diff --git a/lib/MPPTLib/powerSupplies.cpp b/lib/MPPTLib/powerSupplies.cpp
index 02e2afc..5eaf8bc 100644
--- a/lib/MPPTLib/powerSupplies.cpp
+++ b/lib/MPPTLib/powerSupplies.cpp
@@ -3,6 +3,23 @@
 #include <ModbusMaster.h> // ModbusMaster
 #include "utils.h"
 
+PowerSupply* PowerSupply::make(const String &type) {
+  PowerSupply* ret = NULL;
+  String typeUp = type;
+  typeUp.toUpperCase();
+  if (typeUp.startsWith("DP")) {
+    ret = new DPS(&Serial2);
+    Serial2.begin(19200, SERIAL_8N1, -1, -1, false, 1000);
+  } else if (typeUp.startsWith("DROK")) {
+    ret = new Drok(&Serial2);
+    Serial2.begin(4800, SERIAL_8N1, -1, -1, false, 1000);
+  } else { //default
+    ret = NULL;
+  }
+  if (ret) ret->type_ = type;
+  return ret;
+}
+
 
 // ----------------------- //
 // ----- PowerSupply ----- //
@@ -31,7 +48,7 @@ void PowerSupply::doTotals() {
 // -------- Drok -------- //
 // ---------------------- //
 
-Drok::Drok(Stream* port) : PowerSupply(), port_(port) { }
+Drok::Drok(Stream* port) : PowerSupply() { port_ = port; }
 Drok::~Drok() { }
 
 bool Drok::begin() {
@@ -39,8 +56,6 @@ bool Drok::begin() {
   return doUpdate();
 }
 
-String Drok::getType() const { return "Drok"; }
-
 bool Drok::doUpdate() {
   bool res = readVoltage() &&
          readCurrent() &&
@@ -136,11 +151,9 @@ bool Drok::setCurrent(float v) {
 // --------- DPS --------- //
 // ----------------------- //
 
-DPS::DPS(Stream* port) : PowerSupply(), port_(port), bus_(new ModbusMaster) { }
+DPS::DPS(Stream* port) : PowerSupply(), bus_(new ModbusMaster) { port_ = port; }
 DPS::~DPS() { }
 
-String DPS::getType() const { return "DPS"; }
-
 bool DPS::begin() {
   bus_->begin(1, *port_);
   return doUpdate();
diff --git a/lib/MPPTLib/powerSupplies.h b/lib/MPPTLib/powerSupplies.h
index 3fca54f..1b465f0 100644
--- a/lib/MPPTLib/powerSupplies.h
+++ b/lib/MPPTLib/powerSupplies.h
@@ -1,11 +1,13 @@
 #pragma once
 #include <cstdint>
+#include <WString.h>
 
-class String;
 class Stream;
 
 class PowerSupply {
   public:
+    String type_;
+    Stream *port_ = NULL;
     bool debug_ = false;
     float outVolt_ = 0, outCurr_ = 0;
     float limitVolt_ = 0, limitCurr_ = 0;
@@ -13,6 +15,7 @@ class PowerSupply {
     bool outEn_ = false;
     uint32_t lastSuccess_ = 0, lastAmpUpdate_ = 0;
 
+    static PowerSupply* make(const String &type);
     PowerSupply();
     virtual ~PowerSupply();
     virtual bool begin() = 0;
@@ -28,18 +31,17 @@ class PowerSupply {
     virtual bool isCollapsed() const;
     virtual bool getInputVolt(float* v) { return false; }
     virtual String toString() const;
-    virtual String getType() const = 0;
+    String getType() const { return type_; }
+    virtual bool isDrok() const { return true; }
   protected:
     void doTotals();
 };
 
 class Drok : public PowerSupply {
-    Stream *port_;
   public:
-    Drok(Stream* port);
+    Drok(Stream*);
     ~Drok();
     bool begin() override;
-    virtual String getType() const;
 
     String cmdReply(const String &cmd);
     bool setVoltage(float) override;
@@ -60,16 +62,14 @@ class Drok : public PowerSupply {
 class ModbusMaster;
 
 class DPS : public PowerSupply {
-    Stream *port_;
     ModbusMaster* bus_;
   public:
     float inputVolts_ = 0;
     bool cc_ = false;
 
-    DPS(Stream* port);
+    DPS(Stream*);
     ~DPS();
     bool begin() override;
-    virtual String getType() const;
 
     bool setVoltage(float) override;
     bool setCurrent(float) override;
@@ -79,4 +79,5 @@ class DPS : public PowerSupply {
 
     bool isCC() const override;
     bool getInputVolt(float* v) override;
+    bool isDrok() const override { return false; }
 };
diff --git a/lib/MPPTLib/solar.cpp b/lib/MPPTLib/solar.cpp
index 6c10f3f..21caec3 100644
--- a/lib/MPPTLib/solar.cpp
+++ b/lib/MPPTLib/solar.cpp
@@ -9,6 +9,7 @@
 #include <HTTPUpdate.h>
 
 using namespace std::placeholders;
+#define ckPSUs() if (!psu_) { return String("no psu"); }
 
