diy solar

diy solar

hybrid solar inverter

joshua berhe

New Member
Joined
Mar 7, 2023
Messages
4
Location
mineapolis
What does it mean Starting voltage >130V?
If I will have 4 200W 12v solar panels, and 12v 200AH Deep Cycle Hybrid Gel batteries, what size Hybrid inverter do I need?


Thank you
 
Starting voltage is the minimum voltage necessary from your PV array necessary to activate the inverter.
If your panels are 20V, you'd need at least 7 of them in a string (in series).

Inverters are sized by capacity. 200 Watts * 4 = 800 watts input. You'd need a 1KW inverter on the bottom end.

It also depends on what you're going to power. Max continuous discharge of your 200AH battery is probably going to be 100A, so 100A * 12V = 1200 watt draw... For that, you need a 1.2 KW (or better) inverter. I'd say 1.5KW minimum.
 
Thank you for your advise. So If I have four panels which are 12v 200 wats, it means I have two add 11 of thm, which is cost prohibitve. Can you suggest a hybrid inverter that will work with only 4 or 5 12v 200wat panels.
 
Thank you for your advise. So If I have four panels which are 12v 200 wats, it means I have two add 11 of thm, which is cost prohibitve. Can you suggest a hybrid inverter that will work with only 4 or 5 12v 200wat panels.

What are you trying to do? IE- what are you trying to power on the AC side of the inverter?

Look in the RV space, you'll find a lot of "solar charge controllers" that do stuff like this with lower numbers of panels. You may end up with a separate solar charger and then an inverter.

You can also buy panels in the 20-24V range, which would help you get to the input voltage you're looking for.
 
Thank you for your advise. So If I have four panels which are 12v 200 wats, it means I have two add 11 of thm, which is cost prohibitve. Can you suggest a hybrid inverter that will work with only 4 or 5 12v 200wat panels.
I think there are some terminology issues here. A "hybrid" inverter is one that can both connect to the grid, and act as a grid-tie, but also act as a stand-alone inverter in an off-grid application. My Schneider XW+6848 is a hybrid, but the solar input is completely separate, managed by the solar charge controller, which might be successfully feed with a 72V feed.

I believe what you are talking about is instead an "all in one" inverter, or AiO. The unit has a built-in charge controller, inverter, and transfer switch all in one box. Many have differing voltage limits, both low and high. Some Growatts for example has a lower V limit of only 90V, and some have high limits up in the 450V range. Multiple choices here.

Instead of sticking with 12V (nominal) panels, which output in the 18-20V range, go with larger, high-voltage residential "grid-tie" type panels that operate in the 30-40V range. So, just four in series would be able to supply the startup voltage necessary. Shop on Craigslist with cash and carry purchases instead of ordering online. If you don't pay the shipping, you get far more W/$. Right now today, I see 30V 240W grid-ties in my area for 68$. Maybe if you demand only the latest technology panels, you might still get them for 2W/$.

Keep asking questions, but DON'T start buying stuff until you have a complete plan. Start with asking what you want to power, and how many watts it will need, far before asking what components to buy.
 
Thank you

Will run a fridge about 6-8 hours/day, 6 LED bulb for about 5-6 hours and LED TV for about 5 hours. that said, I want the hybrid inverter to connect to 240v AC main utility to charge the batteries, and also when main is off to use the solar panels. Out put needs to be 240 V,
 
Yes, you are right, I am new to this staff, and my terminology is not there. but I hope to learn as I go and get better at it.
 
Thank you

Will run a fridge about 6-8 hours/day, 6 LED bulb for about 5-6 hours and LED TV for about 5 hours. that said, I want the hybrid inverter to connect to 240v AC main utility to charge the batteries, and also when main is off to use the solar panels. Out put needs to be 240 V,
There are no inexpensive solutions that are going to do this. The EG-4 inverters are probably entry level (I have not checked minimum PV input voltage) - they're around $1500 or so.

You cannot connect the output of the inverter back to your grid tied main panel if that's what you're thinking about doing.
 
Will run a fridge about 6-8 hours/day, 6 LED bulb for about 5-6 hours and LED TV for about 5 hours. that said, I want the hybrid inverter to connect to 240v AC main utility to charge the batteries, and also when main is off to use the solar panels. Out put needs to be 240 V,
OK, is this for emergency backup when blackouts occur? Why running a frig for only 6-8 hours/day? Why not 24/7? Is that the typical lengths of blackouts for you? When you say you need 240V output is that only 240V, or do you really mean standard North American split-phase 120V/240V AC?

