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  #21  
Old 03-29-2013
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Re: Battery Bank – Parallel or Series

Scott,

No worries. The bottom line is that it's your boat, and you can do with it as you please -- ain't that a wonderful thing?
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  #22  
Old 03-29-2013
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Re: Battery Bank – Parallel or Series

Fin,

Probably too late for my boat anyway. My batteries are over 5 yrs old. If it does make a difference, the damage is already done.

Scott
Gemini Catamaran Split Decision
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  #23  
Old 03-29-2013
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Re: Battery Bank – Parallel or Series

Quote:
Originally Posted by NautiG View Post
Hmmm. I remain skeptical that the wiring of the leads makes much, if any difference in battery longevity or performance.

The Smartguage link provides a lot of numbers and a theory, but no calculations because "the calculation is incredibly difficult to do." This despite promising at the outset of the article that he will show us the "maths".

Mainsail provides some anecdotal evidence that battery life and performance will be degraded. However, after using the google machine to research "parallel battery bank wiring", I do not see a consensus that this is true, or that there is one correct way to wire the leads.

In fact, one of the links I found was to a rather lengthy cruiser forum discussion of the issue in which Mainsail was one of the participants. There didn't seem to be any consensus among the "experts" in that discussion. And the thread seemed in danger of devolving in to Solarstick territory.

I may switch up my wiring just because, why not? But I remain unconvinced that it would make any difference. If it really makes as much a difference as the Smartguage people insist, I think there would be more agreement that this is true, and some solid experimental evidence to back it up.

Scott
Gemini Catamaran Split Decision
Scott,

I've already done the "experimental evidence" my analyzers don't lie and are 100% impartial. I let them tell me how bad end connections are. Almost without fail, like 99% of the time, the first battery in an end connected string is in the worst shape and the last battery is in the best shape.

Connecting them up incorrectly results in intrabank imbalances. This does not happen over night but does happen over time. I see it & measure nearly daily in my job...

My analyzers are an Argus 500 and a Midtronics 1000HD AMP... They see and measure the differences that miswiring a parallel bank causes. This data repeats itself over, and over and over and over so probably not just luck..

It's always the "experts" who've not done the actual measurements in the real world who doubt the real world. I remember when we were told for 60+ years that a locked sailboat prop causes more drag...... No one believed the esteemed brains at MIT or The University of Strathclyde's Ocean Engineering departments who actually tested sailboat props. I then built a drag jig and made a "real world" video and the doubt seemingly stopped. Guess I need to start making videos of my analyzers measuring bank imbalances......

Apparently he did not just do the "maths"...

Quote:
Originally Posted by Smart Gauge
I have to be honest now and say that when I first did this calculation in about 1990 I completely refused to believe the results. The results seemed so exaggerated. So much so that I wired up a battery bank and did the experiment for real, taking real measurements. The calculations were indeed correct.
Also look in the technical manuals for just about any battery manufacturer and they will show how to properly connect their batteries.

I don't need the "maths" of Smart Gauge to see what my analyzers tell me...

But hey its your bank........
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  #24  
Old 03-29-2013
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Re: Battery Bank – Parallel or Series

Hey Maine,

I'm not saying I don't believe you, and I'll certainly wire my batteries up the way you suggest when my current batteries die, if only because it's just as easy as wiring up the "wrong" way.

I'm just an electrical layman, but I do like to see some evidence when someone makes an assertion. I'm not convinced by the evidence I've seen yet.

We argue seemingly nonstop on this forum about which is the best anchor, even when someone posts a video of their anchor "outperforming" other manufacturer's. Why should this be any different?

Scott
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Old 03-29-2013
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Re: Battery Bank – Parallel or Series

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Originally Posted by NautiG View Post
Hey Maine,

I'm not saying I don't believe you, and I'll certainly wire my batteries up the way you suggest when my current batteries die, if only because it's just as easy as wiring up the "wrong" way.

I'm just an electrical layman, but I do like to see some evidence when someone makes an assertion. I'm not convinced by the evidence I've seen yet.

