Your shield recharge rate also heavily depends on your power distibutor quality. Its goal is to help your ship recharging its system faster. WAY faster.
Basically, you want to do this:
1- get a decent power plant. If you're going to upgrade your ship in any department, you'll find this will be your first obstacle right after money.
2- get a decent, if not excellent power distributor. Even before getting weapons and shield. With that only coupled to your stock shield and lasers, you'll see a huge boost in combat capabilities.
3 -get a nice shield.
Now, learn to manage power distribution in combat situation, and also get yourself a shield cell bank. Those things are life savers.