How long can you listen? With a little help from ICOM and some battery manufactrurers, here is the estimate. We have little excuse for not monitoring because of battery drain unless one is limited to nicad (an unfortunate choice for backcountry paddling). ICOM B3, M7, M9, and M10 and M10a handheld VHF radios all discharge 19 milliamp per hour on standby, i.e. with power on and squelch turned up just slightly to inhibit static. Standard AA batteries operate in series (additively) so that the 6 batteries in an ICOM BP 90 pack produce 9 volts. Each battery produces 1.5 volts. If we presume a "cut off" threshold of 1.2 volts as minimum to activate equipment then at 20 degrees centigrade (68 degrees F), with a constant drain, the batteries will last 70 hours before the threshold is reached. At higher temperatures (113 degrees F.) drain is more rapid and batteries will reach threshold in 30 hours. For further technical information you may wish to contact Norvac Electric, (503) 644-1025 or Micro Power, (503) 626-7086. Also Rogers Marine at (503) 287-1101 and ICOM customer service at (206) 454-7619 then option #5. RGM Richard G. Mitchell, Jr. Department of Sociology Oregon State University Corvallis, OR 97331 U.S.A. (541) 752-1323 phone/fax mitchelr_at_ucs.orst.edu
attached mail follows:
-- Richard G. Mitchell, Jr. Department of Sociology Oregon State University Corvallis, OR 97331 U.S.A. (541) 752-1323 phone/fax mitchelr_at_ucs.orst.edu BATTERY ICOM M7, M9, M10 all discharge 19 milliamp per hour on standby, i.e. with power on and squelch turned up just ®MDUL¯slightly®MDNM¯ to inhibit reception. Standard AA batteries operate in series (additively) so that the 6 batteries in a the BP 90 pack produce 9 volts. Each battery produces 1.5 volts. If we presume a "cut off" threshold of 1.2 volts as minimum to activate equipment then at 20 degrees centigrade (68 degrees F), with a constant drain, the batteries will last 70 hours before the threshold is reached. At higher temperatures (113 degrees F.) drain is more rapid and batteries will reach threshold in 30 hours. Contact Norvac Electric, 644-1025 for fresh batteries and Micro Power, 626-7086 for excellent technical wholesale information. Also Rogers Marine at (503) 287-1101 and ICOM customer service at (206) 454-7619 then option #5. *************************************************************************** PaddleWise Paddling Mailing List Submissions: paddlewise_at_lists.intelenet.net Subscriptions: paddlewise-request_at_lists.intelenet.net Website: http://www.gasp-seakayak.net/paddlewise/ ***************************************************************************
My question would be not when do the batteries drain to much to keep monitoring, but when do they drain so much that you have compromized your own transmit power? If we assume 70 hours of monitoring before we can no longer monitor, then we could also assume that transmit power requirements would be compromised much earlier. This is in part due to the larger current demands which if I remember correctly would produce a corresponding voltage drop. This would seem to indicate that on a day trip using alkaline batteries, we could all monitor, but that on a multi day trip we may have a battery degradation issue. For what it's worth all of my radios are nicad, but I have a spare battery pack that is alkaline for one of them, and I bring that on my multi day trips. And in answer to Daves survey, I only leave mine on when I am on short day trips or when crossing shipping lanes here in the Pacific NW. On any of my more remote longer trips (when as a form of any help may be better than no help) I unfortunatly keep the radios off to save battery life. Has anyone in the group done any standby drain and then transmit tests at different temperatures? -Saul At 03:40 AM 12/3/98 -0800, Richard Mitchell wrote: >How long can you listen? With a little help from ICOM and some >battery manufactrurers, here is the estimate. We have little >excuse for not monitoring because of battery drain unless one is >limited to nicad (an unfortunate choice for backcountry >paddling). > >ICOM B3, M7, M9, and M10 and M10a handheld VHF radios all >discharge 19 milliamp per hour on standby, i.e. with power on and >squelch turned up just slightly to inhibit static. Standard AA >batteries operate in series (additively) so that the 6 batteries >in an ICOM BP 90 pack produce 9 volts. Each battery produces 1.5 >volts. If we presume a "cut off" threshold of 1.2 volts as >minimum to activate equipment then at 20 degrees centigrade (68 >degrees F), with a constant drain, the batteries will last 70 >hours before the threshold is reached. At higher temperatures >(113 degrees F.) drain is more rapid and batteries will reach >threshold in 30 hours. > >For further technical information you may wish to contact Norvac >Electric, (503) 644-1025 or Micro Power, (503) 626-7086. Also >Rogers Marine at (503) 287-1101 and ICOM customer service at >(206) 454-7619 then option #5. > >RGM > >Richard G. Mitchell, Jr. >Department of Sociology >Oregon State University >Corvallis, OR 97331 >U.S.A. >(541) 752-1323 phone/fax >mitchelr_at_ucs.orst.eduMessage-ID: <3666765C.47DF31B5_at_ucs.orst.edu> >Date: Thu, 03 Dec 1998 03:30:36 -0800 >From: Richard Mitchell <mitchelr_at_ucs.orst.edu> >X-Mailer: Mozilla 4.04 [en] (Win95; U) >MIME-Version: 1.0 >To: Richard