Can We Connect Two Separate MPPTs to Two Batteries in Parallel ?

Lysdexicuss

Here is the setup:

12v system

One array of six 100w panels feeds a 60 amp Renogy Rover MPPT

One array of two 200w panels feeds a 40 amp Renogy Rover MPPT

There are two 200ah lifepo4 batteries that i would like to parallel…

An Aims 3500 watt inverter will handle converting all the energy harvested

To power a small off-grid subpanel with six dedicated circuits
 
Both PV feeds are fused & breakered on the line sides before their respective MPPTs

The MPPTs will NOT be connected or in sync via communication ports…

QUESTION:

With batteries fully charged in parallel can we connect one Mppt load to the posts of battery #1, and the other Mppt load to posts on battery #2

Or is a distribution block required ?

Thanx

BB.

This website does a nice job of explaining paralleling strings of batteries--Basically want the resistance between the charger (and loads) to be equal wiring resistance to the parallel batteries. If not, the batteries with the higher resistance wiring will get less charging/discharging current.

http://www.smartgauge.co.uk/batt_con.html

There are other questions too... What is the maximum charging/discharging current for the batteries. What is the voltage drop from charger to battery bank at rated charging current (suggest 0.05 to 0.10 volts max) and battery to loads (at rated load current) (suggest 0.50 volts max drop).

In general, paralleling charge controllers is fine as long as you meet the charging voltage/current/etc. for the battery bank (and BMS requirements).

The two chargers will not always be "in-sync"--But that is OK. Each charger is determining what it thinks the battery bank needs. And they will have small variations in how they read the voltage and such--So one may go to float before the other finishes "charging".

-Bill

Lysdexicuss

ok great thanx Bill !