 WiFiClient espClient;
 
@@ -62,11 +63,11 @@ void Solar::setup() {
   pub_.add("inPin",    pinInvolt_).pref();
   pub_.add("lvProtect", std::bind(&Solar::setLVProtect, this, _1)).pref();
   pub_.add("psu",       std::bind(&Solar::setPSU, this, _1)).pref();
-  pub_.add("outputEN",[=](String s){ if (s.length()) psu_->enableOutput(s == "on"); return String(psu_->outEn_); });
-  pub_.add("outvolt", [=](String s){ if (s.length()) psu_->setVoltage(s.toFloat()); return String(psu_->outVolt_); });
-  pub_.add("outcurr", [=](String s){ if (s.length()) psu_->setCurrent(s.toFloat()); return String(psu_->outCurr_); });
-  pub_.add("outpower",[=](String){ return String(psu_->outVolt_ * psu_->outCurr_); });
-  pub_.add("currFilt",[=](String){ return String(psu_->currFilt_); });
+  pub_.add("outputEN",[=](String s){ ckPSUs(); if (s.length()) psu_->enableOutput(s == "on"); return String(psu_->outEn_); });
+  pub_.add("outvolt", [=](String s){ ckPSUs(); if (s.length()) psu_->setVoltage(s.toFloat()); return String(psu_->outVolt_); });
+  pub_.add("outcurr", [=](String s){ ckPSUs(); if (s.length()) psu_->setCurrent(s.toFloat()); return String(psu_->outCurr_); });
+  pub_.add("outpower",[=](String){ ckPSUs(); return String(psu_->outVolt_ * psu_->outCurr_); });
+  pub_.add("currFilt",[=](String){ ckPSUs(); return String(psu_->currFilt_); });
   pub_.add("state",      state_          );
   pub_.add("pgain",      pgain_          ).pref();
   pub_.add("ramplimit",  ramplimit_      ).pref();
@@ -79,14 +80,14 @@ void Solar::setup() {
   pub_.add("autosweep",  autoSweep_      ).pref();
   pub_.add("currentcap", currentCap_     ).pref();
   pub_.add("involt",  inVolt_);
-  pub_.add("wh", [=](String s) { if (s.length()) psu_->wh_ = s.toFloat(); return String(psu_->wh_); });
+  pub_.add("wh", [=](String s) { ckPSUs(); if (s.length()) psu_->wh_ = s.toFloat(); return String(psu_->wh_); });
   pub_.add("collapses", [=](String) { return String(getCollapses()); });
   pub_.add("sweep",[=](String){ startSweep(); return "starting sweep"; }).hide();
   pub_.add("connect",[=](String s){ doConnect(); return "connected"; }).hide();
   pub_.add("disconnect",[=](String s){ db_.client.disconnect(); WiFi.disconnect(); return "dissed"; }).hide();
   pub_.add("restart",[](String s){ ESP.restart(); return ""; }).hide();
   pub_.add("clear",[=](String s){ pub_.clearPrefs(); return "cleared"; }).hide();
-  pub_.add("debug",[=](String s){ psu_->debug_ = !(s == "off"); return String(psu_->debug_); }).hide();
+  pub_.add("debug",[=](String s){ ckPSUs(); psu_->debug_ = !(s == "off"); return String(psu_->debug_); }).hide();
   pub_.add("version",[=](String){ log("Version " + version_); return version_; }).hide();
   pub_.add("update",[=](String s){ doOTAUpdate_ = s; return "OK, will try "+s; }).hide();
   pub_.add("uptime",[=](String){ String ret = "Uptime " + timeAgo(millis()/1000); log(ret); return ret; }).hide();
@@ -145,10 +146,12 @@ void Solar::setup() {
   //fn, name, stack size, parameter, priority, handle
   xTaskCreate(runPubt, "publish", 10000, this, 1, NULL);
 
