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We Have People That Run 7.6 Volt Radios
From 13.8 volt Trucks (That Are Running)
They Can Use Their 6 Volt Rechargable
CamCorder Battery(Lead Acid) in Series opposing
Mode (Wire The 6 Volt Battery Backwards
With A Fuse And Diode)Between The 13.8 volt
Cigar Lighter And Across The Radio.
It Works Great.It Is Good To Get A Quick
Charge To A Battery Also.
A Nickel Cad Battery is Better For A longer
Project.Some Batlabbers like To use
7808 regulators to give 8 volts to the
portable.Then Again We Said In An
Emergency.
( In The Life Of Emergencies You Need To
Do What You Need To Do)
Is it just me, or does this sound like a very dangerous thing to do? It might work with a good charged battery, but batteries are not regulators and they don't last forever. What happens to a $500 portable when that battery goes bad?
I would think it would be better to build a regulator circuit, you could probably make one for less than $10. Cheap and reliable.
I didn't even think it deserved a response, but since you did, I'll
second it.
Let alone the OBVIOUS fact of a 6 Volt Camcorder Battery being
a LEAD ACID type having more like 7 volts on it when charged, so
why not just use that?? Too easy for ya??
Yeah. Then turn it around backwards, so as the Camcorder Battery
goes DEAD so does the RADIO.
Must stay awake late at night talking with Cowthief.
Not trying to be mean here, but please at least TRY and put on your
thinking Cap before posting. I know it's hard. Especially if you don't
Speak English that well, maybe that causes some confusion for the
rest of us that do. But still, I'm having a hard time with this one,
and ending sentances with prepositions and adjectives is NOT helping the matters either.
Also for the record, using your Walkie Talkie while Dropped in the
Charger is a NO-NO as well.
I think lately the modus operandi here at batlabs has been leaning
towards "Sensationalism Postings"
And Having Started that, I am Perhaps GUILTY Myself. And I am
sorry too. I know when to say enough is enough already with the
how to operate your GP300 with a Polaroid Polapulse Battery using
a paperclip in an emergency.
I agree, that sounds dangerous, for the radio as well as any potential by-standers. However, the key word is "emergency", as in "temporary". Temporary, that's an old Indian word meaning "anything goes"!
P.S. To keep confusion to a minimum: "old Indian word" is just an expression!
Ok, is it just me, or was that message edited to add the word 'emergency'? I don't recall that stuff about 7808 regulators being in there the first time I read it either.
Icom came out with the IC 2a(t).
This had the best battery pack of all time, and was improved.
The pack had drop-in charger tabs, and submini charge port on one side, and a trickle charge port on the other side, if you had the 02at, you could charge it from the radio.
I like the idea so much I have adapted several talkies to this.
When I rebuild MX and STX packs, a charge port is added, simple diode, LED and 220 ohm resistor.
The other side gets a supply port, LM7808H, 2 diodes, and LED.
The total cost for parts is under $3.00
This allows the pack to be charged in the normal manner, as well as the added options.
NiCad works best, as this circuit will not correctly charge the advanced chemistry, but will work without any risk of damage.
The diodes are there for reverse polarity as well as preventing a short/ drain on the charging port, I would not omit this.
OK I'll buy that. In fact I did already. Just so happens I have an
ICOM IC-04AT right here with me. It is front programmable too.
And low and behold it DOES have THREE places to charge it with.
the IC-04 has one on the top(seperate from the output), one
on the Back with a jack (coaxial) and red LED, AND drop-in Fast
Charge contacts on the bottom. Plus the radio has a power jack
on the top that allows the battery to be charged. Also the radio
will operate from 6-13.8 volts, although it prefers 7.5-8 Volts.
But you CAN use 13.8V all day long if you'd like, as long as you use
the top power port on the radio. Powering it from the drop in
charger is not recommended.
It IS a nice idea, and I do believe that aside from the military radios
where this is somewhat normal, ICOM is the only company that
did this, and only the older models.
Using a source voltage from a vehical which can
vary from 10.5 ~ 16.5 Volts depending on when
and if the engine may be running:
The addition of a " Crow Bar " circuit ( with a fuse at the source
voltage ) & Load is a ideal way of preventing the typical 7.5 Volt Radios ( or Handie-Cams / Radios ) from being distroyed
Those who are in the know do not need the details;
What I do ( along with a voltage regulator circuit )
is to ADD a fuse in line from the " Source " voltage 1st
and add a second to the Load as well.
This is always a good idea, and required if a Crow-Bar
Circuit is added accross the load being used.
