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Author Topic: Portable battery power  (Read 23751 times)
KI5FJ
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Posts: 49




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« Reply #15 on: October 10, 2013, 05:17:01 PM »

My emergency power consists of three 35 AHr AGMs in parallel.(105 AHr)
Solar panel to charge regulator to the batteries. To raise the fully charged voltage from 12.8 to 13.8V , a TGE (N8XJK design) Boost Regulator (40Amp) is used. The RF sense improves the effiency by only boosting when transmitting. If you want a pdf of a Off-the-Grid Emcomm presentation I prepared for our local club email me at QRZ address. 73 Joe O NNNN
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W8JX
Member

Posts: 12081




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« Reply #16 on: October 15, 2013, 09:09:15 AM »

My emergency power consists of three 35 AHr AGMs in parallel.(105 AHr)
Solar panel to charge regulator to the batteries. To raise the fully charged voltage from 12.8 to 13.8V , a TGE (N8XJK design) Boost Regulator (40Amp) is used. The RF sense improves the effiency by only boosting when transmitting. If you want a pdf of a Off-the-Grid Emcomm presentation I prepared for our local club email me at QRZ address. 73 Joe O NNNN

You will never see any difference down range from the "boost" but you will in deceased battery life.
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Ham since 1969....  Old School 20wpm REAL Extra Class..
W6EM
Member

Posts: 1664




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« Reply #17 on: October 29, 2013, 04:36:41 PM »

My emergency power consists of three 35 AHr AGMs in parallel.(105 AHr)
Solar panel to charge regulator to the batteries. To raise the fully charged voltage from 12.8 to 13.8V , a TGE (N8XJK design) Boost Regulator (40Amp) is used. The RF sense improves the effiency by only boosting when transmitting. If you want a pdf of a Off-the-Grid Emcomm presentation I prepared for our local club email me at QRZ address. 73 Joe O NNNN

You will never see any difference down range from the "boost" but you will in deceased battery life.

I'm sure that you meant "decreased," but funny oversight.  Not sure what you meant, in that you could reduce usable service life by excessive discharge, but the problem is largely about radios being intolerant of less than 12VDC.  So, an increase in useable battery time interval is what the result will be, if not careless in regard to final battery voltage.
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W8JX
Member

Posts: 12081




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« Reply #18 on: October 30, 2013, 10:44:21 AM »

My emergency power consists of three 35 AHr AGMs in parallel.(105 AHr)
Solar panel to charge regulator to the batteries. To raise the fully charged voltage from 12.8 to 13.8V , a TGE (N8XJK design) Boost Regulator (40Amp) is used. The RF sense improves the effiency by only boosting when transmitting. If you want a pdf of a Off-the-Grid Emcomm presentation I prepared for our local club email me at QRZ address. 73 Joe O NNNN

You will never see any difference down range from the "boost" but you will in deceased battery life.

I'm sure that you meant "decreased," but funny oversight.  Not sure what you meant, in that you could reduce usable service life by excessive discharge, but the problem is largely about radios being intolerant of less than 12VDC.  So, an increase in useable battery time interval is what the result will be, if not careless in regard to final battery voltage.

There is no free lunch here. To maintain 13.8 volts here you will have increased demand on battery(s) and also converter consumes some power too. If you try to make up for this by drawing batteries down more you will reduce their service life. Plus. the extra 10 or 20 watts out you gain will make no noticeable difference down range. So, it is more a state of mind what one thinks is gained here rather than what is actually happening.
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Ham since 1969....  Old School 20wpm REAL Extra Class..
W6EM
Member

Posts: 1664




Ignore
« Reply #19 on: October 30, 2013, 05:26:14 PM »

My emergency power consists of three 35 AHr AGMs in parallel.(105 AHr)
Solar panel to charge regulator to the batteries. To raise the fully charged voltage from 12.8 to 13.8V , a TGE (N8XJK design) Boost Regulator (40Amp) is used. The RF sense improves the effiency by only boosting when transmitting. If you want a pdf of a Off-the-Grid Emcomm presentation I prepared for our local club email me at QRZ address. 73 Joe O NNNN

You will never see any difference down range from the "boost" but you will in deceased battery life.

I'm sure that you meant "decreased," but funny oversight.  Not sure what you meant, in that you could reduce usable service life by excessive discharge, but the problem is largely about radios being intolerant of less than 12VDC.  So, an increase in useable battery time interval is what the result will be, if not careless in regard to final battery voltage.

There is no free lunch here. To maintain 13.8 volts here you will have increased demand on battery(s) and also converter consumes some power too. If you try to make up for this by drawing batteries down more you will reduce their service life. Plus. the extra 10 or 20 watts out you gain will make no noticeable difference down range. So, it is more a state of mind what one thinks is gained here rather than what is actually happening.
No argument about consuming power to run the boost regulator.  However, as others attest to, the minimum voltage that several rigs tolerate is just about 12VDC.  And, you can drop the cell voltage to under 2.0V without damaging them.  So, there is something to be gained.  I don't have a discharge voltage profile handy, but I'd bet that maybe there's a double-digit percentage of usable energy that would otherwise be untapped for those with voltage-sensitive equipment.
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W8JX
Member

Posts: 12081




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« Reply #20 on: October 31, 2013, 06:42:04 AM »

If you want max battery service life you really want to limit discharge to 11.5 volts or so. A "better" solution is to use and large capacitor of a few hundred thousand uf or more in parallel with load. It will keep a weak battery usable longer with SSB than just a converter will. It also improves battery efficiency because they see a lower peak load under SSB modulation.
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Ham since 1969....  Old School 20wpm REAL Extra Class..
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