Advice on Slogie's system
slogie
Registered Users Posts: 6 ✭
Hi there, I need advice on some things. I just got a system installed last week, so I am just learning about this off grid system. I initially wanted to run both my house and my business of the system, but I started with just the house to see how it would go. I really do not know the exact amount of electricity all my appliances use, but I based it off my electricity bill, which puts me at about 24KW or less a day for both the house and shop. In my system I have:
12 250W panels (3KW)
Outback Flexmax 80
Schneider Conext Inverter 24V 3500W continuous power, 4000W for 30 minutes and 7000W for 5 secs.
16 Power King Deep Cycle Flooded Lead Batteries 6V225AH
Now the panels are putting out power, because the batteries are charged by about 12 noon, they produce 13KW for the day. But after a night's usage and in the morning everything is still running but if I use the microwave, the power cuts off and them comes back on. Now, I thought it was the inverter not putting out enough power, but in the day after the batteries are charged, I turned on back everything and used the microwave and it worked fine. So is it a case where my battery bank is not sufficient, because upon calculating my average usage, it should have been able to carry me for about 40 hours. Can someone please explain to me what is going on. Thank you.
12 250W panels (3KW)
Outback Flexmax 80
Schneider Conext Inverter 24V 3500W continuous power, 4000W for 30 minutes and 7000W for 5 secs.
16 Power King Deep Cycle Flooded Lead Batteries 6V225AH
Now the panels are putting out power, because the batteries are charged by about 12 noon, they produce 13KW for the day. But after a night's usage and in the morning everything is still running but if I use the microwave, the power cuts off and them comes back on. Now, I thought it was the inverter not putting out enough power, but in the day after the batteries are charged, I turned on back everything and used the microwave and it worked fine. So is it a case where my battery bank is not sufficient, because upon calculating my average usage, it should have been able to carry me for about 40 hours. Can someone please explain to me what is going on. Thank you.
Comments
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Re: Newbie needs advice on off grid system
Hard to trouble shoot your system, but in the morning your batteries are at their lowest level. Thats the time that a power hog microwave causes issues. You need to see how low it pulls your system voltage. Your Inverter has a LVD ( Low Voltage Disconnect ) as the voltage sags, it disconnects the Inverter, if it's set to high you can lower it within reason. Most off grid people will start a generator to get them over the hump early in the morning. My rule if the microwave is more than a minute, start the generator. The alternative is more panels and batteries. On top of this your batteries are new and still forming the plates and are not at 100% yet, it will take a month or two of cycles to reach their maximum capacity.Hi there, I need advice on some things. I just got a system installed last week, so I am just learning about this off grid system. I initially wanted to run both my house and my business of the system, but I started with just the house to see how it would go. I really do not know the exact amount of electricity all my appliances use, but I based it off my electricity bill, which puts me at about 24KW or less a day for both the house and shop. In my system I have:
12 250W panels (3KW)
Outback Flexmax 80
Schneider Conext Inverter 24V 3500W continuous power, 4000W for 30 minutes and 7000W for 5 secs.
16 Power King Deep Cycle Flooded Lead Batteries 6V225AH
Now the panels are putting out power, because the batteries are charged by about 12 noon, they produce 13KW for the day. But after a night's usage and in the morning everything is still running but if I use the microwave, the power cuts off and them comes back on. Now, I thought it was the inverter not putting out enough power, but in the day after the batteries are charged, I turned on back everything and used the microwave and it worked fine. So is it a case where my battery bank is not sufficient, because upon calculating my average usage, it should have been able to carry me for about 40 hours. Can someone please explain to me what is going on. Thank you.
Added : I tried to look up your batteries and I would question if they will serve you for the long haul. They don't seem to be a true deep cycle battery that would be used in a off grid system. Multi use deep cycle Marine type batteries just will not last long. Maybe I didn't find the batteries you have.
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Re: Newbie needs advice on off grid system
Is there a reason you went off grid instead of grid tie? Is your grid power unreliable? Grid tie is more efficient and you get full effect from the panels.
Conservation is your friend, start looking for power hogs and get them replaced with more efficient items, much cheaper to save a watt than to generate a watt.
If you are running your batteries down with only one night under your belt then the system is way undersized, the usual recommendation is to get 2 days of autonomy. -
Re: Newbie needs advice on off grid systemsolar_dave wrote: »Is there a reason you went off grid instead of grid tie? Is your grid power unreliable? Grid tie is more efficient and you get full effect from the panels.
Conservation is your friend, start looking for power hogs and get them replaced with more efficient items, much cheaper to save a watt than to generate a watt.
