DC to DC converter and 12V Car Battery Maintainer

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Use the input from a solar panel to maintain a car battery. Also provide 5V out from battery to power an arduino at night
Design Fufilled


Shane Oberloier's picture

It is possible to do this with parts from the UPL, but I think things will be more strait forward using this: http://www.ti.com/lit/ds/symlink/lm723.pdf This may be next on my to-do list.
Shane Oberloier's picture

When making a voltage converter it's important to consider power efficiency. I've made this page: http://opencircuitinstitute.org/content/low-drop-out-regulators-vs-buck-converters To talk about the two key circuits that can be used for this. Common voltages out of a solar panel are 17V. Do you know how much your system will output, or are you just looking for a general circuit?

very nice! yup, ive got a solar panel that puts out about 17ish if i remeber correctly. Heres a link i found about the best practices for tweaking the voltage and amps http://batteryuniversity.com/learn/article/charging_the_lead_acid_battery does that sound right? would it make since to use an arduino compatible chip to monitor the voltage over longer time frames? seems like lead acid batteries need a "top up" every so often?

or maybe just a float charge is enough? im not real familiar. https://en.wikipedia.org/wiki/Float_voltage
Shane Oberloier's picture

Hi Dorkmo, I've created your design: http://opencircuitinstitute.org/content/solar-battery-charger . Please check it out at let me know if this is the kind of thing you're looking for. If this is - please edit your request status to "Fufilled". If you'd like to fabricate this board - please let me know and I can recommend the next steps. Unfortunately I do not have the funds to create this board right now. If you're happy with this design please tell you friends about it and OCI in general. Thanks for your request!