Things are in place, now what?

[ulnar_landing]

Hi all,
second post here. I've finally gone ahead and ordered my first system and mostly gotten things mounted up and some things plugged in. I have some remaining questions before I really get the show on the road. I'll give as concise a picture I can of what things look like first.

I have a system that is going to be totally off grid and it will power my tiny house on wheels. The tiny house is not yet on the property, but will be essentially as soon as I have power (I'm living in it somewhere else for the time being). The equipment for solar is in an insulated shed that is next to my tiny house. I plan to run a small space heater in the winter to keep the equipment happy. The tiny house has a 50amp inlet on the outside of it. It is a NEMA SS2-50R generator inlet, if that's helpful. I'll try to get the tiny house as close to the shed as I can so I can keep the wiring short. I don't mind burying or whatever. The tiny house is already fully wired up and is split phase. It has its own breaker panel, etc. pics can be provided if necessary

Equipment:
EG4 6000xp
EG4 280ah 48v wall mount battery
Hyperion by Runergy 400w panels. 2 strings of 9 panels. One on each mppt


My first question is regarding output. I want to have a couple regular plugs inside the shed so I can plug in a space heater and then I'll need something going out to the tiny house's 50amp inlet. The outlet boxes that will was showing in his recent beginner videos seemed like an ideal solution and I'd buy one if it was in stock, but it isn't. I tried to buy something similar, but I didn't realize that what was special about what Will was showing was the wiring. The box I got is basically a couple of breakers that are connected directly to a few outlets, so there is no way to use all of them at the same time. What is my best solution here? I'm wondering if I could rewire the box that I got or if my best bet is to get a small breaker panel and basically just have a 50amp breaker going out to the tiny house and a 20amp that I can connect a regular household 3 prong outlet to, so I can plug in a space heater or whatever. If the latter is the best option, are there any good resources on learning how to do this?

My second question is regarding grounding:
I'm not sure if the fact that I'm asking this means that I should call an electrician to help, but I do want to learn whatever is acceptably diy-able and then call the expert if I have to. You can already probably see the gaps in where my pre-existing electrical knowledge are, but I'm on here because I'm comfortable learning new things and fixing my many mistakes (hopefully before I actually press the on button). I'm a careful person, but I want to actually see this through to the end, so long as I can do so safely.

Anyway, I'm not sure what I should be doing to ground things. I talked to signature solar and they recommended getting a grounding rod and connecting a grounding wire so that the frame of each panel is connected. I know in the build your own system guide (which is the main thing I've been basing my system off of), Will says not to earth ground your system if you aren't qualified. What should I be going off of here? What is safe and what is not?

They said there was no specific reason to ground the battery or any other equipment, but knowing what little bit I do know about electricity, I wonder if I should as people do sometimes hang out where the equipment will be and I'm afraid of someone touching the battery if it isn't properly grounded. If you all think that is necessary, what's the best way to do it?

Thank you in advance for any input you can provide and thank you for even reading this. I've tried to be concise, but sometimes it's hard.

 

[dustyPanels]

I don't have any experience with the equipment you've selected. But going by the ratings of your gear, it looks like you've put some thought into its selection. (I learn about equipment reading the ratings of what people have selected.)

The EG4-6000XP has a maximum PV input voltage of 480 volts and 17 amps per each MPPT circuit. With a recommended voltage range of 120-385v for MPPT operation.

A 9 series string of your panels should produce about 335 volts, giving you a large margin for avoiding overvoltage in winter weather. It also falls well within the desired voltage range for MPPT operation. Your panels should produce up to 13 or 14 amps, which again is well within the operating specs of your MPPT circuits.

Being designed by the same company, your battery and the EG4-6000XP are well matched.
The battery can handle a continous 140 amps charging and discharging. The 6000XP can handle the 140amp discharge and can charge at 110 amps via AC power or 125amps via the PV panels.

No doubt you already know this from reading the ratings yourself. I'm actually impressed that the 6000XP and the battery match so well.

initial hookup

I don't know about EG4 equipment, but some members initially use a wire with a resistor to connect the battery to the AIO inverter system. This is to prevent a sometimes damaging surge than can occur. I forget what they call it ... a precharge or bleed wire?

circuit breaker panels

Some inverters will not function until the neutral and ground are joined together. I don't know if that is true for the EG4 equipment. The electricians in the forum say that should be done in the first breaker box outside the inverter.

