Is there a place that lists all of the inverters and charge controllers specs

[Sleepingbeautyc]

I have been trying to add a battery back up to my system and the thing i keep running into is that I can't find inverters and charge controllers that have specs that work. Does anyone know of a list that tracks all inverters and or charge controllers.

This site and a few blogs have given me leads. The solark and morningstar have promising products.

This is the spiel that i send to multiple manufacturers or solar suppliers

We have a grid tied system that was installed for us. We had not realized upon purchase that the system is useless when the power goes out. We live in the country and the power is not always reliable. We would like to add something to our system to make it hybrid. We understand there are a number of ways to do this. We are open to all but prefer the charge controller option.

1. We could replace the main inverter. (hybrid inverter replacement)

2. We could add a second inverter and a manual switch. (ac-coupled)

3. We could add a charge controller to the battery (dc-coupled)

We have been trying to find a viable option.

Our set up.

We have a 10.3kwh system. It is configured with 2 lines of 13 panels in series. The panels are the longi lr4-72hph. The grid tied inverter is the solaredge 10000h-us. There is a fireman's hard shutdown after the inverver but before out main panel. We have a renogy lycan 5000 battery that we would like to use.

 

[sunshine_eggo]

Answer to subject: No.

Welcome to the typical disappointment of your average homeowner with a GT system.

The Lycan appears to be nothing more than a "solar generator" like a Bluetti. The only way you could use it is if you divert some of your existing PV panels and wire directly to the unit. It can't interface with your existing system, and it is a very expensive, low performing option.

You need a 10kW inverter capable of AC Coupling or Frequency Shifting.

AC Coupling

AC Coupled Solar Power System - use your existing system to feed power into a battery based inverter/charger to charge the battery bank.

www.altestore.com

Your best solutions are expensive Tier-1 inverters, and you're going to need a LOT of batteries. A whole-house solution should be comparable in price to your original system. Most settle on a smaller system with a critical loads panel per that article.

 

[Sleepingbeautyc]

Our needs are small. We bought the big system for sale back to the grid. We are not looking to run our whole home on the batteries. We are looking to run a small subpanel during daylight hours and the battery to keep the freezer running. Does that change the battery issue?

Why do you only mention an inverter?

We are particularly interested in a charge controller with a manual switch to be switched when the power goes out.

 

[sunshine_eggo]

Our needs are small. We bought the big system for sale back to the grid. We are not looking to run our whole home on the batteries. We are looking to run a small subpanel during daylight hours and the battery to keep the freezer running. Does that change the battery issue?

That would be the scenario where you repurpose a small quantity of your PV and tie into the Renogy for power.

Why do you only mention an inverter?

Because that's all that's needed to interface with the GT inverter. Of course, the new inverter will require batteries as I indicated by:

Your best solutions are expensive Tier-1 inverters, and you're going to need a LOT of batteries. A whole-house solution should be comparable in price to your original system. Most settle on a smaller system with a critical loads panel per that article.

The AC coupled inverter is intelligent enough to use the output of the existing GT array to charge the batteries, so you don't need a new charge controller.

We are particularly interested in a charge controller with a manual switch to be switched when the power goes out.

You already have a charge controller in the Renogy, no?

Sounds like you're gravitating to:

The Lycan appears to be nothing more than a "solar generator" like a Bluetti. The only way you could use it is if you divert some of your existing PV panels and wire directly to the unit. It can't interface with your existing system, and it is a very expensive, low performing option.

 

[Sleepingbeautyc]

Maybe I'm confused but we prefer a dc coupled system.

Like this page talks about. https://www.altestore.com/blog/2015/12/dc-coupling-new-way-to-add-backup-power-grid-tie-solar/

It seems perfect for our situation. Cheaper and the only downside i see is a manual switch that needs to be flipped when the power goes down.

Of course the morningstar has a built in switch.

 

[zanydroid]

How do you plan to wire in your existing solar panels?

