jcb G20, Operator'S Manual

Page: 117 / 177

Maintenance
Electrical System
110 9831/0650-3 110
Electrical System
General
Check (Condition)
Batteries
Batteries used in normal temperate climate applications should not need topping up. In certain conditions (such
as prolonged operation in high ambient temperatures or if the alternator overcharges) the electrolyte level
should be checked frequently and topped up as necessary.
The electrolyte level should be checked in accordance with the routine maintenance schedule. Shorter
maintenance intervals are required if the machine is operating at high ambient temperatures or continuously
for long periods.
Later machines may have the new type batteries installed which include a sight glass to check the condition of
the battery. New batteries should be used as replacements if replacing the battery on earlier machines.
Maintenance
For the optimum performance of the battery, follow the steps:
• Make sure that the electrical connections are clean and tight. Apply petroleum jelly on connectors to
prevent corrosion.
• When applicable - never allow the electrolyte level to fall below the recommended level of 6mm above
the plates. Use only distilled water for topping up.
• Keep the battery at least three quarters charged, otherwise the plates may become sulphated (hardened)
- this condition makes recharging the battery very difficult.
Extra precautions must be taken when bench charging maintenance free batteries, they are more prone to
damage by overcharging than the standard type of battery:
• Never boost charge a maintenance free battery (if installed).
• Never charge a battery at a voltage in excess of 15.8V.
• Never continue to charge a battery after it begins to gas.
Quiescent Current Drain
If the machine has no permanently live circuits there should be zero quiescent current drain, when the key-
switch is off and all the lights are switched off.
It should be noted that some permanently live circuits will place a quiescent drain on the battery. Typically the
quiescent drain will be in the range of 10–20 mA. If the quiescent drain measures 40 mA or more, there is a
problem with the wiring insulation or the accessories, if the fault is not rectified it will continue to drain the battery.
Battery
Clean
WARNING Keep metal watch straps and any metal fasteners on your clothes, clear of the positive (+)
battery terminal. Such items can short between the terminal and nearby metal work. If it happens you can
get burned.
1. Make the machine safe.
2. Get access to the battery.
3. If the terminal posts are corroded and covered with white powder wash them with hot water. If there is
considerable corrosion, clean the terminal posts with a wire brush or abrasive paper. Refer to Figure 88.