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The way these multi-phase chargers work is they charge at constant-current=
(Bulk Mode) until a voltage threshold (~14.25V) is reached at which point =
it switches to constant voltage (Absorption Mode) until the current drops b=
elow a threshold where it switches to Float Mode.=C2=A0 The data sheet does=
n't talk much about this (or at all) but it is possible that this charger i=
s calibrated for a 40 A-H battery more typical of what is found in private =
vehicles.=C2=A0 It is possible that the absorption current on a much larger=
battery (100 A-H) never gets below this threshold so the charger never swi=
tches to Float.=C2=A0=20
But this is just speculation.
OTOH, I had a 5-year old Optima in my TR6 that displayed the same symptom.=
=C2=A0 But on my car I can connect the charger in such a manner that I can =
monitor the charge current on the in-dash ammeter which never dropped below=
a few amps.=C2=A0 In fact I first noticed the problem while driving as the=
ammeter was centered indicating zero amps early in the drive but when appr=
oaching the house the current was definitely in showing a few amps of charg=
e which is not at all typical.=C2=A0=20
I took it to the shop specializing in batteries and they rolled out their t=
ester and pronounced it "good."=C2=A0 In my estimation, their test is not c=
omprehensive and only checked for open and/or shorted cells and for current=
capacity.=C2=A0 They were more than happy to take my money when I insisted=
that the battery was not going to last and I was happy with replacing the =
battery since it was at least five years old and had been abused (completel=
y discharged at least once).
So, I guess the short answer is what is the current into the battery when t=
he charger hangs in the Absorption Mode?
=20
Dave=20
=20
=20
-----Original Message-----
From: Jimmie Mayfield via Shop-talk <shop-talk@autox.team.net>
To: shop-talk <shop-talk@autox.team.net>
Sent: Tue, Apr 7, 2020 9:34 am
Subject: [Shop-talk] Float chargers
The recent discussion about solar-powered float chargers has reminded me=20
of an issue that I've yet to understand or resolve...
I have a Battery Minder 12248 (12V 2/4/8A) charger/de-sulfator with=20
temperature compensation sensor.=C2=A0 While I've never been able to=20
appreciably restore a dead UPS battery using the de-sulfation mode, it=20
seems to work fine as a slow charger.=C2=A0 It has several modes -- gel-cel=
l,=20
AGM or flooded -- which, near as I can tell, adjusts the threshold=20
voltage at which the charger switches from bulk-charge mode to=20
float-charge/de-sulfation mode.
Every 12V battery that I've ever connected to the charger, even the old=20
AGM batteries taken out of my UPS units, eventually reached the=20
threshold voltage and switched over to float mode (usually within 30-45=20
minutes for a nearly-fully-charged battery).=C2=A0 Except one.
About 2 years ago I installed an Interstate battery from Costco (size=20
27F, 890CA, 710CCA) in my truck.=C2=A0 It's a flooded battery and if I=20
understand Interstate's spec correctly, its capacity works out to around=20
100Ah.=C2=A0 The battery has a resting voltage of 12.6V so it doesn't appea=
r=20
to have any shorted cells and has no trouble starting my truck.=C2=A0 So it=
=20
seems to be a normally healthy battery, right?
Thing is...I've never seen my charger go into float mode when connected=20
to this battery even when it was nearly new.=C2=A0 With the recent pandemic=
=20
stay-at-home orders, yesterday I decided to connect my truck to the=20
charger to stave off parasitic drain (measured to be 20-30mA) that may=20
have accumulated over the past week of inactivity.=C2=A0 I'm currently at 1=
6=20
hours (@4A) and it still seems to be in bulk-charging mode.=C2=A0 I have=20
difficulty believing that the battery needed 50+ Ah.
So what's going on here?=C2=A0 This is the only battery that I've come acro=
ss=20
that behaves like this.
