Hi I want to power my net5501 from a spare 12V car battery that I have.
I also have an IBM laptop power supply, which says 16V 4.5A on it, and a Kemo M083 charging regulator which says "charging current maximum 1.5A". Currently I use the laptop supply to power the charger, and then I power my 12V broadband cable modem from the battery. It means that the charger is "charging" all the time which is a little suboptimal and makes it hot, but it works. The modem is actually getting just over 13V but it seems happy. I think that as the Soekris 5501 can take from 6-25V a better strategy would be to power the 5501 from the IBM laptop supply via a diode, and also from the 12V battery via a second diode. That way when there is mains power the 5501 will get 16V - 0.6V = 15.4V, and if the power fails it will get 12V - 0.6V = 11.4V, so it will be fine either way. As for the broadband modem, I've had it for nearly seven years and the power supply failed a few years ago. I think my broadband provide should really send me a new one. The newer ones are smaller and probably use less power. I think that the new ones also run from 10V DC. Therefore I could take the 15.4/11.4V supply to the 5501 and regulate it down to 10V. That means that worst case the IBM is supplying 1.5A to the charger 1A to the cable modem 1.5A to the net5501? By the way the 5501 has a laptop hardrive in it, but no other cards or addons. Does this sound like a reasonable strategy? I don't want to blow up my new Soekris. Also, what happens if I have a really long power cut and the battery gets below 6V? Will the 5501 just switch itself off or will it be damaged? thanks Philip _______________________________________________ Soekris-tech mailing list Soekris-tech@lists.soekris.com http://lists.soekris.com/mailman/listinfo/soekris-tech