Then ADD a SCR Directly accross the " Load " Output
Circuit ( Cam-Corder ), ( Battery ), ( Radio ) etc and chose the approprite Zener Diode to " Fire " the Gate of the SCR causing a direct Short to Ground, when and if the source voltage exceeds
what the user has chosen
This in effect will blow the " Source Fuse " in the Event
the Voltage goes beyond whatever selected Zener Diode
is chosen.....If you have a 7.5 Volt Source, chose a 9 Volt
Zener or something close.
VERY IMPORTANT & REQUIRED !
( The use of a Foward Diode to the Load is required, so that
if the SCR should Fire, it will not damage the " Load " in the
event the load souce has a Battery, etc
In other words, the Foward Diode towards the load " Prevents " a voltage retuning back to the Short Created by the SCR when it
has been fired, thus protecting what ever the Load has accross
its terminals.
The only item damage is " the fuse " in mosts cases
I see all to often, Radios, and other items completely distroyed
which operate on 6.00 / 7.5 Volts, and being used on 12VDC
and Higher. Works great for a short time, then smoke may start
comming out through the holes.....
Anyhow, a nice Crow-Bar circuit is ideal should a Voltage
Regulator " Fail " when / if a short develops, or a simple mistake
is made.....
And beleive me, saving a 1000.00 radio or Camcorder
is worth the few extra bucks.
Parts are chosen in accordence with the Specs Required. Low
Current items in the 100ma range are easy to deal with, but
if you get into the 2 or 3 Amp requirement or more, definately
add the extra protection
Also, a Simple In Series Resistor & Lamp Circuit can be
used to , so long as the Load battery is in ideal condition.
The Lamp acts as a current limiter, and if the battery is Low,
the Lamp illumination is high, if the battery is charged, the lamp
does not glow very much. Simple style HT220 Charger Circuit
for those interested.
Make sure its fused too !
Monty
Need help on a Program Cable or (/\/\) Rib Box ?
Contact me anytime/All availible / Free Support Info !
mail to: [email protected] PLease avoid PM's whenever possible. Box gets too full.
The 2 diode and LM78xxH will work to 32 volts, and output up to 5 amps peak, with current and temp' limiting.
You can add a zener, but this will add leak current.
The charge port is the most safe route, as it can only charge the pack, and there is nothing that can fail that will overvoltage the radio, unless the resistor were to be shorted.
Again, this is the field charger, not intended to replace the much improved drop-in charger.
I have a toshiba libretto that the pack has also been "fixed".
This works very well, the computers battery can be charged almost anywhere, in the car, at home, etc, while the PC is in use on another pack, if need be, or this one.
The power adaptor for 12 volts is nothing more than a power cord, and this has been working for 2 years.
Okay,,,,,With all of that said it sounds that maybe just buying an additional batteries and a vehicle charger, or just leaving the house with two extra charged batteries would make a whole lotta sense rather than rigging up some pos camcoder battery and whatever else you want and risk damaging a radio b/c you are to cheap to buy the real thing..Oh, by the way if for some reason you get caught in a massive ice storm or lost in the ozarks and don't have a spare battery or ac outlet most likely you and your HT are SOL..
....Don't be cheap...Buy spare batteries and chargers...Just my 2 cents....
Thank you very much for the SCR Crowbar info. I left that
out of my saber Repeater, and I intend to add that to the Next
one in the PowerSupply Section.
Way Better to be safe than Sorry.
We all know that regulators and pass transistors fail, often with
High Voltage being present to the Radio once Regulation is lost.
That Crowbar with associated fuses before and after it is Truley
the ticket. I'd say it's worth the extra three Bucks.
Thanks for reminding me about that, and making it easy.
P.S. that circuit is often the difference between a LAMBDA and a
something else!
if you are going to take the time to build this gypsy-ass contraption, why dont you just spend 20 bucks and buy a battery eliminator. they are basically empty battery shells with a cord and a cig plug coming out of the bottom. just plug it in to the cigarette power outlet in your vehicle and go nuts. like everyone said, why risk destroying a perfectly good radio and a perfectly good battery just to be able to plug into a cig plug?
To answer you question on everyone's behalf, no... it appears no one has attempted this. Probably because they sell a simple, yet proven and safe device that allows one to utalize the vehicle's power.
good luck!
try not to use any coat hangers building your contraption.
Motorola sells a vehicular battery charger for a reason. If you want to CHARGE a battery in the car without using a battery eliminator ( which doesn't allow you to charge), go out and get a vehicular battery charger. Ex. for the GP350/GP300/P110/P1225/GTX models the part number is HLN9719A.
If You Get A Car 13.8Volt Cigar Power Cable
With center Pin Postive And Plug It Into
The Same Chargers That You Named They Will
Also Charge Your Batteries.This Is Alot Cheaper
Than MA "M" .
(The Words We Used Was "In An Emergency"
When The Normal Parts Are Not There)
Using an inverter to convert 12VDC to 110VAC in order to convert that back to 7.8VDC (or something else) again is extremely inefficient, on account of all the inefficiencies of the individual pieces.
