Matlab Simulink interface problem(Simpower Systems vs Simscape)
Is there any reason you are mixing SimPowerSystems &amp; SimScape?  

With the introduction of SimScape "SimPowerSystems", the legacy method of dealing with electrical simulations has become redundant EXCEPT for some legacy blocks and specialised technologies. 

The legacy SimPowerSystems does have a more specialised battery model so I can understand why you would want to use that IF it provides features the simscape battery does not (or that you cannot reproduce...) 



you can run with both as long as you provide the needed pre-requisites.
I don't see a SimScape reference block nor a solver block. Do they exist. 



The actual problem here is an algebraic loop.  

the subsystem highlighted within the 1st post. What EXACTLY is in there?  I suspect there is some form of SimPowerSystem voltage sensor to bring a signal into the simulink domain, a Simulink-PS converter block to take it into the SimScape domain. This is where it needs to be solved.

Add a memory block in the simulink domain should break the loop and provided the needed initial condition (if you are running continuous consider adding a TF with a small timeconstant todo the same thing)