Radar auto-recharge

[Yukito]

I using a upgrades system for TTT and works perfectly... almost. I trying to figure out how to make the radar auto-recharge when someone have a radar booster...But I really don't know what I need to do, I feel kinda dumb xD
Can someone send me a help?

Code:
if CLIENT then
    EVENT.Hooks = { "TTTBoughtItem" }
else
    EVENT.Hooks = { "Think" }
end

if SERVER then
    function EVENT:Think()
        if GetRoundState() == ROUND_ACTIVE then
            for k,v in pairs(player.GetHumans()) do
                if not v:IsActiveTraitor() and not v:HasEquipmentItem(EQUIP_RADAR) then continue end
                if v.radar_charge > CurTime() and not v.done_radar_charge then
                    v.radar_charge = v.radar_charge - 25
                    v.done_radar_charge = true
                end
                if v.radar_charge < CurTime() and v.done_radar_charge then
                    v.done_radar_charge = false
                end
            end
        end
    end
else
    function EVENT:TTTBoughtItem(is_item, id)
        if is_item and id == EQUIP_RADAR then
            if UpgradeEnabled and UpgradeEnabled("radar_boost_three") then
                RADAR.duration = 6
            else
                RADAR.duration = 30
            end
        end
    end
end