Re: PC suggestions

Greg D

Ah, ok.  Yes, I think that will work, as long as it's offline from the car.  I'm not sure of the details, but it will likely be at a higher voltage when charging.  Also there's the risk if the battery goes open circuit for some reason, you'll have a direct connect to the car's charging system, which is probably too high.

Not as efficient, but couldn't you just use one of the 12v to 120v inverters that are now really small and cheap?  Then just use the regular laptop charging adapter. 

All that said, once upon a time I built a regulator that made use of the fact that the car's charging voltage was higher than 12v.  Simple series-pass; this was before the LM-78xx, but same idea.  It wouldn't work without the car running, but kept the kids happy running an old HP 800 laptop on long trips :)

Greg  KO6TH

bobmorgan@... [aprsisce] wrote:


Hi Greg, I may need to go with a DC to Dc power supply like the one you suggested. However, my power source will be an aux LiFePO4 battery. The battery will maintain a reasonably consistent voltage up to around an 80% discharge state +/-. I have been searching for a Dc to Dc source for a Surface Pro. I have not been successful to date. All I can find is just a straight connection to a 12V battery and that should work based on the above.


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