idahogal
New Member
Last edited:
18v panel to 12v inverter
- Thread starter idahogal
- Start date
Your links don't work for me.
Panels have several ratings and they need to be known for proper setup. Voc, Vmp, Isc, and Imp.
From the panels to the battery you need a SCC (Solar charge controller). This takes the panel voltage and converts it to a proper battery charging voltage. It also has specifications for max Voc and amperage to battery.
Inverters take battery DC voltage and convert it to AC voltages. Once again it has specifications.
Between these things is wires, fuses breakers and connections. All of these must be sized based on the other components listed above.
Panels have several ratings and they need to be known for proper setup. Voc, Vmp, Isc, and Imp.
From the panels to the battery you need a SCC (Solar charge controller). This takes the panel voltage and converts it to a proper battery charging voltage. It also has specifications for max Voc and amperage to battery.
Inverters take battery DC voltage and convert it to AC voltages. Once again it has specifications.
Between these things is wires, fuses breakers and connections. All of these must be sized based on the other components listed above.
sunshine_eggo
Victron's little biatch
No. You need a solar charge controller to connect the panel to the battery, otherwise, the panel would potentially over-charge the batteries (though their BMS should protect them) and you would definitely over-volt the inverter due to the panel's Vmp/Voc value.
idahogal
New Member
I fixed the links, sorry!
The panel has a PWM controller with it, isn't that what is needed? I fixed the links
Only having 110w from the panel will not adequately charge 2-100ah batteries in parallel. Even if it produces all the rated watts during a normal sunny day you are looking at about 500Wh or 45ah. It would take 5 days to reach full charge after they were discharged.
The linked panel kit has all that you need to connect to the batteries.
The batteries would need parallel cables and also adequate cable to the inverter. Since it is 1000w that would be covered by 4awg. A 100amp fuse would be indicated.
The linked panel kit has all that you need to connect to the batteries.
The batteries would need parallel cables and also adequate cable to the inverter. Since it is 1000w that would be covered by 4awg. A 100amp fuse would be indicated.
sunshine_eggo
Victron's little biatch
Should be, but I'm not inclined to trust a cheap PWM controller with LFP batteries. Furthermore, PWM controllers lose out on about 20% of the available power due to the way they work, so that 110W panel will only yield around 90W peak in perfect conditions at high noon.
+1
If you only plan to use about 500Wh of energy per day, and you want 5 days worth of backup power, then this setup is fine, but once you eat into your battery backup, you'll struggle to get fully charged without reducing consumption.
idahogal
New Member
I'm only using one of the batteries. This is a very small setup, only to run a small refrigerator for now.
The inverter presently has alligator clamp things. I will need to change those out?
I swear I don't understand why this is so confusing for me. Thank you for your help.
robbob2112
Doing more research, mosty harmless
125amp MRBF fuses on each positive battery post - needs the holder too - don't trust amazon - this is a good place
www.delcity.net
I know - but Blue Sea Systems can be trusted
1000w inverter runs 83 amps - needs a 100 amp fuse inline - class T is ideal
You also need a disconnect -
here is a sample diagram from an old thread - Similar to what you need
it has a 2 post MRBF mount - one with the inverter on a fuse and the other post has the SCC and a wall
You don't need the large size Victron and you already have a different inverter
Marine Rated Battery Fuses
Explore Del City's Marine Rated Battery Fuses (MRBF) for high-current protection in demanding environments. Rated up to 58V DC, featuring IP66 protection and a clear window for quick identification.
I know - but Blue Sea Systems can be trusted
1000w inverter runs 83 amps - needs a 100 amp fuse inline - class T is ideal
You also need a disconnect -
here is a sample diagram from an old thread - Similar to what you need
it has a 2 post MRBF mount - one with the inverter on a fuse and the other post has the SCC and a wall
You don't need the large size Victron and you already have a different inverter
sunshine_eggo
Victron's little biatch
What is its consumption? Unless it's REALLY tiny, you likely don't have enough.
What fridge? Does it have a yellow energy sticker on it?
Yes. Something else to consider is that inverters consume power as well as loads.
idahogal
New Member
Ok. thanks. I can buy another controller. Any chance you'd link me to an appropriate one? Do they come with different connector types?
