CommRadio CTX-10 User Manual – Rev PRELIMINARY 05 APR 2018
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CTX-10 Technical Notes
CTX-10 Power
Three (3) Tenergy model 30006, type 18650 cylindrical Li-Ion cells, rated at 3.7V @ 2600
mAhr are connected in series. These batteries are user replaceable after removing the
CTX-10 case bottom cover.
The total battery-pack capacity is:
7800 mAhr (3 cells x 2600/ea.)
32,760 mWhr (4.2V x 7800). (4.2 V is the cell voltage when 100% charged.)
Battery Protection Circuit
Each individual battery cell has an internal protection circuit to avoid excessive charging-
discharging current and over or under voltage conditions. The internal battery protection
circuits will trip and the radio will drop off-line without warning if the batteries become
fully discharged. This condition is avoided by the internal PIC24 microcontroller
monitoring battery voltage. However, if any of the batteries trip, the batteries will reset
when external power is applied. The CTX-10 will then power-up normally.
Internal Li-ION Battery Charger
The batteries are maintained by a combined switch-mode converter with internal charge-
controller that maintains a charge rate of approximately 10 to 12 Watts into the battery
Positive regardless of external power-source voltage. Optimal charging performance with
less than 1 Amp current draw requires between 10 – 20 VDC. Charging with as low as 5V is
possible but will require up to 2 Amps current draw. Be aware of the current output
capability of your power source.
The cells are fully charged at 4.2 V (12.6 VDC battery bus) and 90% discharged at 3.5V
(10.5 VDC battery bus). See table below.
Voltage: 3 Cells in Series (VDC) Percent (%) Remaining
12.2 - 12.6
100 RX-TX
11.9
90 RX-TX
11.7
80 RX-TX
11.4
70 RX-TX
11.1
50 RX-TX
10.95
30 RX-TX
10.8
20 RX-TX
10.5
10 RX Only
<10.5
Shutdown by PIC24