I fed my output into a 125amp breaker box. I wish I'd gotten a 200amp box just to have space for more breakers for more shed circuits. But if you just want one circuit in the shed and the rest to the tiny home you might use something smaller than 200amps.

I was new to split phase wiring. So I disassembled my breaker box just to be certain how it was wired. After seeing the conductors under the breakers, I understood how to get two phase power to a sub panel. In my case I installed a two pole 30amp breaker to export four wire power to a sub panel.

It seems like you'll be installing a two pole 50amp breaker and then run four wires to the 50 amp socket on your tiny home? Plus a single pole 20amp breaker for a circuit in the shed.

grounding

Will and the others know much more about grounding than I do. Hopefully they'll share a comment.

I assume your tiny home has a breaker box? Did you put a grounding rod on it?

The main take away on grounding seems to be just having one grounding rod. That way, a nearby lightning strike causing a voltage differential in the earth won't cause a sudden surge in the wiring between two grounds. I haven't read it, but it seems the NEC has a bit of a grey area about grounds.

So, you get to figure out if it is better to have the ground on the larger structure or on the breaker box in the power shed where all your power comes from. I'd vote for the latter, but hopefully experts will add their opinion.

I'd go ahead and ground the PV module frames to the array rack. But I wouldn't install a grounding rod there. I did not run a ground wire between my array and the power shed. Although the MC4 connectors probably include a ground sheath, so perhaps I did.

Hopefully the PV panels are not on the tiny home roof. Putting panels over a residence opens up more restrictions and requirements.

I hope some of this is helpful.

 

[ulnar_landing]

I don't have any experience with the equipment you've selected. But going by the ratings of your gear, it looks like you've put some thought into its selection. (I learn about equipment reading the ratings of what people have selected.)

The EG4-6000XP has a maximum PV input voltage of 480 volts and 17 amps per each MPPT circuit. With a recommended voltage range of 120-385v for MPPT operation.

A 9 series string of your panels should produce about 335 volts, giving you a large margin for avoiding overvoltage in winter weather. It also falls well within the desired voltage range for MPPT operation. Your panels should produce up to 13 or 14 amps, which again is well within the operating specs of your MPPT circuits.

Being designed by the same company, your battery and the EG4-6000XP are well matched.
The battery can handle a continous 140 amps charging and discharging. The 6000XP can handle the 140amp discharge and can charge at 110 amps via AC power or 125amps via the PV panels.

No doubt you already know this from reading the ratings yourself. I'm actually impressed that the 6000XP and the battery match so well.

initial hookup

I don't know about EG4 equipment, but some members initially use a wire with a resistor to connect the battery to the AIO inverter system. This is to prevent a sometimes damaging surge than can occur. I forget what they call it ... a precharge or bleed wire?

circuit breaker panels

Some inverters will not function until the neutral and ground are joined together. I don't know if that is true for the EG4 equipment. The electricians in the forum say that should be done in the first breaker box outside the inverter.

I fed my output into a 125amp breaker box. I wish I'd gotten a 200amp box just to have space for more breakers for more shed circuits. But if you just want one circuit in the shed and the rest to the tiny home you might use something smaller than 200amps.

I was new to split phase wiring. So I disassembled my breaker box just to be certain how it was wired. After seeing the conductors under the breakers, I understood how to get two phase power to a sub panel. In my case I installed a two pole 30amp breaker to export four wire power to a sub panel.

It seems like you'll be installing a two pole 50amp breaker and then run four wires to the 50 amp socket on your tiny home? Plus a single pole 20amp breaker for a circuit in the shed.

grounding

Will and the others know much more about grounding than I do. Hopefully they'll share a comment.

I assume your tiny home has a breaker box? Did you put a grounding rod on it?

The main take away on grounding seems to be just having one grounding rod. That way, a nearby lightning strike causing a voltage differential in the earth won't cause a sudden surge in the wiring between two grounds. I haven't read it, but it seems the NEC has a bit of a grey area about grounds.

So, you get to figure out if it is better to have the ground on the larger structure or on the breaker box in the power shed where all your power comes from. I'd vote for the latter, but hopefully experts will add their opinion.

