Recommendations Wanted - Poor Man's Group 27 Deep Cycle or Marine/Trolling Batteries

Robert Bills

Explorer
I currently have an ancient Wallyworld Everstart 27DC-6 12v marine battery in my Bantam trailer which is in need of replacement. The label claims 115 amp hours but I have never believed it. It is (more accurately, was) used to power my Engel 45 12v fridge and some lights. Occasionally the battery was used with a 12v air compressor to inflate air mattresses, etc. and once or twice was used with an inverter but for what I cannot remember.

I am acquiring a Renogy 100 watt suitcase style solar kit and am in search of a budget-conscious replacement battery to match up with that kit.

The 27DC-6 is listed on Walmart.com at $82 but shows "out of stock." I haven't bothered to look in my local store for inventory or to research whether these have been discontinued or superseded with something else because I am researching all currently available options before I go shopping.

I am limited to one battery, Group 27 size, because it is housed in one of these:




What are your collective suggestions as to cost-effective, budget-conscious Group 27 marine/trolling motor/deep cycle batteries rated at or near 100 amp hours?

Do Costco and/or Walmart currently have Group 27 deep cycle batteries worth looking at? If so, model number and price would be appreciated.

Other readily available brands? Links, model numbers, prices, good or bad warranties, etc.???

Thanks.

[Note: I know there are some great batteries in the $250 price range, but those are beyond my budget]
 

mikekey

Deplorable
I used a Costco deep cycle grp 27 12v battery for awhile before I did my lithium upgrade. They give you a pretty big credit if you bring the battery back to them to replace with the same battery. It's been a year but it was like $80 off at the time.
 

4x4junkie

Explorer
×2, Costco seems to be the best overall value in a deep-cycle battery. The battery itself is rather average, but for $80 for a #27 it's hard to beat (should last 4-5 years, or at least that's what I got out of a pair of identical Delco Voyager batteries I bought around 2009). They are made by Johnson Controls.

A little higher up the quality ladder (though a bit harder to find) is the Deka #DP27 Marine Master (and is what I have in my BII currently). These are USA-made (East Penn) and should be a little longer lived (at least I hope... Past East Penn deep-cycles I've had never lasted less than 8 years, I have one currently that's been in service since 2004).

With any of these batteries, I suggest popping off the vent caps and put a wrap or two of teflon pipe thread seal tape around each of the plugs and then reseat them onto the battery (without this, over time they tend to seep a small amount of acid out from under there since they don't have a real seal, it's just plastic against plastic). This should fully put a stop to the terminal (and tray) corrosion issues occasionally seen with these batteries.
 

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Elfmaze

Observer
I'm in the same boat. I am looking to replace my three year old Everstart group 31's. Hard to justify the $600 trojans when I can replace my Walmart/Costco batteries four times over.

If you are limited in form factor and already have a nice box to contain spillage just go with the cheap battery unless you have a high performance reason to switch.
 

Robert Bills

Explorer
Here is what I have found so far:

Costco

Interstate 27DC - $78.99
Costco Item# 850982
One Year Replacement Warranty
750 CA; 600 CCA; 160 Reserve [@ 25 amps - handwritten in counter book??]
No information regarding amp hours.

Walmart

Everstart 27DC - $81.67
Made by Johnson Controls
One Year Replacement Warranty
750 Marine Cranking Amps
Reserve 65 [???]
109 Ah @ 1 amp [???]


Between these two, I am inclined to pick the Costco Interstate. However, I would like to confirm the Ah for this battery to help determine how well it will match up with a 100 watt solar panel and will hold up to the draw of an Engel 45 12v fridge on days when the panel can't be used.

There is an Interstate group 27 marine battery on Interstate's website, model SRM-27 with a MSRP of $121.95, which shows identical CCA, CA and reserve capacity as the Costco Interstate 27DC #850982. The SRM-27 lists 96 Ah. However, I am hesitant to rely on this number because Costco is known to use their buying power to persuade manufacturers to reduce features/capabilities for "Costco only" items in order to reach a price point. Any thoughts on whether the Costco Interstate 27DC #850982 is actually rated at 96 Ah or some other number?

The Walmart specs seems suspect, i.e. reserve of "65" and "109 Ah @ 1 amp." Any comments on that?


Finally, does anyone have a suggestion as to any other readily available cost-conscious batteries I should consider?
 

4x4junkie

Explorer
Here is what I have found so far:

Costco

Interstate 27DC - $78.99
Costco Item# 850982
One Year Replacement Warranty
750 CA; 600 CCA; 160 Reserve [@ 25 amps - handwritten in counter book??]
No information regarding amp hours.

Walmart

Everstart 27DC - $81.67
Made by Johnson Controls
One Year Replacement Warranty
750 Marine Cranking Amps
Reserve 65 [???]
109 Ah @ 1 amp [???]


Between these two, I am inclined to pick the Costco Interstate. However, I would like to confirm the Ah for this battery to help determine how well it will match up with a 100 watt solar panel and will hold up to the draw of an Engel 45 12v fridge on days when the panel can't be used.

