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12 v or 13.8?
When looking for a power supply for my Alinco dr-590, what type of
power supply would I look for? The radio says 13.8 v dc but if I get a 12 volt power supply will it put out the same wattage at the radio? |
#2
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#3
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Richard Clark wrote: On 25 Jan 2005 08:22:59 -0800, wrote: When looking for a power supply for my Alinco dr-590, what type of power supply would I look for? The radio says 13.8 v dc but if I get a 12 volt power supply will it put out the same wattage at the radio? Hi Don, Do the math. You have the same load - less voltage. The power laws describe this simply as E=B2/R. However, it is very, very, very unlikely that you have 12.0 V of anything as this is a "nominal" voltage, and almost never an actual voltage. The 12 V label is derived from the common application of the Lead-Acid Edison Battery. The cells of this battery develop 2.1 V potential, and with their common combination into batteries of either 3 cells or 6 cells, those bring the total up to 6.3 V or 12.6 V. Many here will recognize these values as common filament voltages for tubes. So even here, common transformers that are either 6 or 12 V specified, actually supply more voltage under load (because they were originally filament power transformers). The specification for 13.8 V is derived from the automotive electrical system that was designed (with its voltage regulator and generator/alternator) to supply a "float" voltage that would keep the battery topped off while simultaneously carrying the load. Hence, mobile applications are designed for this configuration and the source should be robust enough to support the load. Now, it seems to me you were using a deep discharge battery, or you were planning to do so. This is a common application in the shack, I have two batteries in parallel held up with a 20A trickle charge (voltage adjusted to the optimum value). The charger (actually a precision source from Acopian) is not large enough to supply my HF rigs under full power out (my Drake TR-7 is rated well above 100W) but the combination of batteries and charger manage quite well. Also, I have connectored everything so that I can strip down, transport and reconfigure for field day operations (sans charger). 73's Richard Clark, KB7QHC So you are saying it wont matter? I was wanting to use the marine battery I have but someone else posted a negative experience with the fumes ruining part of their house and their own health. It scared me a little. I was looking at power supplies on ebay and some of them stated 12 volts (older ones) some said 13.8. That is why I asked. I am still a little confused on what way I need to go. |
#5
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"Jim Kelley" wrote in message ... snip Richard always writes as if he's entering a prose contest. He has some difficulty communicating with Earthlings. :-) ac6xg Jim That's 'cause he gets his plonk from Reg. ;^)))) 73 H. |
#6
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Jim -
How politically correct! In the military it is called "Getting $12,000 worth of education shoved up your rear end a nickel at a time". |
#7
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wrote in message oups.com... Richard Clark wrote: On 25 Jan 2005 08:22:59 -0800, wrote: When looking for a power supply for my Alinco dr-590, what type of power supply would I look for? The radio says 13.8 v dc but if I get a 12 volt power supply will it put out the same wattage at the radio? Hi Don, Do the math. You have the same load - less voltage. The power laws describe this simply as EČ/R. However, it is very, very, very unlikely that you have 12.0 V of anything as this is a "nominal" voltage, and almost never an actual voltage. The 12 V label is derived from the common application of the Lead-Acid Edison Battery. The cells of this battery develop 2.1 V potential, and with their common combination into batteries of either 3 cells or 6 cells, those bring the total up to 6.3 V or 12.6 V. Many here will recognize these values as common filament voltages for tubes. So even here, common transformers that are either 6 or 12 V specified, actually supply more voltage under load (because they were originally filament power transformers). The specification for 13.8 V is derived from the automotive electrical system that was designed (with its voltage regulator and generator/alternator) to supply a "float" voltage that would keep the battery topped off while simultaneously carrying the load. Hence, mobile applications are designed for this configuration and the source should be robust enough to support the load. Now, it seems to me you were using a deep discharge battery, or you were planning to do so. This is a common application in the shack, I have two batteries in parallel held up with a 20A trickle charge (voltage adjusted to the optimum value). The charger (actually a precision source from Acopian) is not large enough to supply my HF rigs under full power out (my Drake TR-7 is rated well above 100W) but the combination of batteries and charger manage quite well. Also, I have connectored everything so that I can strip down, transport and reconfigure for field day operations (sans charger). 