40 Freedom SW Owner’s Guide
Configuring the Freedom SW using the SCP
Charger settings in a Dual Freedom SW con-
figuration
The Freedom SW2012 includes a 100 A charger. When using two stacked
Freedom SW2012 inverter/chargers connected to the same battery bank, a
total of 200 A of bulk charging is possible into that single common battery
bank. For small battery banks and/or certain battery types this bulk mode
current may be too high, therefore Freedom SW models include the
“Battery Bank Capacity” and “Max Charge Rate” settings.
“Battery Bank Capacity” is the bank’s total Amp-hour capacity, this is
best determined by a qualified RV electrical technician, while the “Max
Charge Rate” is determined by the battery manufacturer/type of battery
model being used, i.e. Flooded, Gel, AGM being the most popular. For
“Flooded” type battery bank, the preferred charger capacity (A)/battery
bank capacity (Ah) is usually 10-15%C (C = Battery Bank Amp-hour
capacity), however the max charge rate allowable is often accepted as 25%
C, while some AGM or Gel battery models are higher (50% C or, in rare
cases, up to 100% C). Do not exceed battery manufacturers recommended
max charge specifications as resultant battery temperature rise will shorten
battery life.
Calculations
Once installed and configured, each Freedom SW charger calculates its
own actual bulk charge current limit as follows:
(User selectable “Max Charge Rate” %) x (User selectable Battery Bank
Ah capacity) = Actual maximum charger #1 output Amps in bulk mode
(note: Limited to the Charger’s maximum capacity) then,
(Charger #1 Actual output Amps) + (Charger #2 Actual output Amps) =
“System Total BULK output” Amps (for the stacked pair).
This “Total bulk output current” flows into the battery bank. As this total
bulk current is split/distributed within the bank thru each individual parallel
and/or series connected battery, the current each battery “sees” must not
exceed each individual battery’s max allowed charge current as
specified by the battery manufacturer. Since most battery banks are/should
be constructed of the same battery type, model and length of
interconnecting cables, current sharing is roughly equal through each
parallel branch of battery(ies), therefore the above generalizations of “Max
Charge Rate %” can be made for the entire bank.
The Freedom SW’s “Max Charge Rate(%)” setting is set to “100%” by
default, but is adjustable 0-100%, therefore if the charger has max possible
100 A (as in the FSW2012), when set to Max Chg Rate of 100% FSW2012
is capable of delivering its full 100 A into the battery bank. However if this
is too high, the installer/operator may reduce this % setting to suit the
system battery type and bank requirements/limitations, to avoid overheating
the battery bank. The user/installer is responsible for configuring the
charger to ensure the battery manufacturer’s recommended max charge
rate Amps is not exceeded for longest battery life and best performance.
Examples
Example 1: In a system composed of two stacked FSW2012’s, industry
commonly accepted practice suggests a typical Flooded battery bank of
capacity (C) 400 Amp-hours should not be charged at a rate in excess of
25% of “C”. i.e. 25% x 400(Ah) = 100 Amps. Therefore, when configuring
the two stacked Freedom SW chargers, each charger must be limited to
contributing max 50 A into the common battery bank. This is accomplished
Freedom SW 3K2K InvChg Owners Guide.book Page 40 Wednesday, October 9, 2013 1:34 PM
