Newbie needs help

stepbanstudio

I have a renogy 100 W panel, a bestek 2000 W inverter that a friend gave to me, 2 Deep cycle marine batteries, and I want to get an MPPT controller. This is where I get confused so I have 100 W, I’m using 12 V batteries,  I have a 2000 W inverter,  now what size mppt do I get? 10, 20 or 40 amp?

Photowhit

Well... you can't really use a MPPT controller efficiently with a single 12 volt nominal panel. You would be better off with a PWM type charge controller.

As to the size of charge controllers, they are generally based on output current. So your single 100 watt panel will output about 6 amps at 17.5 volts. so 10 amp is all you need for it. Often people will buy larger controller in anticipation of increasing the size of their system.

I'd suggest marine batteries are generally not the type of deep cycle battery you need. You would be better off with golf cart batteries. It a question of metal alloys used. Also you would want a balanced system. If your 12 volt batteries are pretty small, say group 24, they may be only 65 amp batteries so in parallel they would represent a 130 amp hour battery bank. You would want a charge rate of 5% or so for weekend use of your system, or around 6.5 amps. For daily use, I'd suggest a minimum of 10% charging capacity or 13 amps. If they are larger batteries even larger array would be suggested.

BB.

From the duplicate thread:

mike95490 

8:03AM #2

your panels do not need a MPPT controller, be happy you can use an inexpensive PWM controller.   After 300-400w, with larger panels in the +200w size MPPT becomes more practical for it's expense.

-Bill "moderator" B.