<html><body><div>I'm using a 2.5amp-hour 12v Gel Cel - PS-1220 Costs $10 in quantity 10. </div><div><a href="https://www.amazon.com/gp/product/B077Y9FT5K">https://www.amazon.com/gp/product/B077Y9FT5K</a><br data-mce-bogus="1"></div><div> I'm using it as a backup supply to keep a Raspberry PI alive if the main 14.2v supply goes away. I have the two main and battery diode ORed through a bridge rectifier to a DROK switcher supply which outputs 5.2v on USB to run the Raspberry PI 4B. Another leg of the bridge rectifier provides 13.8v only from main supply, which I run through a 10watt 50ohm resistor back to the +DC lead on the gel cel. This gives me a really cheap trickle charger. <br></div><div><br data-mce-bogus="1"></div><div>Objectives: </div><div>1. feed stable power to the Raspberry PI with 5.2v even if main supply glitches or goes off<br data-mce-bogus="1"></div><div>2. run off a main power supply supply which can also feed power to 12-15v peripherals<br data-mce-bogus="1"></div><div>3. have backup capability for at least several hours of running the Raspberry PI 4 and it's daughter cards.<br data-mce-bogus="1"></div><div>4. be cheap<br data-mce-bogus="1"></div><div>5. be easy to get now and into the future<br data-mce-bogus="1"></div><div><br data-mce-bogus="1"></div><div>Details on the trivial circuit are here:<br data-mce-bogus="1"></div><div>http://tarpn.net/t/builder/builders_robust_power_for_raspberry_pi.html</div><div><br data-mce-bogus="1"></div><div> Tadd / KA2DEW</div><div><br>On November 18, 2019 at 12:41 PM, Robert Henry via TriEmbed <triembed@triembed.org> wrote:<br><br><div><blockquote type="cite"><div class="msg-quote"><div dir="ltr"><div>(--sending from correct e-mail this time--)<br></div><div>Hey all,</div><div><br></div><div><b>Question for group</b>: I'm curious what battery packages folks in this group use for their projects? If there is quite a variety - perhaps offer your favorite/most flexible.<br></div><div><br></div><div><b>Background:</b> I'm currently selling ~12v LiFePO4 battery packs (4s1p) that I had as surplus from a consumer product. Product launched with limited success, but the battery packs are selling well enough that I'm considering sourcing other chemistries / configurations. Would like to keep with the embedded project market to start (that is - capacities less than 100 Watt-Hours).</div><div><br></div><div>Any insight would be greatly appreciated. Thank you!</div><div>Rob Henry</div><br clear="all"><div><div dir="ltr" class="gmail_signature"><div dir="ltr"><div>Rob Henry<br></div><div>LT Cage Productions, LLC<br></div>ph: +1.919.245.7684<br></div></div></div></div><div class="_stretch"><span class="body-text-content">_______________________________________________<br>Triangle, NC Embedded Computing mailing list<br><br>To post message: <a href="mailto:TriEmbed@triembed.org" data-mce-href="mailto:TriEmbed@triembed.org">TriEmbed@triembed.org</a><br>List info: <a href="http://mail.triembed.org/mailman/listinfo/triembed_triembed.org" data-mce-href="http://mail.triembed.org/mailman/listinfo/triembed_triembed.org">http://mail.triembed.org/mailman/listinfo/triembed_triembed.org</a><br>TriEmbed web site: <a href="http://TriEmbed.org" data-mce-href="http://TriEmbed.org">http://TriEmbed.org</a><br>To unsubscribe, click link and send a blank message: mailto:unsubscribe-TriEmbed@bitser.net?subject=unsubscribe<br><br></span></div></div></blockquote></div></div></body></html>