It happened to the best of us. You're doing really well, you've taken quite a few kills, and that's when you realize: you're out of shield cells and shield batteries. Not even a phoenix kit in your inventory. What good is a body shield if it can't protect you?
Well fear not, if you are having trouble finding cooldown items, now there is another way that works for all legends and most shields.
Fully charge your Evo Shield
With the newly implemented crafting system, you collect crafting materials around the map and by opening supply bins. If you have 45 or more crafting materials, you can purchase an Evo Shield upgrade from the Replicator.
The point of this upgrade is for you to automatically get 100 damage for your next level, however, there is one less talked about side effect. When you take your shield out, regardless of how exhausted it is, out of the Replicator, it will be fully charged.
This means that as long as your Evo Shield can still level up (level 1-4, not level 5), you can repair it using your crafting metals on a replicator, rather than shield cells.
It is important to note that this method is only for Evo Shields and will not work on the Legendary Body Shield, just as it will not work on the Level 5 shield.
Other alternatives
Another way that's been in the game for a long time is that if you or someone on your team is Wattson, his ultimate can recharge your body shield up to 75 HP over time. If you plan on camping for a while in a safe location, this is also a great way to repair your shield without reloading any items. This is the only viable option for Legendary and Level 5 shields.
Finally, if none of the previous options work, your best bet at this point is to find a new shield on the ground or in a death box to swap your own.
Overall, shield cells and the like are extremely important to gameplay, but if the odds aren't in your favor, these workarounds could save you in a pinch.
