28 august 2024

Kenwood TH-D74 battery indicator and some battery measurements

 During the years of use of my Kenwood TH-D74 I noticed that the battery indicator is a little bit confusing.

I never knew precisely how much "juice" I had in the battery from what the radio show on the LCD indicator.

So, being a brave ham I decided to put some clips on the battery contacts and make some measurements and correlate them with that little icon on the upper right side of the screen.

 

Under 7.2V:

 

7.2V - 7.4V 



7.4V - 8.0V


8.0 V - 8.4V

Between 7.2 and 7.3V, the battery indicator is changing the colour from red to green.

The observation was made with the voltage going from 8.4V to 5.5V - the lowest voltage for which the radio is still working.

Having the radio already connected to my smart power supply, I thought it is the right occasion to make some measurements for the current draw in various configurations.

Here they are...

-GPS OFF

-Battery Save OFF

-SQ ON

-TNC OFF

VFO A: 160 mA

VFO B: 168 mA

VFO A + VFO B: 205 mA

VFO A + VFO B, SQ ON, vol@1/2: 270 mA

FM Radio ON: 210 mA

SD Rec ON:  +15 mA

GPS ON: +30 mA

TNC ON: +~ 2mA

What about when transmitting?

Well, here they are, also:

EL (Extra Low)

VHF: 465 mA

UHF: 401 mA

L (Low)

VHF: 775 mA

UHF: 708 mA

M (Medium)

VHF: 1060 mA

UHF: 990 mA

H (High)

VHF: 1868 mA

UHF: 1920 mA

I want to stress out that these values are determined against my radio and can vary on others.

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