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

Smitty77
Explorer
Mar 26, 2018
Point taken that I should have included the link that referred to balance charging.

https://www.iotaengineering.com/pplib/balancedcharging.pdf

And even though I've had a few RV'er's tease me because I do a yearly cleaning of the AGM bolts and interconnects, I did so proudly. Always feel it is good to poke around doing routine maintenance, as it give you chance to spot small problems and resolve them before they become larger ones.

9" and 14" interconnect cables, so the same lengths for their duty. I did not make these cables, and with heat shrink on the connection points, not sure if they're soldered or not.

It was the best practice for charge attach points for a 4 battery setup that got my interest, as mine were not set up this way.

Best to all,
Smitty

Note: Hope to pick up the new Lifeline L16's either later today, or Tuesday. And then will do some measuring on any new cables I might need to attached in a balanced method.
theoldwizard1
Explorer II
Mar 26, 2018
MEXICOWANDERER wrote:
As the owner of 24, 2-volt cells I can tell you the "issue" is amplified at the ends of 12 cell strings.

Do you rotate the position of the cells in your battery string ?
MEXICOWANDERER
Explorer
Mar 26, 2018
Negative. Done correctly, I have less than .4 volt TOTAL DROP end to end at maximum load. The parallel bridge cables are done at one end the same end.

The batteries have "L" pad posts. I used a mill file to establish absolutely parallel full face conductivity. When mating surfaces are 100% contact, full load breakdown is minimal. I IR shoot the entire bank after 400+ amp recharging for >20 minutes.
red31
Explorer
Mar 26, 2018
Smitty77 wrote:
2oldman wrote:

Using 2oldman's image as an example.

The Charger attachment points are not shown.

charging 'points' are shown, they are the same as discharging 'points'.

why would one look at 4 batts in parallel when ya got 2 in parallel?
Almot
Explorer III
Mar 26, 2018
Forget Iota diagram. It is not your situation because it shows 4 batteries in parallel.

What you have is 4*6V batteries in series-parallel, you may consider it to be two 12V batteries in parallel.
Smitty77
Explorer
Mar 29, 2018
Almot wrote:
Forget Iota diagram. It is not your situation because it shows 4 batteries in parallel.

What you have is 4*6V batteries in series-parallel, you may consider it to be two 12V batteries in parallel.

Yes the diagram is not what I'm running with. But the concept of balanced charging would be the same(?).

As my interconnects were disconnected, I laid them out and measured, and the two longer runs were 3" difference. (Never knew that by just eyeballing the S curved cable while on top of the batteries:)!). I also looked over how the shop had single crimped the two cables they made, not impressed with the workmanship. So, with the new bank, I now have two short 12" and two long 15" cables coming from Genuinedealz. They shipped yesterday.

And another observation, is that with only X's 4 batteries in my bank, the connection points of the charge sources is fine. However, I believe (And could be wrong?) that if I had X's 6 or X's 8, etc. That then Iota diagram would come into play, with the charge points being the middle batteries of the bank.

For anyone who reads this thread in the future, please correct me if I'm wrong and 'balanced charging' only applies to parallel?

TIA, and best to all,
Smitty
red31
Explorer
Mar 29, 2018
IMO it is easier to see the balance this way!

http://www.smartgauge.co.uk/batt_con.html
Boon_Docker
Explorer III
Mar 29, 2018
^^
The diagram above will not work with GC-2 (6 volt) batteries.
red31
Explorer
Mar 29, 2018
^^ imagine what ya see as one 12v batt being 2 6v or 2 serial sets of 3 x 2v cells in series.
BFL13
Explorer II
Mar 29, 2018
Almot wrote:
Forget Iota diagram. It is not your situation because it shows 4 batteries in parallel.

What you have is 4*6V batteries in series-parallel, you may consider it to be two 12V batteries in parallel.

ISTR Mr Wiz likes to do four 6s the other way, with two pairs in parallel and then series the two "big 6s", but can't remember why he likes that.