If you are running your batteries down with only one night under your belt then the system is way undersized, the usual recommendation is to get 2 days of autonomy.Blackcherry04 wrote: »Hard to trouble shoot your system, but in the morning your batteries are at their lowest level. Thats the time that a power hog microwave causes issues. You need to see how low it pulls your system voltage. Your Inverter has a LVD ( Low Voltage Disconnect ) as the voltage sags, it disconnects the Inverter, if it's set to high you can lower it within reason. Most off grid people will start a generator to get them over the hump early in the morning. My rule if the microwave is more than a minute, start the generator. The alternative is more panels and batteries. On top of this your batteries are new and still forming the plates and are not at 100% yet, it will take a month or two of cycles to reach their maximum capacity.
Added : I tried to look up your batteries and I would question if they will serve you for the long haul. They don't seem to be a true deep cycle battery that would be used in a off grid system. Multi use deep cycle Marine type batteries just will not last long. Maybe I didn't find the batteries you have.
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Thanks for replying so quickly. I forgot to mention that I live in Jamaica. So I have almost 12 hours of sunshine and Electricity is very expensive here. Going off-grid will more than pay back for itself in about 3 years.
I figured that the microwave was the culprit. I do not have a generator, but I really do not have to use that microwave as I have a smaller one downstairs and also, everything else works perfectly right through the night. But I really thought that it was the wattage that I had to consider. I also thought that the newer the batteries were, the better they would perform. I still really don't understand all this voltage, amps and watts business. I know that V x A = W but how this translates to batteries, inverter and usage, I am still not sure. The supplier for the batteries told me that I should use Trojan specifications for the batteries. So if I were to want to use this large microwave, would that mean that I would need more batteries or a larger inverter 48V. Also, someone told me that I could use a 48V inverter and the 24V inverter with the same battery bank. Is this true? Thanks again for the help. -
Re: Newbie needs advice on off grid system
Maybe an admin will come along and split this off into its own thread. -
Re: Newbie needs advice on off grid systemsolar_dave wrote: »Is there a reason you went off grid instead of grid tie? Is your grid power unreliable? Grid tie is more efficient and you get full effect from the panels.
Conservation is your friend, start looking for power hogs and get them replaced with more efficient items, much cheaper to save a watt than to generate a watt.
If you are running your batteries down with only one night under your belt then the system is way undersized, the usual recommendation is to get 2 days of autonomy.solar_dave wrote: »Maybe an admin will come along and split this off into its own thread.
I honestly did not see how to start a new post
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Re: Newbie needs advice on off grid systemHi there, I need advice on some things. I just got a system installed last week, so I am just learning about this off grid system. I initially wanted to run both my house and my business of the system, but I started with just the house to see how it would go. I really do not know the exact amount of electricity all my appliances use, but I based it off my electricity bill, which puts me at about 24KW or less a day for both the house and shop.
We all start somewhere, so did you install this or did a company install this for you?
Since we're going to look at your system, We always ask about loads. You've told us your unsure about loads, but you use about 24Kwh (kilowatt Hours) a day combined. That is a huge load!12 250W panels (3KW)
Outback Flexmax 80
Schneider Conext Inverter 24V 3500W continuous power, 4000W for 30 minutes and 7000W for 5 secs.
16 Power King Deep Cycle Flooded Lead Batteries 6V225AH .
Doesn't look like a well designed system, 3000 watt array is likely to produce about 2300 watts on a normal afternoon, 2300watts/24 volts = @96 amps, your charge controller can only transfer 80 to your battery bank.
16 - 6V batteries will give you 4 strings of 4 batteries in a 24 volt configuration, it will be hard to keep these balanced. you have about 900 Ah (amp hour) battery bank, or roughly 21.5 kwh of storage down to nothing, but you should only be using the upper 50% and for long life you should try to stay in the upper 20-30%.
How are you determining that the batteries are fully charged? If your using voltage, you are seeing the voltage rise while charging the batteries. A voltage of 27.2 Could indicate that the batteries are 65% full and charging or that they are 100% full and in float.Now the panels are putting out power, because the batteries are charged by about 12 noon,
are you saying your drawing 13kwh out of your battery bank?...they produce 13KW for the day.
Not sure what "it" your talking about if your talking about your battery bank, all your loads will kill it in short order, I know you have the office off the bank, so are you assuming some different load numbers for the home?But after a night's usage and in the morning everything is still running but if I use the microwave, the power cuts off and them comes back on. Now, I thought it was the inverter not putting out enough power, but in the day after the batteries are charged, I turned on back everything and used the microwave and it worked fine. So is it a case where my battery bank is not sufficient, because upon calculating my average usage, it should have been able to carry me for about 40 hours. Can someone please explain to me what is going on. Thank you.
