PhD outside of Germany after a Master's from a German Fachhochschule
In principle, there's no formal obstacle to applying to a US program, since almost all of them require only a bachelor's degree for admission. I similarly don't see a major problem with admissions to Canadian or other European universities, since you would have a master's degree and therefore have an "equivalent" degree, so long as you're staying in the same discipline (electrical engineering to electrical engineering); rules may be different if you're moving between fields (e.g., computer science to materials science).

Where you may run into a problem in admissions is that as a Fachhochschule, your school may not have as strong an international profile as from Hochschule and other schools of equivalent rank in Europe. Consequently, the school you're applying to may not have ever had applicants from your Fachhochschule. Consequently, regardless of how good your profile and application are, you still represent an "unknown" quantity, and therefore there is a greater risk to the department by admitting you instead of someone from a school that is better familiar to the department to which you're applying. 

For non-European questions, the number of credit points aren't that important. For European admissions, there may be an issue regarding this, but that's really decided on a university-by-university basis, so you'll need to consult the individual schools you're interested in for guidance. However, taking additional credits beyond what is required for admission won't help you nearly as much as demonstrating research potential.