Questions & Answers about Imam rezervni punjač u ruksaku.
You usually don’t need ja because the verb ending in imam already tells you it’s I have.
You’d add ja mainly for emphasis or contrast, e.g. Ja imam rezervni punjač, a ti nemaš. (I have a spare charger, but you don’t.)
It’s the direct object of imam, so it’s in the accusative.
For masculine inanimate nouns like punjač, the accusative form is the same as the nominative, so you don’t see a change: punjač stays punjač (not punjača).
Because it agrees with punjač in gender, number, and case:
- punjač is masculine singular
- the phrase is in the accusative, but for masculine inanimate the adjective form here matches the nominative pattern you often learn as rezervni punjač.
So you get rezervni- punjač.