Tom in D.C. wrote:As I recall from years of running 300s, 110s, GTXs, etc. the top-rated battery for these units is somewhere under 2 Amps, so the max current a charger would draw would be in the area of 200 ma. The input voltage could be 12 to 15VDC, which is brought to the proper charging voltage by a regulator in the charger. A wall wart with a capability of 500 mA (half an Amp) would do the job nicely.
0.5A seems a little low for a quick charger for a 1.2AH battery; sure, it's a 7.2v NiCd, but as NiCds charge, they float up much higher (I wouldn't be surprised to see this float to 10V+), and you need to increase charge voltage to compensate.
WB6DGN wrote:
The recommended power supply ("use only" in Motorola speak) is 2580600E01. The rated output on the ID plate is 13.8VDC at 0.9A, center pin positive. This is the same power supply used with the newer HTN9042A IntelliCharger, so I would expect that it is still available though don't know that for sure.
Tom DGN
By the way, the original battery for this series was 9628A or B (first three letters were HNN I think). Original version was 1200 mA/h though I've seen newer versions (mostly aftermarket), as high as 1800 mA/h.
I've got a few HNN9628Bs here.
The wall-wart probably is still available, but I make a point of digging through the wall-wart bin at Goodwill periodically.
As a result, I have a large stock of newer, switching type, 13.8VDC regulated wall-warts, most of which have a 2.1 or 2.5mm connector and are rated for 1.25-1.5A. Those cost $2 ea, which beats $30 (these chargers are for my personal use, not anyone else's, so I don't need to go OEM.)
WB6DGN wrote:
Be careful about doing this. I made a lighter plug cord to plug into a spare Jedi base that I had for my Chevy van. A voltage spike killed the charger base after only about a day's use. The Motorola cord must have some impulse protection to protect the charger base that I didn't account for. So...now I don't have a spare base anymore.
Tom DGN
That's not a problem, I have a switching regulator in the truck for radio use. I'll just take 13.8 from there.
Thanks for the responses everyone. Based on the consensus view that these can take ~14VDC, I did a little testing this evening with a directional wattmeter.
With the bench supply set for 13.84VDC (floating with no load), and current limited at 2A, I get:
Charge phases:
- Base connected: 13.81V, 110 mA
- Discharged radio inserted, battery test: 13.80V, 200 mA
- Quick charging: 13.77V, 1.28A. 1.39A inrush current.
- End of charge float: 13.84V, 160 mA
One HNN9628B took 68 minutes to charge. Total consumption of charger: 1.754Ah
Of course, this makes me wonder if those OEM wall-warts are actually limited at 0.9A or if that's just a minimum spec and most are capable of closer to 1.5A. If someone with one could measure current during the quick charge portion of the cycle, that would be appreciated.