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#1
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stereo loses settings when startup
Help! Got a '55 Studebaker. Aftermkt. mp3/cd/amfm radio. If I set
stations, it remembers fine going from on to off to access to off. But! When I start i, the starter seems to drop the "voltage threshold"(at least that's what I visualize) such that all memory settings are lost. Ideas, please? Thank you, s |
#2
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"sdlomi2" > wrote in message ... > Help! Got a '55 Studebaker. Aftermkt. mp3/cd/amfm radio. If I set > stations, it remembers fine going from on to off to access to off. But! > When I start i, the starter seems to drop the "voltage threshold"(at least > that's what I visualize) such that all memory settings are lost. > Ideas, please? Thank you, s > > > Maybe a small 12V battery or large capacitor that's hooked up with a diode between it and the car battery so voltage to the stereo won't drop when the car battery voltage drops significantly. -Bruce |
#3
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"Bruce Chang" > wrote in message . com... > > "sdlomi2" > wrote in message > ... > > Help! Got a '55 Studebaker. Aftermkt. mp3/cd/amfm radio. If I set > > stations, it remembers fine going from on to off to access to off. But! > > When I start i, the starter seems to drop the "voltage threshold"(at least > > that's what I visualize) such that all memory settings are lost. > > Ideas, please? Thank you, s > > > > > > > > Maybe a small 12V battery or large capacitor that's hooked up with a diode > between it and the car battery so voltage to the stereo won't drop when the > car battery voltage drops significantly. > > -Bruce > > Bruce, thanks. I like these ideas, and prefer the capacitor idea. But, I need specifics; I understand the theory & agree with you on both. But my background is ME instead of EE, so I need someone to do a 'practical design' so I can assemble the components. More help, please? Sorry to ask so much, but I'll admit where my knowledge ends! s |
#4
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"sdlomi2" > wrote in message ... > > "Bruce Chang" > wrote in message > . com... >> >> "sdlomi2" > wrote in message >> ... >> > Help! Got a '55 Studebaker. Aftermkt. mp3/cd/amfm radio. If I set >> > stations, it remembers fine going from on to off to access to off. >> > But! >> > When I start i, the starter seems to drop the "voltage threshold"(at > least >> > that's what I visualize) such that all memory settings are lost. >> > Ideas, please? Thank you, s >> > >> > >> > >> >> Maybe a small 12V battery or large capacitor that's hooked up with a >> diode >> between it and the car battery so voltage to the stereo won't drop when > the >> car battery voltage drops significantly. >> >> -Bruce >> >> > Bruce, thanks. I like these ideas, and prefer the capacitor idea. > But, > I need specifics; I understand the theory & agree with you on both. But > my > background is ME instead of EE, so I need someone to do a 'practical > design' > so I can assemble the components. More help, please? Sorry to ask so > much, but I'll admit where my knowledge ends! s > > I would imagine you could use an IN4001 diode and wire that from a constant 12V to the positive terminal of the capacitor which is connected to the constant power lead of your radio. The negative terminal of the capacitor should be connected to the ground of the radio. Everything else should remain the same. How big a capacitor? That's a good question. Let me think outquiet. Energy stored in a Capacitor = 1/2 C V*2 Joules 1 Joule is 1 watt for 1 second. Your radio will draw 50mA at 12.6 while the engine is off. That's equal to ..63W and multiply for 5 seconds of cranking (I know, I'm doing a lot of assuming that things remain constant. Based on those figures, you'd need a 39000uF capacitor or bigger. (if I did my calculations right). It's been a long time since college. -Bruce |
#5
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"Bruce Chang" > wrote in message . com... > > "sdlomi2" > wrote in message > ... >> >> "Bruce Chang" > wrote in message >> . com... >>> >>> "sdlomi2" > wrote in message >>> ... >>> > Help! Got a '55 Studebaker. Aftermkt. mp3/cd/amfm radio. If I >>> > set >>> > stations, it remembers fine going from on to off to access to off. >>> > But! >>> > When I start i, the starter seems to drop the "voltage threshold"(at >> least >>> > that's what I visualize) such that all memory settings are lost. >>> > Ideas, please? Thank you, s >>> > >>> > >>> > >>> >>> Maybe a small 12V battery or large capacitor that's hooked up with a >>> diode >>> between it and the car battery so voltage to the