diy solar

diy solar

Need help choosing solar panels and inverter

OffGridIdaho

Hobby Farm in N Idaho
Joined
Jun 18, 2020
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254
Location
N Idaho
Sig Solar has free shipping on orders over 2k till the 28th so I am going to take advantage of it. My budget is small so we are ordering just what we need to survive off grid. Currently off-grid and on a 24v 280ah 1200w solar 1200w inv system. My MPPT is a Vic 250/100. We are upgrading the batteries to 16 EVE 280ah up from 8 EVE 280ah. We have a tiny house so we only use about 5kw per day.

After research I have the two choices for inverters and 3 choices for panels as my top picks. We have lots of cloudy days so which panels are best for gray days.

1. Victron quattro 3000w 48v
2. Victron multiplus 3000w 48v
3. Hyperion 395W Bifacial (made in Thailand)
4. Hyundai 395W Bifacial (higher voltage grid tie 49v) (do I want this if off-grid??) (made in Korea)
5. Aptos 370W Bifacial (made in Vietnam)

Can the victron inverters do power assist while charging? Example, if I am charging and also running a microwave and the well pump kicks on will the inverter stop charging and give power to well pump?

Are the Vic quattro and multiplus both low frequency inverters?

Can I work with the Hyundai grid-tie panels or is the voltage too high?

Of the 3 panels is one the best choice?

Why is the quattro 500 dollars more? Is it that much better? Does the multiplus have this feature?
  • Unique PowerAssist - Prevents overload of a limited AC source.
    • First, battery charging automatically reduces.
    • Second, shore side supply will be boosted with power taken from the battery.
 
On the solar panels -

Choose them based on how many watts you can get on the area you want to mount them, and on dollars per watt. Everything else comes in a very distant third. I like bifacials for installations where you can see beneath them, but that's an aesthetic and not a functional choice.

Voltages don't matter too much if you have an MPPT. Just choose a string arrangement that will keep you comfortably under the MPPT's max voltage. Don't forget that cold will increase Voc.

The Quattro will definitely do generator assist. Not sure abou thte Multiplus.
 
Can the victron inverters do power assist while charging? Example, if I am charging and also running a microwave and the well pump kicks on will the inverter stop charging and give power to well pump?
Yes, this is exactly what power assist does.

Why is the quattro 500 dollars more? Is it that much better? Does the multiplus have this feature?
Multiplus and Quattro both have power assist.

Multiplus has one AC input ... Quattro has 2 AC inputs and can automatically select which input to use based on which one has power. So, one input can be grid (or a second generator) and the other can be generator and the Quattro will use whatever input has power. If you don't have a grid connection you probably don't need the quattro, unless you have 2 generators
 
Yes, this is exactly what power assist does.


Multiplus and Quattro both have power assist.

Multiplus has one AC input ... Quattro has 2 AC inputs and can automatically select which input to use based on which one has power. So, one input can be grid (or a second generator) and the other can be generator and the Quattro will use whatever input has power. If you don't have a grid connection you probably don't need the quattro, unless you have 2 generators
Ok thanks. I will get the miltiplus. Any opinion on the panels I have selected?
 
...
  • Unique PowerAssist - Prevents overload of a limited AC source.
    • First, battery charging automatically reduces.
    • Second, shore side supply will be boosted with power taken from the battery.
This is a bit misleading. For one thing if you are running from the inverter, and the loads are less then PV coming in, than your battery charges. If loads rise to exceed PV coming in, than battery begins to discharge to make up the difference. This is imply the nature of it and not a special action taken by your inverter/charger.

Power assist is when you are running with a limited AC input but your loads are greater than it can supply. The Victron units can function in parallel with the AC input to increase capacity of AC output. Thus the inverter adds from battery/PV if there is insufficient AC from shorepower/grid.
 
This is a bit misleading. For one thing if you are running from the inverter, and the loads are less then PV coming in, than your battery charges. If loads rise to exceed PV coming in, than battery begins to discharge to make up the difference. This is imply the nature of it and not a special action taken by your inverter/charger.

Confused about what's misleading. The text you quoted is specific to operating with an AC source and doesn't in any way relate to PV as PV is not an inverter function.

Power assist is when you are running with a limited AC input but your loads are greater than it can supply. The Victron units can function in parallel with the AC input to increase capacity of AC output. Thus the inverter adds from battery/PV if there is insufficient AC from shorepower/grid.

If you are running from the inverter, PowerAssist doesn't apply, and again, the inverter does nothing with PV. It either supplies or draws from the DC bus. PV plays a roll with the DC bus, but it's irrelevant to PowerAssist.
 
