Hi,
Im putting together an off grid setup at present, and the final decision is the controller. The classic seems to fit my needs generally very well. The system is an 1800Wp system servicing 3kWh/day base loads. But in addition there are large amounts of surplus energy for most of the year.
The main thing i dont understand is how to best use this surplus array output.
The only thing i found that looks promising was this post http://outbackpower.com/forum/viewtopic.php?f=29&t=2865&start=25
How i think this should work is something like this: as the controller goes into absorb, the off part of the charging square wave turns on a second matching output FET driver that powers the hot water element directly. No external relays or SSRs required, and there would be some means to control the output via the thermostat. This way every amp is used efficiently and theres no strange feedbacks/oscillations as seems likely to occur if an AUX divert approach, and no arbitrary or unnecessary loading placed on the battery bank.
Of course i have no idea how the classic works inside and this may all be silly. Are you considering how this might be better done in the near future? It seems to me that the recent PV price drop changes the game on all this??? Whats my best bet here? Thanks.
I wish I had some good information for ya,
But something strikes me as seriously wrong with the universe if it makes sense to
convert sunlight into electricity to drive resistive loads to heat water.
seriously.
Have a look at THIS (http://www.fieldlines.com/index.php/topic,147132.0) thread on the fieldlines forum.
Another option (and more efficient use of PV power) is to use a heat pump water heater such as the Nyle Geyser (http://www.nyle.com/water-heating/geyser-r/). I have one and it works great. Draws about 600-800 watts when running. When running in my basement with air temp of 55 Degrees F it will take my cold water (50F ?) and heat 50 gallons to 125F in about 3-4 hours.
@cpm, with pv prices falling its making more sense to design off grid solar to meet year round needs. This inevitably leaves a serious amount of power that would otherwise be wasted. If you want to get an idea how much power checkout my spreadsheet here:
www.zoneblue.org/files/stand-alone-pv-perf.xls.zip
@mtdoc thanks for that link, thats what im talking about. Ive also now read the classic manual cover to cover. Does anyone know how the opportunity aux2 setting actually works? How does it prevent the controller constantly dropping out of float?
Guys i see this energy as a waste product. Hence i dont want to either cycle my battery bank, or load my inverter with it. Just putting it to use, as simply efficiently and cheaply as possible. If the SSR was on the same heatsink as the controller surely it would be cheaper and more integrated.
Hi zoneblue,
So if you are interested in not using the battery bank as a source for this excess power, then I assume that you are not interested in using the AC output from an inverter either.
Believe that you are thinking of using the DC from the PV array. It is my opinion that using OFF period of the CC as the ON period to drive a resistive element in a Waterheater could easily upset the voltage regulation of the CC when it is trying to maintain Vabs or Vfloat.
Seems to me that you would need a PWM function that regulates the amount of average current doing into the resistive element.
Ths Classic does have a built-in PWM function on Aux 2, IIRC. And believe that it must be in the Classic's voltage control loop. This function that is already in the Classic should only need a SSR to control the excess power.
Believe that this prorcess could use either PV DC, battery DC, or inverter AC, with varying degrees of success.
One of the issues with trying to use PV DC is, that finding a heating element that is tailored to the PV voltage of your system could be a challenge. There are some elements that are designed for 12 and 24 volt DC systems. But if your PVs put out, say around 90 VDC it would be too much for even two of the 24 V elements in series, and a bit too low for an element that is looking for 120 VAC, and so fourth.
And, cpm, you are correct in general about using PV electric power to heat water ... But in a fairly well banalced off grid system, there are many times where batts are charged, and water has been pumped, etc, and there is still excess power available. Having yet another place for the power to go, especially somewhere that reduces use of Fossil fuel can be a good thing.
Just opinions, YMMV, Vic
Quote from: cpm on November 17, 2012, 05:12:49 PM
But something strikes me as seriously wrong with the universe if it makes sense to
convert sunlight into electricity to drive resistive loads to heat water.
seriously.
There are a few good reasons for doing this.
Burning up excess power is the biggest one.
I agree it would be kind of short sighted to deliberately turn sunlight into high grade electricity to turn around and use it to create heat when you can do a relatively low tech solar heating setup for pretty cheap.
Not everything is as simple as we would like.
Just Sayin.
Tom
Another idea I have heard of, and kind of like the idea is to use extra energy to make hydrogen.
Not sure how you store that hydrogen but it could be used in several different ways I suppose.
boB
Quote from: Vic on November 17, 2012, 06:06:07 PM
Believe that you are thinking of using the DC from the PV array.
Yes so that the inverter capacity can remain free for base loads. And avoiding the inverter losses, which maybe more than the DC wiring losses?
Quote from: Vic on November 17, 2012, 06:06:07 PM
It is my opinion that using OFF period of the CC as the ON period to drive a resistive element in a Waterheater could easily upset the voltage regulation of the CC when it is trying to maintain Vabs or Vfloat.
