Terra TPX 720 battery question

[tugp...@genevaonline.com]

I have an old TPX 720 handheld radio. It was sitting for 20 + years
and the rechargable batteries were shot. They are 1.2 v nicads, 10 of
them. Before I go out and buy more, does anyone know if I can just
put regular aa cells in it to see if it works? The nicads are 12
volts total, and the dry cells would be 15. I don't want to fry the
radio.

Thanks

Kurt

[Pete Brown]

My TPX 720 manual specifies 10 AA Nicads and operating voltage of 11.8
to 13.7 volts. It also came with a 14 volt DC cigarette lighter charger.
No mention was made about using regular AA cells. If you would like a
copy of the manual in .pdf form, just email me and I will send it out.

--
Peter D. Brown
http://home.gci.net/~pdb/
http://groups.yahoo.com/group/akmtnsoaring/

Going home after a long day
http://farm2.static.flickr.com/1415/1325102827_f322928754_b.jpg

The fleet at Summit. Mt. McKinley is about 45nm away at 20,320 msl.
http://farm1.static.flickr.com/187/437346531_a9cb8d2482_b.jpg

The 170B at Bold near Eklutna Glacier
http://farm1.static.flickr.com/168/437324742_a216d7bb75.jpg

[Steve Leonard]

On Mar 22, 6:51 pm, Pete Brown <p...@gci.net> wrote:

> tugpi...@genevaonline.com wrote:
> > I have an old TPX 720 handheld radio.  It was sitting for 20 + years
> > and the rechargable batteries were shot.  They are 1.2 v nicads, 10 of
> > them.  Before I go out and buy more, does anyone know if I can just
> > put regular aa cells in it to see if it works?  The nicads are 12
> > volts total, and the dry cells would be 15.  I don't want to fry the
> > radio.
>
> > Thanks
>
> > Kurt

Another option would be to hook up 8 of the 1.5 volt dry cells (I know
Radio Shack makes an 8 cell holder), and make a little adapter to go
from that pack to the radio wire harness.

I have two Terra's that are in about the same condition. The previous
owner seemed to think that the radios should be left on charge all the
time so they would be "ready when you needed them." Needless to say,
those NiCads are dead to the world now.

Steve

[Peter Wyld]

There is a company in the UK which will make a battery pack for you,
probably for less than the cost of nicads (and use NiMH if you want, which
has to be better!) email http://www.axessinternational.com/ContactUs.asp or
check their website.
1000mAh Icom battery packs are very reasonable from them.

sa...@axessinternational.co
"Steve Leonard" <zun...@yahoo.com> wrote in message
news:1ac641df-fd69-464b...@8g2000hse.googlegroups.com...

[Tim Mara]

TPX720 uses normal AA NiCad batteries, usually available locally...however,
in nearly all cases (years ago, these have been off the market for a very
long time now) we ended up replacing the battery holder at the same time due
to corrosion.....even if the corrosion was invisible and even if you clean
it there always seemed to be a reduced current and eventually no charge....I
doubt you'll find these cases anymore since they were Terra parts.
The TPX was unique in that it was the only one to TX on more than 1 watt as
a handheld but also offered two very excellent qualities no other handheld
could match....it was the only handheld to also serve as a wheel chock and
it was virtually theft proof! I know of no one who would ever want to steal
one :o)
tim
Please visit the Wings & Wheels website at www.wingsandwheels.com

<tugp...@genevaonline.com> wrote in message
news:3c917509-3060-437a...@i7g2000prf.googlegroups.com...

[Eric Greenwell]

I've used three TPX 720s over the years, panel mounted, starting in 1980
with the first one in my Libelle, in 1984 the 2nd in my ASW 20 C, and
now 13 years with the 3rd in my ASH 26 E. It's a good radio, with clear
transmission and a sensitive receiver. I've run them all directly off
the 12 volt glider battery.

