TRX-1: Internal Charging of NiMH Cells

[N6HHR]

Greetings,

I would like to figure-out how long to charge a set of NiMH cells inside my TRX-1. There is a setting to have the internal charger circuit automatically shut-off after xx hours. I have a new set of 2700mAH NiMH cells on board. Assuming they're discharged to the point where the low battery indicator (beeps and 'empty' cell icon) comes on, how long should I let the charge circuit run?

(I could figure this out if I knew what the charge rate is, but I don't see that in the specs.)

TNX de N6HHR

 

[RaleighGuy]

Greetings,

I would like to figure-out how long to charge a set of NiMH cells inside my TRX-1. There is a setting to have the internal charger circuit automatically shut-off after xx hours. I have a new set of 2700mAH NiMH cells on board. Assuming they're discharged to the point where the low battery indicator (beeps and 'empty' cell icon) comes on, how long should I let the charge circuit run?

(I could figure this out if I knew what the charge rate is, but I don't see that in the specs.)

TNX de N6HHR

From experience, they do not charge well inside a TRX-1, and if charged and left in the scanner while on AC power they drain. Use an external charger for best results.

 

[pb_lonny]

100% charge them externally....

 

[jaspence]

GET AN EXTERNAL CHARGER! A short melted one of my scanners due to a battery that shorted a few years ago while charging internally. There are many threads on RR about this and why it is a much better way.

 

[wtp]

i got up on the box and sent him a wordy PM about it.
N6HHR, look to the top right of this page for the envelope.

 

[N6HHR]

Thank you all, gents, for the responses. I do get it that, once you've destroyed a nice radio via a charging mishap, you'll never use internal charging again. And I thank the guys who have provided this admonition.

But I'm gonna be pig-headed about this one and go ahead with internal charging anyway. Damn the torpedoes ...

I measured the internal charge current of my TRX-1 with 2700mAH NiMH AA cells by 'tipping-out' one of the cells and placing my meter probes in series with the cells under charge. Using a typical 5V 1.0A 'wall wart' USB charger, and the cells at about 50% discharge, I measured a charge current of 45mA. That's a very low charge current - even lower than what is considered to be trickle charging. An online charge calculator says, assuming the cells are 80% discharged, that it would take 60 hours (that's two and a half days) at this rate to fully charge these cells.

Whistler's EZ Scan software allows setting the amount of time the internal charge circuit will run (Advanced Features > Battery Options) anywhere from 1 to 98 hours, after which the charge circuit is turned-off and a "charge complete" message shows on the radio's display. I had been allowing 16 hours of charge, and only getting about 4 hours of operation before the low battery warning sounds. Armed with the above data, I'm going to increase the charge time to 32 hours and see if there's any improvement in run time.

(Side note: The Charge Hours setting can be different in each V-Scanner folder in the program. If you use multiple V-Scanner folders, like I do, check the Charge Hours setting in each V-Scanner folder.)

And if I have a charging mishap and destroy this nice radio, I'll at least man-up and admit it. I have been warned.

73, David, N6HHR

 

[Wackyracer]

Thank you all, gents, for the responses. I do get it that, once you've destroyed a nice radio via a charging mishap, you'll never use internal charging again. And I thank the guys who have provided this admonition.

But I'm gonna be pig-headed about this one and go ahead with internal charging anyway. Damn the torpedoes ...

I measured the internal charge current of my TRX-1 with 2700mAH NiMH AA cells by 'tipping-out' one of the cells and placing my meter probes in series with the cells under charge. Using a typical 5V 1.0A 'wall wart' USB charger, and the cells at about 50% discharge, I measured a charge current of 45mA. That's a very low charge current - even lower than what is considered to be trickle charging. An online charge calculator says, assuming the cells are 80% discharged, that it would take 60 hours (that's two and a half days) at this rate to fully charge these cells.

Whistler's EZ Scan software allows setting the amount of time the internal charge circuit will run (Advanced Features > Battery Options) anywhere from 1 to 98 hours, after which the charge circuit is turned-off and a "charge complete" message shows on the radio's display. I had been allowing 16 hours of charge, and only getting about 4 hours of operation before the low battery warning sounds. Armed with the above data, I'm going to increase the charge time to 32 hours and see if there's any improvement in run time.

(Side note: The Charge Hours setting can be different in each V-Scanner folder in the program. If you use multiple V-Scanner folders, like I do, check the Charge Hours setting in each V-Scanner folder.)

And if I have a charging mishap and destroy this nice radio, I'll at least man-up and admit it. I have been warned.

73, David, N6

You were given great advice.... to sum it up, The scanner sucks at charging.

I use panasonic enloops and a external charger/conditioner