[aprssig] Thd72a power

Greg D. ko6th_greg at hotmail.com
Sun Jan 16 16:27:57 EST 2011


Well, both chargers ended up in the same bag at one point, so  I'm probably remembering it backwards.  I sort of assumed the bigger charger went with the D7...  Thanks for the correction.

My comment about not charging the battery is based on an early experience with the D7, where I was using it as the radio + TNC to drive XASTIR.  I had it on for a while (weeks?), and when I was done, the battery was flat.  Come to think of it, and given your comment about which charger came with which radio, that probably was with the lower-power BC-17.  The radio itself draws about 70ma on receive, so, yeah, the battery wouldn't be getting much of a charge at all.

The battery packs that came with my D7 are shot now; won't hold a charge.  I've moved to the Batteries America BT-11H pack, with 2450mah NiMH batteries.  Installing a jumper across the internal "protection" diode lets me charge them in the pack, though it takes a while at 70ma...

Greg  KO6TH


> Date: Sun, 16 Jan 2011 12:21:33 -0800
> From: noskosteve at yahoo.com
> To: aprssig at tapr.org
> Subject: Re: [aprssig] Thd72a power
> 
>  
> --- On Sun, 1/16/11, Greg D. wrote:
> >...  my BC-17 (came with my Kenwood TH-F6A, but works with the D7 too)...
>  
>   My (fairly old)  F6 came with a higher current unit that will supply the Tx current.  Too bad I blew it up (connector rested on some coins) and haven't repaired it yet. I an surprised a 70ma charger came with this radio since the Li-ion battery wants more current than that when charging. My D7 came with a 70 ma charger.  So it looks like Kenwood has changed it's mind over the years.
>  
> 
> >  I believe the D7 stops charging the battery when it's turned on, ...
> 
> No.  The charging circuit is still connected to the external power jack and, therefore, is still charging the battery _IF_ the external supply can supply what it is asked to.  However, it is also supplying the radio fully and will choke if asked to supply more than it can.
> 
> 
> >... using drop-in desk chargers, with the charger attaching to the battery directly.  Those tend to give you a lot of hum on your signal (PL of 60hz anyone?), however, and aren't very portable. 
> 
>   This 'hum' tells us that they are to be used *only* for charging the battery.  They either are poorly filtered simple supplies or sophisticated chargers using pulsed current to do things like sense the battery voltage with no charging current to assess the level of charge.
> 
> -- 
> 73, Steve, K9DCI   USN (Vet)  MOT (Ret)  Ham (Yet)
> 
> I served during the cold war, so you can be served a cold one.
> 
> 
> 
> 
> Greg  KO6TH
> 
> 
> > From: kg6uae at arrl.net
> > To: aprssig at tapr.org
> > Date: Sun, 16 Jan 2011 08:57:38 -0800
> > Subject: Re: [aprssig] Thd72a power
> > 
> > > The D7 has a rather anemic (60mA?) wall wart - it can't even charge
> > > the battery if the receiver+TNC are on.
> > >
> > > Maybe the D72 has this same "feature"?
> > 
> > Yes, the supplied adapter is rated for .65A (er, 650mA) and the D7's 
> > BC-17 is .7A ... neither are good enough to TX while charging.
> > 
> > /jordan 
> > 
> > 
> > _______________________________________________
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> > aprssig at tapr.org
> > https://www.tapr.org/cgi-bin/mailman/listinfo/aprssig
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