As I've recently started a campaign returning to basics on the care and feeding of my soon to be replaces X's 4 L16's - I have a follow up question.I've confirmed proper wiring to yield parallel/series, with appropriate and good quality cables. It was the placement of the Magnum Charger and MidNite Controller charge cable feeds that does not match my research on obtaining balanced charging. Iota has a nice (Diagrams, makes it easy for a back to basics sanity check!) write up on balanced vs non balanced charging. My current Magnum and MidNite charge feeds are in a 'non balanced' method. However, when I was getting help here and elsewhere on trying to save my battery bank. I took several multi meter voltage readings of the full bank, and the four individual batteries. And noted. less then a tenth variances in the voltage.Iota does talk about Amps vs Voltage in their diagrams. So please forgive this question. Does practically balanced voltage at each battery while under charge, equate to balanced amps too?With a bank of 4 6V batteries vs say 6, 8, etc. - what is the recommended 'Best Practices' for obtaining balanced charging?TIA, and best to all,SmittyPS: OK to say reading too much into this, and not to worry about it...

Maybe I don't understand the question, but if I do, don't worry about it. The minor differences you'll experience in charging won't make hardly any difference while discharging over the long life of the batteries. Seven to 14 years if you do maintenance regularly.You're only talking about a +/- 0.1 volt difference in readings from one battery to another anyway and that's within the tolerance of the meter. (Typically given as +/- 1 least significant digit). If your meter is typical, and you've set it on the 20 Volt scale, readings of 12.4 to 12.6 are reasonable where a precision meter would read 12.5. Noise makes a difference in readings too so if you want an accurate battery voltage measurement, you'll want the charger to be off, wait an hour for the surface charge to dissipate from the phantom loads most RVs have, and than disconnect all the batteries before measuring. Not much fun, not very practical, so most people shrug and don't bother with it. And of course, there's the practical aspect of balanced charging. It's a method more suited to many cells in series and is usually used with Lithium batteries, not a series/parallel wet cell setup. So though Iota does a good job with their diagrams, they never really mention that, or mention that it's probably not possible to have perfect balance. Is it practical (or even possible) to get your setup wired in such a way as to have perfect balance on every cell in every 6V battery? I doubt it. Maybe in the short term, but a month or three down the road, differences will creep in.

It can make more of a difference than you might think.http://smartgauge.co.uk/batt_con.htmlMost folks only worry about it if they will be using high amps wrt bank AH capacity. Low amps give more time for the batteries to adjust among themselves.

Use excellent soldered cables then measure to the millvolt voltage at the LEAD POST of each battery at point of MAXIMUM INTENSITY highest amperes of charge. This way there is no guesswork, no asssssssssssumptions.

Balanced wiring - see the diagram in 2oldman post (also British article, it's a classic).Balanced wiring is important not only for "charging" but for "discharging" as well. More important at high amps, less - at low amps.The bottom-line is, when it's not more difficult to wire balanced, there is no reason to wire un-balanced :)

Balanced Charging X's 4 6V Batteries | Good Sam Community

pnichols
Explorer II
Mar 29, 2018
Boon Docker wrote:
The diagram above will not work with GC-2 (6 volt) batteries.

I believe that you're referring to the two diagrams that "red31" posted above your earlier post.

The left diagram above your earlier post represents four (4) 12 volt batteries connected in parallel in a balanced way.

The right diagram above your earlier post represents eight (8) 6 volt batteries connected in series-parallel to makeup four (4) "12 volt batteries" connected in parallel in a balanced way. (Notice the little black line at an angle in each black outline box - that outline box represents a couple of 6 volt batteries interconnected in series.)

Connecting batteries together in a "balanced way" is not Rocket Science. All it means is that the total wire length (regardless of what wire size is used) going all the way around the loop from each battery's plus terminal to it's minus terminal is the same length for each battery. With a balanced setup, this "same loop length" for each battery will be the identical for every battery whether the battery bank is being discharged while feeding the RV's total electrical load or being charged while being fed by the RV's charging equipment.

The object is for all battery system cabling voltage drops (regardless of cabling gage size used) from currents going to/from each battery to be the same - as seen by each battery.

Balancing the battery bank this way is of course external balancing ... and does not ensure that internal battery construction and chemistry maintains balance at all times internally between the cells within each battery during the life of the battery.
Boon_Docker
Explorer III
Mar 29, 2018
"I believe that you're referring to the two diagrams that "red31" posted above your earlier post."

Yes, the first diagram (on the left) before the edit.
MEXICOWANDERER
Explorer
Mar 29, 2018
The FREE Lifeline battery PDF download has pages of correctly assembled series and paralleled batteries. More batteries and more series configurations than you can imagine.

The connection diagram is valid for all types of batteries not just AGM.
theoldwizard1
Explorer II
Mar 30, 2018
MEXICOWANDERER wrote:
I IR shoot the entire bank after 400+ amp recharging for >20 minutes.

At that rate, any misalignment between the face of the terminal and the battery cable end will WELD the dissimilar metals together ! :B
MEXICOWANDERER
Explorer
Mar 31, 2018
It is unforgiving -- utterly.

Taking a mill file to a battery "L-Pad" then to a terminal, to insure both a absolutely flat made a significant difference in terminal to L-Pad interface temperature. Getting the mounting pad flat on the Trace 4024 was challenging. They were concave. A use friend loaned me a mill cutter with a 1/2" arbol hole and will no small amount of effort I dressed the pads.

A vise, a large mill file or bast(a)rd if the surface is rough can really flatten the irregularities on a lug.

9,000 watts is a lot of energy...

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