If I were to guess from the info you have provided, your drawing down your battery bank to about a 30-40% state of charge, or only 30-40% of your batteries stored energy is left, when you turn on your microwave the voltage sags below a preset low voltage mark for your inverter and shuts down as other have suggested.
Personally I would shoot the installer, tell him you should be running a 48 volt system for your anticipated end use, supplying 24Kwhs. You should then price a system that would provide 24Kwhs and be horrified and ask your installer to make you whole, and take the system with him... If you were not clear on you intentions it's on you, but in the best areas for solar a 24kwh system would be very expensive. I'd say most areas would require 3 - 4 time the array and double the storage and most areas you will need back up even then.
If you tell us your general area where you life we could calculate a likely system for that size of a load.Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites, Midnite E-panel, Magnum MS4024, Prosine 1800(now backup) and Exeltech 1100(former backup...lol), 660 ah 24v Forklift battery(now 10 years old). Off grid for 20 years (if I include 8 months on a bicycle).
- Assorted other systems, pieces and to many panels in the closet to not do more projects. -
Re: Newbie needs advice on off grid system
The reason I ask is my 12.5 Kw grid tie system only produces 65-75 kWh per day no way 3Kw of panels are going to do 24 kWh per day. Your 12 hours of sun may produce what we like to call full sun equivalent of about 4 hours per day, in your case maybe 5 hours a day. If you plot the solar input you will find it is generally a bell curve starting and ending at 0 and peaking at solar noon.
Charging batteries is much less efficient than straight grid consumption, you have to put more back into the batteries than you consume. Then there is the losses of converting the DC to AC, it is an accepted number of 52% from name plate rating of the panels to consumable AC power. -
Re: Newbie needs advice on off grid system
Great news, Jamaica appears to have very good solar insolation Here is the chart for Montego Bay averaging more than 5 hours a day, but with a low in December of 4.15 This chart I believe shows what you can expect in number of hours of effective charging with a fixed array angled due south, with in 10 degrees of you latitudeThanks for replying so quickly. I forgot to mention that I live in Jamaica.
With cheap panels (try www.sunelec.com they have a warehouse in Jamaica) and doing all the labor your self, It is doubtful that you can have a payback in 3 years unless your electric is well over $1 a Kwh. You may have a payback point even up to 40-50 cents a kwh from the grid, but it will likely be 12+ years. When doing your calculations, figure replacing your electronic pieces every 10-15 years, and your batteries every 5-8 years for those batteries. The panels will work past their 25 year warranty, though with some diminished output....and Electricity is very expensive here. Going off-grid will more than pay back for itself in about 3 years.
If it works during the day and likely will be fine during the evening, it is likely your batteries are at a seriously reduced capacity by morning and you are having voltage sag triggering a shut down. This likely indicates that your batteries are being drawn down past 50% SOC(State Of Charge). You do not need to worry about using the microwave as much as you need to know what state of charge your batteries are in, if they are being drawn down below 50% on a regular basis, your system may not survive very long.I figured that the microwave was the culprit. I do not have a generator, but I really do not have to use that microwave as I have a smaller one downstairs and also, everything else works perfectly right through the night.
If you intend to run your home and office off grid, I would look to switch now to a 48 volt system, you can look at my signature and see I'm running a similar sized system, and seriously considered switching to 48 volts even though I already had the battery! If I didn't have the battery there is no question I would have switched. My 800Ah battery I only draw down 15% on average in the winter, My home uses about 4kwh in the Winter and 12-16 kwh in the summer, most of that directly during the day, drawing perhaps 5-6 kwh at nightBut I really thought that it was the wattage that I had to consider. I also thought that the newer the batteries were, the better they would perform. I still really don't understand all this voltage, amps and watts business. I know that V x A = W but how this translates to batteries, inverter and usage, I am still not sure. The supplier for the batteries told me that I should use Trojan specifications for the batteries. So if I were to want to use this large microwave, would that mean that I would need more batteries or a larger inverter 48V.
Well in theory it's possible, but NO would be the correct answer, you would have to use a step down transformer to run the 24 volt and it likely wouldn't work well, drawing more wattage than just having a larger 48v inverter.Also, someone told me that I could use a 48V inverter and the 24V inverter with the same battery bank. Is this true?Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites, Midnite E-panel, Magnum MS4024, Prosine 1800(now backup) and Exeltech 1100(former backup...lol), 660 ah 24v Forklift battery(now 10 years old). Off grid for 20 years (if I include 8 months on a bicycle).