A SolarEdge system is not the easiest to tie into. There is zero way to switch a string between solar edge and non solar edge charge controller due to the solaredge optimizers under each panel. Those only work with SolarEdge systems. You would need to remove the optimizers to work with a non solaredge system. But then the panels after removal can no longer work with SE. OOPSIE.

That is probably why AC coupling was suggested first.

Even if you had a non SolarEdge system you would need to implement a DC switch to transfer a string between existing inverter and off grid inverter. You would likely need to reconfigure your strings to match the MPPT input capabilities of the off grid system. Unfortunately I don't think there is a good table summarizing the capabilities, probably most of the power users here have a mental model of what different classes are and which vendors have what. It would be great if somebody wrote an article taxonomizing it.

I don't feel like you have yet written down a fully fleshed out line diagram with the equipment you'd like to use (FWIW Renogy doesn't have the best reputation on the forum)

Does that Renogy support using an external MPPT or battery charger?

 

[zanydroid]

(typo in your original post -- 10kwh instead of 10kw, adds a bit of emotional labor and math labor for reader to clean it up)

The reason earlier post said that you need a big battery is that an AC coupled system must have a charging capacity bigger than the system that it needs to absorb power from. Happy to get into it if you want to understand the technical details but I'll skip for now. So for every kW-AC of solar you need a kWh of battery and a kW-AC of charger capacity.

DC coupling is superior in part from not having this restriction however as said above it's not viable with SolarEdge without a lot of labor cost to remove optimizers.

You may not need the optimizers. How many roof planes do you have panels on? What is the smallest number of panels per plane? How much shading from trees/building structure? Easier to just share a photo, we can tell you mediately from a picture.

How important is permitting? DC coupled is likely worse because you would contractually/legally need to update your interconnection agreement with power company to continue to be able to sell the power from the non SolarEdge portion of the system. AC coupled has more options to fly under the radar.

 

[zanydroid]

Couple other notes. The SolArk has AC coupling but it seems like there are mixed results in using it without also some DC strings in there.

Your linked article actually talks about the points I mentioned above. Note my second quote from the article actually highlights the folly of using an article this old. The numbers presume using lead-acid when much of the world has moved to LFP. LFP can charge much faster per Ah than lead acid can. Also this article predates some important code changes, namely rapid shutdown and energy storage system (RSD, ESS) being tightened up and expensived up a lot.

I don't think old articles are good to read as a beginner because you have neither the technical knowledge nor domain specific critical reading skills to edit out the outdated info.

CHOOSING THE RIGHT COUPLING SYSTEM FOR YOUR SOLAR SYSTEM
AC Coupling is still your best solution for use with microinverters and DC optimizer/string inverters like the SolarEdge system, as they don’t have 600V DC strings coming to the centralized inverter.

With AC Coupling, if you have a 6,000W inverter backfeeding through an inverter/charger, you need to have an inverter/charger that is at least 7,500W, and a 48V battery bank that is around 1200Ah to keep the charge rate at under C-10 to maintain a healthy battery bank.

 

[Sleepingbeautyc]

You are so right but there just isn't a lot of information out there. And sifting true from false is impossible. I am trying to figure this out and failing miserably. I am a fricken engineer and every time i try and figure something out it turns out that the specs i was given failed to mention a complication. No where in my specs for my system did it mention optimizers.

Okay, rant over. Now from what you say, this is what i understood. Did i understand what you said correctly?

• Can't do a dc coupled system with solaredge because of the optimizers
• Can do a second inverter to add batteries
• We have a sucky battery
• Might be able to remove optimizers. Roof diagram is below. But then we would need to get hydro one's okay (our power company)
• We have a 10.3kwh system so that would mean in order to have any batteries we would have to have a tonne of batteries and a massive inverter.
• So there is no way to use the power that we are generating in a grid down situation without doubling the cost of our system? I don't even need there to be a battery system. I just want to be able to use the power during the day. Insert expletives here. I am so angry at my sales guy. He lied his ass off.

Is this sufficient?

 

[zanydroid]

I am a fricken engineer and every time i try and figure something out it turns out that the specs i was given failed to mention a complication. No where in my specs for my system did it mention optimizers.

