$V_{F}+6+4 I_{1}-30+2 I_{1}=V_{F}$

$I_{4}=4 A$

Right loop$:$

$V_{F}+6+1 I_{2}-15+2 I_{2}=V_{F} 30 V$

or $I_{2}=3 A$ Net current through $6 \mathrm{V}$ battery is

$I=I_{1}+I_{2}=4+3=7 A$

The $6 V$ battery is getting charged. Both $15 \mathrm{V}$ and $30 \mathrm{V}$ batteries produce current in $6 \mathrm{V}$ battery.