Confused about what's misleading. The text you quoted is specific to operating with an AC source and doesn't in any way relate to PV as PV is not an inverter function.



If you are running from the inverter, PowerAssist doesn't apply, and again, the inverter does nothing with PV. It either supplies or draws from the DC bus. PV plays a roll with the DC bus, but it's irrelevant to PowerAssist.
If you had read his OP you will have noticed this
Can the victron inverters do power assist while charging? Example, if I am charging and also running a microwave and the well pump kicks on will the inverter stop charging and give power to well pump?

It is misleading to the OP not to me. And yes the inverter does run during power assist.

BTW. The common DC bus has PV on it as well as the battery leading to the inverter. They all work in conjunction.
 
If you had read his OP you will have noticed this

I did read it.

It is misleading to the OP not to me. And yes the inverter does run during power assist.

Can the victron inverters do power assist while charging? Example, if I am charging and also running a microwave and the well pump kicks on will the inverter stop charging and give power to well pump?

I don't see the confusion or how it's misleading to the OP. This is exactly how it works.

If you are running from the inverter, PowerAssist doesn't apply, and again, the inverter does nothing with PV. It either supplies or draws from the DC bus. PV plays a roll with the DC bus, but it's irrelevant to PowerAssist.

I meant this literally. "Running from the inverter" means you're inverting, not running from an external AC source. PowerAssist doesn't engage when the inverter is inverting, only when charging/passing through AC to loads. Exactly as the OP states, it stops charging and boosts power to loads.

BTW. The common DC bus has PV on it as well as the battery leading to the inverter. They all work in conjunction.

Right, but the presence of PV on the DC bus has no direct influence on PowerAssist operation. OP made no mention of PV in the context of PowerAssist.

I promise I'm not just arguing for its own sake. It appears to me that the OP completely understands how PowerAssist works, and I don't see how either quoted portion introduces confusion. The only confusion I see is tying PV in any way to the operation of PowerAssist. PowerAssist works whether PV is present or not.
 
Should clarify so the cats stop fighting. :)
Generator AC charging not solar DC charging. Yes I understood.

Any other opinions on panels. I think I am going to buy the Aptos 370w @ $96ea. Its a great price. They just came in stock.

DNA-120-BF26-370W​

 
Are the Vic quattro and multiplus both low frequency inverters?

We need to start shifting the LF/HF terms to transformer/no transformer. The transformer is the key part, not the driven frequency.

ALL Victron inverters have a transformer on the output, but its not a low frequency (driven) transformer per say. Its driven at 20khz and they use toroidal transformers. They are pretty efficient for a transformer inverter and they run a low idle draw. Top of the class but not the strongest surge capacity, though way better then an HF or no transformer inverter.

Most of the other LF ( transformer) inverters use a laminate core style transformer. Not as efficient as a victron but I think this is what gives them the huge startup capacity vs toroidal transformer.

Victron has seemed to found a sweet spot between the two. Point is, why would anyone want an inverter where the FETs are connected directly to the output mains? Seems to me a carry over from the old cheap china inverters from the 90s when someone was trying to save a buck and could care less what happens down the line when things go south.
 
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We need to start shifting the LF/HF terms to transformer/no transformer. The transformer is the key part, not the driven frequency.

ALL Victron inverters have a transformer on the output, but its not a low frequency (driven) transformer per say. Its driven at 20khz and they use toroidal transformers. They are pretty efficient for a transformer inverter and they run a low idle draw. Top of the class but not the strongest surge capacity, though way better then an HF or no transformer inverter.

Most of the other LF ( transformer) inverters use a laminate core style transformer. Not as efficient as a victron but I think this is what gives them the huge startup capacity vs toroidal transformer.

Victron has seemed to found a sweet spot between the two. Point is, why would anyone want an inverter where the FETs are connected directly to the output mains? Seems to me a carry over from the old cheap china inverters from the 90s when someone was trying to save a buck and could care less what happens down the line when things go south.
Yeah my current inverter is a Samlex and its built like a tank. The transformer inside takes up half the case and weighs 35lbs by itself. Its a beast. Our samlex is only 1200w @ 24v and it can start/run our well pump, 2 chest freezers and our microwave and a window air conditioner (not all at the same time)

I ended up getting the Aptos panels at $96/panel. Great deal for brand new tier 1 panels with a 30yr warranty.
 
Yeah my current inverter is a Samlex and its built like a tank. The transformer inside takes up half the case and weighs 35lbs by itself. Its a beast. Our samlex is only 1200w @ 24v and it can start/run our well pump, 2 chest freezers and our microwave and a window air conditioner (not all at the same time)

I ended up getting the Aptos panels at $96/panel. Great deal for brand new tier 1 panels with a 30yr warranty.
I accidentally started up everything once on a 2800w/12v Magnum. I calculated it was about 10k Watts. It grunted but started it non the less. I run it pretty hard and it starts freezers and the fridge all the time while it's already ready running near full load. Probably will shorten it's life over time.