We argue seemingly nonstop on this forum about which is the best anchor, even when someone posts a video of their anchor "outperforming" other manufacturer's. Why should this be any different?

Scott
Gemini Catamaran Split Decision

I am going to be uploading two videos I just made.

Bank One: Customers bank of 3 Duracell/Deka group 24 batteries. Bank approx 2 years old and was end connected. Batteries are way out of whack. Rated at 550CCA

Battery #1 = 490CCA (the end connected battery)
Battery #2 = 553CCA (the second battery)
Battery #3 = 649CCA (the last battery in the string)

159 CCA difference between battery 3 and battery one at just two years old.

Bank Two: My own bank of Wal*Mart MAAX-29/group 31 batteries. Entire bank cost me $210.00.... Bank is 7 years old and was always wired in a cross connected manner. Batteries are very well balanced for 7 years old. Rated at 675CCA.

Battery #1 = 818CCA (system positive connection)
Battery #2 = 845CCA (middle battery in string)
Battery #3 = 820CCA (system negative connection)

27 CCA difference between best battery and worst at SEVEN years old......

The videos take a while to upload.....
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Last edited by Maine Sail; 03-29-2013 at 06:23 PM.
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  #26  
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Re: Battery Bank – Parallel or Series

Main,

I'm cool with amps, watts, volts, resistance, amp/hours and a few other high school physics/basic electronics terminology. What is cca?

Scott
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Old 03-29-2013
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Re: Battery Bank – Parallel or Series

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Originally Posted by NautiG View Post
Main,

I'm cool with amps, watts, volts, resistance, amp/hours and a few other high school physics/basic electronics terminology. What is cca?

Scott
Gemini Catamaran Split Decision
The Midtronics analyzers display performance as CCA, MCA etc.. They are cold cranking amps (0F), MCA (32F). My other analyzer does the same but it can also show the batteries internal resistance.

It is a very complex algorithm and test procedure all done based on internal resistance. It can be fairly closely translated to useful life left in the battery. A battery that tests at 80% or less of "new" CCA rating is technically "dead" by industry standards.

Because many batteries ship at higher than their rating, a baseline needs to be done so all future tests are accurate based on "new". Some batteries ship at exactly their rating and others are as much as 100-300 CCA more than the rating.


Because many deep cycle batteries don't display a CCA or MCA rating I have tested many of them when new and keep a file.

Also when I buy batteries I buy them as closely matched as I can..

I also use them to track before and after performance of an equalization or two...



I even used them to do long term testing on "battery desulphators"... Should probably be called de-snake oil"......

"What do you mean my battery is dead? It's only a year old."
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  #28  
Old 03-30-2013
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Re: Battery Bank – Parallel or Series

Howdy,
Been great following this thread, has helped me make some decisions as well as aquiring a broader general knowledge and tips. Though I have a series parallel question, I recently aquired a set of used 6 6v t105's and was planning on running them in a single bank at 12v-675Ah, how should one distribute the varying grades of life/quality? Or does it matter as the system is effected by the lowest common denominator? I still need to fully test them all but was trying to do some research beforehand. Would something like breaking it into 2 banks or even 3 if there that far off eachother in a match work out to be more beneficial then using all of them in a single bank?


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  #29  
Old 03-31-2013
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Re: Battery Bank – Parallel or Series

Mixing battery ages isn't perfect but one bank is always more efficient than separate smaller banks.
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  #30  
Old 03-31-2013
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Re: Battery Bank – Parallel or Series

First thing I'd do would be to:

1. Charge them up fully...at least overnite on a charger;

2. Put them in one series/parallel bank and give them an equalizing charge -- 15.5-16.5 VDC for 4-6 hours (watch them carefully for loss of electrolyte and overheating);

3. Test the capacity of each battery individually, using a good resistance tester like the Midtronics series (beg, borrow or steal one for the 1/2 hour it would take to check all 6);

4. Throw out any bad ones, i.e., those testing less than 550-600 MCA; and

5. See what you've got left. Sometimes, free used batteries aren't such a bargain :-)

Bill

Last edited by btrayfors; 03-31-2013 at 02:33 PM.
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