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Post by byzance on Oct 8, 2018 8:48:26 GMT
Hello everyone I am new to the forum and to solar power in general. I am running a PSW 2000W kickass inverter, and a victron 100/50 mppt charger, but I mostly have it pulling under 400 w during the day. I am wondering if you have any advice on the set up. I have made a few mistakes already (thankfully nothing that killed any equipment) The victron is connected with the appropriate fusing between panels and again between batteries. I got some professional help on the size of those. In australia we are getting sun from basically 8:30 till about 3 and I give the system back the last hour for a top up charge. My real question is I bought this as a weird weather protection system. So if we loose power due to a hurricane (which happens a bit in hurricane season). How long am I likely to be able to run a 80W freezer for. So I have 5 120 sealed AGM batteries. that's 600Amh you would think that would do the job. In the end I would like to add another 40W camping fridge and a few lights. During the day when I have the power behind me obviously I can do a bit more, but what do you guys think. The wife is wondering about the 350w house fridge. Can we run this 24 /7 on our system or will that just kill the math. As to what these panels are bringing in. I am measuring (from the victron) 480w as a best possible noon power. I have one more panel to add which should land it somewhere in the middle 600W range. On a 12 volt system (inverter is a 12 volt inverter 12 volt panels) The panels are rated max of 18v 250w. max power current is suppose to be 13.9a. They are labeled "Mono Panels". I have my 5 batteries lined up in parallel and my panels in parallel with connectors. The big limiting factor in the whole system is the 16+meters of cable between the panels and the victron. What do you guys think. At this point I am sure that the numbers mean more to you than to me. Any good advice would be appreciated. Thanks  |
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Post by Admin on Oct 8, 2018 14:41:47 GMT
Hello,
Let's start with what we know:
1. How many solar panels do you have and what is their rated wattage? 250W panel? How many?
2. You have a 12V 600Ah Battery Bank
3. You have a 100/50 Victron MPPT Controller
4. You have 16 meters between your panels and your charge controller
Now, is your 80W freezer AC or DC? 40W camping fridge AC or DC? Fridges/Freezers have a different daily usage since it should depend on when the compresses starts up. We normally assume it to be actively working for about 8-9 hours in a given day. With this said, and accounting for 50% battery depth of discharge, you should be able to run your freezer 5 days and have 50% of your battery theoretically.
Is your location in Australia more Northern, Southern, Eastern, or Western?
-Renogy Team
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Post by byzance on Oct 8, 2018 20:37:06 GMT
lets talk about your numbers first to be sure we are on the same page.
1 I have soon to be 5 12v 250w solar panels connected in parallel. I know according to the victron they are pulling in 480watts at best time and with the 5th panel (divide by 4 adding to the total) it "should" with 5 panels give me just over 600watt on the victron. assuming full sun.
2-4 are accurate but in the case of 4 I think it is a little over 16 meters of cable length.
both of my fridges must be plugged into the house or the inverter. I am guessing that makes them AC.
I am in Mackay Australia which is very tropical like florida or the southern states. It is on the east coast of North Queensland. I get 6 hours of sun most days. with a min of 5 hours and a max of 7-8 hours of panel sun depending on the season. solar works well down under.
5 days sounds like we will be able to have a freezer on till we get sun again. It would be unusual to get no sun for 5 days even in bad weather season.
I'm off to work thank you for your advice I will get back to you tonight. Thank you in advance for all the replies.
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Post by bupkis on Oct 9, 2018 0:13:44 GMT
hi byzance, I spent a couple of years in Brisbane as a youth. came home talking stralian.
take your 600ah and divide by 2 = 300ah usable for long battery life
convert 80 watt to amps, 80w/12v = 6.66A
Duty cycle of freezer, 1/3 of the time or 8 hrs/day.
6.66A x 8hrs / day = 53.33 amp hrs / day.
300 amp hrs / 53.33 amp hrs / day = 5 + days
some adjustment needs to be made for inverter efficiency and assumes the batteries are FULLY charged at the start without the 400w load you have on them.
your 4x 250w or 1000w of panels should do better than 480w if full sun, more like 750w even flat/horizontal.
480w @ 13v = 37A
750w @ 13v = 58A , I'm sure the victrom will limit current.
what size wire do you have running the 16 meters?
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Post by byzance on Oct 9, 2018 7:58:16 GMT
hello bupkis,
I don't know why the panels are not pulling more. I can only imagine it is because of the length of wire or the fact that they are just cheap ebay panels. any how the wire reads the following along the side of it.
DC solar cable v-125 2 x 4mm pv1-F max dc load 1000v.
I have been here for 10 years and I am now not understandable either in america or australia. The skeeters still walk around here on 2 legs though. If you have even been to Mackay its as hot as and humid as florida. We are looking forward to some nice 40 degree weather. Maybe only 80 or 90 percent humidity.
Talk to you later and thanks for your help.
