While Germany started with around 3500 tanks and attacked Soviet forces that had around 20,000 tanks (even if only half were operational), Germany was seriously under-tanked in comparison. However, during Indy’s coverage of Barbarossa, it seems that when capturing Soviet infantry in hundreds of thousands, German forces also captured thousands of Soviet tanks. If they used those, wouldn’t that sort of quickly make them on equal strength and could replenish lost panzers, or were they so different that crew could not use them is such a large captured numbers?
There were multiple factors in here:
Not all use of captured tanks was documented, because sometimes commanders didn’t want to bother with bureaucracy of reporting the use of Beutepanzer(Trophy tank), so it was used until it was lost and then it’s as if it never existed. The official numbers that I heard point to about 100 used Soviet tanks out of approximately 1500 captured in good condition in 1941.
In 1941, Germans were pretty sure that the war will be over soon, so they didn’t want to spend resources on Soviet equipment and concentrated on maintenance of their current tank park. In subsequent years the proportion of captured Soviet tanks that would be used in combat will rise, but Germans would also capture less tanks. A lot of tanks that were left in the field during Operation Barbarossa degraded from the elements by the time Germans realized they need everything they can get.
Next, there are the questions of the use of captured equipment. You not only require a trained tank crews, which Germans had a limited amount of, but also support personnel that can service the tank, spare parts and ammunition, which is of a different caliber from the ones German tanks used. That’s why some of captured Soviet tanks were first refitted with German guns before being sent back to front.
Also, a lot of German issues with tank usage in 1941 came to a fuel shortages, so just getting more tanks wouldn’t solve much. While the famous T-34 used diesel engine, most of the tanks captured in 1941 were T-26s and BT-series tanks, all of which(with the exception of BT-7M) ran on gasoline and would simply compete with German tanks in this regard.
Finally, as stated before, most of those tanks were T-26s and BT-series, which were somewhere between Pz.II and Pz.III in their combat effectiveness if you equip them with radios(most T-26 didn’t have radios and only some BTs had) and probably about equal to Pz.II if you don’t, so their impact would be limited even without considering general difficulties related to the use of captured equipment.