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Using multiple charge controllers for Liftmaster Gate system

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  • Using multiple charge controllers for Liftmaster Gate system

    Hello all, first post.

    I have a dual gate operated by a Liftmaster LA-400. The system is powered by 2 12 volt 7Ah batteries wired in series for a 24v total system.

    My first attempt at powering something via solar has been a learning process. I originally purchased a Docooler 10A CC off amazon with a single 30W "12v" panel. I thought I could have the CC charge both batteries independently (this was before I realized the batteries were connected in series for 24v). Simply put, I short circuited one of the batteries and had the pleasure of resoldering new battery terminals to the control board for my gate system.

    So my dilemma is now I have this "12v" solar panel (manufactured/sold by Windy Nation). It's a poly PV. What is confusing is the actual voltages of the panel. The Voc (open circuit) is about 21 V in direct sunlight as listed. Under-load it is either 18v (as listed) or sometimes the same as the batteries, nearly 23-25 V. Is this just the process of the PSM trickling small amps to the batteries?

    I do not need a lot of power (1-2 Ah / day) for this gate system so I would like to use only one solar panel (currently purchased 30W). Can I connect multiple CCs to the batteries already connected in series? Should the CCs be connected in series or parallel off of the solar panel? I am assuming the CCs will be connected to the batteries themselves independently. Is there any chance of short circuiting by doing this? The gate system is worth about 10x the solar portion.
    Last edited by Rudolph21; 03-20-2015, 09:50 AM. Reason: Additional question / grammar