DIY Backup for Existing Enphase System

[Bear22]

Hi Guys,

Need some advice about the proper direction to take with adding a DIY battery source to an existing Enphase system (4000 watts of panels plus an IQ-10 battery). Would replacing the existing 8 circuit backup subpanel with one of these manual transfer switch sub panels (e.g., the Reliance Control Pro/Tran 2) allow me to incorporate a DIY battery (basically a backup system to the Enphase system)?

Thanks for the input!
G

 

[DIYrich]

Get a sol-ark 15k. Wire the enphase as AC PV into the Generator connection.

 

[Bear22]

Get a sol-ark 15k. Wire the enphase as AC PV into the Generator connection.

Huh? No.

 

[DIYrich]

What hardware do you propose for the battery system?

 

[Bear22]

What hardware do you propose for the battery system?

Looking for a simple answer. Does a manual transfer switch isolate one power source from another? Example: does switching to the GEN position lockout the LINE (grid) source of power? For some reason I can't find a simplified answer(s) for the fundamental operation of a manual transfer switch.

 

[DIYrich]

The manual transfer switch is designed to switch sources that are presumed to be isolated from each other. Whether you need one, or a simpler disconnect/isolation switch, depends upon your system design.

 

[400bird]

Do you already have the Enphase equipment that includes a internal transfer relays? Does your system already function when the grid goes down?

To make a grid-tie system function (micro inverters are grid tie) you need to provide an external 60hz signal that looks like the grid.
Enphase has a gateway or something that works with their batteries and micro inverters to separate from the grid and tells them to turn on and form a grid by themselves.

A transfer switch would work to separate you system from the grid, but it wouldn't do either option (provide a 60hz signal to sinc to or the Enphase proprietary signal to start outputting) to enable the system to work off grid.


Sorry, if you've got all that figured out already. Just trying to provide some base line to understand what you're looking to do. Adding a diy battery requires an inverter. You responded "no" when a SolArk inverter was suggested.

 

[400bird]

Looking for a simple answer. Does a manual transfer switch isolate one power source from another? Example: does switching to the GEN position lockout the LINE (grid) source of power? For some reason I can't find a simplified answer(s) for the fundamental operation of a manual transfer switch.

Yes. Only one input is connected to the output at a time.

 

[zanydroid]

Looking for a simple answer. Does a manual transfer switch isolate one power source from another? Example: does switching to the GEN position lockout the LINE (grid) source of power? For some reason I can't find a simplified answer(s) for the fundamental operation of a manual transfer switch.

Yes that's what a transfer switch does.

With AC coupling "simple" is pretty complicated. Can you share a line diagram of the system you have in mind? Preferably in both picturebook and prose form. Because I actually do not know of a simple way/cheap way to add batteries onto an Enphase system to extend off-grid autonomy.

And TBH there are some kneejerk reactions on the forum to people oversimplifying this and getting way off track. Pitfalls include randomly adding a battery inverter without thinking about how grid-forming or grid-following is going to work ; getting screwed b/c you can't easily open up a Enphase battery and bridging things in that way...

 

[ksmithaz1]

IMNSHO, if you are sticking with Enphase, then stick with Enphase and buy their sh*t. It will work, as designed, and you have one throat to choke if there is a problem. Otherwise if you really want to get DIY happy dump the micro-inverters and get a SolArk or EG4 and tie it to the grid with whatever batteries you feel like building or buying.

Converting to AC then back to DC to charge batteries is a big efficiency hit, the enphase battery system feel like a kludge to me, and trying to do it feeding AC to third party inverters, just seems dumb, you add a layer of cruft to the design.

 

[Bear22]

Yes. Only one input is connected to the output at a time.

Thanks!

 

[Bear22]

Yes that's what a transfer switch does.

With AC coupling "simple" is pretty complicated. Can you share a line diagram of the system you have in mind? Preferably in both picturebook and prose form. Because I actually do not know of a simple way/cheap way to add batteries onto an Enphase system to extend off-grid autonomy.

And TBH there are some kneejerk reactions on the forum to people oversimplifying this and getting way off track. Pitfalls include randomly adding a battery inverter without thinking about how grid-forming or grid-following is going to work ; getting screwed b/c you can't easily open up a Enphase battery and bridging things in that way...

I am not wanting to integrate another battery source into my existing Enphase system, but rather am wanting an autonomous means (e.g., gas generator and/or solar generator (either a portable DIY battery or perhaps a commercial product such as Bluetti or Ecoflow) to power these 8 circuits. Guess, I should have been more clear about the desire to have back up power source that's isolated/independent of my current Enphase system.

As far as Enphase goes, I think the achilles heal with their product are the certified installers/techs. Through my own experiences I find that these guys are unwilling to work on, maintain, or even add equipment to an existing system that they did not originally install themselves. If your original installer goes belly up (my case) then you are kind of SOL.

Thanks for the input!

 

[CRenner]

Doesn't the Controller have Generator input connections on it?

 

[400bird]

I am not wanting to integrate another battery source into my existing Enphase system, but rather am wanting an autonomous means (e.g., gas generator and/or solar generator (either a portable DIY battery or perhaps a commercial product such as Bluetti or Ecoflow) to power these 8 circuits. Guess, I should have been more clear about the desire to have back up power source that's isolated/independent of my current Enphase system.

A manual transfer switch isn't really autonomous. Mostly the opposite.

 

[zanydroid]

+1 for checking on gen port in the Enphase MID (microgrid interconnection device)

I think the achilles heal with their product are the certified installers/techs.

This is a general solar issue. If you have problems with Enphase, the easiest to install, Dane Cook lowest denominator skill of solar, imagine anything else….

 

[zanydroid]

Doesn't the Controller have Generator input connections on it?

Yup

https://enphase.com/download/iq-system-controller-2-quick-install-guide

I'll add my $0.02 about solar generators. Great for portable use. But a portable one is adding a low 5 of runtime to your 10kWh battery.

A larger 2.5 or 5 kWh battery adds more meaningful runtime. But, why not just invest that in a UL listed assembly that works better and has a better warranty. Moreover those are close to 50lb and 100lb respectively, which defeats the portable use case. Maybe the 2.5 or 5 kWh is good for a car camper

 

[solar8484]

Enphase only supports a limited selection of home standby generators for connection to the iQ System Controller generator port. No portable generator is supported AFAIK.

 

[zanydroid]

Enphase only supports a limited selection of home standby generators for connection to the iQ System Controller generator port. No portable generator is supported AFAIK.

What do they expect in terms of functionality / how do they enforce it?

(I haven't dug into the docs yet)

 

[solar8484]

Enphase requires automatic generator start and stop control. Also, a generator token (i.e. license) purchase is required.

 

[zanydroid]

Enphase requires automatic generator start and stop control. Also, a generator token (i.e. license) purchase is required.

Well start/stop implies a minimum bar for functionality, it’s probably possible to hack it.

Curious to see what the qualification is for a token and how much it is. Because getting past the paywall and hacking it might still be more cost effective.