Deka Marine batt vs Costco / results

Oct 9, 2008
1,742
Bristol 29.9 Dana Point
2 group 27 batts. Maintained. switch 1,2,both. Charles 20 amp dual bank.

The 5 year old (June 2011, bought when obtained the boat) Costco is toast. Won't stay above 12.1 v for more than 15 minutes. Although I keep sailing with it and it starts the motor easily after a 3 hour sail with instruments, VHF, AP, etc running. But it's on its way out.

The Deka, 7 years old (April 2009, already on the boat), still holds its volts.

The odd thing is that I heard that Deka made Costco batteries.

I figure about 160 sailing cycles, 80 each. Plus huge amounts of running them dockside while on the charger. But don't really know how much the Deka was used, as it was already on the boat when I got it.

Not a scientific test, but my real world results.
 
Sep 15, 2009
6,244
S2 9.2a Fairhope Al
is that costco battery a duracell brand or something (ever ready? ) else i think the duracell is made by deka (east penn) and the other brand is made by johnson control in mexico
 
May 24, 2004
7,213
CC 30 South Florida
It's pot luck. Some last 7+ years and others die within a month. That is the reason for the prorated battery warranty industry. It does help to properly use and maintain them but even so provides no guarantees for the length of service. If the Costco battery is faltering I would suggest you replace it now. If you run combined batteries at the switch the Costco could bring the other one down with it. If you run them isolated from each other you are running the chance of loosing redundancy. I mean I don't know how you use your boat but if you take multi-day trips I would replace it now.
 
Oct 9, 2008
1,742
Bristol 29.9 Dana Point
is that costco battery a duracell brand or something (ever ready? ) else i think the duracell is made by deka (east penn) and the other brand is made by johnson control in mexico
It just says "Kirkland" (Costco).
 
Last edited:
Oct 9, 2008
1,742
Bristol 29.9 Dana Point
It's pot luck. Some last 7+ years and others die within a month. That is the reason for the prorated battery warranty industry. It does help to properly use and maintain them but even so provides no guarantees for the length of service. If the Costco battery is faltering I would suggest you replace it now. If you run combined batteries at the switch the Costco could bring the other one down with it. If you run them isolated from each other you are running the chance of loosing redundancy. I mean I don't know how you use your boat but if you take multi-day trips I would replace it now.
Yep, replacing them both. Probably with Deka.
These were the results of their lives.

I run them isolated.
 

dhays

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Aug 2, 2010
93
Catalina C400 Gig Harbor, WA
The Costco 6v golf cart batteries that I installed this last fall were made by Interstate. FWIW