Xantrex Technology Link 20 TV Cables User Manual


 
7
LINK 20 BATTERY MANAGEMENT
SIMPLE BATTERY MANAGEMENT RULE:
Recharge When the Battery is 50% Discharged!
The Link 20 is a guide to the battery's state of charge. Our Mid-Capacity Rule
says you should begin charging when your Link 20 shows that 50% (or more) of battery
capacity has been consumed. In marine and RV systems, which are trying to minimize
charging time with an engine-driven alternator or genset, the battery is normally charged only
to the 85% level. This means only 35% of the battery capacity is actually available for use.
The Mid-Capacity Rule is a very conservative approach to battery use. Occasion-
ally discharging a battery more deeply is perfectly acceptable. The Mid-Capacity Rule
is intended as a design and operating guideline, not a law which must be obeyed without
exception.
We recommend synchronizing your Link 20 to the 100% charged level of the
battery. You should begin recharging when 50% of the your battery capacity has been
consumed.
When recharging from an engine-driven alternator or generator supplied
battery charger you do not need to charge until the meter counts back up to 0 amp
hours consumed. You may end charging even though the final 15% of battery capacity
has not been restored. Later, when you are able to charge for a long period of time, the
remaining amp hours consumed will be replaced.
Periodic conditioning or
equalizing removes any negative amp hours that are not
replaced during normal charging.
OVERCHARGE AMP HOURS
If the batteries are 100% charged and the Link 20 is in sync, overcharge amp hours
are displayed as a positive amp-hour number. Some accumulation of overcharge amp hours
is normal with systems continuously connected to a charger. For example, a 100 Ah battery
at Float voltage will normally have about 0.1 amp flowing into it. This means you would
expect about 2.4 amp hours of overcharge to accumulate each 24 hours. If your battery
system is larger, proportionately more current flows and amp hours accumulate.
With a constant voltage charging system set at 14.2 volts, as much as 1 amp of current
may be flowing all the time even after the battery has reached the charged parameters. This
causes a small overcharge amp-hour reading to appear in the Ah display. When discharging
begins, these overcharge amp hours are erased and the Link 20 resets to zero and begins
to report amp hours consumed.
Prolonged high voltage applied to a fully charged battery will probably cause gassing.
So, if you see a large amp-hour overcharge occuring daily, consider it a warning to check
your system. It could indicate that you are destroying your battery by overcharging.
When you equalize your batteries, you will accumulate some overcharge amp hours.
This is normal and keeps the Link 20 synchronized with the battery state of charge.