Power Electronics Battery Charging System Supplying Power to Ink

Choosing the Battery Battery Type has to first be chosen “Batteries and Charge Control for Stand-Alone Photovoltaic Systems : Fundamentals and Applications” , James P. Dunlop

Battery Capacity How much energy is stored in the battery measured in ampere hours Ah will provide ‘X’ amps of current for ‘Y’ hrs Ah = Device Wattage (W) * Time to run (hrs)/ Battery Voltage (V) From previous calculation we assume the total amount of power that we can use is 29,000 Wh/m2 , are prototype is 3’x5’ (0.92m x 1.525m) Therefore the total power used in a year can be about 40,600Wh Assuming snowfall for 240hrs a year (59 days for 4hrs) the average amount of power of the device will be 170W (40,600Wh/240h) Therefore Ah = (170W*4h)/ 12V = 56Ah To increase battery performance and life the battery should not be consistently discharged below 60% capacity so to be safe the battery capacity should be about 90aH

Battery Options Trojan Deep-Cycle AGM Battery can be used 31-AGM could all be options with 5hr rate-capacity of 82Ah Can be purchased from civicsolar for $270

Battery Chargers Controls incoming charge of the battery AGM batteries are INTOLERANT to overcharge Standard Solar Chargers or MPPT (Maximum power point tracking) charger MPPT chargers are much more efficient Standard chargers can lose between 20-60% of the rated solar panel wattage

Choosing a Battery Charger Charger needs to be able to handle rated watt, voltage, and current rating of PV panel (charging source) Charging source is still being determined (Full Panel or select number of cells) For now we can base the charger chose off a SBM solar 150W panel with the following specs:

Possible MPPT Charge Controller Morningstar SunSaver 15 Amp MPPT Solar Charge Controller ($225) Power used from possible 150W: Power= PV Panel Power * Efficiency Power = 150W * 97.5% Power=146.25 Charge Current = Power/Battery Voltage Charge Current = 146.25W/12V Charge Current =12.2A Charging Time = Battery Ah / Charge Current = 100Ah/ (12.2A) Charging Time = 8.2 hrs

Possible Standard Charge Controller Morningstar SS-20L 20 Amp PWM Solar Charge Controllers w/LVD ($78) Power used from possible 150W: Power = Voltage *Charge Current Power = 12V *8A Power = 96W about 66% efficient Charging Time = Battery Ah / Charge Current = 100Ah/ (8A) Charging Time = 12.5 hrs

Ink Power Supply I out Rtrace1 RTotal Rtrace2 Regulating Circuit Battery Rtrace3 I out Rtrace4