Forum Discussion

jffnkrn's avatar
jffnkrn
Explorer
Mar 06, 2018

to control or not to control and Mono or Poly

So the question now that we are here.
existing set up is two group 31 agm batteries, all led lighting, 2015 fifth wheel with modern stuff. Panel is also unplugged at sunset and secured for theft prevention.
I have been running a small 65 watt solar panel when boondocking. the panel has a 25 foot cord that plugs into the typical power port installed at the battery location. I place the panel in the sunlight and move it along as the day goes on. I have never had an issue with over charging as there is always a draw on the system, pump light, lp detector, fridge, fridge fan, on and off pump, on and off radio and the use of a small 400 watt inverter for charging puters, phones, toys etc. I am upgrading to a 100 watt panel. why would i need a solar controller if i have a continuous draw on the battery bank? thoughts, ideas, tell me i am crazy etc. thanks in advance. Good Luck & Be Safe!!!
  • makes sense. thanks for the input. I have ordered the monocrystalline 100 watt panel adn the 20 amp charge controller. thaks everyone!!!!
  • A basic charge controller can be had for $30 or so. If it saves you from ruining your batteries one time it was money very well spent. Why wouldn't you have one?
  • The reason you are getting away with not using a controller is most likely due to the tiny size of your solar panel charge current compared to the capacity of your two group 31 batteries. You are charging at barely above trickle charge rate for your battery bank. Moving from a 65 Watt panel to 100 is not likely going to change much, either. If you plan on using both (165W) I suggest you do get a charge controller. 165 watts can output about 8-9 amps in full direct sunlight.
  • “I place the panel in the sunlight and move it along as the day goes on.”

    Along with watching for theft this sounds fun.
  • The controller regulates the voltage. A panel is not 12 volts. Its upwards of 17-21 volts.

    You'll destroy the battery
  • The basic idea of a charge controller is so that you dont have to spend all your time monitoring power. The controller does it for you at no cost of your time.
  • I guess if you want to monitor the voltage all day that could work.

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