This is my point, if the controller essentially sent everything it wasnt using for charging to hot water, then all this fiddling with matching the pulse width would be a non issue.
The battery bank only has finite cycles and by guessing the AUX settings doesnt the mismatch mean you are inevitably cycling the battery more?
And the difficulty of finding the right size DC element? That would improve if it was easier to do, no?.
Quote from: Vic on November 17, 2012, 06:06:07 PM
Believe that this prorcess could use either PV DC, battery DC, or inverter AC, with varying degrees of success.
You only have to read the two threads mentioned above to see how hit and miss getting the AUX/PWM/ SSR combination working sensibly is.
Im still interested to know how the midnite AUX2 works. How does it know the difference between loads and charge? how to avoid cooking, say AGMs by long absorbs etc? By constantly messing with the load, how does it have any clue at all where the battery is in the charge process?
Anyway coming back to the OP, are we saying that the AUX/SSR method is the current best way to achieve this?
To directly power a resistive water heating element with DC current, I think you would want to use a diversion controller like a Morningstar TS 45 or Xantrex C40 (these also work as PWM controllers).
Just like the diversion load used for hydro or wind systems, you would connect the diversion controller to your battery bank and the water heating element. I believe there are several options for how the Aux port from the Classic could be set up to trigger this diversion.
You still need to go through the batteries but if set up correctly you would not be cycling them. Personally I think Chris Olson's method using a SSR and the "waste not high" Aux function is more elegant and probably much more efficient. With his method you are not cycling the batteries either.
While it's an added cost to buy a heat pump water heater, the efficiency you gain from doing so would far outweigh the small efficiency losses in the inverter/batteries. On the other hand if your inverter size is such that it can already barely handle your peak loads then your concern about overloading the inverter is valid.
Quote from: mtdoc on November 17, 2012, 08:22:06 PM
To directly power a resistive water heating element with DC current, I think you would want to use a diversion controller like a Morningstar TS 45... you would connect the diversion controller to your battery bank and the water heating element. I believe there are several options for how the Aux port from the Classic could be set up to trigger this diversion.
thanks, any ideas where to start reading on that? A TS60 is cheap enough, im happy with that if it will play nicely with the 150 classic.
QuoteChris Olson's method using a SSR and the "waste not high" Aux function is more elegant and probably much more efficient. With his method you are not cycling the batteries either.
I cant find any reference to 'waste not high' in the manual. There's opportunity hi and lo. Diversion hi and lo. And what is there is pretty brief. Is this documented elsewhere?
Cheers
p40
Aux 2 Function. Output/Input
OUTPUT = 12V/0V Signal
FLOAT LOW Aux2 off when in Float
FLOAT HIGH Aux2 on when in Float
DAY LIGHT Aux2 on at dawn off at dusk
NITE LIGHT Aux2 on at dusk off at dawn
CLIPPER CONTROL PWM Control for Clipper
Pv V ON LOW PWM sig below Pv in setpoint
Pv V ON HIGH PWM sig above Pv in setpoint
TOGGLE TEST Aux2 cycled 1 sec interval
OPPORTUNITY LO PWM divert rltv chg state lo
OPPORTUNITY HI PWM divert rltv chg state hi
DIVERSION LO PWM Divert on Bat voltage lo
DIVERSION HI PWM Divert on bat voltage hi
Quote from: zoneblue on November 17, 2012, 08:37:07 PM
OPPORTUNITY LO PWM divert rltv chg state lo
OPPORTUNITY HI PWM divert rltv chg state hi
What was the software version or date for this MNGP ?
boB
I clicked main nav, documents, manuals, classic manual. Is there a newer manual?
Quote from: zoneblue on November 18, 2012, 04:07:38 AM
I clicked main nav, documents, manuals, classic manual. Is there a newer manual?
No newer manual. OK, swap those words "Opportunity" with "Waste Not".
Thank you for pointing out this error in the manual !!
boB
Quote
You only have to read the two threads mentioned above to see how hit and miss getting the AUX/PWM/ SSR combination working sensibly is.
I've been using that function (which I found out about initially form this forum) for about two months and it's working very well. As I mentioned in the linked "Fieldlines" thread above, I had some early problems with my inverter AC voltage fluctuating too much, but that's largely resolved. There is still some flickering in CFL bulbs when the heating element is on in the "waste not hi" PWM mode, but remember that the element is only on during the day, usually during the brightest part of the afternoon, so the flickering is not a significant issue, since the lights aren't on then except in one windowless bathroom. The battery charging cycles complete normally.
By doing this, I spent about $40 in parts (SSR and some wire) to get hot water from the surplus power my panels were producing, which has basically been enough to take our water heater off grid (probably around 5-10% of heating now is on grid power). Hard to imagine a way to do it more cheaply, and even if it doesn't work out for some reason, it's not like you've made a huge investment.
