wrote:
On Thu, 19 Aug 2010 11:32:44 -0500, bud--
wrote:

wrote:
On Tue, 17 Aug 2010 21:42:58 -0400, "Stormin Mormon"
wrote:

Well, lets see. Now, lets look at the "irrelevant" factors, during a
series charge as you seem to prefer.

We start charging. About an hour later, the battery #4 in the line is
fully charged. We continue to pump in the two amp charge.

Hour two. Battery #3 is now fully charge. Battery #4 has been over
charged for the last hour, and is losing water as it electrolyzes to
hydrogen and oxygen.

Hour three. Battery #2 is fully charged. Battery #3 is rapidly losing
water. Battery #4 is nearly dry. Candidly, I think you are mistaken.
You forget, series charging of a string of batteries is NOT constant
current.
If you have a series string of batteries the current through each
battery is not the same - constant current? Please explain.

It is constant voltage - and the current looks after itself.
And I am NOT mistaken. I worked in the automotive field for many
years, and the batteries in the warehouse were allways recharged every
couple of months with the old Tungar battery charger - which was set
to the proper VOLTAGE for the series string, and after several days of
charging all the batteries were fully charged, and evenly charged. If
someone miscalculated and set the voltage too high, they were all hot
and gassing.
Charging a set of batteries in series, like a golf cart, you want all
the batteries to be the essentially the same - type, amp-hour capacity,
aging effects. And they should be used as a series string so their state
of charge (as they are used) is about the same for each battery. In an
old battery string you shouldn't replace one of the batteries.

Charging over several days is closer to a float charge.

If you charge at significant current you can get what Stormin nicely
describes. Why do you think what Stormin describes won't happen.

Generally we recharged at 2.3 volts per cell for a day or two, then
2.4 volts for another hour to 3 hours, depending on temperature etc.
Hydrometer testing of one or two batteries in the string told when the
batteries were fully charged - or simply checking to see that all the
cells in a battery were gently and evenly bubbling.
You probably have batteries that are close to fully charged when you
start and what you were doing was closer to a float charge.

If you have a few amps to very different batteries or very different
state of charge Stornin has a good description of what will happen.

Evenly bubbling in a series string is an "equalization" charge and is
occasionally done in a series string like a UPS.

If you charge in parallel and one battery is partly shorted (Low
resistance) it hogs all the power and overheats, while the rest of the
batteries get virtually nothing - and if the charge is not high enough
for that scenario, the bad battery drains all the good ones.
Partly shorted is a red herring.

You can charge normal batteries in parallel. You are OK if it is at a
float charge level (which is close to what you were doing). For a higher
voltage (producing a significant charge current) for a timed period, if
the state of charge is different or amp hour capacity is different you
may lose water in some of the batteries (same as leaving a battery on a
charger too long). It is a little safer than series in that batteries
that are more discharged will have a higher charge current. In a series
string the currents are all the same.

If you want an "authorative" answer look at
http://www.batteryuniversity.com/partone-24.htm.
About half way down the first section it discusses series and parallel
connections - And a series connection with a failed cell has reduced
power - or it quits.
A parallel cell with a bad cell has reduced power or it overheats -
and possibly burns.

So what is the point?

There are limitations on both series and parallel setups. Life is a
series of tradeoffs.

--
bud--