Yes, this is only for a small refrigerator that runs 65w at most, but most of the time it's not running the compressor, so much less than that overall. I also have larger panels I could attach one of them if I absolutely needed to. Or will upgrade to a larger panel. This is intended to get me started on a self-built system, familiarize myself with how it all works and exactly what I need. Plus having something portable. I plan on adding/changing components eventually.
robbob2112
Doing more research, mosty harmless
Yes, change out the alligator clips for loops
You can try to run with a PWM controller but they are only about 70% efficient and they limit the panel voltage to near your battery voltage
MPPT are 95% efficient so more of your panel energy goes into the battery
I have a mini battery similar and a 1200va phoenix inverter - it will run my relatively new fridge 14 hours - an older fridge it would fail in 6 hours - in your fridge there should be a model number plate that has the specs on what it takes to run, posta pic.
idahogal
New Member
sunshine_eggo
Victron's little biatch
320kWh of annual energy use is 320/365 = .876kWh/day
Guessing inverter uses 15W of power 24/7.
15*24 = 360Wh
.876 + .36 = 1.3kWh/day
110W of PV means you can't run this fridge/inverter.
You need at least 300W of PV, preferably 400W.
ONE battery allows for 24 hours of backup. I would use both.
400W of PV on 12V needs:
400W/14.4V = 28A of charging.
I would recommend a Victron 100/30 MPPT charge controller.
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idahogal
New Member
ugh. I run it occasionally on my battery box (EcoFlow/Bluetti type) and it doesn't seem like it consumes that much. I just don't like to leave that battery box running 24-7. Ok, I'll deal with that later. I'd still like to charge this one battery with the 110w panel and inverter I have.
320kWh of annual energy use is 320/365 = .876kWh/day
Guessing inverter uses 15W of power 24/7.
15*24 = 360Wh
.876 + .36 = 1.3kWh/day
110W of PV means you can't run this fridge/inverter.
You need at least 300W of PV, preferably 400W.
ONE battery allows for 24 hours of backup. I would use both.
400W of PV on 12V needs:
400W/14.4V = 28A of charging.
I would recommend a Victron 100/30 MPPT charge controller.
Hedges
I See Electromagnetic Fields!
- Joined
- Mar 28, 2020
- Messages
- 23,297
You may want an inverter with "sleep" mode, powers down and occasionally opens one eye to see if any loads are present.
Or if inverter has an "enable" switch, could wire fridge thermostat to turn it on. Call it an "Inverter drive DC refrigerator."
Or if inverter has an "enable" switch, could wire fridge thermostat to turn it on. Call it an "Inverter drive DC refrigerator."
sunshine_eggo
Victron's little biatch
It depends on usage. The standard that defines that number involves running the fridge in 90°F ambient weather while NEVER opening it. If you're running it in more mild conditions, then you won't use as much; however, the number of times its opened will increase it.
idahogal
New Member
thanks for that info.
Ok, if I can just run the fridge on it at night, that would be enough. Either way though, I would like to charge the battery with the inverter and that 110 panel I have.
sunshine_eggo
Victron's little biatch
Not sure what you mean. A fridge in constant operation cycles the compressor on and off as needed to maintain the internal temperature. If you choose to run it only part of the day, then it's going to run the compressor continuously to cool it down, and then start cycling it on and off as the set point is reached.
I have a notably larger fridge (10.1 cuft, but it's almost identical in consumption - probably has the same compressor). Here's what it looks like in a 24 hour period:
The blue line is the fridge cycling on and off (runs longer when it's hotter, shorter when it's cooler). The green line is my battery temperature, which is both hotter and colder than the fridge. The fridge runs about 15° cooler.
Again, if you only ran during the night, your blue line interval would be notably wider, i.e., it might run most of the night using notably more than mine for that period.
Provided you don't use more than about 0.5kWh/day, that's fine.
idahogal
New Member
haha sorry. I'd run it during the day on my battery box. Then switch to this battery overnight. I just don't like to leave the battery box on overnight, because it self-consumes so much power.