There is an Interstate group 27 marine battery on Interstate's website, model SRM-27 with a MSRP of $121.95, which shows identical CCA, CA and reserve capacity as the Costco Interstate 27DC #850982. The SRM-27 lists 96 Ah. However, I am hesitant to rely on this number because Costco is known to use their buying power to persuade manufacturers to reduce features/capabilities for "Costco only" items in order to reach a price point. Any thoughts on whether the Costco Interstate 27DC #850982 is actually rated at 96 Ah or some other number?

The Walmart specs seems suspect, i.e. reserve of "65" and "109 Ah @ 1 amp." Any comments on that?


Finally, does anyone have a suggestion as to any other readily available cost-conscious batteries I should consider?
The Costco/Interstate 27DC is 95 amp-hours. I did a bunch of research in-depth on them a couple years ago and determined they were identical in every way to the pair of Delco Voyagers (#M27MF) I was replacing at the time. The DV also is 95Ah and shares the same specs exactly. Costco is able to make deals on them due to volume.

That Walmart spec is definitely suspect.
Nearly all Ah ratings unless spec'ed otherwise are given at the @20-hour rate (how long it takes to discharge the battery from full to 0%, or to 10.5V).
On a ~100Ah battery, this discharge current will be in the neighborhood of 5 amps.

The greater the current draw, the less Ah the battery will deliver. Conversely, the lesser the draw, the greater it's Ah will be. This is known as the Peukert effect. By stating Ah at a measly 1-amp draw they're trying to make themselves look better than everyone else. Chances are it's a 85-95Ah battery like everyone else.
 

AndrewP

Explorer
Here is what I have found so far:

Costco

Interstate 27DC - $78.99
Costco Item# 850982
One Year Replacement Warranty
750 CA; 600 CCA; 160 Reserve [@ 25 amps - handwritten in counter book??]
No information regarding amp hours.

Walmart

Everstart 27DC - $81.67
Made by Johnson Controls
One Year Replacement Warranty
750 Marine Cranking Amps
Reserve 65 [???]
109 Ah @ 1 amp [???]


Between these two, I am inclined to pick the Costco Interstate. However, I would like to confirm the Ah for this battery to help determine how well it will match up with a 100 watt solar panel and will hold up to the draw of an Engel 45 12v fridge on days when the panel can't be used.

There is an Interstate group 27 marine battery on Interstate's website, model SRM-27 with a MSRP of $121.95, which shows identical CCA, CA and reserve capacity as the Costco Interstate 27DC #850982. The SRM-27 lists 96 Ah. However, I am hesitant to rely on this number because Costco is known to use their buying power to persuade manufacturers to reduce features/capabilities for "Costco only" items in order to reach a price point. Any thoughts on whether the Costco Interstate 27DC #850982 is actually rated at 96 Ah or some other number?

The Walmart specs seems suspect, i.e. reserve of "65" and "109 Ah @ 1 amp." Any comments on that?


Finally, does anyone have a suggestion as to any other readily available cost-conscious batteries I should consider?

I have run those Costco Group 27s for years. They work fine to run your fridge and are very cost effective. My oldest one in service was installed 4/2011 so that's 5 years, not too bad for a 1 year warranty battery. And it's still going strong and holds normal resting voltage.

I saw this battery recently, which would be a worthy contender in the cheap but good department. It's made by East Penn vs Johnson controls. I've not used it but plan to next battery change:

http://www.lowes.com/pd_599946-50656-DC27_0__?productId=50183763
 

Robert Bills

Explorer
. . . I saw this battery recently, which would be a worthy contender in the cheap but good department. It's made by East Penn vs Johnson controls. I've not used it but plan to next battery change:

http://www.lowes.com/pd_599946-50656-DC27_0__?productId=50183763
Thanks for the link to the Deka Marine Master DC27 at Lowe's. At $119.43 it is definitely a contender. The spec sheet for this battery shows 715 Marine Cranking Amps, 575 CCA, reserve capacity of 175 @ 25 amps, and a 20Ah rate of 90. It has the same 12 month warranty as the Costco and Wallyworld batteries.
 

Robert Bills

Explorer
Question to AndrewP:

Do you use a charger to maintain your Costco marine batteries when connected to shore power? What do you use? I am going to add a permanently mounted charger to my trailer such as a Battery Tender or something similar and am looking for suggestions for those as well as batteries
 

AndrewP

Explorer
Question to AndrewP:

Do you use a charger to maintain your Costco marine batteries when connected to shore power? What do you use? I am going to add a permanently mounted charger to my trailer such as a Battery Tender or something similar and am looking for suggestions for those as well as batteries
I use a BatteryMinder. Don't know if it's better than anything else, but it works perfectly and I keep all 3 trucks and 6 batteries on it.
 

Steve_P

Member
You can generally figure that Amp Houra @ 20 hour rate is slightly more than half of Reserve capacity @ 25 amps. There are formulas on the net if you want to get specific.
 

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Photobug

Active member
You can generally figure that Amp Houra @ 20 hour rate is slightly more than half of Reserve capacity @ 25 amps. There are formulas on the net if you want to get specific.

I did the same research and found you can estimate AH rating divide by "Reserve Capacity by two and add 16, divide by two and one calculation did the math and came up with 41% of reserve capacity. One thing to consider is for best life of a deep cycle battery you should only be taking it down to 50% before recharging. So at 160 R.C. using 50% you have a AH rating of 80 using the divide by two formula, you get 40ah of useable power out of one group 27.

I have been using costco batteries with success but have added two to my capacity.
 
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