BATTERY CAPACITY TESTING
Your Link 20 can be used to conduct periodic capacity tests that tell you the actual amount of energy your batteries can store. A capacity test should start with a battery that has been properly charged and equalized. The objective is to find the maximum available capacity.
Many times,
CAPACITY AT VARIOUS DISCHARGE RATES
(As a percent of
Hours to Discharge | Capacity (percent of rating) |
20 | 100% |
10 | 84% |
5 | 67% |
3 | 56% |
1 | 47% |
To test battery capacity, reset amp hours to zero. Then turn on a load that draws approximately5%oftheexpectedbatterycapacity.MeasurethecurrentwithAmpsdisplay. The load should be constant, such as incandescent lighting. Now put the Link 20 in the Voltsdisplaymode.Whenthebatteryvoltagedropsto10.5volts(or21voltsifyou'retesting a 24 V system), hopefully about 20 hours later, turn off the load and look at the
If less than 20 hours passed before the battery voltage fell to 10.5 V you can still determine the capacity with some arithmetic. For example: Assume a 12 V battery rated at 100 Ah. Apply a
10.5volts. The Link 20 would display
USING YOUR INVERTER
TO TEST BATTERY CAPACITY
Yourinvertermightbethetypewhichmakestesting batterycapacityeasy.First,fully charge (equalize if necessary) the battery to be tested. Use a load like incandescent lights running on the inverter whose amperage consumption is 5% or less of the battery capacity. Many inverters will shut down on low voltage below about 10.2 V. When the inverter shuts down, read the number of amp hours that have been consumed from the battery. If it is not close to the expected number use the procedure outlined above to estimate the capacity.
CAUTION! Be sure to completely recharge your battery after a discharge test.
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