NON GS electrical question. 12v power universal adapter?

[skip]

The power adapter for my Sirius satellite radio broke. I can get a new one online for about 10 dollars no big deal but It won't get here for two to three weeks. It is 12 v DC in and 5.2 v DC out to the radio. I have a universal adapter here at home ( read free) But it is only adjustable to either 4.5 v or 6 DC . I am riding the bike both this weekend and next and want to use the radio. Which setting is least likely to hurt the radio, 4. 5 or 6v ? the radio works on both settings and I cant tell the difference between the two. Just curious if either one would do harm until the new adapter gets here...........thanks................skip

[SqDancerLynn1]

I would probably use it on the 4.5 volts. If you checked the voltage with it unhooked it would probably read over 5 volts. depending on how much current the adapter takes it should be ok. Or use the 6 volt and put a
5 ohm ?? 5w resistor in series to drop the voltage

[skip]

I would probably use it on the 4.5 volts. If you checked the voltage with it unhooked it would probably read over 5 volts. depending on how much current the adapter takes it should be ok. Or use the 6 volt and put a
5 ohm ?? 5w resistor in series to drop the voltage

That makes sense. Now after further looking into it the original ( broken)adapter was 1.5 amps but the universal I want to use is 500 MA. I know They use the original adapter on many different modlels so that may be why its was higher rated. Is that a problem? like I said the radio appears to work fine,on both 4.5 and 6v, I just don't want to damage it before the correct adapter gets here.

[Steve]

Most of those little power adapters are poorly regulated. That is why they specify the load on the label. If yours is rated for 5.2 volts and 1500mA, and you want to use a 500mA supply, you might want to use the higher voltage. If you set it for 6 volts and measure the unloaded voltage, you will find that it's considerably higher. If you connect it to your radio and draw more than its rated load of 500mA, it will draw the voltage down farther than 6 volts, probably close to the 5.2 that your radio is looking for. Just be aware that constantly drawing about three times the rated capacity will not contribute to the longevity of the supply. When the supply goes, there is no telling if the radio will go with it. Good luck.

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[skip]

Most of those little power adapters are poorly regulated. That is why they specify the load on the label. If yours is rated for 5.2 volts and 1500mA, and you want to use a 500mA supply, you might want to use the higher voltage. If you set it for 6 volts and measure the unloaded voltage, you will find that it's considerably higher. If you connect it to your radio and draw more than its rated load of 500mA, it will draw the voltage down farther than 6 volts, probably close to the 5.2 that your radio is looking for. Just be aware that constantly drawing about three times the rated capacity will not contribute to the longevity of the supply. When the supply goes, there is no telling if the radio will go with it. Good luck.

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thanks steve. I orderd the new power supply I will just use the universal one till it gets here, the few times I ride between now and then. If its drawing too much from the supply would it blow the fuse in the supply before it did any damage to the radio?

[Steve]

... would it blow the fuse in the supply before it did any damage to the radio?

It would likely either blow the fuse or the supply itself before it did anything to the radio. A lot depends on whether the fuse is rated just over what the supply is rated for, since you are asking the supply to provide three times its rating. It could also fall under what we here on the board call the "Previous Owner Syndrome". It goes something like this: "Darn, just blew the fuse. Oh, my, it's only a 1-amp fuse. I don't have any of those here, I'll just put in this 5-amp fuse." I think you know what I mean.

Since you are overloading the supply, the voltage will be lower than its rating (6 volts, you say?). How much lower would be a guess, unless you can measure it. The radio is not likely to be hurt by the lower voltage, it just won't work as well. However, if the supply fails in a manner that shorts out the regulator, it could spike the voltage.

Kinda reminds you of a GS R/R, doesn't it?

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[skip]

Thanks steve! electricity has always been my down fall, you cleared things up well.

[Steve]

Sometimes it makes it easier if you think of electricity as water. (It flows and it has pressure.) You have a pump that is capable of putting out 6 psi if you are drawing 500 gallons per hour. Now you are asking it to supply 1500 gallons per hour, so it won't be able to keep the same pressure up. If you keep asking the pump to put out 1500 gph, it may burn out or it may not, depends on the type of pump. If you turn off the tap and stop the flow, your pressure might go up to 8 or 10, but at 500 gph, it will be 6. Does that help at all?

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