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--- drafts:hub_notes [2015-01-13 15:03] – [State of Charge (SOC)] pba
+++ assistants:hub1_and_hub2_notes [2019-01-22 10:16] (current) – external edit 127.0.0.1
@@ Line 1: / Line 1: @@
-====== Hub Assistant notes ======
+====== Hub-1 and Hub-2 Assistant notes ======
-**
-Draft - work in progress**
-===== Special states =====
+===== 1. Special states =====
 A system running the Hub-1 or Hub-2 Assistant, has the following special states:
+=== 1.1 Grid assist ===
+Normal mode was inverting, but now the system is temporarily connected to the grid to power high loads, which in total exceed the maximum inverter power. As soon as those loads are below threshold for 60 seconds, the system will switch back to invert mode again.
+=== 1.2 Prevent feedback (hub-2 only) ===
+Normal mode is connected during the grid (at least during the day). When it sees power flowing back into the grid, it will disconnect from the grid and work in island mode. AC output frequency will be increased, to reduce the PV output power from the PV inverter. As soon as there is no excess of PV available any more, (AC output frequency has dropped back to 50 Hz), the system will connect to the grid again.
-=== Grid assist ===
+Note that preventing this switch-over is not instantaneous, it takes 20 seconds. And when feedback occurs while connected to the grid because of a low battery or overload, the prevent-feedback mechanism will be disabled. (The overload will be active for the time the user specifies in the 'Load connect condition' step. The default value is 60 seconds.)
-normal mode was inverting, but now the system is temporarily connected to the grid to power high loads, which in total exceed the maximum inverter power. As soon as those loads are gone for ... , the system will switch back to invert mode again.
-=== Prevent feedback (hub-2 only) ===
+To summarize: 'prevent feedback' is not the solution when connected behind a meter that immediately disconnects upon feedback.
-normal mode is connected during the grid (at least during the day). The Multi has now temporarily switched to inverter mode to prevent feeding power from the PV inverter back in to the grid. Also the AC output frequency will be increased, to reduce the PV output power from the PV inverter. As soon as there is no excess of PV available any more, (AC output frequency has dropped back to 50 Hz), the system will connect to the grid again.
-=== Maintenance charge ===
+=== 1.3 Maintenance charge ===
-A full charge cycle will be completed every 28 days (programmable). This full charge cycle includes the absorption charge, which is normally not included. And the maintenance charge cycle also includes an equalisation charge if appropriate for the chosen battery type.
+A full charge cycle will be completed every 28 days (programmable). This full charge cycle includes the absorption charge, which is normally not included. And the maintenance charge cycle also includes an equalization charge if appropriate for the chosen battery type.
 Power from the grid will be used, if at the end of the day the cycle has not yet been completed. Put differently: power from the grid will be used when there has not been enough PV power available to complete the maintenance charge.
-=== PV Reduction (of een betere naam, misschien gewoon frequency shift) (hub-2 only)===
+=== 1.4 PV Reduction / Frequency shift (hub-2 only)===
-In inverter mode with increased AC output frequency to reduce PV power. Deze state overlapt natuurlijk met prevent feedback, ik zou prevent feedback voorrang geven.
+In inverter mode with increased AC output frequency to reduce PV power.
-=== Sustain ===
+=== 1.5 Sustain ===
-System is connected to the grid and the internal charger is enabled (but with its charge voltage setpoint to a lover voltage) to prevent batteries from being drained fully. System will stay connected to mains as long as the battery voltage stays low.
+The purpose of the Sustain Mode is to prevent leaving batteries in a deeply discharged state during several days. The Sustain Mode is entered when during 30 seconds the following two conditions are met without interruption:
+  - the battery voltage is below the sustain level: 12.5V for Lithium batteries and 12V for other batteries
+  - the current drawn from the battery is smaller than 1/20th of the battery capacity.\\ **Important**: Because of this, one should NOT disable the internal battery monitor (even if the battery monitor is unreliable as it is for instance in a HUB1 system). Disabling the battery monitor will set the battery capcity to zero and this will result in a wrong current limit.
-After running 24hours in sustain (only possible if there has not been enough PV power to get out of that situation) the sustain voltage will be increased with (??) to further charge the batteries a little and prevent damage to the batteries by letting the be at a discharged state for a long time.
+During Sustain, the system will be connected to the grid and the internal charger is enabled. The system will stay connected to mains as long as the battery voltage stays low.
-=== Recovery from Battery low ===
+Note that, for non-lithium systems, the sustain level is 12 V for the first 24 hours, and after that it is raised to 12.5 Volts DC.
-als hij onder de x% is geweest, zal hij de loads uit het net blijven voeden totdat de SOC weer x % is / cq absorptie bereikt is . Lade ngaat alleen vanuit PV).
-[ more info on internal Assistant wishlist page on wiki ]
+DC voltages specified are for a 12V system. These voltages should be multiplied by 2 or 4 for a 24V or 48V system.
-===== State of Charge (SOC) =====
+===== 2. Use and working of State of Charge (SOC) in a Hub2 system =====
 In a HUB2 assistant the SOC is used. From the SOC a flag is derived named SOCLow. This flag can be either true or false. The assistant will allow to enter a SOCLowLevel and a SOCHighLevel.