Rednecktek
Expert Newbie
You've got enough to get your foot in the door, it's all about fine tuning from here. All the parts you need to get started are in the links you've posted. Go ahead and throw the system together with what you have and see how it works. The first thing you're going to notice is that the battery is pretty much dead the next day, but you've got a second battery in the pile so throw both of those in together in parallel right from the get go. Replace the alligator clips with proper ring terminals for good contact, grab at least a DC breaker good for 100a (I've had good luck with T-Tocas, Blue Sea, and Eaton, avoid anything that looks like a tube) to put between the battery and inverter. If you can swing the extra $40, grab one of the Aili shunts or it's clone because the state of charge meters on a controller or regular battery meters are based on lead acid and don't work for LFP. The only real way to figure out how much life is left in the batteries is a shunt that's keeping track of what goes in and what comes out.
That inverter is going to want 4AWG wire to the batteries. When you connect your batteries, it's positive to positive, negative to negative, take your inverter leads from Battery-1 positive and Battery-2 negative to keep them in balance.
The next thing you're going to find is that the battery is draining faster than the little folding solar panel can charge it up, especially if there are clouds or leaves or dust or any kind of weather. Winter out in your neck of the woods is gonna be real bad. You'll want to hit up Craigslist or FBMarket and find a couple few used solar panels. Out in Spokane and Seattle areas I find I can usually get about 250w for about $100 so grab a couple of those and some 2x6's and Z-brackets and go to town building a rack.
You'll also need a proper MPPT controller to take those from the 40-ish volts they run at normally and convert that down to the happy 14v that the battery likes. You don't have to spend $$Victron money, I actually prefer HQST or BougeRV, even PowMr or Vevor or any of their clones will turn solar DC into battery DC just fine. As a rule of thumb you're going to want 10a of SCC per 100w of panel, so if you get 500w of panels, get at least a 40a SCC (more isn't going to hurt though and lets you scale up later). Pro tip: If there's USB on the front of the controller, it's almost always a FAKE controller with a MPPT sticker on it and they're laughing at you all the way to the bank.
It's OK to leave it on and check on it, that's what you're designing the system to do. If you haven't spent any money yet, I'd skip that folding panel all together and go straight to the used panels on Craigslist. Folding panels and flexible panels are always overpriced per watt compared to standard panels. Even on Amazon you can get better setups for $25 more that will get you double the charging power AND last longer AND be easily expandable later. 100w panels are pretty universal nowadays and can be strung together really easily.
As for how to read a panel, there are three numbers on a solar panel that are important:
Vmp - Voltage under load - This is what the panels should produce in clear sun at 25c. Used to calculate how much power you can produce.
Isc - Amperage Maximum - This is how many amps the panel should put out at full load in perfect sun at 25c. Used to calculate how much power you can produce (Isc * Vmp = Total Watts) and how thick your wires need to be.
Voc - Voltage with no load - This is how many volts the panel should produce under no load in perfect sun at 25c - Used to calculate how many panels you can have in a string before you fry your charge controller. Every charge controller will have a limit on how much voltage it can take in, usually labeled something like "Max PV Input". That number is a HARD limit. Like diamond or your ex-boyfiend's skull hard! When panels are cold (like half the year out in Idaho) they produce MORE voltage when the sun comes up, so good rule of thumb is to give yourself 10% to 20% overhead on that limit. So if your controller says "Max PV Input - 100v" and your panels are 20v VoC, only string together 4 of them in series (80v) when you build up your arrays. Sadly, a LOT of solar is about maths.
Most importantly, feel free to ask questions! Everyone here was a newbie once and had to learn too.
That inverter is going to want 4AWG wire to the batteries. When you connect your batteries, it's positive to positive, negative to negative, take your inverter leads from Battery-1 positive and Battery-2 negative to keep them in balance.
The next thing you're going to find is that the battery is draining faster than the little folding solar panel can charge it up, especially if there are clouds or leaves or dust or any kind of weather. Winter out in your neck of the woods is gonna be real bad. You'll want to hit up Craigslist or FBMarket and find a couple few used solar panels. Out in Spokane and Seattle areas I find I can usually get about 250w for about $100 so grab a couple of those and some 2x6's and Z-brackets and go to town building a rack.