I'd go ahead and ground the PV module frames to the array rack. But I wouldn't install a grounding rod there. I did not run a ground wire between my array and the power shed. Although the MC4 connectors probably include a ground sheath, so perhaps I did.

Hopefully the PV panels are not on the tiny home roof. Putting panels over a residence opens up more restrictions and requirements.

I hope some of this is helpful.

I haven't necessarily read a lot of reviews, but I've watched videos and read forum/reddit posts. I did spend a long time deciding what I wanted. I went with this setup because it seemed kind of hard to mess it up given that it's one battery to one inverter and they are from the same manufacturer, both sold by reputable stores in the US that have good customer service. I also was careful about making sure the voltage lined up as well. I'm in the northeast, so I decided to go fairly aggressively with the number of panels to make up for low peak solar hours in the winter.

I'll have to look into that transistor you mention. I didn't see mention of that in the manual. Maybe it is not a thing with this equipment? It seemed like battery to inverter connection was incredibly straight forward

The neutral ground bond is mentioned in the manual, and I'm glad you bring it up because it was something I'm unclear on. The inverter has the ability to create its own ground neutral bond via the settings, but the Signature Solar customer support recommended against using this feature, but didn't really have a specific reason why, just that it was better to create it after the inverter.

As far as the breaker box goes, I don't think I need more than maybe a circuit in the shed. I would maybe want to put a chest freezer in there eventually, but that's about it beyond the necessary heater. Forgive my lack of knowledge on this sort of thing, but would I'm guessing you buy the actual box, then a breaker that would work as the main, or is that included when you buy a panel? Then you would just need breakers for whatever circuits you want. In this case a 50 that would go out to a cable to the tiny house's inlet (directly?) and a 20amp that could just be connected to regular old electrical outlet.

for grounding:
the tiny house does not have a grounding rod attached to it. I actually bought it second hand and I think it was connected to its previous location in a similar way to how we have it now. Extension cord coming from a regular house that was grid tied. I had a handy friend help do this connection for us at this location, but in retrospect I could/should have done the work with them so I'd pick a few things up. I'm pretty sure it's just connected directly to a 50amp breaker at the main house and there is an emergency shut off switch on a pedestal that they installed as well. I'm guessing the reason for lack of grounding on the tiny house would be similar to what you described. If attached to a house that is already grounded, it could create a grounding loop?

Right now, the solar panels are ground mounted. Actually, they are literally just on the ground right now until we come up with a good racking solution. Ideally, I'd just grab the integraracks but they are pretty expensive. My partner wanted to maybe build some sort of rack, so I'm not sure if that makes grounding different When you say ground the frame to the rack, you're basically saying just connect the metal frame to the metal rack with a wire, since the frame sits in the ground, right? Does that change if the rack is all or part wood?

And yeah, I don't think I could even fit more than a few panels on the roof, all ground mounted. I'm trying to make this as diy and simple as possible. Plus there doesn't seem to be much reason to mount on the roof if you have the space, and fortunately I have a lot of space.


You're definitely making some of this clearer and raising more questions where they should be, thank you.

 

[ScrodusGargleRotten]

I'll have to look into that transistor you mention. I didn't see mention of that in the manual. Maybe it is not a thing with this equipment? It seemed like battery to inverter connection was incredibly straight forward

Its a pre charge resistor. Every system should have one.

 

[ulnar_landing]

Its a pre charge resistor. Every system should have one.

Still searching around this one, but it seems like my battery has one built in? I see one thread on here where someone said you don't need one and to follow the instructions and another thread about the allweather version of the battery and there's a video that says it has one built in. So while what you said is true, I don't need to add one because I have one, right?

 

[ScrodusGargleRotten]

Still searching around this one, but it seems like my battery has one built in? I see one thread on here where someone said you don't need one and to follow the instructions and another thread about the allweather version of the battery and there's a video that says it has one built in. So while what you said is true, I don't need to add one because I have one, right?

Perhaps? I have read some eg4 batteries have a "soft start" and if you dont follow the instructions, it doesnt happen.
And some do not.

Its up to you to know.

 

[ulnar_landing]

Perhaps? I have read some eg4 batteries have a "soft start" and if you dont follow the instructions, it doesnt happen.
And some do not.

