Kenwood: Kenwood TH-F6 AA battery pack use

[hornetd]

I'm trying to figure out If I can use 4 rechargeable 3.2 volt LiFePO4 batteries in the AA battery shell for the TH-F6 radio. Total voltage would be 12.8 nominal. The PG-2W power cord connects to a 12 volt power supply and permits operation of the radio at full power. What I need is for someone with a service manual to tell me what the relationship is between that cord jack and the battery terminals. If the cord jack switched the battery pack out of the circuit then the OEM rechargeables could not be charged through that jack. What is the arrangement? Does the jacks internal connection go through a voltage regulator? Does the OEM battery eliminator adapter have a voltage regulator in it. I could modify the AA holder to put 2 cells in series and then put 2 such sets in parallel with each other. That would hold the voltage to the 7.4 volts that the OEM rechargeable batteries provide with more run time if I use the highest MA/Hr capacity available.

Any help would be appreciated.

--
Tom W3TDH

 

[vagrant]

Page 12 of the service manual explains what happens when power is supplied to the DCIN jack externally. I can also confirm that when either the AC wall wart, or the PG-J3 is plugged in to the DCIN jack, the OEM rechargeable battery does charge, as needed. ( See page 12 )

The voltage from my PG-J3 plug is 13.74 volts when measured using a multimeter. The PG-J3 when tested was connected to a power supply that provided 14.07 volts to the PG-J3.

I am unsure how you get 7.4 volts out of four 3.2 volt batteries in your 2S2P configuration, but I like what you're thinking about improving the voltage and amps versus alkaline or NiCad. Still, I am definitely unsure what LiFePO4 batteries will fit into the Kenwood BT-13 AA battery holder and provide more run time. Even if 4S, what LiFePO4 batteries will fit in that holder and provide more than 2000~2400 mAh? I am not saying one can not do that, but rather I am not aware of the solution...that fits.

Alternatively, you could just purchase this 4540 mAh aftermarket battery and call it a day.

 

[vagrant]

I forgot to mention on the BT-13 AA battery pack, there is a blocking diode.

 

[hornetd]

Page 12 of the service manual explains what happens when power is supplied to the DC-IN jack externally. I can also confirm that when either the AC wall wart, or the PG-J3 is plugged in to the DC-IN jack, the OEM rechargeable battery does charge, as needed. ( See page 12 )

The voltage from my PG-J3 plug is 13.74 volts when measured using a multimeter. The PG-J3 when tested was connected to a power supply that provided 14.07 volts to the PG-J3.

I am unsure how you get 7.4 volts out of four 3.2 volt batteries in your 2S2P configuration, but I like what you're thinking about improving the voltage and amps versus alkaline or NiCad. Still, I am definitely unsure what LiFePO4 batteries will fit into the Kenwood BT-13 AA battery holder and provide more run time. Even if 4S, what LiFePO4 batteries will fit in that holder and provide more than 2000~2400 mAh? I am not saying one can not do that, but rather I am not aware of the solution...that fits.

Alternatively, you could just purchase this 4540 mAh aftermarket battery and call it a day.

Your right! The best I could do with the 3.2 volt LiFePO4 1405 cells which will fit in the BT-13 battery holder is 1600 mA/hrs. The configuration I was thinking of is 2 1405 Lithium polymer cells in series to get 7.4 volts & 800 mAh. Then I could wire the same arrangement in parallel with the first set to get 1600 mAh. That is not a spectacular result for all of the work involved in modifying the BT-13 for series / Parallel to do that. I could use the LiFePO4 1405 3.2 volt batteries in series to get 12.8 volts nominal. That would only give me ~800 mAh at that voltage. It looks like your right that the after market LiFePO4 battery packs would be the way to go. That way I'd get the low self discharge rate and much greater number of charge / discharge cycles of the LiFePO4 chemistry.

Thank you for taking the time to help me out. It is much appreciated.

--
Tom W3TDH

 

[vagrant]

Happy to help. At times it is convenient to take the easy road and go for an available solution. Still, critical thinking helps ourselves and those around us, so keep it up.