<html><head><style>body{font-family:Helvetica,Arial;font-size:13px}</style></head><body><div style="font-family:Helvetica,Arial;font-size:13px"><p style="margin-top:0px;color:rgb(34,34,34);font-family:Arial,sans-serif;font-size:15.008000373840332px">I am currently upgrading my existing Electron-based counters with newer Boron-based ones. As I do, I will rework / recycle as much as I can from the older units to reduce waste. These units have been operating on solar power for anywhere from 1 to 4 years.</p><p style="color:rgb(34,34,34);font-family:Arial,sans-serif;font-size:15.008000373840332px">How can I tell if it is time to replace a Single Cell LiPo Battery?</p><p style="color:rgb(34,34,34);font-family:Arial,sans-serif;font-size:15.008000373840332px">Here is the battery I currently use: <a href="https://www.adafruit.com/product/2011">https://www.adafruit.com/product/2011</a></p><p style="color:rgb(34,34,34);font-family:Arial,sans-serif;font-size:15.008000373840332px">I thought it would be straight forward to test the internal resistance of the batteries (at a consistent charge / temp) as the resistance goes up as the battery ages. However, I am struggling to find a battery tester / charger that will measure a single LiPO cell’s internal resistance. </p><p style="color:rgb(34,34,34);font-family:Arial,sans-serif;font-size:15.008000373840332px">I have tried both of these:</p><p style="color:rgb(34,34,34);font-family:Arial,sans-serif;font-size:15.008000373840332px"><span class="Apple-tab-span" style="white-space:pre"> </span>- Tenergy: <a href="https://power.tenergy.com/tenergy-5-in-1-intelligent-cell-meter-capacity-checker-battery-balancer-battery-discharger-internal-resistance-tester-esc-servo-ppm-tester/">https://power.tenergy.com/tenergy-5-in-1-intelligent-cell-meter-capacity-checker-battery-balancer-battery-discharger-internal-resistance-tester-esc-servo-ppm-tester/</a></p><p style="color:rgb(34,34,34);font-family:Arial,sans-serif;font-size:15.008000373840332px"><span class="Apple-tab-span" style="white-space:pre"> </span>- HTRC: <a href="https://www.amazon.com/HTRC-Charger-Battery-Balance-Discharger/dp/B07MWSW3TP/ref=sr_1_4?dchild=1&m=A193SNVHREJU7H&marketplaceID=ATVPDKIKX0DER&qid=1614968073&s=merchant-items&sr=1-4">https://www.amazon.com/HTRC-Charger-Battery-Balance-Discharger/dp/B07MWSW3TP/ref=sr_1_4?dchild=1&m=A193SNVHREJU7H&marketplaceID=ATVPDKIKX0DER&qid=1614968073&s=merchant-items&sr=1-4</a></p><p style="color:rgb(34,34,34);font-family:Arial,sans-serif;font-size:15.008000373840332px"><br></p><p style="color:rgb(34,34,34);font-family:Arial,sans-serif;font-size:15.008000373840332px">Any suggestions?</p><p style="color:rgb(34,34,34);font-family:Arial,sans-serif;font-size:15.008000373840332px"><br></p><p style="color:rgb(34,34,34);font-family:Arial,sans-serif;font-size:15.008000373840332px">Thanks, </p><p style="color:rgb(34,34,34);font-family:Arial,sans-serif;font-size:15.008000373840332px"><br></p><p style="color:rgb(34,34,34);font-family:Arial,sans-serif;font-size:15.008000373840332px">Chip</p><p style="color:rgb(34,34,34);font-family:Arial,sans-serif;font-size:15.008000373840332px"><span style="font-family:Helvetica,Arial;font-size:13px">____________________________________</span></p></div><div class="gmail_signature">Chip McClelland<div><a href="mailto:chip@mcclellands.org">chip@mcclellands.org</a></div><div>919-624-5562</div></div></body></html>