Since installing this, my pv production measured at the Classics has gone up significantly, and I think I'm close to using almost every watt-hour that my panels produce. Right now (November) a sunny day sees them producing over 4 KWh per KW of panel. Pretty cool if you ask me.
I do basically the same thing. I ave 2 SSR's in the house that are run by 2 Classics using Waste Not PWM, I also have a single large SSR in the house driven by Waste Not NON PWM. In the summer the large SSR drives my 40 gallon water heater, in the Winter the 2 SSR's drive 4000 watts of electric heat. This works well although it does use the inverters so there is some loss there. DC diversion is very elegant but not always practical. In my case the batteries are 150ft from the house.
Ryan
Oooh, interesting. My batteries are also 100+ ft from the house. How are you triggering those SSRs Ryan? Would cat5 cable work at those distances? I have often thought a wireless solution would be rather elegant as pulling another cable through conduit and getting it to the proper place would be a pain, as the sheet rock is already hung.
Yes I am using Cat5 cable. We are working on an addition that may just take care of the wireless ideas?
Ryan
Quote from: boB on November 18, 2012, 05:32:14 AM
No newer manual. OK, swap those words "Opportunity" with "Waste Not".
Thank you for pointing out this error in the manual !!
No worries! But could you please explain how 'Waste not Hi' works.
The name suggests that the pwm output is somehow proportional to the percentage of the array's output that the controller considers 'waste'. Is that right? Or is it proportional to the absolute amount of kilowatts considered waste, or put another way the percentage of the controllers possible output ? That would be easier to match with the opportunity load.
Are the pulse freq and peak voltage constant, but the duty cycle modulated? Or is the pulse width constant and the frequency variable?
Ok Rereading the manual:
"There is also a voltage "width" adjustment, the voltage width being the range where the PWM goes
from a short pulse, beginning right at the charge set point voltage, and full on at the diversion set point
voltage "plus" the width voltage" p30.
So do you just adjust it by trial and error?
Quote from: cpm on November 17, 2012, 05:12:49 PM
I wish I had some good information for ya,
But something strikes me as seriously wrong with the universe if it makes sense to
convert sunlight into electricity to drive resistive loads to heat water.
seriously.
Actually it's very satisfying to use sunlight to make electricity to heat water. Remember all our energy originates from the sun, all the energy in fossil fuels, wind, water flow etc..
Its a Much more direct use of energy too , not involving chemical reactions, pollution, by products etc.
The universe is in order, the answer is still 42
Dgd
Quote from: Halfcrazy on November 18, 2012, 11:02:08 AM
Yes I am using Cat5 cable. We are working on an addition that may just take care of the wireless ideas?
Ryan
Really? Cool!
My dream would be to have a black box that plugged into the Classics aux function and sent a wireless signal to another black box a couple hundred feet away. The receiving box would plug into a wall outlet and have a 15A rating so I could run whatever type of opportunity load off the inverter that I chose to plug into it. Ideally, the receiver would have minimal power draw and the transmitter would only wake up when the aux function goes high, minimizing the idle current for the whole device.
You asked! 8)
QuoteMy dream would be to have a black box that plugged into the Classics aux function and sent a wireless signal to another black box a couple hundred feet away.
Not as elegant as that, but it wasn't hard for me to run Cat 5 cable under the house and into rooms using unused old coax tv cable outlets. I used the old coax to pull the Cat 5 through the walls. This lets me get a signal in from my Classics to turn on other opportunity loads like room air-conditioners in summer and oil-filled space heaters in the winter.
QuoteAnother option (and more efficient use of PV power) is to use a heat pump water heater such as the Nyle Geyser. I have one and it works great. Draws about 600-800 watts when running. When running in my basement with air temp of 55 Degrees F it will take my cold water (50F ?) and heat 50 gallons to 125F in about 3-4 hours.
Hi mtdoc,
I would like to try to run a Nyle Geyser water heater on a secondary tank, on Aux when Absorbing. Could you tell me if you control this water heater from Aux with SSR or if you run it directly from your inverter without control? Is Waste not the best Aux mode to do that? I don't think that I need PWM Aux as this heater just draws only 5/7 amps on 120Vac.
Could I use a simple SSR 120V 25A as a switch? Do you think I need a heatsink?
Thanks,
Erik
Erik,
When the grid is down for me, the Nyle Geyser runs from the inverter directly just as any other load. I don't use the Classics Aux function. It draws about 600-800 watts when running.
I could be wrong but I don't think that using the Aux mode/Waste not Hi/SSR method would work well with a heat pump type water heater like the Geyser. The heat pumps method of heating water is inherently different than the traditional resistive heating element type of water heating and I don't think it would be likely to respond well to a rapid on/off PWM type AC input. I haven't tried it so perhaps I'm wrong - maybe other's know more and can comment.
