Specifications

The approximate values are 380 mA on RX and 1.8 A on TX.
01/04/01
BATTERIES - CHARGING TIME ESTIMATION
How is the charging time estimated when using the internal FT-817 charger?
An estimate of charging time for the NiMH batteries (assuming nominally discharged, 0.9 V
per cell or 7.2 V total) is as follows: Tchg = (charging time), Ichg = (charging current), and
F = 1.5 to 1.8 (factor due to charging efficiency < 1). The relationship between these
parameters is Tchg = F * CP / Ichg. Example: 1.6 * 1600 mAh / 190 mA = 13 hr 30 min.
The charging current varies with the voltage of the external DC supply. ZL1BK, KB2TQX
and others have measured the charge current vs. external voltage to be 190 mA for 13.8
V, 180 mA for 13.0 V, 160 mA for 12.5 V, and 100 mA for 12.0 V. The internal charger
provides the nominal charging current during the time the charger is turned on. The
charging current reduces somewhat as the cells approach full capacity. When the charger
is off and the external power supply is connected, the charger provides trickle charging
current of appropriately 14 to 18 mA. The minimum current to affect charging is 60 mA (ref.
Energizer engineering data sheet). The min/max overcharge currents are 60/110 mA. You
should avoid overcharging your batteries. For a fully discharged set of 1600 mAh batteries
(7.2 V), the charge time could vary within the range of 13-15 hours. Two 8-hours cycles
would likely work. Although a 6-hour cycle and an 8-hour cycle would be preferred. The
trickle charging will not harm the NiMH batteries even if fully charged. Caution, the
maximum momentary ( 1 second) discharge current can exceed 15 A.
24/04/01-R
BATTERIES - NiMH
Do NiMH batteries need to be conditioned?
YES. Even though NiMH batteries don't suffer from the "memory effect," new NiMH
batteries should be fully cycles at least 3 times before general recharging. Thereafter, you
should perform a conditioning cycle every 10 charges to ensure top performance from your
battery.
01/04/01
BATTERIES - NiMH
How well do NiMH batteries maintain their voltage under FT-817 discharge rates?
In general, they will hold the 1.2 V value until about 80-90% discharged. Actual
performance varies by battery brand and discharge rate.
01/04/01
BATTERIES - NiMH
What is the hold time or shelf life of NiMH batteries?
It depends upon the storage temperature. Assuming that the batteries were properly
conditioned and fully cahrged when stored, it should be reasonable to expect, after a
month of storage time, a charge retention of 70-85% at room temperature and 30-40% at
40 deg C (113 deg F). If the batteries are cooled, the retention time is significantly
increased. [At room temperature, the capacity decreases about 1% per day.]
06/06/01-R