No you don't need a light you just take your idevice charger and plug it in to the portable charger and charger it for About 2 hrs and then take it with you when you leAve and if your idevice starts to go dead plug it into it and it will charge
I have one just like this. I LOVE it! I charge it at home just like I normally charge my phone, then I put it in my purse until I need it. You just plug into the bottom of your phone and it charges the phone up. Fairly quickly too. It's like having an extra battery and it's great for those places you can't charge your phone but you use it a lot (like hospital waiting rooms or school field trips). It holds it's charge for a long time too. I've had mine in my purse for 2 or 3 weeks at a time and it still has a full charge when I need it. I hope this comment helps those of you who aren't sure how it works. You won't regret this purchase!