diff --git a/code/modules/power/apc.dm b/code/modules/power/apc.dm
index 24152016851..51eb1c8564b 100644
--- a/code/modules/power/apc.dm
+++ b/code/modules/power/apc.dm
@@ -1299,7 +1299,7 @@
 
 	if(cell && !shorted)
 		// draw power from cell as before to power the area
-		var/cellused = min(cell.charge, lastused_total) // clamp deduction to a max, amount left in cell
+		var/cellused = min(cell.charge, lastused_total JOULES) // clamp deduction to a max, amount left in cell
 		cell.use(cellused)
 
 		if(excess > lastused_total) // if power excess recharge the cell