If you want split-phase, that is pretty much standard, with L1, N, & L2 output. L1 to N is 120V, L2 to N is 120V, but L1 to L2 is 240V. I have two inverters that do that, my 48V cabin Schneider XW+6848 (6.8kW), and my 24V Conext SW4024 (4.0kW). Both allow generator or grid charging at 240V, though I'm totally off-grid, so my ACin is connected to a 240V generator (again, split-phase 120/240V).

The Outback Radian series is another example of high-quality, tier-1 products that require a separate charge controller.

You really need to start out with a power audit, determining what you need to power and how long, which will decide for you the sizes of each component you need, the battery bank, the inverter, the solar input. So, start with the itemized list of what you need to keep running over a 24 hour period. Once you come up with the numbers, then we move on to the design stage.
 
I think the cheap way to do this (with a relatively small number of panels) is using an RV type charge controller from PV. You suppliment with (perhaps) a direct charge converter. With your number of batteries, I doubt you need 240V. But all of this, it's "totally typical RV use" - you're just putting it in a home.

I'd just a standard DC to AC to inverter to power what you want out of the batteries.

You'll almost certainly spend more trying to wrap it in a relatively small hybrid inverter. I think signature solar offers a 3K inverter (like the EG-4) that might be "close enough" if you have enough panel.
 
Blurb time!

Well, I'll start the default answer to these questions and we can work from there. Here's you To-Do list:

1: Power audit! This will give you some important information on how big your inverter needs to be as well as how much battery capacity you'll need. There is a link in the FAQ section (I think, or someone here will post it shortly) so fill in the blanks and see what it comes up with. You'll probably need some sort of Kill-A-Watt to get accurate measurements. Are you going to be running a 12v system? 24v system? 48v system? What are the specs on your solar panels? VoC? Vmp? Being as this is a new build, throw together a wish list of what you want and estimate on the high side.

1a: Where do you live? Speccing out a system for Scotland is a LOT different numbers than Arizona due to the amount of light you actually get. Someone here can post the link to the PVwatts.com or JCR Solar Uber-Sun-Hours calculator sites to help figure out how much you'll have to work with. That will be a box in the Power Audit form.

2: Parts list: You don't need a make & model list, just a parts list to start from for reference. You'll need an inverter, a MPPT charge controller, fuses, shunt, buck converter, batteries, wire, etc. Once you have a basic list it can be fine tuned to make & models after that. If you're looking at the All-In-Ones check for correct voltage outputs (120v or 240v Split Phase for North America, 220v Single Phase for European type areas) and make sure it has enough capacity for a little bit of growth and fudge factor.

3: Budget!: Steak is great but doesn't mean anything if your wallet says hamburger. :) Figure out what you're able to spend now vs what you'll have to cheap out on now and upgrade later.

4: Tape measure! Figure out where you're going to stick all the stuff you'll need. A dozen 3000AH batteries sounds great until you're sleeping on the floor because there's no room left for a bed. Is there a compartment that can house all this stuff? Will the server rack batteries fit? Are you going to have to make space? Physics can be pretty unforgiving.

5: Pencil out what you think you need and throw it at us so we can tell you what you've missed (because we ALL miss stuff the first go-round :) ) and help figure out which parts and pieces you're going to want to get.

Well that's the thing about solar systems, there is no 1-Size-Fits-All answer. Your system will need to be designed to fit YOUR needs. When you design and built the system, it's not going to be the perfect system for me, or Will or 12vInstall or anyone else, but it Will be the right system for You and that's the goal.

As for where to get started, let me throw my standard blurb in here to help point you in the right direction. There's going to be a lot of math and research involved, but that's going to be a LOT cheaper than just buying parts off of someone's list and finding out that it doesn't do what you need.

Don't panic on the Power Audit, you'll actually be doing that a few times. When you do the first pass put in ALL the Things that you might want. AirCon? Sure. Jacuzzi? Why not. MargaritaMaster-9000? Go for it.

The second pass will be the "I Absolutely Need This To Survive" list that isn't going to have much on there.

The third pass will be the "This is what is realistic" audit that you'll use to design the rest of the system.

The Power Audit is going to tell you 3 primary things: 1: How big does your inverter need to be to power your loads? 2: How much battery bank do you need to last $N number of days with krappy weather? and 3: How much solar panel will I need to install to refill those batteries in a 4 hour day (the average usable sun hours rule-of-thumb).

Once you know what you Want and what you Need and what your budget can Afford there will be somewhere in that Venn diagram where those three things meet.

After that, THEN you can start looking at parts.

Yes, it's a long drawn out process, but it's worth it in the end. Not every house has the exact same floorplan, not every vehicle is the same make & model, and not every solar system is designed the same.
 
Back
Top