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post #23 of Old 03-29-2013
Maine Sail
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Re: Battery Bank Parallel or Series

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.

Gemini Catamaran Split Decision

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"...

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........

-Maine Sail / CS-36T

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