Most Motorola chargers with wall warts use transformers that produce unregulated DC at a "nominal" 12VDC, which then goes into the charger base, which in turn processes that power however the charger needs it. You can plug those chargers directly into vehicle cigarette lighter socket power with an inexpensive cord.
Ok, understanding emergencies and all,
And The Way Things Are Done
In The Great White North,
(Canada, I Mean)...
...ok, stop phishie..play nice... This is absurd. I have been in a couple of emergencies, i've been shot at, some natural disasters, and genuine con home fire, but i have never been in an emergency which has (in the definition of the word "Emergency" as the loss or impending loss of human life) REQUIRED me to use a portable radio, or when it has, i have not had my battery go dead and REQUIRE me to sacrifice the battery off my prize Sony Handicam to put another couple of minutes of life into the radio.
Maybe i'm the only one here who has never been posed that kind of situation, or maybe there is some other kind of definition to the word Emergency, but i can't fathom doing something that drastic to run a portable. My rationale why i will never have to do that....
1) if you have a 12v source (the rig, a car battery, big ass hampster on a wheel turning polarized magnets inclose proximity to wire) then i atleast have access to our truck radio (or all 4), and i can think of a bazillian different ways to pull 7.8ish volts off something.
2) if you're not in the truck, and your portable craps out w/ a dead battery and you're not pinned under a giant boulder and Lassie can't help you, you can make it to the truck where you should be able to find something....
3)my camcorder does not come on the rig with me, and if it does (parade or expo) the charger doesn't.
am i totally losing it? or does anyone else agree with me?
"How do you plan to outwit Death?"
"With a knight and bishop combination; I will destroy his flank." --Antonious Block
RKG wrote:Using an inverter to convert 12VDC to 110VAC in order to convert that back to 7.8VDC (or something else) again is extremely inefficient, on account of all the inefficiencies of the individual pieces.
Well, I know that. I just threw it out there for the hell of it. I mean, why not... it seemed that every other method of applying power was discussed, although I got a dizzy trying to read it so I just stopped.
Last edited by nmfire10 on Sat Dec 20, 2003 6:10 pm, edited 1 time in total.
"I'll eat you like a plate of bacon and eggs in the morning. " - Some loser on rr.com
eBay at it's finest:
Me: "What exactly is a 900Mhz UHF CB?"
Them: "A very nice CB at 900Mhz speed!"
<snippage>
Some Rescue Guys Have 3 and
4 Different Portables and They Buy a Six Volt
4 Amp Hour Battery ($18.00 Rechargeable ni-cad)
and Use It All The Time In The Car.(Engine Running.)
<end snippage>
oh brother.
"How do you plan to outwit Death?"
"With a knight and bishop combination; I will destroy his flank." --Antonious Block
Does anyone know the maximum current a UHF HT1000 requires? I'd like to build a really robust battery eliminator using a Vicor dc-dc converter(VI-J0R-EZ-S) and an old battery housing.
I've had customers destroy batteries (and a couple of radios doing this for "emergency" purposed. Battery eliminators are definitely the way to go. I have built a few for some of my customers. For true emergencies, a lot of popular radios have primary cell (alkaline) batteeries available. Good shelf life, and you don't need a vehicle to power the unit.
albdiag wrote:I think i am not happy with the range. looks like get mutch beter range runing on batteries compare to 8 v regulator
Any idea?
RANGE? You probably need a good antenna as that IS the most important factor in getting good range.
Some "regulators" will fail when exposed to RF radiation from the radio's antenna. I suspect there is a poor design in the "regulator" or more properly the battery eliminator making it subject to RF.
Like Will says probably RF getting into the regulator, I have been thru this numerous times with unfiltered 7808 and similar 3 terminal regulators with no filtering on the IN/Our leads used on Ht's.
I'd also look at a higher current regulator, something in the 3 amp range and do away with the 7808.
Using the parallel 7808's to try and get higher current is hard to do with a clean layout and you most likely have some type of wires connecting them together and these can act as antennas, you need to have the shortest lead lengths on everything that goes to ground.
Filter the input and the output of your regulator with a good high current Inductor of around 1uh and some good quality RF bypass Chip caps of 100pf and 1000pf in parallel on the in/out pins of the regulator.
The caps that you are using are good for DC but are most likely inductive at RF frequencies providing little if any bypass at VHF and above, also shield the entire regulator in a metal case.
Also what are you using for a heat sink, if the 7808 gets hot it will start to fold back on the output voltage and your radios output power will drop accordingly.
Additionally don't use point to point wires anywhere inside the case, use a good PCB ground plane under the regulator so that you can have short leads on the bypass capacitors and bond the ground plane to your metal case.
