In any piece of wire, there is some resistance. Itís usually very small, on the order of milliohms. This causes a tiny voltage drop when you charge or discharge a battery.
The reason for the wiring directions you quoted is to equalize this tiny voltage drop so the individual batteries see essentially the same voltage. This is done in an attempt to keep the exact same voltage, same current through each set of cells, and hopefully the same state of charge on both batteries in a parallel setup. Over time, a tiny voltage difference between two batteries in parallel can cause imbalance issues. This hookup attempts to minimize the problems, and is simply a ďgood engineering practiceĒ.
That said, Iím an advocate of using honking big 6 volt golf cart-sized flooded batteries in series, and that way Iím effectively only dealing with ONE battery.
Rich, KE4GNK/AE, Overkill Engineering Dept.
'The Silver HamShack' ('07 International 22FB CCD 75th Anniversary)
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