I'm sure there is probably a good solution for using one of the Classics other -non PWM - Aux functions to turn on a SSR allowing power to a heat pump water heater when batteries are in absorb or float -but I haven't investigated this. Others can probably tell you more..
Good luck - I'll look forward to hearing what you end up doing since eventually I'd like to set my Geyser up to do the same during extended power outages....
Allo mt,
I was thinking I could use Aux1 opportunity hi (not PWM) or Float to switch a SSR on Abs voltage and power a Geyser-RO with its own temp control in the same way I use Vent Fan High on Aux1 to power a 48V fan on batteries with a 12V relay. Of course I could be wrong, I have send a request to Nyle to see what they'll say. I will post their answer. Right now I don't see a problem except that I need to move toilet to have enough place to add a secondary tank ;)
What was the price of your Geyser?
Do you like it?
Erik
Just a passing thought: why not use the 'cooling' from the Nyle to cool the battery enclosure? the Batts might like to be cooler than ambient temp... rather than just cool the whole basement?
Good idea West but at this time my batts are somewhere in the 7/13°C range, inside... So a little cold to me.
My old 40 gal gas heater tank had failed in December and I had to change it very quickly for a 30 gal. This would be the time to upgrade to a more efficient heating system using this old storage tank and the Nyle's Geyser would be a great/smooth update with it's little 5/7 amps. I'm pretty sure that I could run it without problems for 3-4 hours from March to September from my 3.2Kw PV on Absorb/Float, this could save me a ton of propane in summer. I rent this off-grid lodge for fishing time with showers x8-10/day. I've also read Eric and Chris posts and found it interesting but I would need to buy another electric water heater and I'm not sure my system could take it.
Erik
Quote from: SolarMusher on February 01, 2013, 07:31:13 AM
this could save me a ton of propane in summer. I rent this off-grid lodge for fishing time with showers x8-10/day. I've also read Eric and Chris posts and found it interesting but I would need to buy another electric water heater and I'm not sure my system could take it.
Erik
since we are likely talking Opportunity loads maybe time for a few more (dedicated?) panels for those cabin loads? or is your CC maxed out?
Erik,
I bought the Geyser direct from Nyle systems - since there is no dealer near me. I can't remember exactly what I paid - I think it was something like 10% off their list price - around $700 if I recall correctly.
I've been very happy with it. It seems very well made and the installation was easy. I also bought the RO version which has a Johnson Controls thermostat - control unit on it. This makes it very flexible for different installs.
Your plan for using the opportunity Hi Aux function sounds good. I'll look forward to hearing how that works for you.
Quotesince we are likely talking Opportunity loads maybe time for a few more (dedicated?) panels for those cabin loads? or is your CC maxed out?
Ha, Ha, good catch, West. I'm 106.7Vmp, 30.54Imp input. So my Classic 200 outputs a 54/55Amps @59.2Vdc, but I've reached 60A several times this winter. I could still add 3 or 6 more cheap 185W panels to reach 4.3Kw and limit the output at 65/68A max to not overcharge the Classic, maybe I could find a little free place on roof...
But for now, I have to give priority to the heater :-\
QuoteErik,
I bought the Geyser direct from Nyle systems - since there is no dealer near me. I can't remember exactly what I paid - I think it was something like 10% off their list price - around $700 if I recall correctly.
I've been very happy with it. It seems very well made and the installation was easy. I also bought the RO version which has a Johnson Controls thermostat - control unit on it. This makes it very flexible for different installs.
Your plan for using the opportunity Hi Aux function sounds good. I'll look forward to hearing how that works for you.
Thanks mt for the infos.
Great to hear that you're happy with your Geyser and that it's working the way you want.
I've sent an E-mail to Nyle and explained exactly how I would like to use it. I would like to have it installed and running before spring.
Thanks for your help,
Erik
QuoteMr. Felix
I was looking at your email about adding a Geyser-RO to your system. There are a few problems. First, an old, gas heated, water tank is nothing but a huge radiant heat loss. If you were to look inside a direct fire tank, it's nothing but a steel tank that has a huge hole in the middle that is uninsulated. The heat pump would have to run all the time to try to keep up with the inevitable heat lose that that would be incurring. As the tank temperature came up, the rising heat would act like a chimney and would pull heat out of the tank. The inefficiency of that system would be atrocious. I try to get customers with old inefficient water tanks to get rid of them and spring for something new with lots of insulation. It's hard to convince people that it's more cost effective to more spend money upfront and get a good quality, well insulated high efficiency water heater or tank. Over the life of the tank, the long term costs of an inefficient tank get rather high. It makes the payback of the Geyser Heat Pump a lot longer and sometimes not at all. Even if you get your electricity for free from solar panels, the Geyser Heat Pump would run for the designated time and heat the tank as best it could but that heat would quickly be radiated away. The Geyser Heat Pump will heat water at a rate of 12.5 gallons per hour @ 120 degrees tank temperature and at 60 degree water supply. It would take over 3 hours to heat that 40 gallon tank but the tank sits for 21 hours cooling off.