You'll also need a proper MPPT controller to take those from the 40-ish volts they run at normally and convert that down to the happy 14v that the battery likes. You don't have to spend $$Victron money, I actually prefer HQST or BougeRV, even PowMr or Vevor or any of their clones will turn solar DC into battery DC just fine. As a rule of thumb you're going to want 10a of SCC per 100w of panel, so if you get 500w of panels, get at least a 40a SCC (more isn't going to hurt though and lets you scale up later). Pro tip: If there's USB on the front of the controller, it's almost always a FAKE controller with a MPPT sticker on it and they're laughing at you all the way to the bank.
It's OK to leave it on and check on it, that's what you're designing the system to do. If you haven't spent any money yet, I'd skip that folding panel all together and go straight to the used panels on Craigslist. Folding panels and flexible panels are always overpriced per watt compared to standard panels. Even on Amazon you can get better setups for $25 more that will get you double the charging power AND last longer AND be easily expandable later. 100w panels are pretty universal nowadays and can be strung together really easily.
As for how to read a panel, there are three numbers on a solar panel that are important:
Vmp - Voltage under load - This is what the panels should produce in clear sun at 25c. Used to calculate how much power you can produce.
Isc - Amperage Maximum - This is how many amps the panel should put out at full load in perfect sun at 25c. Used to calculate how much power you can produce (Isc * Vmp = Total Watts) and how thick your wires need to be.
Voc - Voltage with no load - This is how many volts the panel should produce under no load in perfect sun at 25c - Used to calculate how many panels you can have in a string before you fry your charge controller. Every charge controller will have a limit on how much voltage it can take in, usually labeled something like "Max PV Input". That number is a HARD limit. Like diamond or your ex-boyfiend's skull hard! When panels are cold (like half the year out in Idaho) they produce MORE voltage when the sun comes up, so good rule of thumb is to give yourself 10% to 20% overhead on that limit. So if your controller says "Max PV Input - 100v" and your panels are 20v VoC, only string together 4 of them in series (80v) when you build up your arrays. Sadly, a LOT of solar is about maths.
Most importantly, feel free to ask questions! Everyone here was a newbie once and had to learn too.
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Rednecktek
Expert Newbie
Just to do a little napkin math to show you where you're aiming for:
Fridge - 65w
Inverters are about 1% standby, so call it 10w
75w of load * 24 hours = 1800 watt hours per day
Each battery is 1280 watt hours (wh) so 1.3 batteries per day to run that fridge.
Rule of thumb is 4 hours of sun per day so 1800wh / 4 hours of sun = 450w of panels, call it 500w for inefficiencies. Fortunately that's only 2 used panels on a frame. That assumes you get good sun every day which is a big ask out there.
Depending on how far north you are in Idaho, you'll eventually want to double that for winter, so 1000w of panel and 75+ amps of charge controller. Check out PVWatts and plug in your location, it'll tell you about how much sun you can get each month and plan for the worst month. You might well end up with 4 panels on 2 40a MPPT's when all is said and done. Not a big deal but about $600 plus lumber by the end of it all.
Just for reference.
Fridge - 65w
Inverters are about 1% standby, so call it 10w
75w of load * 24 hours = 1800 watt hours per day
Each battery is 1280 watt hours (wh) so 1.3 batteries per day to run that fridge.
Rule of thumb is 4 hours of sun per day so 1800wh / 4 hours of sun = 450w of panels, call it 500w for inefficiencies. Fortunately that's only 2 used panels on a frame. That assumes you get good sun every day which is a big ask out there.
Depending on how far north you are in Idaho, you'll eventually want to double that for winter, so 1000w of panel and 75+ amps of charge controller. Check out PVWatts and plug in your location, it'll tell you about how much sun you can get each month and plan for the worst month. You might well end up with 4 panels on 2 40a MPPT's when all is said and done. Not a big deal but about $600 plus lumber by the end of it all.
Just for reference.
robbob2112
Doing more research, mosty harmless
The victron phoenix 1200va inverter only consumes 7.5 watts when idle and has an ECO mode where it consumes less. ECO mode it sleeps then wakes up and checks for load, then sleeps again. So if the fridge doesn't have any extra crud it won't kill a battery with idle usage.