To test it, you could try 9 AA batteries (about 13.5 volts) and short
the last position in the battery holder. Or, remove the batteries, then
temporarily connect a 12 volt battery to the output leads from the
battery holder. Make sure you get the polarity right.

If the radio works satisfactorily, you can put in new ni-cads to make it
portable again. If it doesn't, there are several good choices for
hand-helds these days at bargain prices compared to what the TPX 720
cost when it was new!

--
Eric Greenwell - Washington State, USA
* Change "netto" to "net" to email me directly

* Updated! "Transponders in Sailplanes" http://tinyurl.com/y739x4
* New Jan '08 - sections on Mode S, TPAS, ADS-B, Flarm, more

* "A Guide to Self-launching Sailplane Operation" at www.motorglider.org

[d_w_t...@yahoo.com]

Tim is right about the corrosion. It is doubtful, but If the case is
still ok, you can get "dummy" batteries from Radio Shack (at least you
used to be able to - they don't seem to have the selection that they
used to) to convert to alkalines. the dummies are available at other
electronics suppliers and probably most places that sell nicad or nimh
cells. Basically, it is a plastic spacer with a conductor to bridge
between the battery contacts on the case. Otherwise, it would be very
easy to cobble something up from the old Terra battery case. It will
most likely need to be rebuilt anyway due to the corrosion. I ran a
couple of Terra's on alkalines, but the corrosion was too much of a
headache. I never got around to rebuilding the battery case.
Ideally, now I would call up Batteries America (formerly Mr. Nicad) or
some other reputable battery shop to put together a battery pack that
would fit in the Terra or just order cells with solder tabs and do it
myself.

I have seen some "nickel-alkaline" rechargeables that are supposed to
retain charge much longer than nimh or nicads. They don't seem to
have the storage capacity of nimh but they are still quite a bit more
than the old nicads. Anybody know anything about them?

On Mar 23, 3:02 pm, "Tim Mara" <t...@wingsandwheels.com> wrote:
> TPX720 uses normal AA NiCad batteries, usually available locally...however,
> in nearly all cases (years ago, these have been off the market for a very
> long time now) we ended up replacing the battery holder at the same time due
> to corrosion.....even if the corrosion was invisible and even if you clean
> it there always seemed to be a reduced current and eventually no charge....I
> doubt you'll find these cases anymore since they were Terra parts.
> The TPX was unique in that it was the only one to TX on more than 1 watt as
> a handheld but also offered two very excellent qualities no other handheld
> could match....it was the only handheld to also serve as a wheel chock and
> it was virtually theft proof! I know of no one who would ever want to steal
> one :o)
> tim
> Please visit the Wings & Wheels website atwww.wingsandwheels.com
>

> <tugpi...@genevaonline.com> wrote in message

>
> news:3c917509-3060-437a...@i7g2000prf.googlegroups.com...
>
>
>
> >I have an old TPX 720 handheld radio.  It was sitting for 20 + years
> > and the rechargable batteries were shot.  They are 1.2 v nicads, 10 of
> > them.  Before I go out and buy more, does anyone know if I can just
> > put regular aa cells in it to see if it works?  The nicads are 12
> > volts total, and the dry cells would be 15.  I don't want to fry the
> > radio.
>
> > Thanks
>

> > Kurt- Hide quoted text -
>
> - Show quoted text -

[Adam]

Hook it up to a car battery to test it.

I rebuilt my 700 mah, 10 cell Delcom handheld radio battery pack with
new 2200 mah nimh batts. Got them from Ebay for $1 each. They are
green with solder tabs on them. So far they work very well, take the
2200mah as advertised, and power the radio for at least 12 hours. You
can get them with or without solder tabs. Be sure to check the
dimension of your AA cell before buying a replacement.

/Adam

[micrsof...@gmail.com]

What's your email? for the manual...

[Cookie]

I have the same radio...bought if back in the day when it was the coolest thing out there....(and oh so compact!)

