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#1
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Battery drain question
About how long can a fixed mount VHF radio be left on, receive only,
at anchor, engine off, before the battery is unable to crank the engine? The radio being the only accessory switched on. Thanks, HJJ |
#2
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Battery drain question
It depends how much current the radio draws. We all know that leaving your
car dome light on will kill your battery within a couple of hours... Why not install a Perko dual battery switcher? This will eliminate those worries about leaving things on too long. Battery 1 - For engine cranking only Battery 2 - For Accessories only Using the perko switch, when the motor is running select ALL. This will charge & use both batteries for cranking. When the motor is off, select battery 2. This will only drain the 2nd battery. I use this setup in every boat I ever owned. Jim Rojas wrote in message ... About how long can a fixed mount VHF radio be left on, receive only, at anchor, engine off, before the battery is unable to crank the engine? The radio being the only accessory switched on. Thanks, HJJ |
#3
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Battery drain question
Jim,
While stationed in the Navy on guard duty I observed a car that had its head lights left on, it took about two to three hours, if memory still serves, to extinguish. I leave my radar detector on all the time without problem, I've come back to the vehicle after 10 hours to find a goose-necked halogen map light I have left on. Had no problem starting the vehicle. Paul "Jim Rojas" wrote in message ... It depends how much current the radio draws. We all know that leaving your car dome light on will kill your battery within a couple of hours... Why not install a Perko dual battery switcher? This will eliminate those worries about leaving things on too long. Battery 1 - For engine cranking only Battery 2 - For Accessories only Using the perko switch, when the motor is running select ALL. This will charge & use both batteries for cranking. When the motor is off, select battery 2. This will only drain the 2nd battery. I use this setup in every boat I ever owned. Jim Rojas wrote in message ... About how long can a fixed mount VHF radio be left on, receive only, at anchor, engine off, before the battery is unable to crank the engine? The radio being the only accessory switched on. Thanks, HJJ |
#4
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Battery drain question
Yes, it all depends on the battery size and the age.
Jim Rojas "Paul Schilter" paulschilter@comcast,dot,net wrote in message ... Jim, While stationed in the Navy on guard duty I observed a car that had its head lights left on, it took about two to three hours, if memory still serves, to extinguish. I leave my radar detector on all the time without problem, I've come back to the vehicle after 10 hours to find a goose-necked halogen map light I have left on. Had no problem starting the vehicle. Paul "Jim Rojas" wrote in message ... It depends how much current the radio draws. We all know that leaving your car dome light on will kill your battery within a couple of hours... Why not install a Perko dual battery switcher? This will eliminate those worries about leaving things on too long. Battery 1 - For engine cranking only Battery 2 - For Accessories only Using the perko switch, when the motor is running select ALL. This will charge & use both batteries for cranking. When the motor is off, select battery 2. This will only drain the 2nd battery. I use this setup in every boat I ever owned. Jim Rojas wrote in message ... About how long can a fixed mount VHF radio be left on, receive only, at anchor, engine off, before the battery is unable to crank the engine? The radio being the only accessory switched on. Thanks, HJJ |
#5
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Battery drain question
Probably days. The receive portion takes very little power. My handheld
will go a couple of days in listen mode. Bill "Jim Rojas" wrote in message news Yes, it all depends on the battery size and the age. Jim Rojas "Paul Schilter" paulschilter@comcast,dot,net wrote in message ... Jim, While stationed in the Navy on guard duty I observed a car that had its head lights left on, it took about two to three hours, if memory still serves, to extinguish. I leave my radar detector on all the time without problem, I've come back to the vehicle after 10 hours to find a goose-necked halogen map light I have left on. Had no problem starting the vehicle. Paul "Jim Rojas" wrote in message ... It depends how much current the radio draws. We all know that leaving your car dome light on will kill your battery within a couple of hours... Why not install a Perko dual battery switcher? This will eliminate those worries about leaving things on too long. Battery 1 - For engine cranking only Battery 2 - For Accessories only Using the perko switch, when the motor is running select ALL. This will charge & use both batteries for cranking. When the motor is off, select battery 2. This will only drain the 2nd battery. I use this setup in every boat I ever owned. Jim Rojas wrote in message ... About how long can a fixed mount VHF radio be left on, receive only, at anchor, engine off, before the battery is unable to crank the engine? The radio being the only accessory switched on. Thanks, HJJ |
#6
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Battery drain question
wrote in message ... About how long can a fixed mount VHF radio be left on, receive only, at anchor, engine off, before the battery is unable to crank the engine? The radio being the only accessory switched on. That mostly depends on the battery you have and how much current the motor will take to start. If you have an old, weak 24 series battery need to crank up a 6 liter diesel the answer may be zero. On the other hand, if you have a 400 amp-hour battery bank and only need to crank up a 75 Hp 2 cycle outboard the answer might be weeks! If you have the specifications for your VHF (owner's manual, or perhaps a catalog page) it should provide the receive "standby" current draw. This is usually the current draw when the receiver is quiet, and not driving its speaker. I would expect a standby current of 0.25 amps or so for a modern radio. When the radio is noisy (driving the speaker) the current draw will be a function of how high the volume is, but I would expect it to be less than a watt. If you are monitoring channel 16 then there should be a fair amount of traffic, so I would assume about 0.5 amps on an average. A typical 27 series deep cycle battery (the larger of the standard battery sizes) will provide around 100 amp-hours. That battery could run the VHF in standby mode for 200 hours. In a 24 hour period it would have only drained your battery about 12 %. I would certainly hope that your battery has more than a 12% margin for capacity on starting the engine. Or at least it did when the battery was new. There will come a day, however, when the battery is getting old and you may have no reserve at all. Rod McInnis |
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