- Assorted other systems, pieces and to many panels in the closet to not do more projects. -
Re: Newbie needs advice on off grid system
Thought I'd better split this off before it got too big.
If it weren't so late I'd do an evaluation too, but it's been a pretty awful day here. -
Re: Newbie needs advice on off grid system
So at 5hrs of sun, 3kW you should be able to produce 15kWh per day... right. Well no.
First, you are losing say 20% from the controller clipping at 2kW.
Then you lose some in battery charging losses, say 15%.
Then you lose some more in inverter effciency, say 10%.
So you are down to about, for the "average day" about 15kWh * 0.8 * 0.85 * 0.9, which is about 9kWh/day.
I may have slightly overestimated the controller loss, because theres not a huge amount of area under the flat top of the peak solar production. I could work it out.
So, that means in general thats what you have to play with, adn attempts to use more than that will end in tears.
For the inverter, it should be fine, its a good inverter. However it needs very thick cables, tight connections and good batterys with low inernal resistance to make it work.
Lets say you use 10kW/day to keep it simple. That means, in order to get a daily DOD of 25%, you need 40kWh of storage. You have only half that at 20kWh. And they arent proper off grid cells...
So what others have said above is bang on.
48V would lower the overall current losses, but for a 4kW inverter you ought be able to make 24V work, with some decent batterys. If you plan on growing even a tiny bit, then dont hesitate to go up to 48V right now.1.8kWp CSUN, 10kWh AGM, Midnite Classic 150, Outback VFX3024E,
http://zoneblue.org/cms/page.php?view=off-grid-solar -
Re: Newbie needs advice on off grid system
Ok first of all let me say thanks to everyone for replying and also for giving me my own thread. I will try to take in this information and see how best I can work this out. I realised that in all of this I forgot to mention that my panels rotate with the sun. There are a few more questions that I need to ask but I will take them one step at a time. Thanks guys. I will tackle them tomorrow.
Respect! -
Re: Newbie needs advice on off grid system
That will help a lot, there might be a solar insolation chart that will take that into account.I realised that in all of this I forgot to mention that my panels rotate with the sun.
Once you have the base line hours of average hours of available sun, you can multiply that number of hours x the array size in watts x .5 to take into account all the system losses to figure out what the maximum available energy(kwhs) you will have to use less than this figure, so you can keep the batteries near a full charge daily. Example if you have 7 hours of available sun with a tracker, and a 3 kw array, you have 21kwhs x .5 for 10.5Kwhs of energy to use. You need to be sure you use somewhat less than this. The battery bank will help with the averaging, but the bigger cushion you have the more reliable the system will be.
To figure your storage with flooded lead acid batteries, you can use that kwhs number and multiply it by the number of days you may need to go with out sun and the multiply it x 2 since you don't want to draw the batteries down below 50% SOC unless you have dire need. This number of kwhs can be converted into amp hours x voltage. Example; If you have 10.5 kwhs to store and you need to be able to run 2 days off the battery bank, 2 days x 10.5Kwhs = 21Kwhs x 2 so you don't draw the battery bank down past 50% = 42 Kwhs of storage. To convert this to a battery bank storage, for a 24 volt battery bank 42,000 watts / 24 volts = 1750 Amp hour battery at 24 volts. You can do all that math again for a 48 volt, but of course it's half the Amp hour in size.
50% sounds like a lot of losses for the system, here are some of the losses;
Panels typically produce 77% of their panel rating, even less when very hot. You can check your panel NOCT (normal operating cell temperature) value
the Charge controller runs 95-98%
Inverter typically runs 90%
Battery storage runs 80-85%
Also note that during the day you don't have to store the energy your using so that's a plus, normally you would size your system for your worst case, so available sun in December, if your usage is pretty even through out the year.
Also note the losses do NOT include the extra losses your current system has with an over sized array to charge controller! Charge controller work on amperage, if you switch to a 48 volt system, your 80 'amp' charge controller can handle up to about a 4600 watt array cost effectively, 4800watts x .77 (NOCT value)=3696watts... ...3696watts/48 volts= 77 amps. Your losing most of what your array can produce over a 2300 watt array, since in a 24 volt system a 2300 watt array would typically produce 77 amps.Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites, Midnite E-panel, Magnum MS4024, Prosine 1800(now backup) and Exeltech 1100(former backup...lol), 660 ah 24v Forklift battery(now 10 years old). Off grid for 20 years (if I include 8 months on a bicycle).
- Assorted other systems, pieces and to many panels in the closet to not do more projects. -
Re: Newbie needs advice on off grid system
This may be the reason. It may not.If it works during the day and likely will be fine during the evening, it is likely your batteries are at a seriously reduced capacity by morning and you are having voltage sag triggering a shut down. This likely indicates that your batteries are being drawn down past 50% SOC(State Of Charge).
