eTower Installation Manual Revision 0
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The CAN 2.0 Part A and Part B standard uses the SAE J1939 standard in the eTower. It is
necessary to install a 120 Ohm resistor on each extreme end of the CAN cable (splices or
branch connections do not require a resistor). Most devices operating on CAN have two
plugs to connect an incoming cable in and then outgoing cable on the CAN Bus. The first and
the last device in the chain must have a termination resistor plugged into the spare (second)
plug. These resistor plugs are available from Freedom Won (if you are using Victron then
you can use the Victron supplied resistors). SMA and Victron operate on this basis for
example. The eTower however is designed to always be one of the end-of-line devices, and
hence has only one CAN port, and has a built-in termination resistor.
Ingeteam for example has a separate CAN terminal block for bare wires to be inserted from
the BMS and these units have an internal resistor fitted into the device.
The third-party device manuals must be referenced for all details regarding connecting the
CAN interface.
Most inverter brands use 500kbps BAUD rate and so does the eTower. Systems requiring
250kbps are not compatible with the eTower. Consider using a Freedom LiTE battery
programmed to operate at 250kbps if this BAUD rate must be used.
6.4
Parallel Configurations
It is permissible to connect multiple eTower e5000 modules in parallel. It may however be
more cost effective to purchase one Freedom LiTE model of the applicable size than
connecting multiple eTower units in parallel. The eTower is more intended as a solution
where 5kWh is adequate for the starting point of the system but where future expansion is
planned in multiple phases.
One eTower must be programmed as the Master by setting it to Address 01 (see 2.2.6),
while the rest of the eTower modules connected to the DC bus are programmed as Slaves by
default when they have addresses of 02 or higher. A total of 15 eTower modules can be
connected in parallel, however for this capacity level there are better solutions from the
Freedom LiTE Business and Commercial ranges.
Each eTower module communicates with the master module through an independent
RS485 bus by “daisy chaining” the modules together using standard Ethernet cables with
and RJ45 plugs. Note that these cables are included in the eTower box.
New units can be placed in parallel with old units up to about 5 years or 1 500 cycles, after
which it is preferable to trade in for a new unit(s) should a capacity upgrade be required.
7.
Programming the eTower
The eTower firmware and parameter programming is performed only by Freedom Won or
authorised distributors and instruction of such is outside the scope of this manual.