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Post by byzance on Oct 9, 2018 8:20:24 GMT
hello again,
by popular demand here are the numbers off the back of the panels
They are all the same.
ocv 22.5v
mpt +/- 3%
mpv 18v
msv 1000v
temp -40/85
cell tech mono si
mod application class A
tuv(tcv?) yes
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Post by bupkis on Oct 9, 2018 15:01:41 GMT
No idea what the wire size is! one thought is to use 2 series pairs of panels to cut input current in half, or all four in series to cut input current by 4. Voltage drop in wire is current based. Either would result in increased power. Adding a fifth is series would likely exceed the input voltage of the Victron. Series pairs or all series will be beneficial in the summer when panels get hot and their Vmp and power drop due to heat.
other option is to twin the wire you have now or replace with a bigger wire.
another panel in parallel may be too much for the wire if 55A is it max.
I'm guessing that you are loosing 15-25% of your power to voltage drop/wire resistance (heat), that's a guess based on 6g or 10g wire.
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Post by byzance on Oct 11, 2018 6:57:38 GMT
I forgot to mention I do have 3 sets of wire running from the panels. So only two wires have more than one panel on them. The other has one panel on its own wire. I don't know if that makes a difference, but from what you were saying about heat being a problem that might adjust the equation in favor of a 12 V system.
The big burning question I have is can I change my panels to a 24 volt configuration while leaving the batteries and the inverter on a 12 V configuration. The inverter is 12 V only. Will the victron 100/50 MPPT change the volts to meet battery requirements or will I need to match my battery voltage with the panel voltage.
Thanks again for all the advice. I do appreciate it.
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Post by tattoo on Oct 11, 2018 9:09:07 GMT
I forgot to mention I do have 3 sets of wire running from the panels. So only two wires have more than one panel on them. The other has one panel on its own wire. I don't know if that makes a difference, but from what you were saying about heat being a problem that might adjust the equation in favor of a 12 V system. The big burning question I have is can I change my panels to a 24 volt configuration while leaving the batteries and the inverter on a 12 V configuration. The inverter is 12 V only. Will the victron 100/50 MPPT change the volts to meet battery requirements or will I need to match my battery voltage with the panel voltage. My understanding is everything has to be either 12v or 24v you can't mix and match..... Plus you can't change the voltage on the panels... You can buy new panels but then you will need to buy everything else new....
Best of luck...
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Post by bupkis on Oct 11, 2018 12:04:50 GMT
MPPT can handle higher voltage input and convert it to 12v.
Your input voltage limit is 100v and your amp output is limited to 50A (Victron 100/50).
The above poster has 2 strings of 4 100w panels in series and a 12v battery bank.
when you series panels, the current does no increase but the voltage is additive.
Having the extra wires helps but I would still use series pairs or all 4 in series.
You might want to probe around and see if one panel is not connected/working you should be seeing 700w from your 1000w panels.
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Post by byzance on Oct 14, 2018 5:47:03 GMT
okay so now I have a real interesting problem. I have drawn a recorded 1975 watts from a 2000watt inverter. Go figure it shut down. Which is what it is suppose to do when it gets close to an overdraw of power. I unplugged and reset (power on and off) and waited 30-40 seconds. It did reset and after the red light cleared I got solid green with no fault light. Which is what it is suppose to do. When I plugged even a 40 watt fan into it I got with in 20 seconds a fault and no power. then the power comes back on but not full power, but the alarm keeps ringing. So I start measuring things. All the batteries are either 13 or 13.2 volts. All my connections were tight. all my fuses were good. (even the ones inside the inverter)
Then I measured the voltage while the inverter is connected to the batteries, at the poles on the inverter. This voltage reading was not constant under any load. It kept fluxing from 7 volts up to 10 volts and everything in between. This does not seem correct but I don't know how to fix it. Or is it the inverter. Also It could be the cables between the 5 batteries. Do I need to consider this or is this just a shot inverter that I now need to replace?
Thanks again for any advice or comments you choose to give.
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Post by tattoo on Oct 14, 2018 13:55:36 GMT
So your saying each of the batteries are around 13v with all the wires unhooked at rest with no draw or charging?
Also you need a larger inverter if your getting that close to the limit.... Is the fan running in the inverter....
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Post by bupkis on Oct 14, 2018 15:02:03 GMT
I'd be checking the wiring from the battery to the invert first, bad wire, bad terminations, bad connections, dirty/loose connections, too small ...
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Post by byzance on Oct 26, 2018 7:20:09 GMT
Hello sorry it has been a while. I have had the whole debilitating man flu that put me down for a few days. Anyhow for the unexpected conclusion. So i got a new inverter for the system and did all the proper hook ups and what do you know I am getting good voltage for about 20 minutes then all of a sudden I got fluctuating voltage again. What is up with THAT? I mean really? YES really. I had battery cables connecting my 5 120ah 12 volt batteries that were only about 8 gauge. I figured it out only because this was the only part of the system that I did not isolate. The guy who sold me the batteries sold them to me in pairs and I never suspected that putting 5 together would require bigger cables. Then I read online how the cables between the batteries should be the thickest cables in the whole system because of the heavy voltage demands of first the charger and then the inverter. Well the new inverter had a rating of 10awg. Not sure what that is but its big. at least 2 x larger then the cables I had connecting the batteries. So I went to a local battery shop and got cables from an electrician to do the job. cost me $120 but the system has not stopped working since. So problem solved and it looks like I have a spare inverter for backup.
Thanks for the help guys. It was just me not being as smart as the equipment.
Later guys.
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Post by tattoo on Oct 26, 2018 13:49:12 GMT
Glad you figured it out.... And yes the bigger the cables the better as you found out....
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