Mastervolt Masterlink BTM III User Manual

ADDITIONAL INFORMATION
EN / Masterlink BTM-III / November 2006 29
the lifetime of the battery the efficiency will slowly
decline depending on its age and the number of
discharge cycles. If an efficiency of 70 % is reached,
it will basically mean that the battery is at the end of
its lifetime and needs to be replaced.
For each battery set connected to the Masterlink
BTM-III the setting of the Charge Efficiency Factor
can be specified. See chapter 10. Only with battery
set 1, the CEF is continuously recalculated by the
Masterlink BTM-III itself (after two recharges up to
100% with a proceeding discharges of at least 5%).
This recalculated value (see 8.7) is used for new
calculations of the Amphours, the time remaining
function and the State Of Charge (SOC)
11.3 PEUKERT EXPONENT
Standard batteries are rated for a 20-hour discharge.
This means that a 100 Ah battery can supply 5
Amps for 20 hours before a voltage of 1,75 V/cell
(i.e. 10.5V for 12V batteries / 21.0V for 24V
batteries) is reached. If the discharge current is
higher, for example 10 amps the battery will not be
able to supply the full 100 Ah. In this case the
voltage of 1,75 volt/cell or 10.5/21.0V is reached
before the battery has supplied its full 20-h rated
capacity.
In fact the maximum time the battery can be used in
the above mentioned example is approx. 8 hour i.e.
80 Ah
The Peukert equation describes the effect of
different discharge rates on battery capacity and can
be used to calculate the real available capacity of a
battery, if it is used above or below its 20 h rating.
This equation is also used by the Masterlink BTM-III
to calculate the time remaining function and the state
of charge (SOC)
In normal circumstances it is not necessary to
change the Peukert exponent. It will only be
necessary if traction batteries e.g. on a forklift, are
used. See chapter 10 to adjust the Peukert exponent
for each battery bank.
11.4 STATE OF CHARGE.
The state of charge (see chapter 6) is expressed as
a percentage. This value is automatically
compensated by the charge efficiency factor (C.E.F.)
and the Peukert exponent. When the battery is fully
charged, the State of charge (see chapter 6) will be
reset to 100%. A battery is considered to be fully
charged if one of the following conditions is met:
1 (Battery bank 1 only) below parameters are met
for at least 30 seconds:
• All of the Ah's discharged are charged back
into the battery (real counting without CEF)
• The actual charge current is less than the
setting for charge amps for full battery (see
chapter 10.7).
2 For at least 4 hours the actual battery voltage is
higher than the float voltage (see 10.8) plus 1.0 /
2.0 (at nominal battery voltage 12/24V)
3 For at least 8 hours the actual battery voltage is
higher than the float voltage (see 10.8) plus 0.3 /
0.6V (at nominal battery voltage 12/24V)
4 For at least 12 hours the actual battery voltage is
higher than the float voltage (see 10.8) minus
0.1 / 0.2V (at nominal battery voltage 12/24V)
11.5 REPLACEMENT OF BATTERIES
Refer to chapter 4 (Installation) if you want to
replace the batteries.
If new batteries are installed, the historical data of
the old batteries needs to be erased to leave only
historical data from the newly installed batteries. See
chapter 10 to reset the historical data for each
battery bank. If necessary, do not forget to change
the at setting of the nominal capacity (see chapter
9.3)

Mastervolt Masterlink BTM III Specifications

General

Brand	Mastervolt
Model	Masterlink BTM III
Category	Monitor
Language	English