-  if (!psu_->begin())
-    log("PSU begin failed");
-  newDesiredCurr_ = psu_->currFilt_ = psu_->limitCurr_ = psu_->outCurr_;
-  log(str("startup current is %0.3fAdes/%0.3fAfilt/%0.3fAout", newDesiredCurr_, psu_->currFilt_, psu_->outCurr_));
+  if (!psu_) log("no PSU set");
+  else if (!psu_->begin()) log("PSU begin failed");
+  else if (psu_) {
+    newDesiredCurr_ = psu_->currFilt_ = psu_->limitCurr_ = psu_->outCurr_;
+    log(str("startup current is %0.3fAdes/%0.3fAfilt/%0.3fAout", newDesiredCurr_, psu_->currFilt_, psu_->outCurr_));
+  }
   nextAutoSweep_ = millis() + 10000;
   log("finished setup");
   log("OSPController Version " + version_);
@@ -167,16 +170,10 @@ String Solar::setPSU(String s) {
   log("setPSU " + s);
   if (s.length() || !psu_) {
     //TODO Parse softserial pins, bluetooth comms, and moar.
-    s.toUpperCase();
-    if (s.startsWith("DP")) {
-      psu_.reset(new DPS(&Serial2));
-      Serial2.begin(19200, SERIAL_8N1, -1, -1, false, 1000);
-      if (measperiod_ == 200) //default
-        measperiod_ = 500;
-    } else { //default
-      psu_.reset(new Drok(&Serial2));
-      Serial2.begin(4800, SERIAL_8N1, -1, -1, false, 1000);
-    }
+    psu_.reset(PowerSupply::make(s));
+    if (psu_ && ! psu_->isDrok() && (measperiod_ == 200)) //default
+      measperiod_ = 500; //slow down, DSP5005 meas does full update()
+    ckPSUs();
     psu_->begin();
     return "created PSU=" + psu_->getType();
   }
@@ -216,7 +213,7 @@ String SPoint::toString() const {
 }
 
 void Solar::applyAdjustment() {
-  if (newDesiredCurr_ != psu_->limitCurr_) {
+  if (psu_ && newDesiredCurr_ != psu_->limitCurr_) {
     if (psu_->setCurrent(newDesiredCurr_))
       pub_.logNote(str("[adjusting %0.3fA (from %0.3fA)]", newDesiredCurr_ - psu_->limitCurr_, psu_->limitCurr_));
     else log("error setting current");
@@ -231,19 +228,20 @@ void Solar::startSweep() {
   if (state_ == States::error)
     return log("can't sweep, system is in error state");
   log(str("SWEEP START c=%0.3f, (setpoint was %0.3f)", newDesiredCurr_, setpoint_));
-  if (state_ == States::collapsemode) {
+  if (psu_ && state_ == States::collapsemode) {
     psu_->enableOutput(false);
     psu_->setCurrent(psu_->currFilt_* 0.75);
     delay(200);
     log(str("First coming out of collapse-mode to clim of %0.2fA", psu_->limitCurr_));
   }
   setState(States::sweeping);
-  if (!psu_->outEn_)
+  if (psu_ && !psu_->outEn_)
       psu_->enableOutput(true);
   lastAutoSweep_ = millis();
 }
 
 void Solar::doSweepStep() {
+  if (!psu_) return;
   if (!psu_->outEn_)
     return setState(States::mppt);
 
@@ -306,7 +304,7 @@ void Solar::doSweepStep() {
 }
 
 bool Solar::hasCollapsed() const {
-  if (!psu_->outEn_) return false;
+  if (!psu_ || !psu_->outEn_) return false;
   bool simpleClps = (inVolt_ < (psu_->outVolt_ * 1.11)); //simple voltage match method
   float collapsePct = (inVolt_ - psu_->outVolt_) / psu_->outVolt_;
   if (simpleClps && psu_->isCollapsed())
@@ -326,7 +324,7 @@ void Solar::loop() {
     return delay(100);
 
   if (now > nextVmeas_) {
-    if (psu_->getInputVolt(&inVolt_)) {
+    if (psu_ && psu_->getInputVolt(&inVolt_)) {
       psu_->doUpdate();
       psu_->getInputVolt(&inVolt_);
     } else {
@@ -336,7 +334,7 @@ void Solar::loop() {
     pub_.setDirtyAddr(&inVolt_);
     if (state_ == States::sweeping) {
       doSweepStep();
-    } else if (setpoint_ > 0 && psu_->outEn_) { //corrections enabled
+    } else if (setpoint_ > 0 && psu_ && psu_->outEn_) { //corrections enabled
       double error = inVolt_ - setpoint_;
       double dcurr = constrain(error * pgain_, -ramplimit_ * 2, ramplimit_); //limit ramping speed
       if (error > 0.3 || (-error > 0.2)) { //adjustment deadband, more sensitive when needing to ramp down
@@ -349,7 +347,9 @@ void Solar::loop() {
     }
 
