Battery Tender Heavy Duty DVD-40 Modified 12V-12V Dual 12V @ 20A (PN 021-1158-12) - Manual (Page 4)

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The BATTERY TENDER® HEAVY DUTY 12V-12V DUAL 20 AMP CHARGER
charges at a maximum rate of 20 Amps per channel, simultaneously (20 Amp-
Hours per hour per channel). Therefore, a fully discharged 60 Amp-Hour
battery will take approximately 2.25 hours to recharge to 75% capacity. To
complete the full, optimum charge cycle on a 12 Volt battery will take
approximately 6 hours.
WORKING WITH A DEAD BATTERY OR A BATTERY WITH A VERY
LOW VOLTAGE:
If you try to charge a dead battery having a voltage below 3 Volts, an internal
safety circuit prevents the BATTERY TENDER® HEAVY DUTY 12V-12V
DUAL 20 AMP CHARGER from delivering full charge power. The charger will
deliver a small, low-power current to bring the battery voltage up to 3 Volts.
NOTE:
If a 12 Volt, Lead-Acid battery has an output voltage of less than 9 volts when
it is at rest, when it is neither being charged nor supplying electrical current to
an external load, there is a good chance that the battery is defective. As a
frame of reference, a fully charged 12-Volt, Lead-Acid battery will have a rest-
state, no-load voltage of approximately 12.9 volts. A fully discharged 12-Volt,
Lead-Acid battery will have a rest-state, no-load voltage of approximately 11.4
volts. That means that a voltage change of only 1.5 volts represents the full
range of charge 0% to 100% on a 12-Volt, Lead-Acid battery. Depending on
the manufacturer, and the age of the battery, the specific voltages will vary by
a few tenths of a volt, but the 1.5-volt range will still be a good indicator of the
battery charge %.
STATUS INDICATOR LIGHTS: The following describes the LED
indicator light operation:
¾ RED BATTERY SELECTOR LIGHT ON – AGM Battery selected.
¾ GREEN BATTERY SELECTOR LIGHT ON – FLOODED Battery selected.
This is the default setting.
¾ RED CHARGE AMPERES STATUS LIGHTS ON STEADY – Whenever
the red charge amperes status lights are on steady, the present value of
the charge current is in the range of the highest numerical label on the
farthest light to the right that it illuminated. The 5 red charge amperes
status lights are labeled 4, 8, 12, 16, & 20. Each label indicates the
highest value of the charge current being delivered when the red light is
on. All red lights with lesser value labels than the highest light illuminated
will also remain illuminated. If the charge current being delivered by one
of the charger channels is between 12.1 and 16 amps. (The lowest value
is an approximation. The actual low value may be closer to 12 amps as
long as it is more than 12 amps.) In this case, the16 ampere light will be
on, and so will the 4, 8, and 12 ampere lights. The 20 ampere light will not
be on. If the charge current is between just over 16 amps, then all 5 of the
red lights will be on.
¾ GREEN CHARGE COMPLETE STATUS LIGHT FLASHING - When the
green light is flashing, the battery is fully charged and ready for service. It
is also possible that the red charge ampere status light labeled “4” may
also be on when the green light comes on and begins to flash. It is also
possible that additional red charge ampere status lights may come on after
the green charge complete status light begins to flash. This may happen if
the battery is supplying power to a load after the charge is complete, but
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the charger is still connected and operating in Float / Maintenance mode.
¾ GREEN CHARGE COMPLETE STATUS LIGHT ON STEADY - This will
occur when the AC power is first turned on and again when the battery is
connected to the charger with the AC power on, and then finally when the
battery is fully charged.
WHEN YOU TURN ON THE AC POWER: All 4 of the voltage selector LEDs
around the voltage selector rocker switches turn on and stay on. The green
charge complete status light turns on & each of the 5 red charge ampere
status lights turn on in sequence from low to high until all 5 red lights are on.
Then the process reverses itself and in sequence from high to low, each of the
5 red lights turn off until finally the green charge complete light also turns off.
Immediately after the green charge complete light turns off, both red battery
selector LEDs turn off, and the 2 green battery selector LEDs remain on.
WHEN YOU CONNECT THE ALLIGATOR CLIPS TO A BATTERY: The
green charge complete status light comes on. As soon as the first red charge
ampere status light comes on, the green charge complete status light turns off.
Then more red lights will come on, in sequence until the optimum charge
current for the battery is achieved.
BATTERY SELECTION: AGM OR FLOODED: The selections can be made
separately. One channel can be charging with the FLOODED battery type
while you change the battery type selection on the other channel to AGM. To
select the battery type for each charger channel, with the AC power on, first
make sure that the alligator clips for that channel are NOT connected to the
battery.
1. To
select FLOODED, do nothing, this is the default value. The Green
LED should be on with the Red LED off.
2. To select AGM, just move the MOMENTARY rocker switch to the AGM
position. The Red LED should turn off immediately and the Green LED
should come on.
TROUBLESHOOTING CHECK LIST:
1. NO CHARGER LIGHTS TURN ON AFTER THE AC POWER PLUG IS CONNECTED
TO THE AC ELECTRICAL OUTLET AND THE AC ON/OFF SWITCH IS TURNED ON:
Check the charger AC power plug connection at the AC electrical outlet. Check the cartridge
fuse (Bussmann ABC15A or equiv) on the back of the unit. Verify that the AC electrical outlet is
functioning properly by plugging in another appliance or a voltmeter.
2. THE GREEN CHARGER STATUS LIGHT GOES ON TOO SOON AFTER THE AC
POWER IS APPLIED TO THE CHARGER: The battery might already be fully charged, or
the charger connections at the battery may be intermittent, or the battery may be defective.
3. CHARGER IS CHARGING BUT THE GREEN CHARGE COMPLETE STATUS LIGHT
DOES NOT TURN ON IN A REASONABLE AMOUNT OF TIME: Remember, a large
battery may require more time to fully charge than originally expected. There may be another
appliance drawing electric power from the battery while it is charging, or the battery may be
defective. Also, a newly purchased battery may not be fully charged and may take longer to
charge initially.
4. THE GREEN BATTERY SELECTOR LIGHT COMES ON AFTER THE CHANNEL
OUTPUT WAS SET TO AGM AND THE RED VOLTAGE SELECTOR LIGHT WAS ON.
The AC power may have flickered off & on. You must remove the alligator clips from the battery
and repeat the AGM battery selection process.