Ok... So I found a guy that went aboard and disconnected our 3 8d batteries and turned off charger. He fought me all the way and wanted to use his special meter to give me the CCA readings (1400 spec... readings were 1000, 900, and 250... yes, 250).
Preface: I am discussing house banks here and you've not made it very clear what you are doing with the batteries, how they are wired, which type of boat etc...
Keep in mind his "special meter", an impedance tester, can not tell you the Ah capacity. It just measures the impulse or cranking capacity. That said all your batteries are "dead" by industry standards. By industry standards a battery is deemed "dead" when it can no longer deliver 80% of its as new rating. If the as new spec was 1400CCA and you are at 1000 then even your best battery is on its last legs. Based on those readings and knowing how batteries test for Ah capacity vs. an impedance tester I can say without a doubt
all of those batteries should be replaced.
Are Impedance Testers Worth It?
Anyway, when I explained that I wanted to not have him install a new 8D battery and I wanted to replace them myself with deep cycle GC batteries as a house bank, He really got defensive and pressed me to just put another 8D back in there because of his many years of experience.
"
Many years of experience" only matters if you actually learned something from it. This guy apparently learned little, as it relates to batteries and boats....
They will last you another 5+ years and the boat was designed for 8D's and it is a cheaper fix.
Here is where it is sad how
under educated the marine market is on batteries. Firstly there is NO BOAT DESIGNED FOR X BATTERY. This is a complete line of BOVINE DUNG.... The builders fit 8D batteries because they are bough in bulk and require less labor to install because they drop them in with cranes. They also require
less complicated wiring for the very likely
under educated employees who apparently can't figure out simple series/parallel wiring. Production buiolders also choose to install 12V batteries because they worry about owners and law suits when teh owner also does not understand simple series or series parallel wiring. Custom builders install 6V batteries all the time, not so much for the big production shops. 4D & 8D's also
look impressive at boat shows to buyers who know even less than the builder does about
proper batteryselection for "cycling" applications.
8D batteries are NOT
cheaper batteries and the reality is they are MUCH MORE COSTLY when you do the
actual math.. Battery cost is factored by
cost per Ah when compared to
predicted cycle life. There are only a couple of companies making true deep cycle 8D's flooded batteries, Rolls/Surrette & Dyno Battery, and your batteries are NOT true deep cycle batteries.
Based on the 1400CCA spec I can almost guarantee they are an East Penn made 8D. The East Penn 8D closer to a starting battery than a deep cycle and is really a "dual purpose" battery not a deep cycle product. These really have NO PLACE being used in a
deep cycling application. Sure if you want to start massive Cat's on a 60' Buddy Davis sport fisher an 8D product is fine for that application, but it is simply a poor choice for a sailboat.
DEka/East Penn, Crown, Superior, Exide, Interstate etc. do not make an 8D deep cycle flooded battery no matter what the sticker says. If you see a sticker that says otherwise it is simply a lie, or as some might call it, "
marketing".......
What Is a Deep Cycle Battery?
Ok, fine. That may be true, BUT... While I may keep two 8Ds moving forward, I think it is smart to have at least one proper deep cycle bank.
There is NO NEED for any 8D batteries on-board your boat, IF IT IS A SAILBOAT. Your existing batteries, all of them, are at the end and all could be close to another internal failure or short which can be very, very dangerous.. Your engine should not need an 8D for cranking, unless it has a massive engine, and a proper house bank would be assembled with batteries purposely designed as
cycling batteries. 8D flooded batteries, unless made by Rolls or Dyno, are not deep cycle batteries.
While I am not up-to-speed on exactly how she is wired up yet and I may be replacing a starter battery with a deep cycle bank, I can fix that down the road. We plan to do some anchoring and feel I am right here.
You are exactly correct in wanting a proper deep cycle battery for a deep cycle application. The 6V US Battery US2200 XC2 can be had for about $120.00 each and two of them would be $240.00 for 232 Ah's and about 1000 lab rated cycles. The 8D will yield about 200Ah's have about 200-350 lab rated cycles and will cost about $230.00 to $400.00 but it is NOT a real deep cycle battery.. Even if we were to 100% ignore cycle life, the 8D flooded battery still costs more per Ah than what a pair of 6V batteries do.. This math is pretty simple $$$/Ah's. Add cycle life in and it becomes $$/Ah's = / lab cycle life (see link above). Heck you can even buy the Duracell EGC2, which is a 230Ah Deka/East Penn 6V at Sam's Club for $109.00 each....
So I want to use two 12V GC US Battery replacements (I am pretty sure they can fit in an 8D box) and need to buy them TOMORROW to go down Friday and fix the problem.
While you can use a US Battery 12V GC battery (155Ah Model # US 12V XC2) I would urge you to instead use two of their 6V batteries GC batteries, in series, for 12V (232Ah Model # US 2200 XC2). Two of them wired in series will easily fit in an 8D box, if you have the height..
Six volt golf car batteries are by far the most cost effective battery out there in terms of $$ to Ah's to cycle life. The 12V golf car battery has a much smaller market and thus is considerably more expensive than the 6V golf car battery. In terms of
cycle life a 12V golf car battery & 6V are the same, don't confuse a 12V
golf cart battery with a 12V group 24, 27 or 31 they are NOT the same in terms of cycle life.. The 6V GC2 golf car is by far and away your best value in a deep cycle battery for a boat, if you can fit the height.
Am I right? Is this a good plan going forward? Would just one larger 12V hold me as a stop-gap until I can build a new box to hold 4 or 5? Regardless of what that battery's job is, It's unlikely we will be venturing out of the slip until Spring... So I kinda have time.
Yes you are on the right track. If you just need a
stop gap get rid of the bad battery and continue to use the 1000CCA and 900CCA batteries until you have the time and funds to do this the right way. I would not spend money on new batteries if you plan to only do a partial refit now but I would get rid of the really bad battery and cross your fingers on the other two until spring. Just make one house and one start.
Bottom line you want a deep cycle house bank and a battery for starting that can handle the engine spec. The engine battery can be deep cycle if a sailboat or if a power boat a dual purpose or start.