Rexracer
New Member
I have the 160w version of that solar panel. I am still testing and making changes, but it seems to work well and pumps out the wattage it claims. No idea about longevity yet since I've never run anything for more than an hour or so yet... New England winters are cold and wet here lately.
If you go with the Victron charge controller ( I would ) I would upgrade to the Smartsolar instead of the Bluesolar. For $15 more it has built in Bluetooth and allows use of the app, which gets you a lot of good info right from your phone, with no extra cost except the $15. I ended up with (2) 160 watt panels and the Smartsolar 100/30. Room to grow. My system will also be a portable/camping system. Just added a Victron dc-dc charger so my battery can charge while driving. The whole system will be portable, aka NOT mounted to my jeep permanently...except the charger.
BTW, I'm also new to this. These guys giving advice know a LOT about this stuff, and I've learned a bunch, so you're in the right place IMHO. Good luck!
If you go with the Victron charge controller ( I would ) I would upgrade to the Smartsolar instead of the Bluesolar. For $15 more it has built in Bluetooth and allows use of the app, which gets you a lot of good info right from your phone, with no extra cost except the $15. I ended up with (2) 160 watt panels and the Smartsolar 100/30. Room to grow. My system will also be a portable/camping system. Just added a Victron dc-dc charger so my battery can charge while driving. The whole system will be portable, aka NOT mounted to my jeep permanently...except the charger.
BTW, I'm also new to this. These guys giving advice know a LOT about this stuff, and I've learned a bunch, so you're in the right place IMHO. Good luck!
Fellow newbie here…
First invest in a kilowatt meter. It will give you some exact usage data.
I have a 4.4cf danby fridge with a max surge of 100w. Most times it runs between 30w-50w when the compressor kicks on. The compressor doesn’t run for hours on end so it doesn’t actually consume 50w per hour 24 hours a day.
Btw those mini peltier ones that chill a can of soda do have 24/7 consumption!!!
An EF delta2 and 260w of panels (2x130) can run it 24/7. When I add the 100w freezer to the mix it may or may not make it 24 hrs depending on if I get good sun. We had a couple power outages this fall and I made it thru a 2 day block but was lucky. I doubt it would have been sustainable long term running both of them. I had to go below the 30% discharge limit the second day. It also started with a full charge so it only had to keep up during the first day and saw discharge at night.
This is in MT so you might have similar climate. Your usage scenario with a fridge/freezer combo will vary depending on environmental conditions. A kilowatt meter will be able to track that long term.
victron makes some efficient equipment. I was able to get a used like new 375va inverter for $69.99. That comes in at about 6w self consumption and 1w in ecomode.
Bluesolar vs smartsolar mppt:
Blue uses less watts since it doesn’t run BT. It can have a dongle added.
Smart has built in bluetooth and can talk to other victron mppts to increase efficiency in a larger system.
Use what you got, upgrade when you can, learn your needs and goals then grow from there.
First invest in a kilowatt meter. It will give you some exact usage data.
I have a 4.4cf danby fridge with a max surge of 100w. Most times it runs between 30w-50w when the compressor kicks on. The compressor doesn’t run for hours on end so it doesn’t actually consume 50w per hour 24 hours a day.
Btw those mini peltier ones that chill a can of soda do have 24/7 consumption!!!
An EF delta2 and 260w of panels (2x130) can run it 24/7. When I add the 100w freezer to the mix it may or may not make it 24 hrs depending on if I get good sun. We had a couple power outages this fall and I made it thru a 2 day block but was lucky. I doubt it would have been sustainable long term running both of them. I had to go below the 30% discharge limit the second day. It also started with a full charge so it only had to keep up during the first day and saw discharge at night.
This is in MT so you might have similar climate. Your usage scenario with a fridge/freezer combo will vary depending on environmental conditions. A kilowatt meter will be able to track that long term.
victron makes some efficient equipment. I was able to get a used like new 375va inverter for $69.99. That comes in at about 6w self consumption and 1w in ecomode.
Bluesolar vs smartsolar mppt:
Blue uses less watts since it doesn’t run BT. It can have a dongle added.
Smart has built in bluetooth and can talk to other victron mppts to increase efficiency in a larger system.
Use what you got, upgrade when you can, learn your needs and goals then grow from there.
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