Solar configuration

[Pi Curio]

@Camp20144

Sunday

Since I just managed to improve my system build fuse and wiring quality by going with MRBF all the way, thought to share.

Similarly, this build is made with further expansion in mind, ranging from 400W-800W solar going forward while @12v.
Before After

All in all, very satisfied with how the build is more streamlined now.





Best,
D.

 

[byteharmony]

Comparing apples to oranges.

Again, his application requires a maximum of 1060W continuous load for about 4-10min, max.

I think you nailed it @Daxo, apples to oranges - to get a solution your happy with you have to pick.

The original post was missing some important details for system design, namely output requirements.

As the topic was flushed out and a 120v AC output for a large draw item (Microwave) was added my post about 48v hybrid systems put in place where you go with larger draw AC systems.

A hybrid 48v system may add more weight and less portability to this task than the larger wire required for the AC draw.
A hybrid 48v system may add more weight by adding 120v input charger that is not required.

However, if the user is considering but hadn't mentioned those prospect items then the individual parts add up to become less mobile and more hodge podge:
1. AC Charger
2. DC Charge Controller
3. AC Inverter

I find if the AC draw is small, aka laptops, led lighting, cpap machine, etc. Then a small inverter on a low voltage system works just fine.

If the AC draw is going to grow to anything over 1,000 Watts then the inverters get hungry and idle draw starts coming into play and portability suffers.

Another element that is apples to oranges I didn't see mentioned was battery voltage and kwh sizes.

a 12 v 100 Ah battery contains 1200 kwh of power and may weight about 10 - 15 lbs.
a 24 v 100 Ah battery contains 2400 kwh of power and may weight about 20 - 30 lbs.

So keep that in mind when you are considering portability and how you want to design your system.

 

[Pi Curio]

I think you nailed it @Daxo, apples to oranges - to get a solution your happy with you have to pick.

The original post was missing some important details for system design, namely output requirements.

As the topic was flushed out and a 120v AC output for a large draw item (Microwave) was added my post about 48v hybrid systems put in place where you go with larger draw AC systems.

A hybrid 48v system may add more weight and less portability to this task than the larger wire required for the AC draw.
A hybrid 48v system may add more weight by adding 120v input charger that is not required.

However, if the user is considering but hadn't mentioned those prospect items then the individual parts add up to become less mobile and more hodge podge:
1. AC Charger
2. DC Charge Controller
3. AC Inverter

I find if the AC draw is small, aka laptops, led lighting, cpap machine, etc. Then a small inverter on a low voltage system works just fine.

If the AC draw is going to grow to anything over 1,000 Watts then the inverters get hungry and idle draw starts coming into play and portability suffers.

Another element that is apples to oranges I didn't see mentioned was battery voltage and kwh sizes.

a 12 v 100 Ah battery contains 1200 kwh of power and may weight about 10 - 15 lbs.
a 24 v 100 Ah battery contains 2400 kwh of power and may weight about 20 - 30 lbs.

So keep that in mind when you are considering portability and how you want to design your system.

Indeed, you've made some valid points here.

Certainly, another perspective on things worth considering.


Best,
D.

 

[Camp20144]

@byteharmony @Daxo Yes, my first post in this thread was not complete. As I was envisioning two operating modes, a 400W array at times and an 800W array at other times, I was locked in on trying to figure out with two Wattage arrays if operationally I could use one SCC or needing two smaller SCCs. I should have followed up with a second post fleshing out my system. I’m still learning how to present information and questions in the forum world. I actually see a third operating mode where on short trips I only have battery power with no solar.

The main driver of my system is my cpap which is direct to battery 12V powered. The other important driver was portability, that “without too much hassle”, I can bring the system with me (moved between more than one mode of camping, home power outages). With that I wasn’t worried about future expansion. As I began considering a system I focused on powering my cpap. I considered, and still do consider, anything above and beyond my cpap as “luxuries”.

As my main driver of my system is my cpap I decided to go 12V so I didn’t have a “built-in” efficiency problem of converting 24V to 12V for my main, and many times only use, of my battery system.

The only time I foresee potentially having 120V use would be in my slide-in camper which would be the 800-900W microwave with very minimal use. As such, I would mount the inverter in the camper. Another component that I would add for the camper would be shore power charging for the batteries. Both the inverter and shore charger would be hard mounted in the camper as that is the only place they would be used.