I used this as a sort of panel mount radio in two homebuilt airplanes...It's cool that you can plug in a standard aviation headset...no tiny special plugs or adapters...

I've purchased new 10 pack AA holders on the internet...


I also have a 10 battery charger for AA nickle metal hydride batteries...

Years past I ordered 10 pcs Ni cad with solder tabs and soldered up a pack.

Now I have to take the cells out of the radio to charge...since the charging jack crapped out years ago...but I still use this radio from time to time..


Cookie

[richd...@gmail.com]

Why not just use the cigarette lighter adapter????
Rich

[Dan Marotta]

I put AA lithium batteries in mine and it works just fine.  They're not rechargeable, however.

--
Dan Marotta

[Martin Gregorie]

On Fri, 27 Mar 2015 10:27:25 -0700, richdugger wrote:

> Why not just use the cigarette lighter adapter????
> Rich
>

Some older devices aren't happy being connected to external power without
a set of good batteries in them. I don't know if that radio is one of
them.

I'm currently reviving my 1976-vintage HP-25 calculator by adapting its
battery holder to use AAA rechargeables mounted so they can be replaced:
it used to use AA size NiCds with the lid glued on its battery holder.
The originals were 550 mAh while the AAA cells I're replace them with are
800 mAh so thi sis a win-win replacement.

The HP-25 needs working rechargeable batteries installed to buffer it's
external PSU's output: run it up with either no batteries or dead ones
installed and the display flickers violently. If I temporarily fit a pair
of AA alkalines it works as expected with a nice, steady display.


--
martin@ | Martin Gregorie
gregorie. | Essex, UK
org |

[Eric Greenwell]

Yes, indeed. I used three TPX 702s in three different gliders, running
off the 12 volt battery in the glider. Three radios for a total 27 years.

If you want it as a portable, see if you can find one of the factory
battery boxes that used AA cells (I may not be recalling this right),
and how many it used. Alternatively, just put 9 AA cells into the nicad
box, for 13.5 volts. That would be within the voltage range of 10 fully
charged nicads.


--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to
email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorgliders/publications/download-the-guide-1
- "Transponders in Sailplanes - Feb/2010" also ADS-B, PCAS, Flarm
http://tinyurl.com/yb3xywl

[rafic...@gmail.com]

Yes you can!
But buy AA Nimh types 2500 mah each or 3000 mah get 10 just install like any battery case.
I have one New and just did that and bought a wall adapter of 12 vdc 300 mah and soldered a new Dc connector of the size used in this radio, make sure that polarity is inverted!
What is the positive the center hole of the connector goes the negative wire, And the positive goes to the outer barrel of the Connector.
It should charge the battery packs in 5 hours or so.’use a voltmeter to verify they are fully charged.
Battery sharks.com and others sell good quality batteries in bundles of 10.
If you need help please e mail me
Rafic...@gmail.com
Thanks
Julio

[moshe....@gmail.com]

On Monday, January 29, 2018 at 9:14:51 PM UTC-5, rafic...@gmail.com wrote:
> Yes you can!
> But buy AA Nimh types 2500 mah each or 3000 mah get 10 just install like any battery case.

The highest capacity cells often have the highest self-discharge and early failure rates. I'm much happier with 2000 mAH low-self-discharge cells, such as Sanyo Eneloop. Especially for devices that are used occasionally, it's frustrating to pick it up when you need it and find the batteries went dead.

Don't know whether you can get low-self-discharge NiMH cells with solder-able tabs though.

Another battery type I've been experimenting with are AA-size 3V Lithium Iron Phosphate (LiFePO4). Paired with dummy cells (since they are 3V each) they are a very lightweight and low-self-discharge alternative for occasionally-used devices such as headlamps, cameras, etc. As long as the device uses an even number of AAs. These cells need a special charger, and I would charge them individually and not in a pack. Their capacity is lowish, too, about 600 mAH - similar to the capacity of NiCads, but at about 1/3 the weight.