stereo won't drop when >> the >>> car battery voltage drops significantly. >>> >>> -Bruce >>> >>> >> Bruce, thanks. I like these ideas, and prefer the capacitor idea. >> But, >> I need specifics; I understand the theory & agree with you on both. But >> my >> background is ME instead of EE, so I need someone to do a 'practical >> design' >> so I can assemble the components. More help, please? Sorry to ask so >> much, but I'll admit where my knowledge ends! s >> >> > > I would imagine you could use an IN4001 diode and wire that from a > constant 12V to the positive terminal of the capacitor which is connected > to the constant power lead of your radio. The negative terminal of the > capacitor should be connected to the ground of the radio. Everything else > should remain the same. > > How big a capacitor? That's a good question. Let me think outquiet. > > Energy stored in a Capacitor = 1/2 C V*2 Joules > > 1 Joule is 1 watt for 1 second. > > Your radio will draw 50mA at 12.6 while the engine is off. That's equal > to .63W and multiply for 5 seconds of cranking (I know, I'm doing a lot of > assuming that things remain constant. > > Based on those figures, you'd need a 39000uF capacitor or bigger. (if I > did my calculations right). It's been a long time since college. > > -Bruce > I'd be cautious of using a 1N4001 diode for this purpose as it has a current capacity of 1 amp. Unlike some older units, most newer head units draw full power from the "constant" lead and use the "switched" lead only as a signal for the head unit to power on/off - backwards of what one might tend to think. Other head units used the [typically orange] "constant" wire only for memory retention. The reason they have started using the "contant" wire instead of the "switched" wire for power is so that head units with logic-controlled cassette mechanisms, CD players, and motorized faceplates can load/eject with the ignition off. Roger |
#6
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In article > ,
Bruce Chang > wrote: > >"sdlomi2" > wrote in message ... >> Help! Got a '55 Studebaker. Aftermkt. mp3/cd/amfm radio. If I set >> stations, it remembers fine going from on to off to access to off. But! >> When I start i, the starter seems to drop the "voltage threshold"(at least >> that's what I visualize) such that all memory settings are lost. >> Ideas, please? Thank you, s >> >> >> > >Maybe a small 12V battery or large capacitor that's hooked up with a diode >between it and the car battery so voltage to the stereo won't drop when the >car battery voltage drops significantly. > You need two diodes. One diode prevents the car from trying to charge the small batteries, and the second to keep the small batteries from trying to help crank the starter. The large capacitor will cause a voltage spike, just after the motor starts, so a choke coil will be needed to protect the sound unit. Here, in the Great White North (How's it goin', eh?), we would advise you that your battery is seriously short of cold cranking amperage and that you should buy the biggest battery that will fit in the tray. However, being designed for old-tech batteries, you should accept anything that covers half of your '55 studebaker's battery tray. While cold weather starting may be the least of your worries, a larger battery is the simplest (if not the cheapest) solution to your problem. |
#7
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"Richard Bell" > wrote in message ... > Here, in the Great White North (How's it goin', eh?), we would advise you > that > your battery is seriously short of cold cranking amperage and that you > should buy the biggest battery that will fit in the tray. However, being > designed for old-tech batteries, you should accept anything that covers > half > of your '55 studebaker's battery tray. While cold weather starting may be > the least of your worries, a larger battery is the simplest (if not the > cheapest) solution to your problem. > I couldn't agree more, all those other fixes are just going to hide the symptom and not repair the problem which is either a bad battery, a bad connection or bad wiring. Bob |
#8