It took me 3-6 months of actively posting on the forum to pick it up. I’m mainly a software and distributed systems engineer, but doing solar has helped a lot with my lackluster electrical engineering.

Thanks for the diagram, it will help. Was it accurately entered by the installer? The smallest array there is 4 panels, which yields a high enough series voltage for the lower voltage types of non optimizer string SCC and can also be used with 4 port microinverters.

Your battery is a inverter + battery combination. I don’t believe Renogy would be approved for permanent grid tie install due to lack of certifications, and it also has a bad reputation lately on the forum. Grid tie lets you offset some % of the cost by selling power back to the grid at peak. In some markets that is. If you have cheap power then this isn’t worth it. It’s not profitable here in California but it does maybe knock off 30% of the system cost to play this game.

You don’t need a ton of batteries. It is two server rack batteries (10kWh) or one wall battery (15kWh). 3 KWh is what I call a small battery and the minimum eligible for US tax credit. 10kWh is probably the minimum to be able to run all loads off grid anyway.

The other way SolarEdge users have gone is splitting their system to smaller chunks. If you got a second SE inverter and put 5kW on it, then you can connect just that part to your AC coupled system, and downsize to a 5kWh battery. SE inverters probably aren’t that expensive to buy used. It’s not that difficult to reconfigure the strings provided the individual strings are pulled down separately.

Another option people have tossed around is programming the inverter to switch to a lower output power limit when off grid. This programming isn’t rocket science by any means but it’s probably easier to get a reliable/maintainable system via physically splitting the solar output to allow a smaller battery. Because no software would need to be written & controller maintained, you would instead just use the native functionality of the hardware in a boring but straightforward way.

Other things to keep in mind with AC coupling:

• it is essential to check around to verify that the inverters are proven to be compatible with each other (anti islanding on the grid tie inverter is sometimes overzealous, and the grid forming inverter may not be stable). Unfortunately the knowledge about compatible combos is kind of a mess on this forum, ideally there would be a neat matrix summarizing the hardware being used and how much DC, AC, and battery are provisioned.
• AC coupling requires better hardware and engineering so is limited to the higher end hybrids right now
• AC coupling as used in marketing material is fecking obnoxious. For instance Anker’s new battery claims to have AC coupling but it only works on grid. It cannot grid form and turn on the grid tie inverter, it just isolated them when grid goes down. Hahahahhahahaha
• Actually even the term Hybrid is unregulated. It’s supposed to mean AIO with grid tie capability. But not all manufacturers use that term. Some people on the forum also assume a Hybrid should be able to AC couple but that does not make sense to me given the additional hardware and programming needed

So your other option to avoid the cost and complexity of AC coupling would be to take optimizers off part of the roof and wire those panels to an AIO. Since the panels are already lifted up, it’s not THAT dangerous or difficult to DIY. I have about 20 hours in mounting panels from doing my first self install this summer (no roof work experience prior to that and only recently getting over a fear of heights) and I can solo a lot of the maintenance including lifting panels to swap electronics and wiring. But it is a steep learning curve for the first one especially for some shapes of array/steepness and height of roof.

Unfortunately battery less backup power is challenging to engineer from a fundamental level and when code compliance is tossed in. With the latest code you need power to tell the rapid shutdown devices to turn on. Easiest way is to have a battery.

There are cheap AIO that are marketed to turn on in batteryless mode and I believe confirmed to do so by folks on the forum. Not sure how many if any have certifications.

Yeah solar salespeople are annoying.

 

[zanydroid]

The other options to price out are staying within SE ecosystem. EG add battery only if you have a hybrid SE inverter. Or swap to a hybrid SE inverter with a battery.

Another one is big battery only system with no solar panels and hope your outages are all short enough. Can extend the endurance with a generator. For instance one of the concepts I’ve considered for myself is a 5kWh battery topped off by my 3kW generator. The generator runs pretty efficiently when run at a constant high ish output, and I am happy to babysit a portable, non weather resistant generator for an hour.