Its up to you to know.

ok, well I will plan to just follow the instructions as written when I go to actually turn it on and if things aren't working right, the pre-charge transistor will now be on my radar. Thank you for putting a name to it as well.

 

[ScrodusGargleRotten]

ok, well I will plan to just follow the instructions as written when I go to actually turn it on and if things aren't working right, the pre-charge transistor will now be on my radar. Thank you for putting a name to it as well.

What will happen, if you dont, is your batteries will start complaining when you start the inverter. The inverter breaker might pop.
You could ruin the input caps of the inverter
You could ruin the discharge transistors on the battery BMS

Small chance for sure but, it has happened

 

[Kid Solar]

I'll have to look into that transistor you mention. I didn't see mention of that in the manual. Maybe it is not a thing with this equipment? It seemed like battery to inverter connection was incredibly straight forward

Yeah no need.

Your battery BMS has a built-in pre charge resistor.

Plug n Play!

My battery has this too, super convenient.

 

[Daddy Tanuki]

Its a pre charge resistor. Every system should have one.

that or be ready to replace a lot of gear... mine is manual... push button wait for lights to flicker on the remote, and then "as picard says" Engage!

 

[dustyPanels]

Note: I'm a rookie at split phase wiring. I learned split phase about six months ago. Although I've serviced simple AC and DC circuits for more than 20 years.

Most circuit breaker panels will include a two pole main breaker to protect the breaker box from accepting more current than they are designed to handle.

You'll have to add the two pole 50 amp breaker to supply the tiny home. It may be a little redundant, as the tiny home's panel should have a pair of 50 amp breakers too. But trying to get 50amps out of the breaker box in the shed without using a two pole breaker would be making things more difficult than they need to be.

You'll also have to add a 20amp breaker to provide outlets in the shed. I used both legs of the inverter's output for two individual sets of outlets in the shed. I think I used two individual 15 amp breakers.

If you study how a breaker box is built, you will find that each leg of split phase power feed alternate slots in the breaker box. Two single pole breakers installed side by side will be getting power from different legs. That is also how a double pole breaker picks up power from both legs. As I said before, breaker boxes were a mystery to me until I disassembled one and examined the conductors built into it. Then all the material I'd been reading about split phase power made sense.

You will also learn -- if you don't already know -- that there are two or three manufacturers that make breakers that will only fit in their style of breaker box. If your tiny home has standard breakers in its box, you might pick the same style of breaker box and breakers for the power shed. Then if you have a spare breaker, it might work in either location.

 

[ulnar_landing]

For anyone in the future looking at this post, it appears the battery does have a precharge resistor built in

8:00 in the above video

EDIT: the video is for the outdoor version, but i *suspect* the indoor should have one.

 

[Quattrohead]

Feels like not enough inverter or battery, consider a 12,000 XP and two batteries. PV seems adequate though. What is the location ?

 

[dustyPanels]

Feels like not enough inverter or battery, consider a 12,000 XP and two batteries. PV seems adequate though. What is the location ?

That's a good point. I have 300ah on my small system and feel more would be helpful.

 

[ulnar_landing]

Feels like not enough inverter or battery, consider a 12,000 XP and two batteries. PV seems adequate though. What is the location ?

my load is fairly low. I have a good amount of propane stuff going on. I'll be in Maine, but not too far north.
My daily load right now is around 10kw-14kw. I have not reached beyond a 2KW peak, so I assumed the 2 3000w legs on the 6000xp would suffice. The amount of PV is mostly to make up for the severe dip of peak solar in the winter. I also bought a chargeverter so I could have a wider variety of generators I could use.

I have an electric heat pump as well as a propane heater, so I plan on using a combination of the two if necessary. My hot water is heated by a propane on demand hot water heater. Cooking is also propane. I don't mind being not 100% solar yet while I figure things out. I figure if I need to I can add a battery or a second 6000xp down the line, but I also don't mind changing my usage a little. Right now my biggest draws are the heat pump and my fridge which is one of those propane fridges, but I've plugged it in. I plan on switching it for something more efficient since it's not really designed to run on electricity full time which is what I'm doing. It's a 200sq foot space, so there also just isn't a ton of opportunity to use a ton of power anyway. especially not all at once.

 

[Quattrohead]

Sounds like you have it covered then.