I just wanted to share my latest activities. I hate using the ac
adapter due to noise and I also hate the fact that it would only get
about 20 hours of use on a set of 4 batteries. So I took it apart,
soldered to wires to the pos/neg terminals of the battery compartment
and an connecter on the other ends. I bought a 10aH Coleman jumpstart
compact power supply at Radio Shack and a 6V DC-DC convertor. Now I can
run my 909 for quite a while off a single charge with no electrical
noise I formerly got. Used to when I plugged my cell phone into its
charger I was overwhelmed by noise. Same with ceiling fan, laptop use
etc. Last night with the new DC supply took care of all of that. Now I
just need to make a mod to the backlight so it will stay on constantly.
I might also put different LEDs in to brighten the display a bit. I
think I will also figure out how to eliminate the stepping on the tuning
knob. It is annoying to me. Does anyone know if this will have an
adverse effect on anything?

Lessons learned so far:

Do NOT place a 12V-6V supply in parallel with *rechargeable* NiMH AAs.
The AAs get mighty hot. :-/ Alkalines will be fine. This way I can
still use the AAs if I want but don't have to remove/replace them.

There is little room in the case of the 909 for additional stuff. I had
to run the added wires into the battery compartment and out a small hole
drilled in the battery compartment cover. Tight fit.

Clear Skies and 73,
-Al

Al Arduengo wrote:
Do NOT place a 12V-6V supply in parallel with *rechargeable* NiMH AAs.
The AAs get mighty hot. :-/ Alkalines will be fine. This way I can
still use the AAs if I want but don't have to remove/replace them.

G! Actually I'm a bit surprised you don't have trouble with the
alkalines too, but I don't have much experience with alkaline batteries.

If you hook a power source across a battery, and the battery isn't fully
charged, the battery will draw as much charging current as the power
source can provide. If that current is high enough, it can certainly
cause things to get rather warm. Indeed, it's not impossible to cause
an explosion!

The little wall chargers have enough internal resistance to keep the
charging current under control. A good "stiff" well-regulated supply is
lacking this resistance and can be a problem... (you could try putting
a 6v light bulb in series though in practice I've had trouble getting
the battery to charge fully that way)
--
Doug Smith W9WI
Pleasant View (Nashville), TN EM66
http://www.w9wi.com

Al Arduengo wrote:

I just wanted to share my latest activities. I hate using the ac
adapter due to noise and I also hate the fact that it would only get
about 20 hours of use on a set of 4 batteries. So I took it apart,
soldered to wires to the pos/neg terminals of the battery compartment
and an connecter on the other ends. I bought a 10aH Coleman jumpstart
compact power supply at Radio Shack and a 6V DC-DC convertor. Now I can
run my 909 for quite a while off a single charge with no electrical
noise I formerly got. Used to when I plugged my cell phone into its
charger I was overwhelmed by noise. Same with ceiling fan, laptop use
etc. Last night with the new DC supply took care of all of that. Now I
just need to make a mod to the backlight so it will stay on constantly.
I might also put different LEDs in to brighten the display a bit. I
think I will also figure out how to eliminate the stepping on the tuning
knob. It is annoying to me. Does anyone know if this will have an
adverse effect on anything?

Lessons learned so far:

Do NOT place a 12V-6V supply in parallel with *rechargeable* NiMH AAs.
The AAs get mighty hot. :-/ Alkalines will be fine. This way I can
still use the AAs if I want but don't have to remove/replace them.

There is little room in the case of the 909 for additional stuff. I had
to run the added wires into the battery compartment and out a small hole
drilled in the battery compartment cover. Tight fit.

Clear Skies and 73,
-Al

It would have been more efficient to use an external 6-V rechargeable
battery and connect it to the radio through the AC adapter jack. The 6-V
battery could be charged with a car battery charger that has a 6-V
setting.


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In article , says...
I just wanted to share my latest activities. I hate using the ac
adapter due to noise and I also hate the fact that it would only get
about 20 hours of use on a set of 4 batteries. So I took it apart,
soldered to wires to the pos/neg terminals of the battery compartment
and an connecter on the other ends. I bought a 10aH Coleman jumpstart
compact power supply at Radio Shack and a 6V DC-DC convertor. Now I can
run my 909 for quite a while off a single charge with no electrical
noise I formerly got. Used to when I plugged my cell phone into its

Not to discourage such experimentation, but I think for most people it
would be more practical to just buy some NiMH batteries and a charger. I
was rather surprised when I first read of people's displeasure with the
battery life on the 909. I've always used NiMH batteries with mine and
just didn't give it much thought when it was time to swap in a freshly
charged set of batteries. I always have several sets charged and ready
to go. If you know where to shop you can get NiMH batteries for not much
more than alkalines of the same size would cost.

