DIY Battery Packs with Multiple Taps - Charging

How about bringing out all the taps, and balancing your tests among suitable tap combinations?

You can only expect some balancing at a rate equivalent to the battery's self-discharge rate (which is very slow) Anything faster than that will damage the less discharged cells drying their electrolyte at second half of charging cycle. S.M.

GA

Why am I the first??????

The GA I gave for the comment is actually true for any battery chemistry, many do not understand it, ever, you appear to be one of them if I understand your comment, a "" as being critical of that comment!!!!

Every cell, no matter when or how manufactured is slightly different to the next one, even from the same production line, on the same day etc etc..

Batteries get replaced when only one cell (the weakest) is defective.

But if the battery could be used further, but at a lower voltage of course, the next weak cell would eventually collapse and so on........few can allow a battery to be used further once one cell is down.

Hi Andy. Forgot to sign. meant something like "I'd better keep my mouth shut"

Of course ther's always the Philosophical approach, like yours, asking questions. Hell, does everything have to be answered? S.M.

I misunderstood your smiley as negative, it could have gone each way. If you had posted as yourself, maybe I would have understood it better.......

At least with most of my comments, you would have a hard time misunderstanding them, but if someone does, I see it as my fault not theirs.......

Do please not lose sight of the fact that the post I GAed was accurate and correct as well......just you made a smiley comment that was cryptic to say the least!!!!

Have a good day Sado Masochistic?

Nah. Not a good idea at my age. S.M.

And I do believe it was a GA. I happen to believe it with many of my posts. Original?. (lol) S.M.

A very simple answer to your series of questions (perhaps oversimplification) is: The batteries, if not identical in discharge level, can only be recharged to their individual full level by either connecting them in parallel and charging them with a 6 volt charger or charge each battery individually with a 6 volt charger. Once the batteries have been each been brought up to full charge they can then be put back into a series configuration to provide the voltages that you select (multiples of 6 volts).

Connecting these batteries in series is the same arrangement used to put 6 individual cells (2 volts) in series to construct a 12 volt car battery. If one cell in this battery goes bad or has a less that full performance it effects the rest of the cells and thus the whole car battery. It is possible but not feasible to cut one cell out and replace it in a car battery but that is what is done in large industrial batteries such as used in fork lifts. The bad cell is removed, all other cells are brought up to full charge with a special charger and procedure, the new cell is installed and connected electrically and you have a reconditioned battery.

Good Luck, Old Salt

I would probably use 3 x 12 volt (quality, but cheaper) chargers (or better - 6 x 6 volt, one for each battery), each connected over 2 batteries. Both allow for using the battery set at the same time as its being charged.

Using a single 36 volt will work also, but as pointed out, elsewhere here, for good cell life you must make sure that no single cells are under or over charged. Difficult. But not impossible if proper care is taken with the design of loads and capacities etc. This must of course be done for any charging system used, but generally the fewer the chargers, the earlier a weak cell gets even weaker.....

As batteries are replaced as a unit, that makes the 6 volt chargers the best alternative, but probably not the cheapest.....

Probably it would be best to setup 3 separate (live!) test systems with 1 or 3 or 6 chargers and work out the costs of chargers, as against maintenance and replacement battery costs.......The study should be carried out over several years, sorry!

Best of luck.