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Old 06-08-2015, 08:31 PM   #11
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Originally Posted by rgreenwell8962 View Post
I currently have 3 sets of 6v batteries in series wired in parallel. The specs on the Deka Promaster GC25 are:
488 Min @25Amps, 132 Min @75Amps, 235Ah @20Amps, 67 Lbs
20AH capacity: 235
5AH capacity: 188

So with three sets of these wired in parallel, what exactly does that mean I am getting for the 350 pounds of batteries I am carrying? What I am getting at is, should I replace these with a different kind of 12v battery setup that will weigh less but give me comparable results? During the winter ski season, I will be utilizing only the battery bank and genset for 2-3 days and nights running the propane heater (with electrically driven fan) interior lights, electric head, water pump, microwave, tv, dvd, stereo....... you know, the usual stuff to make "camping" as glorious and as comfortable as possible.

Again, my main concern here is weight. I do not want to compromise quality and quantity I get from the batteries but weight is a bigger concern in my motorhome than it is is my boat.

Thanks for the input!

Rich
In the same type of battery (AGM, Wet, etc.) it is all about plate capacity, so two 6V batteries in series will provide the same number of 12V amp hours as two similar size/weight (and type) 12V batteries in parallel. Li is higher energy density than AGM, which in turn is higher than Wet, so if you are trying to save weight, the more exotic batteries might be your choice, but at a premium price.

Also, the other benefit of the 6V series/parallel setup vs all 12V in parallel is that it minimizes the number of parallel connections to the common points (+ and -), which aids in keeping the bank balanced. Eight 6V batteries will have four parallel connections to each bank + and -, while eight 12V batteries will have eight connections to each. The connections should also be "homeruned" instead of daisy chained to minimize preferrential discharging.
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Old 06-08-2015, 11:05 PM   #12
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CaptJerry welcome aboard

Thanks for your input, being that this is a 2 year old thread the OP has probably already made a decision. None the less your input will be helpful to others.
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Old 06-09-2015, 02:30 AM   #13
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I recognize that, but as a real Capt with a real MSEE, I thought some basic physics might contribute to the discussion for future inquiries.
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Old 06-09-2015, 02:37 AM   #14
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I recognize that, but as a real Capt with a real MSEE, I thought some basic physics might contribute to the discussion for future inquiries.

Which is why I said you input will be helpful to others
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Old 06-09-2015, 03:02 AM   #15
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And yet you were compelled to point it out.
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Old 06-09-2015, 10:57 PM   #16
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Ooh!!!! A REAL captain! And yet so humble and professional!
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