I mention this cause I am also building my next system and am going 48v with Victron gear. You should consider a 5K inverter if you think you would be pushing the 3k hard. I have not run the 3k or 5k Victron yet, but I believe they have a stricter over load protection. They make a 5K multiplus II thats a bit cheaper then the quattro. A 3K Victron will likely shut down sooner under over load then your Samlex 1200w.

Maybe someone else can share their experience with Victron's overload/surge ability vs other "LF" transformer inverters.
 
Should clarify so the cats stop fighting. :)
Generator AC charging not solar DC charging. Yes I understood.

Any other opinions on panels. I think I am going to buy the Aptos 370w @ $96ea. Its a great price. They just came in stock.

DNA-120-BF26-370W​

Was not attempting a fight. Just was hoping to help with understanding the processes involved.
 
Not sure if it was mentioned, but your solar panels should be sized for your SCC by VOC and ISC and …. Maybe your roof or ground mount.

Your combined Solar panel string VOC should be 80% or less than your max SCC VOC of 250v. Depending on your available space from roof or ground mount, you may be bettter off with strings of 4 or strings of 5. Again, there is no mention of this info which will drive the decision to which panels.

Shade if any kind means you want to parallel some strings to minimize loss from shade. No shade or open fields means you don’t have to worry about how your strings are setup since they will get full sun at the same time.


They have an Excel and website for plugging in your solar panels and selecting a SCC model. Just google Victron SCC calculator or something close to that.

The 250/100 is the sweet spot in terms of cost since the 450/100 is a bit outrageous for having the same charging capacity but only allows for higher VOC.


More comments. Victron uses a modular design for products in the USA. The inverter is separate and independent from the SCC. Also, Victron is designed for marine where grid or generator is treated as a luxury and is used as primary when available. That’s why you can set max draw for your grid or generator, and the independent SCC and battery will provide the remaining power as needed.
 
Not sure if it was mentioned, but your solar panels should be sized for your SCC by VOC and ISC and …. Maybe your roof or ground mount.

Your combined Solar panel string VOC should be 80% or less than your max SCC VOC of 250v. Depending on your available space from roof or ground mount, you may be bettter off with strings of 4 or strings of 5. Again, there is no mention of this info which will drive the decision to which panels.

Shade if any kind means you want to parallel some strings to minimize loss from shade. No shade or open fields means you don’t have to worry about how your strings are setup since they will get full sun at the same time.


They have an Excel and website for plugging in your solar panels and selecting a SCC model. Just google Victron SCC calculator or something close to that.

The 250/100 is the sweet spot in terms of cost since the 450/100 is a bit outrageous for having the same charging capacity but only allows for higher VOC.


More comments. Victron uses a modular design for products in the USA. The inverter is separate and independent from the SCC. Also, Victron is designed for marine where grid or generator is treated as a luxury and is used as primary when available. That’s why you can set max draw for your grid or generator, and the independent SCC and battery will provide the remaining power as needed.
Yeah I have the 250/100 assuming I would upgrade soon.

4- 310w panels + 10- 370w bi-facials (to 450w), 16-EVE 280ah cells i48v, Victron 250/100, I Victron multiplus 3k 48v inverter charger, midnight breaker box, midnite combiner box, Victron smart shunt, Victron Cerbo
 
I accidentally started up everything once on a 2800w/12v Magnum. I calculated it was about 10k Watts. It grunted but started it non the less. I run it pretty hard and it starts freezers and the fridge all the time while it's already ready running near full load. Probably will shorten it's life over time.

I mention this cause I am also building my next system and am going 48v with Victron gear. You should consider a 5K inverter if you think you would be pushing the 3k hard. I have not run the 3k or 5k Victron yet, but I believe they have a stricter over load protection. They make a 5K multiplus II thats a bit cheaper then the quattro. A 3K Victron will likely shut down sooner under over load then your Samlex 1200w.

Maybe someone else can share their experience with Victron's overload/surge ability vs other "LF" transformer inverters.
Just cannot afford the 5k inverter. Got a vaccine that crippled me and now I live on disability checks that last 3 days for the whole month.
 
Just cannot afford the 5k inverter. Got a vaccine that crippled me and now I live on disability checks that last 3 days for the whole month.
Yea, it seems to be about $500-$600 more. You would likely be fine since you have been on the 1.2k Samlex. Your system design will make it easy to add gear later and you could just add another 3k down the road.
 
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