73's Richard Clark, KB7QHC So you are saying it wont matter? I was wanting to use the marine battery I have but someone else posted a negative experience with the fumes ruining part of their house and their own health. It scared me a little. I was looking at power supplies on ebay and some of them stated 12 volts (older ones) some said 13.8. That is why I asked. I am still a little confused on what way I need to go. As far as I know, 100% of supplies sold for ham use are 13.8V, or thereabouts. 12 Volts was a standard voltage for many linear ICs, along with 15 V. My Astron switching supply came set for 14.05 V. I don't see that as a problem because all my stuff can be used in a car, and I have never seen the car voltage drop below 14 V with the engine running. Tam/WB2TT |
#8
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"Tam/WB2TT" wrote in message ... wrote in message oups.com... Richard Clark wrote: On 25 Jan 2005 08:22:59 -0800, wrote: When looking for a power supply for my Alinco dr-590, what type of power supply would I look for? The radio says 13.8 v dc but if I get a 12 volt power supply will it put out the same wattage at the radio? Hi Don, Do the math. You have the same load - less voltage. The power laws describe this simply as EČ/R. However, it is very, very, very unlikely that you have 12.0 V of anything as this is a "nominal" voltage, and almost never an actual voltage. The 12 V label is derived from the common application of the Lead-Acid Edison Battery. The cells of this battery develop 2.1 V potential, and with their common combination into batteries of either 3 cells or 6 cells, those bring the total up to 6.3 V or 12.6 V. Many here will recognize these values as common filament voltages for tubes. So even here, common transformers that are either 6 or 12 V specified, actually supply more voltage under load (because they were originally filament power transformers). The specification for 13.8 V is derived from the automotive electrical system that was designed (with its voltage regulator and generator/alternator) to supply a "float" voltage that would keep the battery topped off while simultaneously carrying the load. Hence, mobile applications are designed for this configuration and the source should be robust enough to support the load. Now, it seems to me you were using a deep discharge battery, or you were planning to do so. This is a common application in the shack, I have two batteries in parallel held up with a 20A trickle charge (voltage adjusted to the optimum value). The charger (actually a precision source from Acopian) is not large enough to supply my HF rigs under full power out (my Drake TR-7 is rated well above 100W) but the combination of batteries and charger manage quite well. Also, I have connectored everything so that I can strip down, transport and reconfigure for field day operations (sans charger). 73's Richard Clark, KB7QHC So you are saying it wont matter? I was wanting to use the marine battery I have but someone else posted a negative experience with the fumes ruining part of their house and their own health. It scared me a little. I was looking at power supplies on ebay and some of them stated 12 volts (older ones) some said 13.8. That is why I asked. I am still a little confused on what way I need to go. As far as I know, 100% of supplies sold for ham use are 13.8V, or thereabouts. 12 Volts was a standard voltage for many linear ICs, along with 15 V. My Astron switching supply came set for 14.05 V. I don't see that as a problem because all my stuff can be used in a car, and I have never seen the car voltage drop below 14 V with the engine running. Tam/WB2TT Bingo Try Sealed Lead Acid batteries, BTW. 73 H. |
#9
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"Tam/WB2TT" wrote in message
... I was wanting to use the marine battery I have but someone else posted a negative experience with the fumes ruining part of their house and their own health. It scared me a little. I have a marine battery charged by an Astron RS-20M and a 75w solar panel. I monitor the battery voltage and shut off the charging system when the battery is charged. That decreases the possibility of battery failure. -- 73, Cecil http://www.qsl.net/w5dxp ----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! 100,000 Newsgroups ---= East/West-Coast Server Farms - Total Privacy via Encryption =--- |
#10
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wrote I was wanting to use the marine battery I have but someone else posted a negative experience with the fumes ruining part of their house and their own health. It scared me a little. Starting with a new battery, I have used a 12v marine deep-cell with small float-charger to power a 25w VHF transceiver for over two years. For short periods, this will handle 100w xmit on an HF rig that draws 20-30amp. When a charger is connected to a battery, adequate ventilation must be provided, and the smoking lamp is "out". There is nothing wrong with using an emergency backup battery as part of normal (indoor) operations. It will provide hundreds of hours of monitoring and several minutes of low-power transmit w/o requiring a charge. Jack Painter Virginia Beach, Virginia |
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