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Stand alone WbJr device

Started by WillEert, January 24, 2016, 10:42:42 AM

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WillEert

Diversion system configurations

It is interesting how diversion systems are configured. Same problem - how to maximize pv production from a system. Many different solutions.

I divert on the AC side using a dedicated Magnum 4448 mspae inverter. I also use this inverter for charging when required. This allows me to use a smaller generator as the other two ms4448's carry the load as the diversion inverter charges the batteries. Also the changes in diversion load does not affect my lighting or general piece of mind as the inverter alters its output. Likely I could tie the inverters together as one system again as the diversion control pwms at 10Hz but initially when I started the system the Classic pwm rate was so high the inverters could not keep up to changes and my whole electrical system resembled a Krazy discotec going wild while diversion was taking place. I use a Crydom Evolution Dual ssr cd48503wu 50A per channel mounted on on a Crydom HS053 heat sink. I think now the heat sink was overkill as the ssr does not get hot but maybe that's good  :). The relay feeds 2 2Kw 240 V elements individually in the hot water tank. The diversion control turns the lower one on incrementally first and when the lower is full on pwms the upper element. I sense the tank temperature at the top, middle and bottom of the tank and control my thermostats and floor heating with the middle sensor.

I appreciate that I lose efficiency diverting on the ac side however before arduino I could not find dc thermostats. Also I had not figured out that I could configure my array strings to produce about 200+ V at vmp which would allow the use of conventional elements. I though about rewiring the strings and going to dc diversion during the upgrade however when I add the additional 2 Kw of panels I now get two separate arrays. Each array would have to divert separately which would not fully load the elements as often. I want to have the full array output available to be applied to each element in turn as load output allows to get the most heat out of the elements.

Will
(1)24 ET 185 mono, Classic 150,8x Surrette 6CS25p, 4x Magnum 4448, homecooked diversion system;(2)15 Heliene 330 mono,Classic 150;(3)2X6 Hansol345mono, 2 stand alone Hotspot ACDC12C Minisplit heat pumps.(4)15 Hanwha Q cell 400 1/2 cell, Classic 200: (5)1X6 HanwhaQcell 400 1 Hotspot minisplit ACDC18C

ClassicCrazy

It does not sound any electron will go to waste on your system Will !
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

dgd

Will,

I think the AC Crydom SSR I played with was a 2450 when I tried PWMing to an AC heating element.
It wasn't just the light flickering that made me change to DC, even though I used AUX1 that was a much slower duty cycle pwm rate, but it was fact that all power for both battery charging and water heating was going through the Classics and the inverter.
This just didn't seem right  as it felt like the inverter, batteries and controllers were being unnecessarily beaten up/pushed to limits for the sake of water heating.

I considered DC water heating at battery voltage but that still pushes all the energy through the Classics
hence I decided to divert energy directly from PVs.
Its probably not so important for me to be concerned with diversion during absorb as water heating is primarily done with a small 24 evac tube solar heating system that generates lots hot water even on clouded over days.
The problem I have more often now is what to do with all the energy that I could generate but don't have a use for.

dgd

Classic 250, 150,  20 140w, 6 250w PVs, 2Kw turbine, MN ac Clipper, Epanel/MNdc, Trace SW3024E (1997), Century 1050Ah 24V FLA (1999). Arduino power monitoring and web server.  Off grid since 4/2000
West Auckland, New Zealand

WillEert

Hi David,

I agree - dc diversion is much preferable. If the strings are wired to produce about 200+V  then conventional 220-240V elements could be used with a reduction in wattage. The Classic of choice would then be the 250. The arduino would function as a diversion control and  thermostat and use a suitable  ssr for control. That is what I would like to do. The problem I face with dc diversion is that it limits the array size to what one Classic can handle or if the array is larger than one Classics input limit each array would have to divert on it's own as you cannot tie the arrays together on the dc side. This means I would have to have 2 diversion systems. In low light conditions I want to put all the available spare power into one element. I notice with the 2 KW elements I presently use that the tank does not seem to change temperature unless I am putting in about 500w or so as a minimum. I think a 2 KW element that is supplied 500w just does not heat up very much. With Manitoba winters and since I use this system for heating I can use all the hot water I can get - particularly on low light days.

Will
(1)24 ET 185 mono, Classic 150,8x Surrette 6CS25p, 4x Magnum 4448, homecooked diversion system;(2)15 Heliene 330 mono,Classic 150;(3)2X6 Hansol345mono, 2 stand alone Hotspot ACDC12C Minisplit heat pumps.(4)15 Hanwha Q cell 400 1/2 cell, Classic 200: (5)1X6 HanwhaQcell 400 1 Hotspot minisplit ACDC18C