Sunday, July 15, 2018

Maybe About Ready to Go Photovoltaic for the Telescope Garage

I have wanted power in the telescope garage for some time, partly to recharge the battery packs I use for the telescope drives,  and partly because my wife would like the machine shop out of the garage in the house.   I have a 15W panel in the window which charges a 12V car battery and feeds a 110V inverter.   Unfortunately,  it is not a pure sine wave inverter.  While it charges the battery packs,  the green CHARGED  LED never lights up.  My Green Beret handyman is willing to run wiring for a few outlets, a switch for the ceiling light and connect a pure sine wave inverter.  At some point,  I will have a licensed electrician run power to the shed from the garage in the house (and the other direction for when Idaho Power loses the plot, as they often do).  Bur having the wiring, switch,  and light outlet in place let's me put up wallboard and reduce the bugs (I hope).  A lot of the PV panels have MC4 connectors.   I assume that the sine wave inverters have MC4 connectors.  Any thing else I should be watching for?   If I put 200W of panels up,  That should produce about 2800W in summer. So a battery that holds 2800W divided by 12V should tell me how many amp - hours capacity of batteries I need?   I believe you can stack several 12V batteries serially to store beyond the capacity of a single battery?


  1. Anderson Powerpole type Connectors might be a better solution for 2800 watts.

    Series increases voltage.

    Parallel increases power and keeps voltage the same.

  2. I think you mean 2800 watt-hours.

    Batteries can be put in series or parallel. It depends on what voltage you want to use. Generally, you put them in parallel to increase capacity, since you want a relatively constant discharge voltage. But, if you want higher voltage from the battery to the inverter, you can put them in series.

    In fact, a "battery" is usually 6 "cells" in series. So, if you put two batteries in series, it's like making a single 12 cell battery.