The Low-Voltage Disconnect is clearly activating. While Photowhit is correct that it could be because the batteries don't have enough charge in the morning. It could also be beacause the wiring is too long or too thin for the amperage. If this is the case, the microwave would work (and the LVD not trip) when the PVs keep the voltage up but the batteries in the morning don't have the extra voltage to overcome the voltage drop.
The LVD on your inverter is probably adjustable. Setting the voltage higher prevents you from discharging the batteries too much but can prevent an occasional high-amperage use. Setting the voltage lower lets you use the microwave occasionally but you'll have to watch that you don't leave the batteries discharged.
The higher voltage for the LVD may be necessary for people who ignore their system and use the batteries until they're flat. A higher voltage for the LVD works when energy use is relatively constant.
I didn't see any mention of your battery voltage in the evening or morning. One good measurement is the battery voltage in the morning just before the PV panels start charging. Another pair of measurements would be voltage before turning on the microwave and while using the microwave.
Telling us the length and gauge of cables from your batteries to the inverter may also help.
It does sound like your system is not ideal and you're getting lots of good feedback on that. I just wanted to point out that the LVD could have been set to be too intrusive. -
Re: Newbie needs advice on off grid systemNow the panels are putting out power, because the batteries are charged by about 12 noon
Welcome to the forum slogie,
Photowhit's question is very important:How are you determining that the batteries are fully charged?
Many beginners think that battery voltage gives a good indication of SOC (state of charge). It doesn't.
Many beginners think that when their controller goes to float, the batteries are fully charged. Not necessarily.
Many beginners think that when their battery monitor says 100%, the batteries are fully charged. Not necessarily.
I look forward to trying to help you out... after I get a few more details.
--vtMaps4 X 235watt Samsung, Midnite ePanel, Outback VFX3524 FM60 & mate, 4 Interstate L16, trimetric, Honda eu2000i -
Re: Newbie needs advice on off grid system
Now that all the problems with you system have been pointed out to you, it's probably time to figure what you can make work and what won't. A lot of us wish we had the perfect on paper system, but we make due what we have. Where you have Grid you can use it as a Generator to fill in the spots where you system comes up short. There are plenty of household appliances that make no economic sense to ever power off grid with PV. Generally in a system like your's the Inverter has a separate Service Panel that powers only the loads the Inverter is capable of powering with in it's system design limits and the rest stays on grid. If your goal is for 100% Solar Power, your going to come up short, but that was a given from the start. I wish I could generate 50kwh a day, but I make due with 25 kwh. When I have to use the Grid a hour or two a day , I consider it a bonus.Thanks for replying so quickly. I forgot to mention that I live in Jamaica. So I have almost 12 hours of sunshine and Electricity is very expensive here. Going off-grid will more than pay back for itself in about 3 years.
I figured that the microwave was the culprit. I do not have a generator, but I really do not have to use that microwave as I have a smaller one downstairs and also, everything else works perfectly right through the night. But I really thought that it was the wattage that I had to consider. I also thought that the newer the batteries were, the better they would perform. I still really don't understand all this voltage, amps and watts business. I know that V x A = W but how this translates to batteries, inverter and usage, I am still not sure. The supplier for the batteries told me that I should use Trojan specifications for the batteries. So if I were to want to use this large microwave, would that mean that I would need more batteries or a larger inverter 48V. Thanks again for the help. -
Re: Newbie needs advice on off grid system
Thanks guys for all the information you have provided. From what has been said, it seems like I'm going to have to try and get my inverter sold and purchase a 48v one and also increase my battery bank. But for now, I know that I just have to park my large microwave in the mornings and use the smaller one. Cause it is the only thing that does not work in the morning. The small one does, without problems.
As Blackcherry04 said, we can't have all that we want as put on paper. We have to make do with what we have. I just have to make it work for now till I am able to change it. -
Re: Newbie needs advice on off grid system
I suspect you might look at simple improvements, before replacing the inverter.
I don't know how you are monitoring your batteries state of charge, If you don't have a SHUNT BASED battery monitor system, you should get one. Compared to replacing your inverter, it's cheap $150-200.
You should add another controller so you can make full use of the solar panels you have. Losing 20% of your charging capacity can't help.
You can put in 80 amps into a 900 Ah 24 volt battery bank, if you add a charge controller you could put closer to 95, with your added hours of charging ability with your tracker, I suspect the 11% charge rate would be fine for the battery bank you have, More batteries likely will not fix your problem, unless you are also adding to your array as well.