Your system sounds like it would supply the necessary amount of power but the switching would the problem. The power plug would have to be plugged into an outlet that was switched on and off by a relay. The Aux mode can be either a dry relay or a 12 volt signal. 120 volt line power could be run though the dry relay to power the heat pump or the 12 volt signal could be used to turn the Solid State relay to power the heat pump. That would be up to you. The Geyser starts with 12-13 amps so the inverter would have to handle that large surge for about a second. If the voltage drops too much during compressor start-up, the relays in the Geyser could chatter and stick because the voltage necessary to hold the relays would be insufficient. Allotting 600-800 watts is going to be a little on the light side. It would be best to have 1000/1200 watts available be cause of the amp pull during start-up. The Geyser will "run" just fine on the inverter, it's the start-up that can cause problems.
The Geyser heat pump needs to be located in an area that is over 50 degrees F. Under that temp, they have to run a lot to make hot water and it kills the efficiency.
The price for a Geyser-RO is $899 plus $160 for the shipping. If you want to become dealer, you can get them at dealer pricing.
We don't have a lot of experience integrating the Geyser into a PV array so there is only one way to see if the Geyser-RO wil work and that is to get one, install it and see how it works. It looks, in theory, that it should work fine.
Alan Simberg
Here is the reply fom Nyle to my questions about the Geyser in a renewable energy system.
Erik
Erik,
I'm sure your Magnum inverter will handle it just fine. Interesting about the heat loss from an old gas fired water heater - it makes sense. Perhaps find a non functioning electric water heater to use as a cheap storage tank. Of course you can build one for cheap if you have the time see HERE (http://www.builditsolar.com/Projects/SpaceHeating/Components.htm#Storage)
I looked back and found what I paid for my Geyser RO. It was $799 plus $92 shipping. It was on "sale"at the time.
Not cheap but a worthwhile investment IMO. It's nice to be able to heat my water efficiently with 120 VAC from PV - at least for part of the year....
Hi mt,
After watching carefully my old gas tank, I've to say he's right. Did a quick search on used electric tank here, but nada!
I've finally found a brand new Giant 40gal for 339$. Another idea would be to use my old gas tank and to insulate burner and chimney with mineral/glass wool (total cost 0$) but the problem is that I pump from the lake and I'm afraid of dirt in tank that could flow through the Geyser ???
Even with a new tank, it makes sense. For sure, it will reduce my propane bill by 40/50%, not so bad!
Do you think I really need a heat sink to run this DC/AC SSR on 120Vac/6-8amps for 3-4hrs?
Thanks for the link, mt. Very interesting!
Erik
If your thinking of spending that much money just to heat water go buy a good quality tankless heater, I have a Rheem tankless water heater and a propane kitchen range, just filled my tank yesterday and used 164 gallons for 17 months, also sounds like you need a $60 whole house water filter on your water supply , I have about $700 in my water heater.
Quote from: SolarMusher on February 02, 2013, 08:01:49 AM
Do you think I really need a heat sink to run this DC/AC SSR on 120Vac/6-8amps for 3-4hrs?
I was quite surprised to find how hot these AC SSRs can get. Although I'm switching 230vac at about 6 amps for 3 to 5 hours each day and the ambient temp here is quite high 19 to 24 degC. Definitely use a heatsink.
dgd
QuoteI was quite surprised to find how hot these AC SSRs can get. Although I'm switching 230vac at about 6 amps for 3 to 5 hours each day and the ambient temp here is quite high 19 to 24 degC. Definitely use a heatsink.
Thanks for the info dgd , I have never used SSR before, always used 12V relay to power little loads from 48V. I will follow your tip and use a heatsink. I was also looking for a solution to switch off Ac lights x10 in lodge when people
are fishing on sunny day >:(, I think I have found it... ::)
QuoteIf your thinking of spending that much money just to heat water go buy a good quality tankless heater, I have a Rheem tankless water heater and a propane kitchen range, just filled my tank yesterday and used 164 gallons for 17 months, also sounds like you need a $60 whole house water filter on your water supply , I have about $700 in my water heater.
Hi Jim,
Why do you want me to buy/add another gas heater that don't meet my needs (8/10 pers) and spend more money on propane when I've right now enough PV energy which would be lost to run/preheat an efficient electric heater ??? The way I'm looking, could save me a lot on propane on a large part of the year. Of course, it could be built cheaper but IMO, a large residential off grid system needs to be oversized to meet the needs on an annual basis and then generates excess that would be wasted if not used.
