominal voltage of 12V and C/5, C/20, and C/100 capacities (e.g., the 5 hour, 20 hour, and 100 hour rates) of 72Ah, 88Ah, and 99Ah respectively. It weighs 63 pounds and is 12.83 inches long, 6.56 inches wide, and 9.3 inches tall including the size B (T876) terminals. It is self-sealing, rated as non-spillable, includes a lead calcium plate alloy and a sulfuric acid thixotropic gel electrolyte. The charge voltage at 77 degrees Fahrenheit spans 13.8-14.6 volts while the float voltage spans 13.4-14.6 volts. It is designed to be maintenance free (e.g., it does not require refills or level checks).

MK E27-SLD-G Compatibility with Various DC Backup and Combination Sump Pumps

We found the E27-SLD-G compatible with a range of DC backup and combination sump pumps. More generally, you can expect it to work with any device that needs a 12 volt power supply. So far, we’ve been able to confirm compatibility and functionality with the Wayne WSM3300,  Wayne ESP25, Wayne WSSM40V, Wayne ESP15, and Big Dog Basement Watchdog. We’ll continue to test it with a range of backup and combination sump pumps, but our notes from fellow plumbers and homeowners suggests it has a high range of compatibility with just about every current system on the market.

Our Short and Long Term Experiences Installing and Using the MK E27-SLD-G Battery

MK claims an average lifespan of 7-8 years with a general life expectancy of 5-10 years; in comparison, they state regular deep cycle batteries are designed to last for 3 years or less. We’d agree with both of their assessments; a cheap deep cycle battery will typically die and require replacement within 1-3 years. Buying such a battery is a poor investment of time and money. From comparing notes with fellow plumbers and homeowners, we’d rate the average lifespan of an E27-SLD-G as between 6 and 9 years, which fits nicely within their broader predictions.

MK E27-SLD-G Battery Pros, Cons, and Value Comparison

Overall, we’d rate the E27-SLD-G as a strong choice for DC backup and combination sump pump applications. It’s capable of delivering a good and consistent amount of power and we’re more than satisfied with its short and long term reliability. It’s not the cheapest deep cycle sump pump battery on the market, but we’ve been in business long enough to know that you’re not going to be patting yourself on the back for saving a hundred dollars when your sump pit is filling in the middle of a flash flood and your backup sump pump won’t start. Spend a bit more for quality gear that won’t let you down when you need it most. The E27-SLD-G is quality gear.

You can buy the MK E27-SLD-G battery here on Amazon. You can buy the Wayne WSM3300 DC smart sump pump here. You can buy the Wayne ESP25 DC sump pump here. You can buy the Wayne WSSM40V combination AC/DC sump pump system here.

If you find our work at PumpThatSump helpful, you can put our relentless reviewing of every pump and fixture on the market to the test by shopping via our links above for whatever you need to make your house a home. Despite being self-employed, we promise not to spend it all on health insurance.

How to Choose an AC or DC Main, Backup, or Combination Sump Pump: The Best Deals Under $200, $400, and $600

The best gear isn't cheap to buy, but it's much cheaper than cleaning up after lesser gear.
The best gear isn’t cheap to buy, but it’s much cheaper than cleaning up after lesser gear.

When installing sump pumps for homeowners, we’re often asked about insiders’ secrets or tips about sump pump selection and maintenance. People basically want to know how to keep their basements dry and spend as little time and money as possible on plumber house calls. We don’t blame them. However, we’ve noticed that the problem isn’t so much the advice we give as people not wanting to spend money on following it. We strongly advise against being penny wise and pound foolish. The time saved, peace of mind earned, and money needed to clean a flooded basement (and replace damaged furniture, electronics, and other treasures within) is far more costly than a few hundred dollars on pumps that will last for decades.

When it comes to the best AC sump pump on the market, we recommend the Zoeller M267 over and over again. However, an AC sump pump isn’t enough; we always recommend a backup, and the best dedicated DC backup sump pump is the Wayne WSM3300. For people who want both together, the best combination AC/DC-backup unit is the Wayne WSSM40V. Any of these units will cost you at least $300. We’d like to make things cheaper, and if you’re willing to compromise, there are good (but not great) versions below, but if you’re just looking for the best, you’ve just read it.

That said, lots of people try to skip steps and go with cheap gear, and they inevitably return to us with flooded basements wondering why they didn’t follow our advice to begin with. Unfortunately, we can’t turn back time. But if you follow our recommendations, we can help keep your basement dry and additional plumbers out of your home.

