Designing a Diversion Water Heater Load For AUX 1 using an SSR - AC or DC?

Started by Matrix, November 01, 2017, 03:19:35 PM

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ClassicCrazy

Quote from: Matrix on February 05, 2018, 09:00:35 AM
Quote from: boB on February 04, 2018, 02:31:33 AM

Will look into this, Mr. Matrix !   :)

boB
Thanks boB that would be awesome.

And by the way, I meant no disrespect to MidNite in my comment.  I was being "tongue-n-cheek".    I know Midnite has a lot of other irons in the fire.  Just my dry way of saying "Please" as I know no other way to accomplish what I need.    I realize what I would like to do could possibly be accomplished thru modbus,  but I have looked at that and concluded modbus set up would be way over my head.  Hope I did not come off snarky.

Mike

Mike  - maybe we need to make an Arduino to control Modbus beginners step by step page .  I know how to mess around with Arduino's a bit but haven't ever gotten it all together to connect to Classic yet. If I do I will make a new post and document ever step of the way .

You can get Arduino boards on Ebay for a few bucks . 

Larry
system 1
Classic 150 , 5s3p  Kyocera 135watt , 12s Soneil 2v 540amp lead crystal for 24v pack , Outback 3524 inverter
system 2
 5s 135w Kyocero , 3s3p 270w Kyocera  to Classic 150 ,   8s Kyocera 225w to Hawkes Bay Jakiper 48v 15kwh LiFePO4 , Outback VFX 3648 inverter
system 3
KID / Brat portable

Matrix

That would be great Larry.  Do you have to write your own control software with that though?  I assume the local app would be of no use (or of no more use than it is now thru a LAN)
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REC TwinPeak 2 285W 3S-3P 2565w-STC 1926w-NMOT Array / Classic 150 / Conext SW 4024 Inverter
Trojan L16H-AC 435Ah bank 4S  with 7' of 4/0 cable
24 volt system /  Need 3200Whs Daily
My System Install

ClassicCrazy

If  you look in the other forum post on Arduino's you will see that others have written code to do various things and shared it. It is possible to modify or use parts of their control codes to do what you want to . So you don't have to start off from scratch if others have already figured it out.

Larry
system 1
Classic 150 , 5s3p  Kyocera 135watt , 12s Soneil 2v 540amp lead crystal for 24v pack , Outback 3524 inverter
system 2
 5s 135w Kyocero , 3s3p 270w Kyocera  to Classic 150 ,   8s Kyocera 225w to Hawkes Bay Jakiper 48v 15kwh LiFePO4 , Outback VFX 3648 inverter
system 3
KID / Brat portable

Iboondock

I don't have any experience with an Arduino device, although it's on the list of things to learn in the future. So I opted for an off the shelf PLC and some ladder logic to implement cpfl's method of tweaking the AUX 2 WasteNot threshold setting. So far it's working well and I'm happy with the results.

Reading one(or a few) registers, comparing them, and then turning on an output is pretty easy to do with a PLC. It may be an option to tighten up the SOC settings for your diversion.






Iboondock

I had some time to test a SOC based PLC program and it works. Screenshots of the ladder logic attached.

The first small program is a simple on/off based on a single SOC value.

The second program turns on at a lower SOC and then turns off when the SOC drops back one percent from it's high. It would also turn back on if the SOC increased again during that charge cycle.

I'm using a Click PLC with an ethernet port, connecting to the Classic over LAN. The program reads once every 5 minutes(adjustable), so the Local App is still able to get a connection in btw those reads.

ClassicCrazy

You program the PLC to do the modbus read of SOC register and then the program you wrote turns external relay on and off ?

Larry
system 1
Classic 150 , 5s3p  Kyocera 135watt , 12s Soneil 2v 540amp lead crystal for 24v pack , Outback 3524 inverter
system 2
 5s 135w Kyocero , 3s3p 270w Kyocera  to Classic 150 ,   8s Kyocera 225w to Hawkes Bay Jakiper 48v 15kwh LiFePO4 , Outback VFX 3648 inverter
system 3
KID / Brat portable

Iboondock

Quote from: ClassicCrazy on February 27, 2018, 08:44:04 PM
You program the PLC to do the modbus read of SOC register and then the program you wrote turns external relay on and off ?