If you install a shunt based battery monitor, you could get a more accurate idea of what is going on. The shunt will be connected to the positive terminal of your battery and the monitor can give you a more accurate idea of the state of charge, the amount of current going into your battery during the day and out of it at night... That is where I would start.
A voltage monitor, is less than useless!!! Since you don't yet have a feel for the battery cycles, a reading above 25.4 volts looks like a battery is fully charged, yet that battery might yet be in the early stages of charging in the bulk cycle and be at 50%. Also since your system is used continuously, your amperage which might be charging the battery, might well be going to day time loads. A Shunt based monitor will tell you your getting very minimal charging if you have loads using the power during the day. A Voltage based monitor just knows that the batteries are at a certain voltage, and doesn't know that your actually using more power than your solar panels are generating and might be drawing down your battery bank rather than charging it due to daytime loads.Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites, Midnite E-panel, Magnum MS4024, Prosine 1800(now backup) and Exeltech 1100(former backup...lol), 660 ah 24v Forklift battery(now 10 years old). Off grid for 20 years (if I include 8 months on a bicycle).
- Assorted other systems, pieces and to many panels in the closet to not do more projects. -
Re: Newbie needs advice on off grid systemThat will help a lot, there might be a solar isolation chart that will take that into account.
Nice Reply Old & in the way !! My Hat is off Photowhit.
I see the same ..
slogie , post as much as you can . we all follow & try to input as we can to help .
ONE thing this "International" site needs is for everyone / EVERYONE to put in there location . next would be if they want (pushed to ) what the setup is they have installed & use. This would help many from the same questions , to weeding out the " GIVE ME THE BEST !@#$%^& " ..
Reading & watching here , I see great minds (a few have left) just to see ground hog years . Same stuff / questions because the forum needs structure to improve !!
Sales will come , I've bought 4g plus , looking for the next sale , to increase .
VT
EDIT ADD :
Even the edit profile is a pain.
Make it simple , it's not worth the time or stress.
Im living in the PNW in Canada / USA , Have a apartment in Ontario (Pearson Airport ) power off when not there.
Think I can figure out where that's added or edited in , Not worth .5 +
Forum needs serious re-working..
XenForo™ ©2010-2014 XenForo Ltd is the leader , but emulation of them is offed by most.
VT -
Re: Newbie needs advice on off grid systemIf you install a shunt based battery monitor, you could get a more accurate idea of what is going on. The shunt will be connected to the positive terminal of your battery <snip>
If you have a negative ground system, put the shunt in the cable to the negative battery terminal. It would work just as well in the positive side, but then the voltage sense wires that run from the shunt to the monitor would need fuses. remember: anything and everything attached to the positive battery terminal must have over current protection (fuses or breakers).
--vtMaps4 X 235watt Samsung, Midnite ePanel, Outback VFX3524 FM60 & mate, 4 Interstate L16, trimetric, Honda eu2000i -
Re: Newbie needs advice on off grid system
Yes, agreed on the battery monitor. At the moment you dont know how low you are drawing it overnite, or what your daily usage is. The inverter will most likely know your usage, but not sure how to get the data out, what addons you have combox/various other display widgits schnieder has.
The other ways are SG, use a hydrometer in the morning, and see what it says. Rest voltage can also be a guide.
With your existing battery, you need to keep an eye on the amount of Wh you take out overnight. In order to run a 25% DOD, thats 0.25 * 20kWh or 5kWh. Thats only half your usable production. 50% is ok occasionally, which is closer to your production level.
Before you go spending any more money you need to do a system design, starting from the target load. This gets the three major components in balance.1.8kWp CSUN, 10kWh AGM, Midnite Classic 150, Outback VFX3024E,
http://zoneblue.org/cms/page.php?view=off-grid-solar -
Re: Newbie needs advice on off grid system
Makes one wonder about the advise given on here at times. Good Catch VT-maps !!If you have a negative ground system, put the shunt in the cable to the negative battery terminal. It would work just as well in the positive side, but then the voltage sense wires that run from the shunt to the monitor would need fuses. remember: anything and everything attached to the positive battery terminal must have over current protection (fuses or breakers).
--vtMaps
Installing a single shunt monitor a on a system with more than one I/O source is useless, without being able to totalize the complete picture. Without being able to calibrate all the perimeters that are ever changing the results you end up in a black hole that is worse than a Voltage based monitoring system at times.
