Disabling temperature compensation on a NetSure plant
This is one of the two settings that most often makes a lithium retrofit misbehave. It is also one of the quickest to fix — if the firmware lets you.
Why it has to go
Temperature compensation exists because lead-acid batteries need a different charge voltage hot than cold, so the plant raises and lowers the bus with the battery temperature sensor. A LiFePO4 pack has a BMS that manages its own cells and does not want the bus moving underneath it. Leaving compensation enabled on a lithium retrofit means the plant is applying a correction curve for a chemistry that is no longer installed.
The setting itself
On a NetSure plant the controller is normally an NCU, and the parameter is the temperature compensation sensor selection — it has to be set to None rather than merely unplugging the probe. Alongside it, automatic equalize should be set according to the application rather than left on a lead-acid cycle, because lithium is not equalized at all.
The setting nobody remembers: thermal runaway management
NetSure plants also carry a battery thermal runaway management function (BTRM). On a lithium installation it should be off: thermal protection belongs to the BMS, which measures cells directly, not to a plant controller inferring from a string-level sensor. Two controllers fighting over the same protection is worse than either one alone.
The firmware condition
Firmware version is a condition of entry, not a footnote. On NCU controllers, setting a charge current limit above 0.25C requires a minimum firmware version, and adjusting the module default voltage and walk-in requires a later one again. If the plant is below the threshold, the correct response is not 'we'll try' — it is to quote the controller upgrade as part of the work, or to decline the site.
If it is not a NetSure
On an Eltek Smartpack or Smartpack2 the equivalent parameters exist but carry different names, and the mapping has to be done before the quotation rather than during a commissioning window with the site already down. That mapping — plant by plant, controller by controller, firmware by firmware — is exactly what our compatibility audit produces and hands over signed.
Common questions about this family
Can I just unplug the temperature probe instead?
No. Unplugging a sensor usually raises an alarm and can drive the controller into a default behaviour you did not choose. Set the compensation sensor selection to None so the plant is configured for what is actually installed.
What else changes at the same time?
Float and equalize go to the same value, automatic equalize is disabled, thermal runaway management goes off, the string capacity is entered as Ah × number of modules, the charge current limit is enabled and set, and the low-voltage disconnect is placed at least 0.5 V above the battery's own disconnect. They are one change, not six independent ones.