A tankless heater would be interesting on a smaller system but the goal here is to use a max watts generated from PV ;)
Just my opinon,
Erik
Quote from: SolarMusher on February 03, 2013, 07:43:21 AM
I was also looking for a solution to switch off Ac lights x10 in lodge when people are fishing on sunny day >:(, I think I have found it... ::)
Erik
there have been several threads that beat on that topic heavily, and it seems to keep coming back...tell us more?
I do everything on a cost to benefit ratio , I have a 1635 sq ft home, a 1650 watt pv system which is going to increase by 1000 watts and propane where it is more efficient than electrical and wood heat, if I put heating coils in the wood stove then I could really get with the program which is something I 'm considering. Yes it cost to fill the tank every two yrs ($345.00) but it also cost to maintain my solar system, like the inverter I smoked last week experminting, these are a couple of the reasons for my thoughts, I'm not always going for the cheapest but what makes my life simpler and interesting.
Quote
QuoteI was also looking for a solution to switch off Ac lights x10 in lodge when people are fishing on sunny day , I think I have found it...
Erik
there have been several threads that beat on that topic heavily, and is teems to keep coming back...tell us more?
Hi West,
I was just thinking doing this using Aux2 Nite Light with SSR supplying a dedicated subpanel, but all other ideas are welcome.
Erik
what about motion sensors on your most troubling lights? ie bathroom, bedroom? bathroom fan/light timers?
Quote from: jim k. on February 03, 2013, 01:42:57 PM
I do everything on a cost to benefit ratio , I have a 1635 sq ft home, a 1650 watt pv system which is going to increase by 1000 watts and propane where it is more efficient than electrical and wood heat, if I put heating coils in the wood stove then I could really get with the program which is something I 'm considering. Yes it cost to fill the tank every two yrs ($345.00) but it also cost to maintain my solar system, like the inverter I smoked last week experminting, these are a couple of the reasons for my thoughts, I'm not always going for the cheapest but what makes my life simpler and interesting.
Cost to benefit ratio was the rationale, for many years, behind my energy make or buy decisions. This held me back from getting into the RE business by 5 to 10 years. In 1990 the payback or cost recovery time for a PV based modest system was way longer than the life of the system. In any case the folklore then was that it cost more energy to manufacture a PV panel than the panel could produce in its lifetime. So cost too high, benefit to me and environment too low.
I stopped using that rationale about 1995 and planned to become energy self sufficient AFAP. Never looked back, off grid 2000. Neighbours think Im eccentric or maybe just crazy.
Cost of LPG refills $180 a year, cooktop and hot water only - installed LPG instant hot water system, removed electric cyclinder when I went off grid.
Now with the Classic and PVs costing under 10% of 1995 prices I decided to remove LPG system install hot water cyclinder with AC element and let the Classic work it.
Now the doing something interesting, feeling good, making free energy, self satisfying smugness, and non reliance on a greedy price gouging profit focussed corporate that the fools in govt (in New Zealand) sold the public owned power generating industry too, is way better than even sparing a nanosec considering costs to benefits.
dgd
I get what you are saying, but I've got the same kind of neighbors, they think I' crazy and my pv system is a waste, but when the storms hit this winter and the grid went down my life didn't change, this is the first winter with no gen set running.
DGD, is your avatar supposed to be a Kia? its so small I cant make it out...
Q 2 did you mean too = also or to = to in this... sold the public owned power generating industry too either way it makes sense and is not good
Quote from: Westbranch on February 04, 2013, 08:19:10 PM
DGD, is your avatar supposed to be a Kia? its so small I cant make it out...
Q 2 did you mean too = also or to = to in this... sold the public owned power generating industry too either way it makes sense and is not good
West.. avatar is a Chattering Lory, one of my many pet exotic birds. The Kia is a NZ native protected species so no private ownership. too
HaHa.. well spotted too, the too should be a to too.. :o
dgd
Hello and thanks to all who have made it possible for me to have a winter of waste not powered hot showers! I set it up pretty much as Chris White describes
At first I was worried about that flickering light problem but got over it until I was giving myself my self inflicted spring haircut. The surging power to the hair clippers made me wonder what harm I may be doing to the compressors on my fridge and freezer.
Anyone?
Has anyone tried using an auxiliary controller to control excess power for hot water heating. I am using WBjr. on aux 2 and don't want to give that up. My idea is to use a C-40 to do this as I have one around that needs a better use than as a doorstop or maybe being nailed to a tree. (Just kidding about the tree, I will let Robin have that one, tee hee)
td
Im working on a blackbox solution. Its currently on a breadboard in a half chaotic state. It has a small solar panel which tells blackbox via an ardiuno nano the total available power. Subtract that from what the controller is putting out and run back through the nanos PWM timer, and bobs yer uncle.
ZB,
I will stay tuned to that. I was hoping that I could use a Trace C-40 PWM controller between the battery bank and the dump load. I think it would be an issue with the voltage settings between the Classic and the C-40 but with the right settings I think it will work. The big issue I see is the C-40 has a fixed bulk charge timer and the Classic is voltage based ending of bulk. I would need to find a way to get the C-40 to switch charge stages in time with the Classic. Any ideas anyone?