This OP needs to get familiar with his operators manual or have someone that understands the Conext Inverter / Charger helping tune it. For Instance, he needs to have a AGS connected to the Zanbus to be able to activate all the settings where he can use Generator support with the Grid as the power source when need's to augment the Batteries and to keep them out of a deficit. -
Re: Newbie needs advice on off grid systemBlackcherry04 wrote: »Installing a single shunt monitor a on a system with more than one I/O source is useless, without being able to totalize the complete picture. Without being able to calibrate all the perimeters that are ever changing the results you end up in a black hole that is worse than a Voltage based monitoring system at times.
This OP needs to get familiar with his operators manual or have someone that understands the Conext Inverter / Charger helping tune it.
Controllers (FM80 with flexnet or Classic with whizbangjr) can use a single shunt to do end amps and a few other tricks. Not useless.
But I agree that battery monitors can be treacherous if they are not set up properly and their limitations understood. For that matter, the controller and the inverter can also be treacherous if they are not set up properly and their limitations understood. The OP did not install the system...
Slogie, does your installer have any responsibility to help you get the system tuned up?
--vtMaps4 X 235watt Samsung, Midnite ePanel, Outback VFX3524 FM60 & mate, 4 Interstate L16, trimetric, Honda eu2000i -
Re: Newbie needs advice on off grid systemThe other ways are SG, use a hydrometer in the morning, and see what it says. Rest voltage can also be a guide.
A hydrometer is the correct way of determining the current State Of Charge(SOC). I guess, I wasn't even thinking about this. It takes a little time, but in the long run you will want to check each battery cell to determine it's SOC as well as comparing it to the other cells. When you see imbalances in the SOC you should equalize the battery bank, I also recommend a monthly equalizing.
More information on Battery's their health and upkeep can be found in the FAQ's.
Examples of shunt based battery monitors;
Trimetric has been the standard for years.
The RV version is surface mounted so might be easier to mount.
There is also the Victron units which have received good reports.
These are the stand alone units, though Xantrex Schieder makes a unit which I think can be a stand alone or incorporated into a system, magnum has one that works with it's inverters.
The Midnite Classic has a battery monitor option with it's charge controller and now comes standard with the display model. The route I'm switching to since it can directly work with the charge controller. A "Whiz Bang" of an idea!
Outback has a shunt based monitor which works with it's system as well.Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites, Midnite E-panel, Magnum MS4024, Prosine 1800(now backup) and Exeltech 1100(former backup...lol), 660 ah 24v Forklift battery(now 10 years old). Off grid for 20 years (if I include 8 months on a bicycle).
- Assorted other systems, pieces and to many panels in the closet to not do more projects. -
Re: Newbie needs advice on off grid system...If you install a shunt based battery monitor, you could get a more accurate idea of what is going on. The shunt will be connected to the positive terminal of your battery and the monitor can give you a more accurate idea of the state of charge, the amount of current going into your battery during the day and out of it at night...
Sorry, The Shunt should be connected to the negative side of the battery connection!
Also on connecting the battery monitor, it might be a good idea to 'reset' your battery bank, Make sure your battery is fully charged, check the Specific Gravity (SG) with a hydrometer, and equalize it if needed. Then input the battery bank size and check it the SOC against the Specific Gravity for a little while to make sure your battery bank has not been compromised by under charging. If it has you may need to reduce the battery banks amp hour rating so you are seeing the correct SOC.Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites, Midnite E-panel, Magnum MS4024, Prosine 1800(now backup) and Exeltech 1100(former backup...lol), 660 ah 24v Forklift battery(now 10 years old). Off grid for 20 years (if I include 8 months on a bicycle).
- Assorted other systems, pieces and to many panels in the closet to not do more projects. -
Re: Newbie needs advice on off grid systemBlackcherry04 wrote: »Installing a single shunt monitor a on a system with more than one I/O source is useless, without being able to totalize the complete picture. Without being able to calibrate all the perimeters that are ever changing the results you end up in a black hole that is worse than a Voltage based monitoring system at times.
I'm not sure why you would say this, unless your referring to connections made to the battery bank that don't go through the shunt. That is the nice thing about a shunt based battery monitor. It can measure all sources of charging and discharging to and from the battery bank.Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites, Midnite E-panel, Magnum MS4024, Prosine 1800(now backup) and Exeltech 1100(former backup...lol), 660 ah 24v Forklift battery(now 10 years old). Off grid for 20 years (if I include 8 months on a bicycle).
