RPEDs now work on APCs

code/game/machinery/_machinery.dm

@@ -108,6 +108,7 @@ Class Procs:
 	var/wire_compatible = FALSE
 
 	var/list/component_parts = null //list of all the parts used to build it, if made from certain kinds of frames.
+	var/works_with_rped_anyways = FALSE //whether it has special RPED behavior despite not having component parts
 	var/panel_open = FALSE
 	var/state_open = FALSE
 	var/critical_machine = FALSE //If this machine is critical to station operation and should have the area be excempted from power failures.

code/modules/power/apc.dm

@@ -56,6 +56,7 @@
 	integrity_failure = 50
 	resistance_flags = FIRE_PROOF
 	interaction_flags_machine = INTERACT_MACHINE_WIRES_IF_OPEN | INTERACT_MACHINE_ALLOW_SILICON | INTERACT_MACHINE_OPEN_SILICON
+	works_with_rped_anyways = TRUE
 	FASTDMM_PROP(\
 		set_instance_vars(\
 			pixel_x = dir == EAST ? 24 : (dir == WEST ? -25 : INSTANCE_VAR_DEFAULT),\
@@ -291,6 +292,34 @@
 	if(issilicon(user))
 		. += span_notice("Ctrl-Click the APC to switch the breaker [ operating ? "off" : "on"].")
 
+/obj/machinery/power/apc/exchange_parts(mob/user, obj/item/storage/part_replacer/W)
+	if(!istype(W))
+		return FALSE
+	if(!opened && !W.works_from_distance)
+		return FALSE
+	var/current_cell_rating = cell ? cell.get_part_rating() : -1
+	var/best_cell_rating = current_cell_rating
+	var/obj/item/stock_parts/cell/best_cell
+	for(var/C in W.contents)
+		var/obj/item/stock_parts/cell/cell = C
+		if (!cell || !istype(cell))
+			continue
+		var/cell_rating = cell.get_part_rating()
+		if (cell_rating > best_cell_rating || (cell_rating == best_cell_rating && cell.charge > best_cell.charge))
+			best_cell_rating = cell_rating
+			best_cell = cell
+	if (best_cell)
+		if (cell)
+			SEND_SIGNAL(W, COMSIG_TRY_STORAGE_INSERT, cell, null, null, TRUE)
+			to_chat(user, span_notice("[capitalize(cell.name)] replaced with [best_cell.name]."))
+		best_cell.forceMove(src)
+		var/amount_to_charge = min(best_cell.maxcharge - best_cell.charge, cell.charge)
+		if (cell.use(amount_to_charge))
+			best_cell.give(amount_to_charge)
+		cell = best_cell
+		W.play_rped_sound()
+
+
 // update the APC icon to show the three base states
 // also add overlays for indicator lights
 /obj/machinery/power/apc/update_icon()

code/modules/research/stock_parts.dm

@@ -15,7 +15,7 @@ If you create T5+ please take a pass at gene_modder.dm [L40]. Max_values MUST fi
 	var/alt_sound = null
 
 /obj/item/storage/part_replacer/pre_attack(obj/machinery/T, mob/living/user, params)
-	if(!istype(T) || !T.component_parts)
+	if(!istype(T) || (!T.component_parts && !T.works_with_rped_anyways))
 		return ..()
 	if(user.Adjacent(T)) // no TK upgrading.
 		if(works_from_distance)
@@ -25,7 +25,7 @@ If you create T5+ please take a pass at gene_modder.dm [L40]. Max_values MUST fi
 	return ..()
 
 /obj/item/storage/part_replacer/afterattack(obj/machinery/T, mob/living/user, adjacent, params)
-	if(adjacent || !istype(T) || !T.component_parts)
+	if(adjacent || !istype(T) || (!T.component_parts && !T.works_with_rped_anyways))
 		return ..()
 	if(works_from_distance)
 		user.Beam(T, icon_state = "rped_upgrade", time = 5)