When I’m not in my slide-in camper, I have a NOCO10 genius, LiFePO4 capable, charger that I would carry with me in the event I had the need and chance to throw it on the batteries. I do not plan on a DC-DC charger off my pickup. If I did that it would be hard mounted in my pickup.

In my reading of the inverter parasitic draw, people keep the inverter powered off if they only have periodic inverter use. I figured that is what I would do. If I find that I don’t have enough storage in my batteries either due to poor solar conditions or use, as I mentioned the microwave is a luxury. I will always have other meals available that don’t require the microwave.

I had decided to go with Battleborn batteries and purchased them earlier. Their 12V 100Ah battery is 31lbs and their 24V 50Ah battery is 31lbs. I have 2 100Ah batteries for 62lbs but had figured the weight in. I will handle the batteries separately so I don’t end up with one large “crate” to deal with. In my slide-in pickup camper, the batteries fit in the battery compartment.

Thank you for the consideration and input towards my project. Your participation is very much appreciated as I continue to learn. Your advice/input will also be important if/when I build a larger system.

Thank you again,
Mark

 

[Pi Curio]

@byteharmony @Daxo Yes, my first post in this thread was not complete. As I was envisioning two operating modes, a 400W array at times and an 800W array at other times, I was locked in on trying to figure out with two Wattage arrays if operationally I could use one SCC or needing two smaller SCCs. I should have followed up with a second post fleshing out my system. I’m still learning how to present information and questions in the forum world. I actually see a third operating mode where on short trips I only have battery power with no solar.

Honestly, you did a very good job describing your use case and all the specifics for it.

Btw, did you by any chance check with a watt meter just how much power your microwave uses? A photo of the power specification on your microwave would suffice as well.

I'm still considering the bits and pieces for the Inverter so knowing the microwave power specs would be of great help.

Best,
D.

 

[Camp20144]

@Daxo Thank you for the kind words. Thank you for continuing to ponder the inverter part of my puzzle, much appreciated!!

I will not be able to get power to my camper for awhile as it’s currently in storage. If I recall correctly it may not be possible to put a kill-a-watt on it due to plug location. They don’t seem to think of stuff like that when they build things ???. I have the manuals/paperwork from it here with me I believe. I’ll check when I have a chance and see if the microwave paperwork is model specific and has a good listing of power use/requirements.

I may or may not be able to access the back of the microwave for the specs plate. I tried to figure out how to remove the microwave once as it’s hard mounted. I’ve yet to figure it out - haven’t found screws/clips/secret keys/fasteners - nothing!! Would be nice to know. It appears to me that there is a full surround mount that is installed first and then the microwave itself is “popped in” - just don’t see the “popping out” part???

 

[Camp20144]

@Daxo It appears from the shadow line on your pv frame, from the white pen??, that the sun is at a very shallow angle, far from perpendicular to the panel at 8:33 am (time on app?)?

It appears that, in some locations, it is possible to transition from mega and other fuses to MRBF fuses, which post mount, to eliminate mechanical connections which decreases points of resistance, and simplifies build?

The white colored “box” at the top is a 2P breaker for your solar panels? I ran across those, saw them advertised as solar cutoffs and was thinking that may be a good way to disconnect the panels as opposed to a switch that only cuts off one line (+) to the panel, or, having two switches, one on each (+) and (-) lines.

After stripping the wire, like the ones connected to the 2P breaker, do you crimp on those metal “sleeves”? Or, do you just tighten down on the bare wire strands?

Thank you,
Mark

 

[Pi Curio]

@Daxo Thank you for the kind words. Thank you for continuing to ponder the inverter part of my puzzle, much appreciated!!

I will not be able to get power to my camper for awhile as it’s currently in storage. If I recall correctly it may not be possible to put a kill-a-watt on it due to plug location. They don’t seem to think of stuff like that when they build things ???. I have the manuals/paperwork from it here with me I believe. I’ll check when I have a chance and see if the microwave paperwork is model specific and has a good listing of power use/requirements.

I may or may not be able to access the back of the microwave for the specs plate. I tried to figure out how to remove the microwave once as it’s hard mounted. I’ve yet to figure it out - haven’t found screws/clips/secret keys/fasteners - nothing!! Would be nice to know. It appears to me that there is a full surround mount that is installed first and then the microwave itself is “popped in” - just don’t see the “popping out” part???