Larry

Yes, that's correct. The PLC output would power the diversion SSR.


Matrix

Quote from: boB on February 04, 2018, 02:31:33 AM
Quote from: Matrix on February 03, 2018, 10:23:39 PM
But set the ON to 98% and you are stuck with a 93% OFF -  Come on MidNite Solar,  this would be easy for you to fix,  and even better if you could really tweak the settings per this discussion ... :D


Will look into this, Mr. Matrix !   :)

boB
@boB ... I have been thinking about that suggestion of having SOC Hi (or whatever) turn the AUX on at a lower % as charge was going up (say as charging reached 90%) and then off as discharge went back down from 100% say to 99% as I was suggesting.

In a perfect world this would be great ... BUT ... I just the other day realized while thinking about it,  If the charging system never reached 100% ... the AUX would turn on BUT NEVER TURN OFF.  Ummm ... that would be bad,  very bad.   :-[

So there would have to be other safe guards put into my idea. 
Grid-Assist Off-Grid
REC TwinPeak 2 285W 3S-3P 2565w-STC 1926w-NMOT Array / Classic 150 / Conext SW 4024 Inverter
Trojan L16H-AC 435Ah bank 4S  with 7' of 4/0 cable
24 volt system /  Need 3200Whs Daily
My System Install

Matrix

My Latest Settings and Setup

As of now I have have pretty much solved the quick light flicking issue with the water heater diversion load coming on and off several times in a short period of time at the end of the day due to low power. 

Back a few months ago I installed my latest Hot Water Heater Element.  I am now using a 240v AC 1000 Watt element off of my 240v split phase inverter.  This helps to balance the load on the inverter much better and lessens the light flicker when the element turns on. I had to order the Element from Grainger,  This was the only place I could find such an odd spec element.

I have drifted away from SOC Hi because of the obvious power drain issues on the battery and less control of the SSR.

I have over the past few months been using Waste Not Hi again and the following settings that seem to be working pretty well balancing available power for heating water, Battery charging/discharging and light flickers when the load comes on.   Note:  I use a hi absorb voltage settings, So the first setting may need to be lower if you use a lower absorb voltage settings.

Relative - (V) =   -1.7  (this setting is relative to the absorb volt setting and  leaves the AUX on long enough for the CC to settle in to the load.  If there is enough solar power, the volts will return to the absorb charge settings)

Relative + (V) = -0.2 (this is the setting that turns on the AUX control relative to the absorb volt setting)

Delay Time = 30 secs (this longer delay keeps they Diversion load from cycling too often)

Hold Time = 10 secs (this keeps the AUX on for 10 secs after the Relative - (V) has dropped below that setting in case of clouds etc)

This has worked pretty well the past few months.  I am interested to here what others are having success with. 


Grid-Assist Off-Grid
REC TwinPeak 2 285W 3S-3P 2565w-STC 1926w-NMOT Array / Classic 150 / Conext SW 4024 Inverter
Trojan L16H-AC 435Ah bank 4S  with 7' of 4/0 cable
24 volt system /  Need 3200Whs Daily
My System Install

ClassicCrazy

For now I am using SOC Hi to turn water heater on . It goes on at  96% and off at 94%  . So if day is sunny it goes on and will stay on because my load is not so great as to bring back down too fast . I also have a temperature controller in series with the signal from the Classic to the SSR relay which is controlling the heating element in the water heater. So either the water temperature or the temperature controller can shut off the SSR. So far so good. Just using a cheapy ebay Fotec ( most likely fake ) which is mounted on heat sink and cheap $4 temperature controller. Heater element is AC so the built in water heater thermostat is also active . Only using one heating element on bottom of water heater and water heater is not filled up all the way so when water is heated it shuts off. 