I went to your website! Some mountains you have in your backyard. I was born in the Matanauska Valley in Alaska and could see Denali Mount from our homestead 20,320 feet, highest point in North America. Your pics reminded me of that. Gorgeous country! Thanx for sharing. Are the huts for travelers? We have trail cabins in Alaska maintained by State Parks for visitors to use. One is an old railroad caboose, some are former fishing cabins donated to the state. I think no two are the same.
Will manage to visit NZ within my lifetime.
td
Quote from: zoneblue on May 30, 2014, 12:56:11 AM
Im working on a blackbox solution. Its currently on a breadboard in a half chaotic state. It has a small solar panel which tells blackbox via an ardiuno nano the total available power. Subtract that from what the controller is putting out and run back through the nanos PWM timer
Very nice!
Quoteand bobs yer uncle
Ah - another Dave Jones (http://www.eevblog.com/) fan ?
If im clear about how you are wanting to use the C40, youd put it diversion mode. The setpoints will as you say be the challenge. But its a bunch of fets mounted on a big heatsink with very little fuss to implement. And not overly expensive.
Im thinking that if you set it too high it wont turn on, too low and it will stop the classic setpoints being reached. Maybe the trick is to size the diversion low enough to leave something for the classic. I also heard that the C40/60 does have a serial port of some description accessible inside the case somewhere. Forget where i heard that. If you could get the two to communicate?
Mountains, yes lots of mountains. NZ has a network of around 900 huts for use by hikers. They have bunks, stoves and water tanks, and maintained by the department of conservation, largely for tourism purposes now adays,.
Quote from: tecnodave on May 30, 2014, 01:32:00 AM
The big issue I see is the C-40 has a fixed bulk charge timer and the Classic is voltage based ending of bulk. I would need to find a way to get the C-40 to switch charge stages in time with the Classic. Any ideas anyone?
Too complicated :)
A simple water heating solution is to simply divert some of your PVs to a heating element when the Classic is in Float. This way the power for water heating is not going through your Classic and you get to retain your doorstop.
All you need is an SSR and diode
Dgd
Zoneblue
That is exactly what I am trying to do. I am going to need PWM control of the load side due to my summertime fog here. If I just do on off control through aux 1 I will not have enough control.
The C-40 does have a serial port but I think that the controller puts out data , volts , amps , watts , batt temp. It does not accept input.
Dgd ,
Thanks for the idea, I had read that but I think that is too limited and the ssr would cost more than a well used original Trace C-40 that I acquired in a trade.
td
Quote from: Roy on May 15, 2014, 02:05:26 PM
Hello and thanks to all who have made it possible for me to have a winter of waste not powered hot showers! I set it up pretty much as Chris White describes
At first I was worried about that flickering light problem but got over it until I was giving myself my self inflicted spring haircut. The surging power to the hair clippers made me wonder what harm I may be doing to the compressors on my fridge and freezer.
Anyone?
I assume you mean me, Chris Olson.
I don't think the flickering light problem or "surging power" as you describe is a problem at all, other than being an annoyance. With some inverters the voltage regulation is not good enough to prevent this. But as far as I know it does not change the frequency of the AC output of the inverter, just the voltage varies due to the PWM pulsing the SSR. Your refrigeration compressors can handle a pretty wide variation of voltage without hurting them at all. But they can't handle a wildly varying AC frequency, since it is the frequency that determines their operating speed, and not voltage.
The hair clippers is a different deal than a fridge compressor because hair clippers are not a rotary motor (unless you're using sheep shears or something). The hair clippers is a linear motor so it will be affected just like light bulbs are by varying voltage varying the magnetic field in the two windings that makes the motor oscillate.
If you have some other super-sensitive stuff like HDTV and it's causing "snow" on the screen of the TV, then I would think twice about it. But otherwise I just can't see it hurting anything. What causes it is the fact that the SSR's are zero cross so they continue to conduct even after the PWM pulse is done, and conduct until the sine wave goes to zero before they shut off. So the voltage varies with the AC frequency on inverters that are not able to regulate this, and that's what makes it so pronounced with some loads. It takes a big inverter with a dang big transformer with a heavy core and with lots of copper in it (Xantrex SW/SW Plus/XW) to not be affected by this. The lighter duty units are going to flicker your lights.
Quote from: tecnodave on May 31, 2014, 06:37:44 PM
... I am going to need PWM control of the load side due to my summertime fog here. If I just do on off control through aux 1 I will not have enough control.
I seem to remember that (slow?) PWM was available via AUX1. This was in a discussion about using AUX1 to provide CLIPPER CONTROL signalling to a Clipper.
dgd
Yes Aux1 can be dialed down (or up) to 0.1 seconds
I imagine even 10s or 20s would work ok. Without knowing more about battery "capacitance" aka how batterys manage pulse loads, i couldnt say what the difference is between a 1000Hz, v 0.1Hz pulse frequency is on battery cycle life.
