Convert voltage to percent in popular battery
Easy way to conver estimate percentage of capacity from voltage of battery. You can select chemistry type: li-ion, lifepo4 you can select cells count: int
Returns desire topic and calculated percent
[{"id":"dbfc88c7ea986b06","type":"subflow","name":"lithium volt to percents","info":"","category":"","in":[{"x":120,"y":120,"wires":[{"id":"f4a7f93f55cf6b85"}]}],"out":[{"x":640,"y":120,"wires":[{"id":"f4a7f93f55cf6b85","port":0}]}],"env":[{"name":"cellsCount","type":"num","value":"4","ui":{"icon":"font-awesome/fa-battery-3","label":{"en-US":"Cells count"},"type":"input","opts":{"types":["num"]}}},{"name":"topic","type":"str","value":""},{"name":"batType","type":"str","value":"lifepo4","ui":{"label":{"en-US":"battery type"},"type":"select","opts":{"opts":[{"l":{"en-US":"lifepo4"},"v":"lifepo4"},{"l":{"en-US":"li-ion"},"v":"liion"}]}}}],"meta":{},"color":"#3FADB5","icon":"node-red-dashboard/ui_gauge.png","status":{"x":520,"y":240,"wires":[{"id":"f4a7f93f55cf6b85","port":1}]}},{"id":"f4a7f93f55cf6b85","type":"function","z":"dbfc88c7ea986b06","name":"","func":"function mapIt(x, in_min, in_max, out_min, out_max) {\n x = parseFloat(x);\n in_min = parseFloat(in_min);\n in_max = parseFloat(in_max);\n out_min = parseFloat(out_min);\n out_max = parseFloat(out_max);\n return (x - in_min) * (out_max - out_min) / (in_max - in_min) + out_min;\n}\n\nfunction get_percents_from_volts( volts ){\n\n percent = 0.00;\n volts = parseFloat( volts ) / parseFloat(env.get(\"cellsCount\")); // 4 cells in the 12v pack\n \n if( env.get(\"batType\") == \"lifepo4\" ){\n li_voltage_to_percentage = [\n [10.00,999],\n [3.65, 100],\n [3.40, 90],\n [3.35, 80],\n [3.32, 70],\n [3.30, 60],\n [3.27, 50],\n [3.20, 40],\n [3.15, 30],\n [3.10, 20],\n [3.05, 10],\n [3.00, 5],\n [2.80, 0],\n [0.00,-999]\n ];\n }else{\n li_voltage_to_percentage = [\n [10.00,999],\n [4.20, 100],\n [4.06, 90],\n [3.98, 80],\n [3.92, 70],\n [3.87, 60],\n [3.82, 50],\n [3.79, 40],\n [3.77, 30],\n [3.74, 20],\n [3.68, 10],\n [3.45, 5],\n [3.00, 0],\n [0.00,-999]\n ];\n }\n li_voltage_to_percentage_len = li_voltage_to_percentage.length;\n mmax = li_voltage_to_percentage[0];\n mmin = li_voltage_to_percentage[1];\n \n for(i=0,ic=li_voltage_to_percentage_len-2; i<ic; i++){\n if( volts <= parseFloat(li_voltage_to_percentage[i][0]) &&\n volts >= parseFloat(li_voltage_to_percentage[i+1][0]) ){\n mmax = li_voltage_to_percentage[i];\n mmin = li_voltage_to_percentage[i+1];\n //min = i;\n break;\n }\n }\n \n percent = mapIt( volts, mmin[0], mmax[0], mmin[1],mmax[1] );\n \n //return 'volts:'+volts+' range:'+min+' max:';//percent;\n return percent;\n}\n\nmsg = {\n topic: env.get(\"topic\"),\n payload: get_percents_from_volts( msg.payload ),\n cells: env.get(\"cellsCount\"),\n type: env.get(\"batType\")\n};\n\nmfill = \"green\";\nif( msg.payload <= 10 || msg.payload >= 90 )\n mfill = \"red\";\n\n\n\nreturn [\n msg,\n {\n payload:{\n fill: mfill, \n shape:\"ring\",\n text: msg.payload.toFixed(2)+\"%\"\n }\n }];","outputs":2,"noerr":0,"initialize":"","finalize":"","libs":[],"x":340,"y":120,"wires":[[],[]]}]