-- Jay

In article ,
Jay Heyl wrote:

Not to discourage such experimentation, but I think for most people it
would be more practical to just buy some NiMH batteries and a charger. I
was rather surprised when I first read of people's displeasure with the
battery life on the 909. I've always used NiMH batteries with mine and
just didn't give it much thought when it was time to swap in a freshly
charged set of batteries. I always have several sets charged and ready
to go. If you know where to shop you can get NiMH batteries for not much
more than alkalines of the same size would cost.

I get mine on eBay. About $1.50 each for 2100 MAH batteries, including
shipping.

Dan

Drake R8, Grundig Satellit 650
Radio Shack DX-440, Grundig YB400
Tecsun PL-230 (YB550PE), Kaito KA1102
Hallicraters S-120 (1962)
Zenith black dial 5 tube Tombstone (1936)
E. H. Scott 23 tube Imperial Allwave in Tasman cabinet (1935)

I would think the Nimh batts would have
been a better way to go too. I just picked
up a 4 pack at my local computer store
for $4.99 a 4 pack. I already have a
one hour charger. I can use them in several other things too..But I cant jump
start my car with them either.

Jay Heyl wrote:
In article , says...

I just wanted to share my latest activities. I hate using the ac
adapter due to noise and I also hate the fact that it would only get
about 20 hours of use on a set of 4 batteries. So I took it apart,
soldered to wires to the pos/neg terminals of the battery compartment
and an connecter on the other ends. I bought a 10aH Coleman jumpstart
compact power supply at Radio Shack and a 6V DC-DC convertor. Now I can
run my 909 for quite a while off a single charge with no electrical
noise I formerly got. Used to when I plugged my cell phone into its


Not to discourage such experimentation, but I think for most people it
would be more practical to just buy some NiMH batteries and a charger. I
was rather surprised when I first read of people's displeasure with the
battery life on the 909. I've always used NiMH batteries with mine and
just didn't give it much thought when it was time to swap in a freshly
charged set of batteries. I always have several sets charged and ready
to go. If you know where to shop you can get NiMH batteries for not much
more than alkalines of the same size would cost.

-- Jay

Actually I feel very stupid. My brain was on vacation when I decided to
add wiring to my 909. It is completely obvious that all I needed was a
6V adapter that I could plug into a 12V source and it only had to plug
into the ac adapter jack. I must have been thinking... well, never
mind. My desire to do all of this stems from some sort of obsessive
compulsive disorder that inclines me to want more power. The thought of
merely AA batteries that are half full powering my radio makes me
shudder. I also hate to change them out (another disorder). Anyway, I
removed the wores I added and merely got an adapter for my 6V converter
that fits the ac adapter input jack. Voilla!

Now I can use ac, AAs or 12V from my truck or other 12V source.

:-]

ROBMURR wrote:

I can use them in several other
things too..But I cant jump
start my car with them either.


They barely work in my Toyota Echo. If it doesn't start right away, I
have to use the 'D' cells..



mike



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..let the cat out to reply..

Al Arduengo wrote in message

Do NOT place a 12V-6V supply in parallel with *rechargeable* NiMH AAs.
The AAs get mighty hot. :-/ Alkalines will be fine. This way I can
still use the AAs if I want but don't have to remove/replace them.

You should be nice to your batteries and regulate the charging
current. If the power supply was stout, you could fry a battery, or
even have it explode from the overheating unless it's protected some
way. The simpliest method is probably using light bulbs in series. IE:
if you want to limit charging current to 100ma, place a small bulb
that draws 100ma, in series from the power source to the battery. The
current drawn from small bulbs can vary from about 25 ma for a 12v
"grain of wheat" bulb, to 200-300 or more ma for a larger auto lamp
bulb. IE tailight bulb, marker bulbs, etc..The best charge is a slow
charge. Thats 1/10 the capacity of the battery in mah for current, for
appx 15 hours. IE: if the battery is a 1500mah, you should charge at
150ma for appx 15 hours. If you have a VOM, you can check the current
draw when trying different bulbs. MK

In article QEhbc.19$mn3.5@clgrps13, says...
They barely work in my Toyota Echo. If it doesn't start right away, I
have to use the 'D' cells..

I think it's the Prius that runs on AA cells.

-- Jay