Larry
system 1
Classic 150 , 5s3p  Kyocera 135watt , 12s Soneil 2v 540amp lead crystal for 24v pack , Outback 3524 inverter
system 2
 5s 135w Kyocero , 3s3p 270w Kyocera  to Classic 150 ,   8s Kyocera 225w to Hawkes Bay Jakiper 48v 15kwh LiFePO4 , Outback VFX 3648 inverter
system 3
KID / Brat portable

Matrix

Grid-Assist Off-Grid
REC TwinPeak 2 285W 3S-3P 2565w-STC 1926w-NMOT Array / Classic 150 / Conext SW 4024 Inverter
Trojan L16H-AC 435Ah bank 4S  with 7' of 4/0 cable
24 volt system /  Need 3200Whs Daily
My System Install

Matrix

I also just added an update to the bottom of the first post with a quick reference guide to this thread.  If anyone knows of any other info in this thread that might be helpful to others let me know and I will add it to the first post
Grid-Assist Off-Grid
REC TwinPeak 2 285W 3S-3P 2565w-STC 1926w-NMOT Array / Classic 150 / Conext SW 4024 Inverter
Trojan L16H-AC 435Ah bank 4S  with 7' of 4/0 cable
24 volt system /  Need 3200Whs Daily
My System Install

Matrix

Quote from: ClassicCrazy on May 26, 2018, 10:10:35 AM
For now I am using SOC Hi to turn water heater on . It goes on at  96% and off at 94%  . So if day is sunny it goes on and will stay on because my load is not so great as to bring back down too fast . I also have a temperature controller in series with the signal from the Classic to the SSR relay which is controlling the heating element in the water heater. So either the water temperature or the temperature controller can shut off the SSR. So far so good. Just using a cheapy ebay Fotec ( most likely fake ) which is mounted on heat sink and cheap $4 temperature controller. Heater element is AC so the built in water heater thermostat is also active . Only using one heating element on bottom of water heater and water heater is not filled up all the way so when water is heated it shuts off. 

Larry
Larry,  re-reading what you wrote,  why are you using the temp controller in series with the SSR?   For Redundancy?  Wouldn't the control on the DHW turn it off when the water reached temp?   
Grid-Assist Off-Grid
REC TwinPeak 2 285W 3S-3P 2565w-STC 1926w-NMOT Array / Classic 150 / Conext SW 4024 Inverter
Trojan L16H-AC 435Ah bank 4S  with 7' of 4/0 cable
24 volt system /  Need 3200Whs Daily
My System Install

Westbranch

Larry, you say that the tank is only half full... is that draining by gravity? Is there air in the tank?
KID FW1811 560W >C&D 24V 900Ah AGM
CL150 29032 FW V.2126-NW2097-GP2133 175A E-Panel WBjr, 3Px4s 140W > 24V 900Ah AGM,
2 Cisco WRT54GL i/c DD-WRT Rtr, NetGr DS104Hub
Cotek ST1500 Inv  want a 24V  ROSIE Inverter
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West Chilcotin 1680+W to come

ClassicCrazy

Quote from: Westbranch on May 26, 2018, 11:24:52 AM
Larry, you say that the tank is only half full... is that draining by gravity? Is there air in the tank?

Yes it is an open system in that it is not pressurized. I manually fill it . I have removed the top element and use that hole to recirculate water from the bottom drain hole . I use a small AC electric washing machine pump - this one has never blinked at pumping hot water and does the job of recirculating and also enough to get it up to a shower head .

Regarding the manually fill - I just got pressure switch from a washing machine - those are used to control the solenoid in a washer for low, medium , high water levels - so I am going to use it to either shut the pump off when the water is at high enough level or as a safety to shut the heating element off if the water level gets too low ( so the heater element won't burn out ) .

Larry
system 1
Classic 150 , 5s3p  Kyocera 135watt , 12s Soneil 2v 540amp lead crystal for 24v pack , Outback 3524 inverter
system 2
 5s 135w Kyocero , 3s3p 270w Kyocera  to Classic 150 ,   8s Kyocera 225w to Hawkes Bay Jakiper 48v 15kwh LiFePO4 , Outback VFX 3648 inverter
system 3
KID / Brat portable