Mitchell <mitchelr_at_ucs.orst.edu> >Subject: Batery >Content-Type: multipart/mixed; boundary="------------DE5FC531F4E0E0145F5E61FC" > >-- >Richard G. Mitchell, Jr. >Department of Sociology >Oregon State University >Corvallis, OR 97331 >U.S.A. >(541) 752-1323 phone/fax >mitchelr_at_ucs.orst.eduBATTERY > >ICOM M7, M9, M10 all discharge 19 milliamp per hour on standby, i.e. with power on and squelch turned up just ®MDUL¯slightly®MDNM¯ to inhibit reception. Standard AA batteries operate in series (additively) so that the 6 batteries in a the BP 90 pack produce 9 volts. Each battery produces 1.5 volts. If we presume a "cut off" threshold of 1.2 volts as minimum to activate equipment then at 20 degrees centigrade (68 degrees F), with a constant drain, the batteries will last 70 hours before the threshold is reached. At higher temperatures (113 degrees F.) drain is more rapid and batteries will reach threshold in 30 hours. > >Contact Norvac Electric, 644-1025 for fresh batteries and Micro Power, 626-7086 for excellent technical wholesale information. Also Rogers Marine at (503) 287-1101 and ICOM customer service at (206) 454-7619 then option #5. > > Saul Kinderis saul_at_isomedia.com tel:(425)402-3426 *************************************************************************** PaddleWise Paddling Mailing List Submissions: paddlewise_at_lists.intelenet.net Subscriptions: paddlewise-request_at_lists.intelenet.net Website: http://www.gasp-seakayak.net/paddlewise/ ***************************************************************************
Saul Kinderis wrote: > > My question would be not when do the batteries drain too much to keep > monitoring, but when do they drain so much that you have compromized your > own transmit power? > > If we assume 70 hours of monitoring before we can no longer monitor, then we > could also assume that transmit power requirements would be compromised much > earlier. This is in part due to the larger current demands which if I > remember correctly would produce a corresponding voltage drop. This would > seem to indicate that on a day trip using alkaline batteries, we could all > monitor, but that on a multi day trip we may have a battery degradation issue. [snip] > Has anyone in the group done any standby drain and then transmit tests at > different temperatures? Sort of. See below. > At 03:40 AM 12/3/98 -0800, Richard Mitchell wrote: > >How long can you listen? With a little help from ICOM and some > >battery manufactrurers, here is the estimate. We have little > >excuse for not monitoring because of battery drain unless one is > >limited to nicad (an unfortunate choice for backcountry > >paddling). > > > >ICOM B3, M7, M9, and M10 and M10a handheld VHF radios all > >discharge 19 milliamp per hour on standby, i.e. with power on and > >squelch turned up just slightly to inhibit static. [snip] > >the batteries will last 70 > >hours before the threshold is reached. At higher temperatures > >(113 degrees F.) drain is more rapid and batteries will reach > >threshold in 30 hours. I have not done any controlled, quantitative studies of the sort Saul describes. However, I am confident that my typical use on an extended trip gives me about 5 - 6 days of monitoring, and that I can expect good battery performance for an hour of TX, even on that fifth (or sixth) day. Here's my rationale: The radio is on, in Rich's "19 milliamp mode," when I am on the water, which is only about 5 - 6 hours per day, with maybe another 15-20 minutes of weather monitoring each day. That's about 30 - 35 hours at the end of the sixth day. Because I only paddle in temperate places (<70 F), that leaves me about "half" of the alkaline's capacity remaining, enough for the 30 - 60 minutes of TX I might need in an emergency. (Calculation: TX current is about 500 milliamps: 500 mA x 1 hr = 500 mA-hr capacity needed; 19 mA x 35 hr = 665 mA-hr capacity available.) To confirm that I still have live batteries with the capacity to handle 30 - 60 minutes of TX, I pull a battery from the pack at the end of each day and hit the "PowerCheck" strip. When the indicator falls below 70 per cent, I would replace the batteries with fresh, *even if I have not used the batteries for 5 - 6 days yet.* So far, I have never seen the indicator go below 70 per cent with this use method. I think this means I'm OK. This protocol generates a pile of "half-spent" alkalines, which I cycle through headlamps, etc., to avoid wasting their energy. Yeah, I go home with a handfull of alkalines. But, I have a radio I can leave on for monitoring, AND which can handle TX needs, on an extended trip. During the rest of the year, when most of my trips are day trips -- and sporadically placed -- I use the PowerCheck strip to confirm that I have capacity, before I leave home. Naturally, there is always at least one complete set of fresh alkalines in my E-bag every time I launch, in case the set in the radio pukes. -- Dave Kruger Astoria, OR sea kayaker / chemist *************************************************************************** PaddleWise Paddling Mailing List Submissions: paddlewise_at_lists.intelenet.net Subscriptions: paddlewise-request_at_lists.intelenet.net Website: http://www.gasp-seakayak.net/paddlewise/ ***************************************************************************
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