The Best High-End AC Sump Pump

Zoeller M267 – Review here. Buy here.

If you want a sump pump that will give you up to 20 years of worry free service, you’d be hard pressed to find one better than the Zoeller M267. We noted its longevity and water removal power in our review and have yet to find a better AC sump pump under the $400 mark. With a max flow rate of more than 7,600 gallons per hour, the ability to grind solids up to 2″ in diameter, and an estimated lifespan of 10-20 years, this is a sump pump you’ll be able to set and forget. We’ve yet to have a dissatisfied customer involving this sump pump, and the fact that it’s used in sewage applications with equal reliability is a testament to its construction.

The Best Sump Pumps Under $200: AC Units

  

Zoeller M63 – Review here.  Buy here.
Zoeller M57 – Review here. Buy here.
Wayne CDU1000 – Review here. Buy here.

If you don’t have $300 to spare on the Zoeller M267, the good news is that there are still several sump pumps out there that will give you good levels of water removal while lasting several years longer than anything you’re going to find in the big box stores. The Zoeller M63, Zoeller M57, and Wayne CDU1000 are powerful and reliable AC sump pumps that we’ve seen last through a variety of difficult conditions. The M63 and M57 are better choices for reliability, while the CDU1000 is a better choice if you need a much higher water removal rate.

The Best Sump Pumps Under $150: AC Units

  

Zoeller M53 – Review here. Buy here.
Wayne CDU980E – Review here. Buy here.
Wayne CDU800 – Review here. Buy here.

If $200 is still out of budget, you can still find a few decent sump pumps on the market that will do better than the budget offerings in the local Wal-Mart, Home Depot, Menards, and Lowe’s-type stores. The Zoeller M53 is the little sibling of the M63 and M57 profiled above, and offers similar levels of reliability at the expense of a slower water removal rate. The Wayne CDU980E and CDU800 clear water much more quickly, but aren’t quite as reliable in the long term, although both are still far better than box store options.

The Best DC-Only Backup Sump Pumps

 

Wayne WSM3300 – Review here. Buy here.
Wayne ESP25 – Review here. Buy here.

As we’ve noted above, having a DC backup to your AC sump pump is essential, no matter how reliable your AC system appears to be. The best DC-only backup sump pump we’ve found so far is the WSM3300. With the ability to call a range of numbers if it starts running or runs into problems, it’s the smartest DC sump pump on the market. If it’s out of budget, the ESP25 is a decent, if less intelligent substitute. The key factor is to have a backup so your basement doesn’t start to flood in the middle of a power outage (because no AC sump pump will be able to save you then).

The Best Combination AC/DC All-in-one Sump Pump

 

Wayne WSSM40V – Review here. Buy here.
Wayne WSS30V – Review here. Buy here.

If you don’t have a functional AC or DC sump pump, you can either buy them separately or you can look into a combined package. There are a lot of cheap combinations out there that tend to fail together when you need them most. Spend a bit more and consider either the Wayne WSSM40V or the WSS30V. The WSSM40V is the best combination AC/DC sump pump system on the market; it features the WSM3300 smart DC backup sump pump (which runs monthly self-tests and can call up to 5 numbers to report a range of problems before your basement starts taking on water). If it’s out of budget, the WSS30V is another good alternative. Both use the Wayne CDU800 as an AC sump pump base while the WSS30V uses the ESP25 as its DC base.

The Best Laundry / Sink / Drain Pump System

Zoeller 105 Package – Review here. Buy here.

Finally, if you’re looking for a good drain pump for your laundry tub, dishwasher, washing machine, basement sink, or any other system that involves low level water removal, we’d recommend steering clear of the cheapest pumps you can find and spending a bit more on the Zoeller 105 laundry pump package. The core pump is the Zoeller M53, which, as we’ve noted above, is one of the most reliable and affordable sump pumps on the market.

Remember: the goal shouldn’t be to spend as little money as possible, but to figure out which tools will a.) keep your basement dry for as long as possible while b.) keeping you or paid plumbers out of your sump pit for as long as possible. Your basic box store budget sump pump is always going to be cheaper than anything we recommend, but for us, it all comes down to prevention being cheaper (and less insanity-inducing) than the cure.

If you find our work at PumpThatSump helpful, you can put our relentless reviewing of every pump and fixture on the market to the test by shopping via our links above for whatever you need to make your house a home. Despite being self-employed, we promise not to spend it all on health insurance.

We share best practices in pump and fixture selection, installation, and maintenance for families and small business owners who want water (or worse) gone for good.