Make and model from the manual?

@Daxo It appears from the shadow line on your pv frame, from the white pen??, that the sun is at a very shallow angle, far from perpendicular to the panel at 8:33 am (time on app?)?

Yes, very shallow angle! Usually, I can get 0.5A on solar in a complete shadow past 12:00 in winter. Why I thought of taking a pen for sun direction reference and showing the Vmp/ChargeV ratio in action.

Where you can see how production starts a lot earlier.

It appears that, in some locations, it is possible to transition from mega and other fuses to MRBF fuses, which post mount, to eliminate mechanical connections which decreases points of resistance, and simplifies build?

It's possible, no doubt, just a bit of planning and consideration on how many components and cables you would need to fuse for. If I was to use 2xSCCs(which I will eventually) I'd go with a triple terminal post block so I can similarly, fuse the cables for 2x SCCs independently and for the inverter cable.

In my current build, I wasn't satisfied with the busbars I initially installed. After scratching the surface of the metal I realized it was made of brass instead of copper, 45$ wasted.

So I figured since my build isn't a complex one, why not get a shunt(essential component anyways) and use it as a busbar for the system main negative and combine the Main Isolator switch with the current EATON double terminal post block and use it as the system main positive busbar, thus for fuses for the SCC and Inverter cables.

Plus, I've used a single terminal post block and installed the main fuse where most appropriate, as close to the battery-positive terminal as possible. It doesn't get any closer than using a single terminal post block with an MRBF fuse on the battery positive-terminal.

The white colored “box” at the top is a 2P breaker for your solar panels? I ran across those, saw them advertised as solar cutoffs and was thinking that may be a good way to disconnect the panels as opposed to a switch that only cuts off one line (+) to the panel, or, having two switches, one on each (+) and (-) lines.

After stripping the wire, like the ones connected to the 2P breaker, do you crimp on those metal “sleeves”? Or, do you just tighten down on the bare wire strands?

Thank you,
Mark

Yes, it's a non-polarized, DC, isolator, double pole 50A circuit breaker.

The idea was to use it as an isolator switch to isolate both, the PV negative and positive cables from the system if I needed to for whatever reason.

In general, it's never a good idea to switch it off when under load(SCC charging batteries or for load), which can cause the circuit breaker to burn down.


As for the wire ends, I've used cable ferrules. Once I got the cables into the DC circuit breaker terminals and tighten them down, these cables weren't going anywhere


Best,
D.

 

[Camp20144]

@Daxo We got lucky! The microwave manual is model specific. It is a Goldstar MS-71MDU. This is a picture of the specs.

 

[Camp20144]

9.3A @ 120V = 1116 Watts. Maybe my thought of a 1200W inverter would not work?

 

[Pi Curio]

9.3A @ 120V = 1116 Watts. Maybe my thought of a 1200W inverter would not work?

Yes, the 1200W inverter wouldn't suffice.

It's not just the 1050W the microwave oven needs for operation, but also the inrush current @startup, which can be much higher. An inverter that has a much higher Wattage with a soft start is probably a good idea.


Personally, I'd make a thread and ask folks what would they recommend for this application, there are far more knowledgeable people on this topic than me.


The inverter
Something like a 2000W inverter, a 1600W-ish actual.


Hope it helps a bit.

Best,
D.

 

[Camp20144]

@Daxo Thank you very much. I’ll study and run a separate thread on the inverter.

I have two Victron 100/30’s ordered and I ordered four 200W 24V Solar panels. Once I have everything in one place I’ll work on setup/layout and then I’ll be able to size cables and order them. When I’m at that point I may be popping back in here to run things past you.?

Thank you again for your time and assistance. It’s been very valuable,
Mark

 

[Pi Curio]

@Daxo Thank you very much. I’ll study and run a separate thread on the inverter.

I have two Victron 100/30’s ordered and I ordered four 200W 24V Solar panels. Once I have everything in one place I’ll work on setup/layout and then I’ll be able to size cables and order them. When I’m at that point I may be popping back in here to run things past you.?

Thank you again for your time and assistance. It’s been very valuable,
Mark

Happy to help.

Best,
D.