@@ Line 68: / Line 68: @@
   - Changed to  'low level' -10%
     - when a connected BMS signals a 'Low cell'
-    - when (on any connected Multi) UBat< (Ubat2LowInvert+1V) for 5 seconds\\    (1V is for 12V systems)
+    - when (on any connected Multi) UBat< ('DC input low shut-down'+1V) for 5 seconds  (note: 1V is for 12V systems)\\    The user can freely choose 'DC input low shut-down'. The assistant will only change this value while stepping through the assistant and if needed to guarantee that "DC input low restart" is below 11 V for Lead-acid or 12V for Li-Ion batteries. (These are the default levels the assistant uses for 'DC input low Pre-Alarm')
     - while sustain active\\    (sustain is actived when IBat is llow and Ubat< 12 or 12.5 for at least 30 seconds)\\ \\
   - Changed to 'high level' -10%
@@ Line 74: / Line 74: @@
   - Changed to 100%
     - when a Lynx BMS signals 'High voltage/cell'
-===== FAQ =====
+===== 4. FAQ =====
 === Why does my Hub-2 system start charging the first day after setting it up? ===
-This is the maintenance charge. If later on you reconnect VEConfigure and make changed to the Assistant, the same thing will happen: a maintenance charge, using power from the grid (if necessary) to fully charge the batteries.
+This is the maintenance charge. The moment you switch on a HUB2v3 system the daycounter will be on day [0], the day after [day 1] is the first day the first maintaince will be done. If there is no surplus energy for 24h the system will automaticly go to day [1], so start the charge period from grid. If you later on you reconnect VEConfigure and make changed to the Assistant, the same thing will happen, The day counter will be set to [0] again: a maintenance charge, using power from the grid (if necessary) to fully charge the batteries.
 === How long does it take for the Hub-2 clock to sync with the grid? ===
+This depends on the surplus of PV power. After switching in the hub system assumes its day.
+When surplus power is seen flowing into the grid this is confirmed and when the SOC reset is met the system will go into day/night mode (when selected in the policy tab) after the pv surplus has stopped.
+This will not always be at the correct point of the day in the first few days but will get corrected automaticly
 === How does Hub-2 know when it is day or night? ===
-It looks at the direction of the current at the AC output of the Multi or Quattro. If there is excess PV , etc.
+It looks at the direction of the current at the AC output of the Multi or Quattro. If there is excess PV.
+The day/night will be adjusted constantly and has a maximal drift of 7 min a day (season changes).
-Note: configure an hub-2 during day time, because (hoe zat dit ook alweer Peter?)
+Note that because it looks a the power being fed back to the grid, day/night syncing in a hub-2 system only works well if there really is an excess amount of PV available. If not, for example on most days, or during most part of the day ...
+Also, when having a grid connected wind turbine or such the day/night switch cannot be used!
+=== Can I add a small solar charger to a hub-2 installation? ===
-=== How does Hub-1 know when it is day or night? ===
+In order to have the SOC calculation work as accurate as possible this should be avoided.
-It looks at the direction of the current at the AC input of the Multi or Quattro. When there is power being fed back to the grid, it knows that it has to be day time.
-Note that because it looks a the power being fed back to the grid, day/night syncing in a hub-1 system only works well if there really is an excess amount of PV available. If not, for example on most days, or during most part of the day ...
-=== Can I add a small solar charger or wind turbine to a hub-2 installation? ===
-Yes you can, and it even has certain advantages as well. [johannes, graag uitleggen].
-You might think that the internals of the Hub-2 might get confused. The only thing that might happen is that the battery is a bit more charged than what the Assistant actually thinks, which can't hurt.
-During charge, the SOC used for the algorithms is synced at several moments:
 === Input current limiting options ===
   * It is possible to set (and change) the input current limit with a remote control panel, For example the Digital Multi Control or the Color Control GX.
   * This limit will be used when charging the battery during the periodic battery maintenance cycle. During normal operation it will normally not be used. As long as there is enough sun, the Multi will use a lower current than set with the remote control panel.
+The level that is used is depending on the model which is used. (the threshold for powerassist is depending on the size of the inverter and the AC input current range of an inverter)
+(example for threshold ; 3k/50Amp relay --> 6Amp minimal)
+=== Why does my shown SOC jump (VE.Bus SOC, not BMV SOC) ===
+The SOC is auto-corrected. For example in a low voltage warning, if the SOC is too high, it will be auto-corrected downwards.
+Mostly when having a charge current higher then 10-15% the rate of charging, the calculated SOC does not match reality. Then the Absorbtion voltage is reached too soon, setting the SOC directly on a certain level (set in the battery monitor page in ve configure)
+Same at discharging, If the DC voltage become lower then expected at a certain SOC (DC low pre alarm) the SOC at that moment is corrected to be the minimal value -  10%
+=== Why does AES not work when using Hub-1 policy 3? ===
+Hub1 policy3 is 'Disconnect from the mains when possible'. This suggest that the ACin is disconnected and that the AES function should behave the similar to when the ACin is really disconnected. This is not so.
-[ elaborate ]
+With this policy the unit will be in Inverter mode when possible but will stay synchronized to the mains. So it will be able to switch quickly when the Load connect condition becomes active. Therefor AES does not work.
-===== DISQUS Comments =====
+===== DISQUS =====
 ~~DISQUS~~