On Sep 13, 10:58*pm, wrote:
On Tue, 13 Sep 2011 17:10:21 -0700 (PDT), "





wrote:
On Sep 12, 9:39*pm, wrote:
On Mon, 12 Sep 2011 18:13:30 -0700 (PDT), Andy

wrote:
On Sep 12, 5:39 pm, Jack wrote:
Float chargers are attached to the 12v in the generator, and also to
two 12v that provide back-up for the sump-pump. *Neither of these
units is used every day; in fact, the sump-pump batteries have never
been used in seven yrs. *So, presumably, the chargers main function in
these applications is to keep the 12v from discharging due to lack of
use.

But beyond that, do chargers, theoretically, keep batteries ready and
able to run indefinitely? *Or will the cells eventually die of old age
despite the chargers, much like a well-preserved, fit old person: Bob
Hope, Geo. Burns, Jack LaLanne?

Andy comments:

* Float chargers, such as the one from Harbor Freight, do a pretty
good job of maintaining the charge, but that doesn't mean that
it can keep things going for long periods of time without checking.
Much like planting flowers --- they need to be weeded...
When working with chemical reactions over a wide temperature
range, there is no such thing as "hook it up and forget it "....

* *Every month, check the water level in each cell. Top them up with
distilled water if *is low. *Depending on the temperature variations,
the float charger can't compensate for every single variable, and
occasionally will feed in a little bit too much and boil off a little
water..... *I'm not aware of ANY device which will compensate
exactly for the changes that occur with the electrolyte which
require minor changes in the float voltage.....

* *I've used the Harbor Freight float charger for years, and easily
double
the battery life in my lawn tractor.... but it won't give the battery
immortality, and you have to check up on it......

* Remember, it is a FLOAT charger, not a BATTERY CHARGER....
A real charger, with a hydrometer, should be used to charge the
battery... Then the float charger is attached to compensate for
internal leakage..... A FLOAT CHARGER will not "charge up"
the battery by itself.... That is a mistake that many people
make. * If you use the Harbor Freight float charger, read the
manual.....

* * * * * * * * * * * * * * * * Andy in Eureka, Texas , P.E.

*What you guye REALLY want is a "battery maintainer" - not a float
charger. A float charger is NOT an intelligent device. A "battery
maintainer" is.- Hide quoted text -

- Show quoted text -

Says who? *In my world, the terms are interchangable.
Now a trickly charger, that will continue to deliver a slow
charge no matter if the battery is fully charged or not.
A float charger or "battery maintainer" will not.

* You don't live in the real world.

A "battery maintainer" may be a trickle charger - but a trickle
charger is not necessarily a "battery maintainer"


I never said a trickle charger is a battery maintainer. I said
the terms float charger and battery maintainer are one and
the same. A float charger senses when a battery reaches
full charge, then backs off and allows the voltage to lower.
It will start charging again when it senses that the battery
voltage has dropped below a certain point.

Here's an example:

Black & Decker Bm2b Smart Battery Charger 2 Amp Automatic Float Mode
$17 online

1 review The Black & Decker Smart 12-Volt Float Mode Maintainer
Battery Charger is a hand-held engine starter that can be run on
either alternating or direct current. It has reverse polarity
protection.



MOST "trickle chargers" are nothing more than a small center-tapped
transformer with a half wave rectifier that will put out up to 16
volts (at 125 volts, input, for instance - less at lower line
voltages) and is resistance limited to 2 amps output. Some of the
better ones have a regulated output - and will put out a maximum of
something like 14.6 *volts (might be a little less) regardless of
input voltage swings.

An intelligent battery maintainer usually runs in a pulsed mode -
checking the voltage of the battery between pulses, and adjusting the
voltage and duty cycle to keep the battery at full charge without the
possibility of over-charging. *There are other types of "intelligence"
as well - some better than others.

The "battery tender" is one example of a smart battery maintainer.- Hide quoted text -

- Show quoted text -

It's also an example of what the rest of the world
calls a float charger, just like the Black and Decker.

Here, from Wikipedia:

"Float charger
A float charger differs from a trickle charger in having circuitry to
prevent overcharging. It senses when the battery voltage is at the
appropriate float level and temporarily ceases charging; it maintains
the charge current at zero or a very minimal level until it senses
that the battery output voltage has fallen, and then resumes charging.
"