     //update system states:
-    if (state_ != States::sweeping && state_ != States::collapsemode) {
+    if (!psu_) {
+      setState(States::error);
+    } else if (state_ != States::sweeping && state_ != States::collapsemode) {
       int lastPSUsecs = (millis() - psu_->lastSuccess_) / 1000;
       if (psu_->outEn_) {
         if      (lastPSUsecs > 11) setState(States::error, "enabled but no PSU comms");
@@ -373,7 +373,7 @@ void Solar::loop() {
   if (now > nextSolarAdjust_) {
     try {
       if (state_ == States::error) {
-        if ((now - psu_->lastSuccess_) < 30000) { //for 30s after failure try and shut it down
+        if (psu_ && (now - psu_->lastSuccess_) < 30000) { //for 30s after failure try and shut it down
           psu_->enableOutput(false);
           psu_->setCurrent(0);
           throw Backoff("PSU failure, disabling");
@@ -386,7 +386,7 @@ void Solar::loop() {
           log(str("collapsed! %0.2fV set recovery to %0.1fA ", inVolt_, newDesiredCurr_) + psu_->toString());
           psu_->enableOutput(false);
           psu_->setCurrent(newDesiredCurr_);
-        } else if (!psu_->outEn_) { //power supply is off. let's check about turning it on
+        } else if (psu_ && !psu_->outEn_) { //power supply is off. let's check about turning it on
           if (inVolt_ < psu_->outVolt_ || psu_->outVolt_ < 0.1) {
             throw Backoff("not starting up, input voltage too low (is it dark?)");
           } else if ((psu_->outVolt_ > psu_->limitVolt_) || (psu_->outVolt_ < (psu_->limitVolt_ * 0.60) && psu_->outVolt_ > 1)) {
@@ -398,7 +398,7 @@ void Solar::loop() {
             psu_->enableOutput(true);
           }
         }
-        if (psu_->outEn_ && state_ != States::collapsemode) {
+        if (psu_ && psu_->outEn_ && state_ != States::collapsemode) {
           applyAdjustment();
         }
       }
@@ -420,7 +420,7 @@ void Solar::loop() {
     nextPrint_ = now + printPeriod_;
   }
 
-  if (now > nextPSUpdate_) {
+  if (psu_ && now > nextPSUpdate_) {
     bool res = psu_->doUpdate();
     if (res) {
       pub_.setDirty({"outvolt", "outcurr", "outputEN", "outpower", "currFilt"});
@@ -433,13 +433,13 @@ void Solar::loop() {
   }
 
   if (lvProtect_ && now > lvProtect_->nextCheck_) {
-    if (!lvProtect_->isTriggered() && psu_->outVolt_ < lvProtect_->threshold_) {
+    if (!lvProtect_->isTriggered() && psu_ && psu_->outVolt_ < lvProtect_->threshold_) {
       log(str("LOW VOLTAGE PROTECT TRIGGERED (now at %0.2fV)", psu_->outVolt_));
       sendOutgoingLogs(); //send logs, tripping this relay may power us down
       delay(200);
       lvProtect_->trigger(true);
       lvProtect_->nextCheck_ = now + 5 * 1000;
-    } else if (lvProtect_->isTriggered() && psu_->outVolt_ > lvProtect_->threshRecovery_) {
+    } else if (lvProtect_->isTriggered() && psu_ && psu_->outVolt_ > lvProtect_->threshRecovery_) {
       log("low voltage recovery, re-enabling.");
       lvProtect_->trigger(false);
       lvProtect_->nextCheck_ = now + 10000;
@@ -475,7 +475,7 @@ void Solar::publishTask() {
   db_.client.setCallback([=](char*topicbuf, uint8_t*buf, unsigned int len){
     String topic(topicbuf), val = str(std::string((char*)buf, len));
     log("got sub value " + topic + " -> " + val);
-    if (topic == (db_.feed + "/wh")) {
+    if (topic == (db_.feed + "/wh") && psu_) {
       psu_->wh_ = (psu_->wh_ > 2.0)? val.toFloat() : psu_->wh_ + val.toFloat();
       log("restored wh value to " + val);
       db_.client.unsubscribe((db_.feed + "/wh").c_str());
@@ -509,7 +509,7 @@ void Solar::publishTask() {
       }
       sendOutgoingLogs();
       heap_caps_check_integrity_all(true);
-      nextPub_ = now + (psu_->outEn_? db_.period : db_.period * 4); //slower when disabled
+      nextPub_ = now + ((psu_ && psu_->outEn_)? db_.period : db_.period * 4); //slower when disabled
     }
     db_.client.loop();
     pub_.poll(&Serial);
@@ -521,10 +521,10 @@ void Solar::publishTask() {
 void Solar::printStatus() {
   String s = state_;
   s.toUpperCase();
-  s += str(" %0.1fVin -> %0.2fWh ", inVolt_, psu_->wh_) + psu_->toString();
+  s += str(" %0.1fVin -> %0.2fWh ", inVolt_, psu_? psu_->wh_ : 0) + (psu_? psu_->toString() : "[no PSU]");
   if (lvProtect_ && lvProtect_->isTriggered()) s += " [LV PROTECTED]";
   s += pub_.popNotes();
-  if (psu_->debug_) log(s);
+  if (psu_ && psu_->debug_) log(s);
   else Serial.println(s);
 }