7
FREQUENTLY ASKED QUESTIONS
Q. How do I know if the battery is fully charged?
A. A. The Charge Meter’s needle will decrease towards the left. A fully charged battery is indicated by a very low
reading. Refer to STEP 6A for an illustration of the Charge Meter.
Alternatively use a Battery Hydrometer (Projecta Part No. BH100). A reading of 1.250 or more in each cell
indicates a fully charged battery.
Q. Why does the Charge Meter indicate a fully charged battery straight away?
A. There are four possible reasons why the Charge Meter may indicate a fully charged battery straight away.
1. The battery is fully charged.
2. The battery has taken a surface charge.
3. The battery has a faulty cell.
4. The BATTERY VOLTAGE setting on the charger is set lower than the battery voltage (HDBC33 only).
Q. What is Surface Charge?
A. Batteries unused or left flat for some time build up a resistance to being recharged. When the charger is first
connected, these batteries will take a surface charge, and the Charge Meter will indicate a fully charged
battery within a short while. The battery however is not fully charged, the charger is voltage sensitive and
cannot differentiate between a surface charge and a fully charged battery. After a few hours the battery may
start to accept some charge but most batteries with this condition will not recover.
Q. What is a Faulty Cell?
A. 12 Volt batteries contain 6 cells and one faulty cell is enough to ruin your battery. If after eight hours of
charging your battery is still flat, you should test the cells using a hydrometer. If one reading is lower than the
rest it indicates a faulty cell. It is pointless to continue charging, as the battery needs replacing.
Q. Why does the charger cut out when in Boost Mode?
A. Boost mode is intended for short periods of use only. It increases the charge rate for a short, powerful charge.
This can create increased operating temperature. When the charger reaches a predefined temperature it will
automatically cut out to protect the charger and the battery. Once it has cooled down it will restart.
Q. Can I use the charger as a power supply?
A. No. The HDBC21 and HDBC33 cannot be used as a power supply. Do not attempt to connect the clamps to
anything other than a suitable battery.
Q. What are Volts and Amps?
VOLTS
The term voltage refers to the electrical force or electric potential to do work between two terminals or a good
analogy is water pressure in a pipe. For example a battery has 12 Volts between the positive and negative
terminals, or a 6 Volt battery has 6 Volts between the positive and negative terminals.
AMPS
The term AMPS is the unit of measure used for current. This can be described as the flow of electric charge in
a circuit. Again if you use the water analogy this would refer to how much water is flowing through the pipe.
For example if the current is reading 12 Amps then this is the amount of energy going into the battery.
Q. How does a typical battery charge?
A. A typical flat battery has a low internal resistance, when first connected to a charger the battery will accept a
high current. As the battery slowly charges, the voltage and internal resistance will rise causing the battery to
accept less and less current.
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