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Charging a battery with a single panel

Off Grid Home Forums Technical Discussion Charging a battery with a single panel

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    Sealed lead acid batteries are persnickety on charge voltage levels. Too high and ya ruin them. You need a controller that is adjustable so you don’t destroy your battery..

    I suggest one of these..


    Bulk.. 14.1 volts.. Float.. 13.6 volts.. Might take you a week to get the voltages set but it’s easy to understand and very reliable..



    Thanks 12vman, I am after a no cost/very low cost solution. Was thinking this morning about the regulator in an old car? I guess there is one and it would be doing a similar thing when a car is running – charging but not overcharging the battery. Just wouldn’t have a function to turn off power to light if battery gets low, but it would only be used a few hours a night at most. Could it work?


    Hi all, I have just been given an old panel, 60W, 12V. It seems to be working as I checked the voltage with a voltmeter and it read 16V without direct sun.


    My question is:

    On a little guest room separate from the house, I want to mount the panel, then charge a small sealed battery inside. What is the best DIY way to charge the battery? I know I cannot just connect the panel output to the battery – it needs some control to prevent it overcharging. Could an old laptop charger do it? will it stop charging once it is ‘full’ ? I would like to run a 12W light in the room. Otherwise are there chargers/controllers available for such a small job?


    Thanks for your help


    Use one of these. Monitor the voltage at the battery with the panel connected and when it reaches 14.1 volts, disconnect the panel from the battery. Disconnect the panel over the night to avoid draining the battery back into the panel..



    Walmart sells  a smart 3 stage charge controller. It does bulk to 80% then slower to 98% then trickle and maintenance to 100%


    That is a 7Amp you may need a bigger one. They sell larger ones.



    Thanks 12vman, i tried that today and it seemed to work well. Thanks, caverdude, will try and see if there is a similar low priced controller here in Australia, will do the job nicely i think – cheers

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