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From: John De Armond
Subject: Re: Battery - Red Eye Remains
Date: Sat, 18 Mar 2000 16:16:54 EST

Kit Maloney wrote:
> My trolling battery is about a year old but sat for six month without being
> used. It now has a "red eye" instead of a green eye. Using my onboard
> charger didn't change the eye back to green overnight, so I took the battery
> out, put in on a regular 15 amp charger (set in Deep Cycle mode) and ran it
> for about 6 hours until the "charge complete" light came on.
> Problem is that the light is still red, not green. The unloaded voltage
> across the terminals is 12.9 volts. Should I be concerned about the "red
> eye"? Is there a charging routine that I can use to restore life to this
> underutilized battery?

Run an equalizing charge on it.  The indicator works on specific
gravity.  The electrolyte gets heavier as the battery charges and
sulfuric acid is emitted from the plates.  If the battery is just
charged and not equalized, the acid tends to remain down in the
plate area (heavier than the lighter depleted electrolyte on top)
and your eye can't see it.  Sloshing the battery around a bit can
stir the electrolyte but the easiest way is to overcharge it
(equalize it) until vigorous bubbling occurs.  This will stir the
electrolyte.  If the eye's still not green, then the battery is
probably sulfated and may or may not be recoverable.  Note that the
eye is only "calibrated" at near room temperature so if your battery
is very cold or very hot, it will not indicate properly.


From: John De Armond
Newsgroups: rec.outdoors.rv-travel
Subject: Re: To equalize or not to equalize
Date: Mon, 04 Apr 2005 19:08:58 -0400
Message-ID: <>

On Mon, 04 Apr 2005 14:45:57 GMT, "Frank Howell"
<> wrote:

>My MH battery bank consists of 3 Trojan SCS200(115ah). I have read articles
>on the benefits of equalization for deep cycle batteries, but I would like
>to hear from anyone who has actually done it.

OK.  I equalize my RV's house batteries several times a year.
Equalizing does several things:

* It brings all the cells up to full charge.  This is probably the
most important function.  Left to their own devices, the individual
cells will drift apart in their capacities and therefore their states
of charge.  This happens mainly because of the formation of hard
sulfate crystals on the plates of the stronger cells when they're not
fully charged.  Another cause is unequal shedding of the plates.

* It stirs the acid, making your hydrometer readings actually mean

* it helps remove shedded material from between the plates where it
can settle to the bottom of the cells.  Shed material tends to raise
the impedance of the affected cell which is not good.

There are many opinions on when to do the equalization.  I do it every
15 to 20 charge/discharge cycles. The reason is that I don't want to
give the unconverted lead sulfate in the less-than-fully-charged cells
time to harden up to the point that it can't be converted by normal

It doesn't take much current to do an equalization cycle, perhaps 5 to
10 amps per battery.  I have two Group 29 batteries in my rig.  I use
10 amps, 5 per battery, starting out.  I built a variable voltage
battery charger to do mine with.  There are any number of ways to do
it with improvised equipment.  Two battery chargers in series and in
series with a sealed beam headlight (passes about 5 amps over a wide
range of voltage) will do the trick.  As will two batteries in series
with the lamp, a battery and a charger in series, etc.  Don't worry
about the voltage too much, just keep the current down.

Yet another way is to use a dumb charger with the "boost" or "jump
start" option.  This feature cranks out >15 volts on the chargers I've
looked at.  You can control the current either with the sealed beam
headlight or you can use a light dimmer (rated for motor speed
control) to regulate the 120vac going in.  Harbor Freight has a
"router speed control" rated for 15 amps on sale right now for $9.99.
I just picked up a couple for general purpose AC voltage control.

I equalize until all the cells are gassing more or less equally and
until the specific gravities quit changing.  Usually no more than an
hour after the batteries are fully charged with my Vector smart

That's about all there is to it.


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