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    I like my SP4 and am using it primarily for my astronomy hobby that takes me to dark and cold places where I have to carry my own electrical power. After much search I chose and bought a car charger designed for the SP4. It's rating matches that of the brick that comes with SP4: 12v, 2.58A. But when I hook it up to my portable power source which is a 12v 35Ah deep cycle AGM battery, the charger only pulls about 1.6 amps and pretty much just keeps the SP alive - it does not charge.

    I am not sure if the label on the charger simply means it can handle 2.58 amps or it falsely claims that it can pull and provide to the SP4 the 2.58 amp current that it needs.

    My main question here is about the role that the computer plays in charging of its battery. Is it possible that the computer is simply not pulling enough?

    As opposed to voltage which is pushed into a machine, current is something that the using and needing machine pulls from a source. So a charger, car charger or the brick, seem to play a role as a bridge. Ultimately the computer is the one that is inhaling the amperage from the brick and from the char charger. So if the car charger doesn't have the ability to satisfy the need of the computer then IT suffers and maybe gets damaged because of over-pulling by a commuter desperate for the current? Or is it possible that the computer just doesn't like the non-native power sourc and is programmed to pull in less just to be on the safe side?

    I want to look for and find a more reliable portable power supply for it but I am not sure if I should bother. Anyone here have a feel for ho tablets get charged?

    Thanks a lot.
    12-30-2016 06:22 PM

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