So now you have a suitable PWM signal from AUX1, I suppose the question is how to use this to manage your water heating diversion load. The obvious method is via an SSR of some type and circuits for this are easy.
The expense of an SSR aside the ideal scenario would be to use the Classic's AUX1 to somehow control the C40 - or just the FETs which in effect will do the same as an ssr. Looks reasonably complicated but if you can work out the C40 circuit it should not be impossible to do.
Maybe selling/swapping the C40 for a DC SSR is the way to go
Ebay has cheap chinese SSRs, a mere fraction price of Crydom, Teledyne etc..
dgd
Nah id stay away from cheap ebay SSRS. I bought some and later found out they pop real easy. Peace of mind, spend the bucks.
I did figure out a way to do it. The C-40 voltage sets are pots, very easy to lift the leads and have the aux1 out control a daughter board in the c-40 to change voltage state when the Classic commands it.,
Now to work out the details. I want to divert some of the power in absorb as well as in float. I don't see a way to do that easily. I do see pv on high which will do want I want as the cc will begin to unload the panels when in absorb due to the reduction in current drawn, but this will be on-off only , not PWM on the control side. Maybe this will be enough and let the C-40 do the PWM for the load.
I had sort of this arrangement to turn on my refrigeration when my PV arrays went 15-20% over V@Pmax. On my system before I bought the Classic. This logic board then fed 12 volts to the referigerator board "ignition signal" causing it to switch from propane to 12 power source derived from a Pyle buck converter.
I now have compressor referigator. This was done when I was using a Tracer dumb controller which had no aux function at all.
The C-40 does have other duties as well so I just might hook up the Classic and kid in follow me and let the kid handle the BTM and WBjr. and share that with the Classic and use Aux 2 opportunity to do the PWM to the diversion load.
Sad note: the Trace C-40 is connected with the epSolar Tracer to charge the aux battery bank. The Tracer voltage cannot be set so the C-40 is switched on by clock @ 1:00 pm to top off the batteries.
Outputs in parallel, inputs switched by time clock derived relay.
The Trace (a PWM controller with a 70 volt series string) tops the batteries better than the Tracer which is MPPT with the same string of 4 series Siemens SM-55 panels.
Yeah, I know, wasted power, the PWM controller is running maybe 20 % efficiency like this but Mario is babysitting my kid right now.
Half the fun of solar is tweeking it to get a little more. There is no "Final finished form".
td
Quote from: tecnodave on June 03, 2014, 10:06:55 AM
Half the fun of solar is tweeking it to get a little more. There is no "Final finished form".
The other half of the fun is tweaking your consumption to use a little less 8)
--vtMaps
Has anyone tried opportunity hot water with a kid?
This seems doable as the kid can divert a load through the load output using PWM control.
I am going to try this,
880 watts PV in, 70 volt strings
One kid
4 L-16 batteries, 380 ah, 24 volt nom.
600 watt DC water heater element and thermostat, Missouri wind and solar
WBjr and shunt
BTM
Kid mode. Solar
Load mode: battery, PWM Divert/auto
This would not be ideal as charge rate for these batts should be a bit higher.
td
Has anyone come up with a solution to flickering lights when utilizing PWM diversion?
I have added a timer and a relay next to the SSR from the aux so I can just turn on the water heater for an hour when the flickering is making me crazy (not ideal). I am also worried about what this flickering is doing to things like fridge and freezer compressors
I have been making 98% of my domestic hot water this way for almost 2 years now. It is great and cheaper than going solar thermal.....just that damn flickering!
I was going to be slack and just hook up 2-3 x 200 watt panels to the 24 volt 600 watt dc element and leave it run!
No regulator involved just a circuit breaker.
On a 200 liter system I doubt whether it get the water hot enough to vent the system.
Just use trial and error and fine tune it as needed.
Probably said the wrong thing! :)
The flicker is likely from the high power load being cycled ON and OFF. I'll assume the lights are DC ?
I have the flicker in all my AC powered led lites but not he ones that run on 24 v.dc not only the diversion does this but the big culprit.... My high power switch mode power amp, On music peaks it will completely extinguish the AC powered LEDs Annoying but I love that Carver sound
Note: the DC lites are : Gold Star RV 1176 bayonet style bulbs found on Amazon. These work on 12-30 volts! No flicker connected to main 24 volt bus. They fit into standard RV fixtures. They are not round cylinders like most but are built like a paddle with all the LEDs on one side and rotatable in the fixture to aim the lite where needed. Chinese but way better the run of the mill led bulbs
I have built some fixtures using Home Depot can lite covers.....not the whole can but just the waterproof shower cover for the can lite with an led array mounted behind....only 1" thick!
td