_______________________________________________
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Content-Transfer-Encoding: quoted-printable
<div style=3D"color:black;font: 12pt Arial, Helvetica, sans-serif;">
<div> <font size=3D"3">The way these multi-phase chargers work is they char=
ge at constant-current (Bulk Mode) until a voltage threshold (~14.25V) is r=
eached at which point it switches to constant voltage (Absorption Mode) unt=
il the current drops below a threshold where it switches to Float Mode.&nbs=
p; The data sheet doesn't talk much about this (or at all) but it is possib=
le that this charger is calibrated for a 40 A-H battery </font><font size=
=3D"3">more typical of what is found in private vehicles. It is possi=
ble that the absorption current on a much larger battery (100 A-H) never ge=
ts below this threshold so the charger never switches to Float. <br>
</font></div>
<div><font size=3D"3"><br>
</font></div>
<div><font size=3D"3">But this is just speculation.</font></div>
<div><font size=3D"3"><br>
</font></div>
<div><font size=3D"3">OTOH, I had a 5-year old Optima in my TR6 that displa=
yed the same symptom. But on my car I can connect the charger in such=
a manner that I can monitor the charge current on the in-dash ammeter whic=
h never dropped below a few amps. In fact I first noticed the problem=
while driving as the ammeter was centered indicating zero amps early in th=
e drive but when approaching the house the current was definitely in showin=
g a few amps of charge which is not at all typical. <br>
</font></div>
<div><font size=3D"3"><br>
</font></div>
<div><font size=3D"3">I took it to the shop specializing in batteries and t=
hey rolled out their tester and pronounced it "good." In my estimatio=
n, their test is not comprehensive and only checked for open and/or shorted=
cells and for current capacity. They were more than happy to take my=
money when I insisted that the battery was not going to last and I was hap=
py with replacing the battery since it was at least five years old and had =
been abused (completely discharged at least once).<br>
</font></div>
<div><font size=3D"3"><br>
</font></div>
<div><font size=3D"3">So, I guess the short answer is what is the current i=
nto the battery when the charger hangs in the Absorption Mode?<br>
</font></div>
<div> <br>
</div>
<div style=3D"clear:both"><font size=3D"4">Dave </font><br>
<br>
</div>
<div> <br>
</div>
<div> <br>
</div>
<div style=3D"font-family:arial,helvetica;font-size:10pt;color:black">-----=
Original Message-----<br>
From: Jimmie Mayfield via Shop-talk <shop-talk@autox.team.net><br>
To: shop-talk <shop-talk@autox.team.net><br>
Sent: Tue, Apr 7, 2020 9:34 am<br>
Subject: [Shop-talk] Float chargers<br>
<br>
<div dir=3D"ltr">The recent discussion about solar-powered float chargers h=
as reminded me <br clear=3D"none">of an issue that I've yet to understand o=
r resolve...<br clear=3D"none"><br clear=3D"none">I have a Battery Minder 1=
2248 (12V 2/4/8A) charger/de-sulfator with <br clear=3D"none">temperature c=
ompensation sensor. While I've never been able to <br clear=3D"none">=
appreciably restore a dead UPS battery using the de-sulfation mode, it <br =
clear=3D"none">seems to work fine as a slow charger. It has several m=
odes -- gel-cell, <br clear=3D"none">AGM or flooded -- which, near as I can=
tell, adjusts the threshold <br clear=3D"none">voltage at which the charge=
r switches from bulk-charge mode to <br clear=3D"none">float-charge/de-sulf=
ation mode.<br clear=3D"none"><br clear=3D"none">Every 12V battery that I'v=
e ever connected to the charger, even the old <br clear=3D"none">AGM batter=
ies taken out of my UPS units, eventually reached the <br clear=3D"none">th=
reshold voltage and switched over to float mode (usually within 30-45 <br c=
lear=3D"none">minutes for a nearly-fully-charged battery). Except one=
.<br clear=3D"none"><br clear=3D"none">About 2 years ago I installed an Int=
erstate battery from Costco (size <br clear=3D"none">27F, 890CA, 710CCA) in=
my truck. It's a flooded battery and if I <br clear=3D"none">underst=
and Interstate's spec correctly, its capacity works out to around <br clear=
=3D"none">100Ah. The battery has a resting voltage of 12.6V so it doe=
sn't appear <br clear=3D"none">to have any shorted cells and has no trouble=
starting my truck. So it <br clear=3D"none">seems to be a normally h=
ealthy battery, right?<br clear=3D"none"><br clear=3D"none">Thing is...I've=
never seen my charger go into float mode when connected <br clear=3D"none"=
>to this battery even when it was nearly new. With the recent pandemi=
c <br clear=3D"none">stay-at-home orders, yesterday I decided to connect my=
truck to the <br clear=3D"none">charger to stave off parasitic drain (meas=
ured to be 20-30mA) that may <br clear=3D"none">have accumulated over the p=
ast week of inactivity. I'm currently at 16 <br clear=3D"none">hours =
(@4A) and it still seems to be in bulk-charging mode. I have <br clea=
r=3D"none">difficulty believing that the battery needed 50+ Ah.<br clear=3D=
"none"><br clear=3D"none">So what's going on here? This is the only b=
attery that I've come across <br clear=3D"none">that behaves like this.
<div class=3D"yqt8910329057" id=3D"yqtfd39778"><br clear=3D"none"><br clear=
=3D"none"><br clear=3D"none">______________________________________________=
_<br clear=3D"none"><br clear=3D"none"><br clear=3D"none"></div>
</div>
</div>
</div>
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_______________________________________________
Shop-talk@autox.team.net
Archive: http://www.team.net/pipermail/shop-talk http://autox.team.net/archive
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