Author Topic: Designing a battery bank, and pairing it with a charge controller  (Read 121 times)


  • Newby
  • *
  • Posts: 1
I'm trying to set up a cargo trailer with a battery bank that can pull 49 amps, at 12.8 volts, (630 watts) on and off for around eight hours. This is for an 12v AC unit that will come on intermittently in order to keep a cool trailer. I would say probably on for four or five of the eight total hours. I will trickle charge the batteries until full each night. Also I eventually want to add 3-500 watts of solar power, in putting at different amounts due to sun) and the ability to charge from my truck when driving. Question is... Which charge control module, paired with what type of battery bank would best suit my needs? I like the idea of lithium batteries because of weight, and the ability to run them down to a lower level, but am open to other ideas. My biggest concern is what controller can handle, and has the proper ports to handle solar at up to 500 watts, the input from being connected to my Toyota Tacoma, and a trickle charge each night? What would be the best battery bank I could build, to pair with this charge controler, that meets my approximate 650 watt draw, for an estimated five hours? I'm fairly new to all of this, so let me know what you think?


  • Hero Member
  • *****
  • Posts: 2525
Just a few quick thoughts.
The charge controller is designed for the solar panels and not for charging via a truck alternator.
You are limited to how much charge you will get from the truck by it's charge regulator  and  it is going to be limited to 14.2 v or so anyway.
Also if you are trickle charging overnight - I guess that means using an AC powered charger - then that charger will take care of its own charging without need of another charge controller.
If you are using a compressor you also need to size your battery capacity to be able to handle any surge the compressor needs when it starts up .
Use the Midnite sizing tool to see if the Kid controller can handle which ever solar panels you would want to get.
If that doesn't work you need to step up to the Classic and there is a sizing tool for that also on midnite webpage.
As far as batteries - there are many variables - with lead acid the deeper you discharge them every day the less lifetime they will have. So if you size properly batteries can last a long time.
For Lithium - there are lots of  options and different battery maintenance systems either included or you have to add . You would want to make sure whatever kind you get can be properly charged with the solar charge controllers . So research is needed.

system one
Classic 150 , 5s4p  Kyocera 135watt , 12s Soneil 2v 540amp lead crystal for 24v pack , Outback 3524 inverter
system two
Classic 150 ,5s 135 watt Kyocero , 16s Calb 100AH LiFePO4 , Outback VFX 3648 inverter
system three
Midnite KID MPPT 24 DC in to  12 volt AGM batterie