naganthunter Posted July 30, 2016 Share Posted July 30, 2016 Hey everyone. First of all, sorry for the large photos. I can't resize them. I just purchased this weather station for the Toy. The AC adaptor output shows 5vDC at 150mA. https://www.amazon.com/gp/product/B00PKU3LEW/ref=oh_aui_detailpage_o02_s00?ie=UTF8&psc=1 I want to hardwire it in to the 12v system. While it will run on AAA batteries, in that mode the display only lights up when you push a button. I would imagine I need to step the 12v down to 5v for the unit? If that's correct, would something like this work? It shows it will stepdown to 5v 3a. Is the 3a a maximum rating, or will it always pull 3a? Am I on the right track? Other suggestions? I want to keep power consumption low. I know the best way to keep consumption low would be not to include this - but I like gizmos. Thanks in advance. https://www.amazon.com/Nextrox-Converter-Power-Supply-Module/dp/B00A71CMDU/ref=sr_1_4?s=automotive&ie=UTF8&qid=1469896482&sr=1-4&keywords=12v+to+5v Quote Link to comment Share on other sites More sharing options...
Maineah Posted July 31, 2016 Share Posted July 31, 2016 5 volts is a common voltage phones tablets GPS etc. Lot of stuff out there that would plug into a lighter socket. Quote Link to comment Share on other sites More sharing options...
Back East Don Posted July 31, 2016 Share Posted July 31, 2016 (edited) 20 hours ago, naganthunter said: If that's correct, would something like this work? It shows it will stepdown to 5v 3a. Is the 3a a maximum rating, or will it always pull 3a Maximum. The load from the weather station is marginal as it has a150ma power supply. Rule of thumb is usually no more than 75% load from the device and often half. The voltage adapter should only draw slightly more than load if it is a switching regulator. The old style IC regulators are far less power efficient as they dissipate the excess voltage as heat and its excess draw would be likely more than the load itself. Most of the ones like you list are much more efficient. So I am thinking somewhere in the range of less than half a watt consumption tops for the weather station. The voltage adapter power draw should be only marginally higher due to loss. So no, the amperage load will be dependent on the load that is plugged into it plus a small percentage of efficiency loss. If you have a meter with an DC amp range, it would be easy to test and that way you'd know exactly how much power it is drawing but I suspect less than the 150ma overall even with the voltage adapter. So something like 3 amps a day consumption. Keep in mind I've not had my coffee yet and math accuracy is a function of the caffeine intake inverse squared law. Edited July 31, 2016 by Back East Don Quote Link to comment Share on other sites More sharing options...
naganthunter Posted August 5, 2016 Author Share Posted August 5, 2016 Thanks Don! I appreciate you taking the time to answer before you were properly caffeinated!! Quote Link to comment Share on other sites More sharing options...
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