Post by totalnet32How many amps does the sportster 4 need?
I was looking for a 12 volt cigrette splitter that could handle 3
devices. THe only one so far only supported 5 amps total.
Indirect reasoning . . . With 8 alkaline D cells, the boombox
with Sportster 4 is supposed to be good for 9 hours. Energizer's
Milliamp Capacity bar chart in their product datasheet for their
Energizer E95 alkaline D cell rates them like so :
Current mAh # hours*
25ma 23,000 920
100ma 15,000 150
250ma 13,000 52
500ma 10,000 20
1,000ma 6,000** 6
* calculated from the Current and mAh values
**estimated from a different "Industry Standard Test" chart in the
datasheet, using a 1.5ohm resistance.
The boombox probably draws closest to the 500ma level, but that
doesn't mean that it would get anything near 20 hours of use from
the batteries. The Sportster 4 would probably cut out well before
the batteries reached their specified number of service hours, where
the voltage would be 0.8volts/cell, or providing 6.4 volts to the
boombox. My guess would then be that the boombox probably draws
from 600ma to 750ma, and the Sportster 4 itself would have to use
less current than this. If I was to buy a transformer that would
power the Sportster all day long, for long term use I'd want one
rated for at least 1 amp. The one supplied with the boombox is
rated at 12v at 3 amps, but then it has to be able to handle the
current when the boombox's volume is turned way up.
The 5 amp power supply splitter you found should be more than
adequate, unless the other two devices are real power hogs.
Supplementary info. from the Sportster 4's manual. It's not
actually powered by 12v, but indirectly, by 4.9 to 5.6 volts. The
cigarette lighter adapter uses a 2A Slow Blow fuse. As expected,
the manual doesn't provide any information about how much current
the Sportster actually uses, but from the above calculations, I'd
think that with nothing else drawing much current, Sirius's
cigarette lighter adapter could probably use a 1A slow blow fuse.