Kenwood: TH-D74 batteries

[jazzboypro]

Whatever you do, don't lose the D74A stock antenna, it's over $80 from Kenwood or PacParts.

Yep, was also looking for an extra battery, pretty expensive also.

 

[AK9R]

There are aftermarket batteries available. Here is one source: KNB-75L : 7.4v 2000mAh Li-ION battery for TH-D74

 

[jazzboypro]

There are aftermarket batteries available. Here is one source: KNB-75L : 7.4v 2000mAh Li-ION battery for TH-D74

Have you tried it ? i don't mind aftermarket antenna but i'm not sure about batteries

 

[vagrant]

Here is another low cost D74A battery for $38, but read the reviews on that page. Some sayings come to mind.
1. Roll the dice and see what you get.
2. You get what you pay for.

I use the Kenwood PG-3J 12v power cord. For $40 I preferred this to the cost of another battery, as it allows charging or power. I also have the AAA battery case and use rechargeable batteries in it. Still, that only offers low power. Thus, I don't use the AAA case to transmit, but only when as a receiver. This keeps the regular battery ready for TX. Still, my needs may be different from others.

 

[AK9R]

Yes, I've purchased batteries from Batteries America in the past and they are generally good quality.

A couple of considerations with the TH-D74 battery life:

• You absolutely must "condition" the batteries. Fully charge them and then discharge them in the radio to where the radio shuts itself down. I set up an APRS beacon that transmitted once every 10 minutes and just let it go until the radio was dead. Repeat this process 8-10 times. That will generally improve the battery life. I know they are Li-ion batteries, but they still need to taught how to fully exercise themselves.
• Do not leave batteries on the charger once they are charged. The Kenwood desk charger isn't all that smart. Because I'm lazy and forgetful, I plug my chargers into a power strip that's on a 6-hour timer. Plenty of time for the batteries to get a charge and then the power strip shuts down so the batteries don't "cook" in the chargers.

 

[jazzboypro]

Here is another low cost D74A battery for $38, but read the reviews on that page. Some sayings come to mind.
1. Roll the dice and see what you get.
2. You get what you pay for.

I use the Kenwood PG-3J 12v power cord. For $40 I preferred this to the cost of another battery, as it allows charging or power. I also have the AAA battery case and use rechargeable batteries in it. Still, that only offers low power. Thus, I don't use the AAA case to transmit, but only when as a receiver. This keeps the regular battery ready for TX. Still, my needs may be different from others.

I agree with you especially on 2, i usually prefer to buy original parts when possible even if it costs more.

Yes, I've purchased batteries from Batteries America in the past and they are generally good quality.

A couple of considerations with the TH-D74 battery life:

• You absolutely must "condition" the batteries. Fully charge them and then discharge them in the radio to where the radio shuts itself down. I set up an APRS beacon that transmitted once every 10 minutes and just let it go until the radio was dead. Repeat this process 8-10 times. That will generally improve the battery life. I know they are Li-ion batteries, but they still need to taught how to fully exercise themselves.
• Do not leave batteries on the charger once they are charged. The Kenwood desk charger isn't all that smart. Because I'm lazy and forgetful, I plug my chargers into a power strip that's on a 6-hour timer. Plenty of time for the batteries to get a charge and then the power strip shuts down so the batteries don't "cook" in the chargers.

Thanks for the tips

 

[palmerjrusa]

Yes, I've purchased batteries from Batteries America in the past and they are generally good quality.

A couple of considerations with the TH-D74 battery life:

• You absolutely must "condition" the batteries. Fully charge them and then discharge them in the radio to where the radio shuts itself down. I set up an APRS beacon that transmitted once every 10 minutes and just let it go until the radio was dead. Repeat this process 8-10 times. That will generally improve the battery life. I know they are Li-ion batteries, but they still need to taught how to fully exercise themselves.
• Do not leave batteries on the charger once they are charged. The Kenwood desk charger isn't all that smart. Because I'm lazy and forgetful, I plug my chargers into a power strip that's on a 6-hour timer. Plenty of time for the batteries to get a charge and then the power strip shuts down so the batteries don't "cook" in the chargers.

That's contrary to the information stated below which advises to avoid "full discharges" of Li-ion cells to prolong their life:

BU-808: How to Prolong Lithium-based Batteries

BU meta description needed...

batteryuniversity.com

 

[AK9R]

You will note that I said "discharge them in the radio to where the radio shuts itself down". That is not a full discharge of the battery pack. That is a partial discharge as the radio has a minimum voltage requirement below which the radio shuts itself down.

 

[jazzboypro]

You will note that I said "discharge them in the radio to where the radio shuts itself down". That is not a full discharge of the battery pack. That is a partial discharge as the radio has a minimum voltage requirement below which the radio shuts itself down.

This is what I've been doing so far, it seems to work ok

 

[palmerjrusa]

You will note that I said "discharge them in the radio to where the radio shuts itself down". That is not a full discharge of the battery pack. That is a partial discharge as the radio has a minimum voltage requirement below which the radio shuts itself down.

And that voltage point is the discharge level beyond which damage to the Li-ion cell will occur.
That discharge point is what is meant in the link.
All Li-ion cells function in this way, the voltage has to be kept within a certain range.

In addition, full discharges to that point will stress the cell (as clearly stated in the link).
Also, contrary to your post, Li-ion cells do not need to be conditioned.
Keeping a Li-ion cell within the 100-50% discharge band of its charge cycle will considerably prolong the life of the cell.

 

[palmerjrusa]

Some devices powered by Li-ion batteries continue to draw a small current even after they've powered themselves down once the critical lower voltage point is detected. Leaving the battery in place will eventually damage/destroy it, making it unrevivable.

I never leave Li-ion batteries attached to devices if I'm not going to use them for a while and avoid full discharges that take the cell to its shut-off point.

 

[palmerjrusa]

On my SDS100/200 scanners I set the low battery voltage/alert at 3600 mV to avoid stressing the Li-ion cell and to prolong its useful life.

I have a couple spare batteries and I'll take the trade-off of a shorter run time over stressing the battery and shortening its life.
Once the voltage is around 3450 mV it's dropping fast anyway and there's not much time before the scanner will shut itself down (3200 mV).