discharged completely in two hours, it may only give you 56Ah (because of
the higher rate of discharge).
As you can see the battery's capacity is almost halved. This phenomenon is
called Peukert efficiency (see chapter 2.3.2). Also, when the temperature of
the battery is low, its capacity is decreased even more. This is why simple
Amp hour counters or Voltmeters give you far from an accurate state-of-
charge indication.
The BMV can display both the Amp hours removed (not compensated) and
the actual state-of-charge (compensated by Peukert efficiency and charge
efficiency). Reading the state-of-charge is the best way to read your battery.
This parameter is given in percentages, where 100.0% represents a fully
charged battery and 0.0% a completely flat battery. You can compare this
with a fuel-gauge in a car.
The BMV also makes an estimation of how long the battery can support the
present load (time-to-go readout). This is actually the time left until the
battery needs to be charged again. If the battery load is fluctuating heavily it
is best not to rely on this reading too much since it is a momentary readout
and must be used as a guideline only. We always encourage the use of the
state-of-charge readout for accurate battery monitoring.
Besides the main function of the BMV, displaying the actual battery status,
this monitor offers many other features. The readout of actual battery
voltage and current, and the ability to store historic data are just a few of
many features of the BMV. These features are more specifically explained
in the corresponding chapters of this manual.
1.4 Special features of the BMV-602
1.4.1 Starter battery monitoring
In addition to the comprehensive monitoring of the main battery system, the
BMV also provides basic monitoring of a second voltage input. This is
useful for systems such as those with a separate starter battery. Unless
otherwise indicated, all values and settings described in this manual refer to
the main battery system.
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