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Richard Bell wrote: > In article > , > Bruce Chang > wrote: > > > >"sdlomi2" > wrote in message > ... > >> Help! Got a '55 Studebaker. Aftermkt. mp3/cd/amfm radio. If I set > >> stations, it remembers fine going from on to off to access to off. But! > >> When I start i, the starter seems to drop the "voltage threshold"(at least > >> that's what I visualize) such that all memory settings are lost. > >> Ideas, please? Thank you, s > >> > >> > >> > > > >Maybe a small 12V battery or large capacitor that's hooked up with a diode > >between it and the car battery so voltage to the stereo won't drop when the > >car battery voltage drops significantly. > > > > You need two diodes. One diode prevents the car from trying to charge the > small batteries, and the second to keep the small batteries from trying to > help crank the starter. The large capacitor will cause a voltage > spike, just after the motor starts, so a choke coil will be needed to > protect the sound unit. > > Here, in the Great White North (How's it goin', eh?), we would advise you that > your battery is seriously short of cold cranking amperage and that you > should buy the biggest battery that will fit in the tray. However, being > designed for old-tech batteries, you should accept anything that covers half > of your '55 studebaker's battery tray. While cold weather starting may be > the least of your worries, a larger battery is the simplest (if not the > cheapest) solution to your problem. Replacing the battery tray with one from a 56-64 Stude (assuming it's a C-K body, I'm not sure about sedans) will allow a larger battery to fit. nate |
#9
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Richard Bell wrote: > In article > , > Bruce Chang > wrote: > > > >"sdlomi2" > wrote in message > ... > >> Help! Got a '55 Studebaker. Aftermkt. mp3/cd/amfm radio. If I set > >> stations, it remembers fine going from on to off to access to off. But! > >> When I start i, the starter seems to drop the "voltage threshold"(at least > >> that's what I visualize) such that all memory settings are lost. > >> Ideas, please? Thank you, s > >> > >> > >> > > > >Maybe a small 12V battery or large capacitor that's hooked up with a diode > >between it and the car battery so voltage to the stereo won't drop when the > >car battery voltage drops significantly. > > The large capacitor will cause a voltage > spike, just after the motor starts, so a choke coil will be needed to > protect the sound unit. Inductors generate spikes, not capacitors. The best arrangement has a choke in the supply line, with a capacitor between the hot side of the choke and ground. That'll swallow most interference. It would take a pretty big capacitor to keep a stereo happy. Spikes are generated by the starter solenoid and by the starter itself when the current is cut off. A capacitor cannot provide any higher voltage than it was provided with in the first place, but an inductor like a solenoid can make a 600-volt spike. I've measured it. It's the principle behind the ignition coil. > Here, in the Great White North (How's it goin', eh?), we would advise you that > your battery is seriously short of cold cranking amperage and that you > should buy the biggest battery that will fit in the tray. However, being > designed for old-tech batteries, you should accept anything that covers half > of your '55 studebaker's battery tray. While cold weather starting may be > the least of your worries, a larger battery is the simplest (if not the > cheapest) solution to your problem. A 35-watt electric battery blanket will make that battery perform. Some guys use them instead of a block heater. A battery loses something like 60% of its capacity at -25 degrees C. Dan |
#10
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In article om>,
> wrote: > >Richard Bell wrote: >The large capacitor will cause a voltage >> spike, just after the motor starts, so a choke coil will be needed to >> protect the sound unit. > >Inductors generate spikes, not capacitors. The best >arrangement has a choke in the supply line, with a capacitor between >the hot side of the choke and ground. That'll swallow most >interference. It would take a pretty big capacitor to keep a stereo >happy. The car sits with the engine not running for a long time, so the voltage on the capacitor drops to the battery terminal voltage (hopefully 12.6v). During cranking, the battery voltage drops to below the keep-alive threshold (whatever that is), but the low load of the audio system keep the cap at about 12.6v. The engine catches, and the alternator now cranks out current at a voltage that will charge the battery (14+ volts). The cap draws a current appropriate to two or more volts divided by the wire's resistance in ohms, or a few tens of amps. As all wires in the real world, running close (or within) large steel objects have non-zero inductance, the circuit will ring. Without the capacitor, the switching transient is not as bad, as there is no apparent short circuit to a lower voltage, so there is no inrush overcurrent. Switching transients always happen. Capacitors make them worse. On some powerlines, switched capacitor banks are more serious than lightning strikes. |
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