- Assorted other systems, pieces and to many panels in the closet to not do more projects. -
Re: Newbie needs advice on off grid system
Because if you have more that ONE Input / Output , unless you measure Every thing coming into and out of the batteries, it's a waste, your only getting half of the picture. Whats your battery charging efficiency ?? Whats you Peukert Exponent ?? Is your Charge Controller connected to the Inverter shunt ??I'm not sure why you would say this, unless your referring to connections made to the battery bank that don't go through the shunt. That is the nice thing about a shunt based battery monitor. It can measure all sources of charging and discharging to and from the battery bank. -
Re: Newbie needs advice on off grid system
That is the point every thing goes through the shunt. The monitor sees the cycles and resets on full charge, it can see the charging tapper off...Blackcherry04 wrote: »Because if you have more that ONE Input / Output , unless you measure Every thing coming into and out of the batteries, it's a waste, your only getting half of the picture. Whats your battery charging efficiency ?? Whats you Peukert Exponent ??
Yes, everything. Not the inverter shunt, but the system shunt. Epanels come standard with one, The trimetrics and Victron units can come with them if one isn't installed in your system. The larger DC disconnect box by Midnite has a place to mount one. Outback load centers have one as well.Blackcherry04 wrote: »Is your Charge Controller connected to the Inverter shunt ??
I haven't hooked up my trimetric in the last few years, but check my SG monthly(at least) and understand the charging cycles.
I actually prefer that people learn to understand the cycles of the battery, and get a feel for the SOC. I think battery monitors are very good for people who are new to off grid solar and needs to have a visual idea of where they are at...
That said if setup incorrectly, like setting the wrong Ah rating of the battery bank, they can actually be problematic. But setup correctly they help people understand what is going on with their charging and discharging.Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites, Midnite E-panel, Magnum MS4024, Prosine 1800(now backup) and Exeltech 1100(former backup...lol), 660 ah 24v Forklift battery(now 10 years old). Off grid for 20 years (if I include 8 months on a bicycle).
- Assorted other systems, pieces and to many panels in the closet to not do more projects. -
Re: Newbie needs advice on off grid system
Okay I've deleted the start of the latest slug fest caused by people talking at cross purposes.
The problem with installing a battery monitor after you've started using a system is that you need to have the batteries fully charged to begin with so that when you tell the monitor "this is 100% SOC" it truly is. If you get it wrong at the start, it continues to be wrong thereafter and gets worse as time goes by.
In fact they get worse as time gos by anyway as battery capacity decreases over time no matter how good a job you do charging. This should be a matter of several years, however, and not cause a significant effect on the monitor's performance.
Nothing beats measuring SG for accurate battery SOC. So even with a monitor it is a good idea to check the SG once in a while and compare the two just in case something is going wrong. Catch it before it gets too far our of whack.
With AGM's you do not have the SG option, so a battery monitor is preferable to Voltage readings alone.
It's not just the equipment: it's knowing how to use it. I know people who buy expensive DMM but don't know what they're doing with it so they aren't as accurate as a $10 special. The same applies to hydrometers and battery monitors. -
Re: Newbie needs advice on off grid system
Ok guys, you almost lost me here. From what you are saying, it seems I need to know how well my batteries are being charged or discharged. So I should have a battery monitor installed. First let me say, solar technology is somewhat of a new technology to some parts of Jamaica, especially where I live. I think I'm one of very few to do it. The one guy who urged me to get it done really wanted me to start off slowly and increase as time went by. I however found a dealer that sold the items and informed me based on the products my initial technician told me. So I got them, the only major mistake being that I got the wrong inverter. That being said, I am 100% ahead of where I'd be had it been up to the installer alone, based on pricing. Anyway, after checking with other so called technicians. Everyone had something different to say, so that is my main reason for joining this forum...to get some clarification.
So, I know my Schneider inverter does have battery monitoring capabilities but the control panel is sold differently and the dealer does not have it in stock right now. But from reading the books, I realize that the default LVD is 21.0V. I don't know if that is a correct level or if it can go lower. I also think that my current usage for the night is quite good for now as I have power right through for everything so far. I do not have air conditioning, but in time after I have things at an optimal level, it would be something I would like to pursue.
Seeing that I really don't know about these battery monitors, could any of you provide the name of a good one that I could try to find out here. Because, as you have all said, it would be great to know the level of the battery if it is really full or if it is really drained in the mornings so as to have an idea of what I have consumed from it throughout the night. -
Re: Advice on Slogie's system
The first thing to do is as Photowit said. "A hydrometer is the correct way of determining the current State Of Charge(SOC). I guess, I wasn't even thinking about this. It takes a little time, but in the long run you will want to check each battery cell to determine it's SOC as well as comparing it to the other cells. When you see imbalances in the SOC you should equalize the battery bank, I also recommend a monthly equalizing.
if you don't already have a hydrometer. you should be able to get one locally at the solar store where you got your parts or an auto parts store. Also pick up a gallon of distilled water. When you have these both in hand, come back here first and ask for further instruction on it's operation. Good Luck
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