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● Inhibit charging or adapt the charge current when the temperature is too low, as might be
useful for Lithium-ion batteries.
If you want to improve this, you can always hook the RD60xx up to a computer, and act on the
temperature from there. You can even add some more sensors that way.
All in all:
● Do not use the temperature monitoring as your only “end of charge” trigger. Combine it
with other methods.
● Make sure that the temperature sensor has a good thermal contact, as close as possible
to the center of the battery.
● You may want to wrap some thermal insulation around the battery to improve the
temperature measurement fidelity. But never airtight, as some batteries gas out (most
Lead Acid types for example, even the “airtight”/sealed types).
● Especially for Lithium-ion and NiMH: set the charge current just low enough that it will
not cause significant heating during the charge, and you will better be able to detect the
sudden temperature rise at the end of charge.
21.4.5. dV/dT
The dv/dt method, or better, -dv/dt method, is for NiMH and NiCd batteries. These batteries are
normally charged with Constant Current (not Constant Voltage). When the battery charges, the
terminal voltage slowly rises. But when the battery is near full, the terminal voltage drops again
(or stagnates). This voltage drop happens before a temperature rise, so it is very interesting to
take into account.
To explain: (full credit goes to the excellent site
):
-dv is voltage drop and dt is time, i.e. a voltage drop over time.