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Noob Grounding Question - DIY Solar Generator

cosermann

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Oct 19, 2021
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Hopefully this is in the right spot. . .

I'm putting together a DIY small solar generator from components mounted in a milk crate that will include an A/C charger, A/C inverter, solar charger controller, and some DC circuits. The A/C charger will be used most often to top off the batteries as needed, and solar panels will be used in situations where/when no utility A/C is available.

It will be used as portable power, camping, and in situations when the utility power is out (for lighting, small appliances, etc.). No integration into my residence.

My question is about grounding. Since this isn't a permanently mounted system, is/how is grounding handled (ex. the grounding lug on the inverter)? Is everything just tied back to the neg side of the battery or what? I've read the Grounding Basics 4 resource (and a few other threads), but this won't be a vehicle mounted system, so not sure how it all applies or doesn't (i.e. no chassis to connect to).
 
If it was in a metal crate, it would ground to the crate.
Otherwise, only need to connect the equipment grounds in the crate together.
 
In an Inverter Installation Manual it instructs to tie the case lug to the battery negative away from the negative connection on the inverter. That would be the negative BusBar or the chassis if metal, the chassis connects to the battery negative.
The correct method in a plastic milk crate would be to have a negative BusBar for all the negatives and case lugs. Or tie all the case lugs together and to the battery negative. The BusBar would be a cleaner assembly.
 
I would never suggest that you not follow the instructions, that came with a piece of equipment. But, I "myself" definitely wouldn't do that.
From working in shipyards, we found it safer to not interconnect current carrying conductors, from separate power systems.
 
I did not work in a 'Ship Yard'. I built boats. 30 foot to 260 foot. All the negative dc was tied to the engine blocks as a common negative. The ac grounds were also tied to the negative dc. I can't get into a discussion over corrosion protection, that was a different group of engineers playing with magic.
 
That's a bit different. I installed multiple electrical systems, on oil tankers. Small boats like that, are very similarly treated like RV's.
 
Isn't that what the OP wants? Advice about a small portable system? They don't plan to get into world shipping. :)
Oh well, some information just misses because reading comprehension falls off the edge.
 
If it was in a metal crate, it would ground to the crate.
Otherwise, only need to connect the equipment grounds in the crate together.
This.
All devices with a grounding connection, need to be grounded together. The crate is portable, and plastic, so nothing outside the crate needs to be connected.
If you are connecting to a vehicle, or a building, then the chassis or grounding system of the structure needs to be tied to the case grounding system.

For instance, if you take the milk crate and set it on a trailer or rv, and plug in metal chassis appliances to it, then THE EQUIPMENT GROUNDING conductor needs to be tied to the trailer chassis.
If the items you plug into the SG are all plastic, and do not have ground pins on the conductors, it won’t matter.
 
Thanks for all the thoughts so far.

So, how do the commercial solar generators handle this (Jackery, Bluetti, Ecoflow, etc.)? Are they just tying all the negatives together in the case? As far as I know, they don't have an external ground terminal (the Jackerys don't anyway).

Essentially, my goal is to assemble a DIY version of a commercial solar generator.
 
Thanks for all the thoughts so far.

So, how do the commercial solar generators handle this (Jackery, Bluetti, Ecoflow, etc.)? Are they just tying all the negatives together in the case? As far as I know, they don't have an external ground terminal (the Jackerys don't anyway).

Essentially, my goal is to assemble a DIY version of a commercial solar generator.
Exactly.
All plastic, no equipment ground, no ac ground terminal, for light duty use only.
 
This.
All devices with a grounding connection, need to be grounded together. The crate is portable, and plastic, so nothing outside the crate needs to be connected.
If you are connecting to a vehicle, or a building, then the chassis or grounding system of the structure needs to be tied to the case grounding system.

For instance, if you take the milk crate and set it on a trailer or rv, and plug in metal chassis appliances to it, then THE EQUIPMENT GROUNDING conductor needs to be tied to the trailer chassis.
If the items you plug into the SG are all plastic, and do not have ground pins on the conductors, it won’t matter.

Sorry to hijack but this thread is as close as I've found to my own confusion and anxiety with grounding a small off-grid portable system. If I could take the thought experiment one step further...so I have my plastic milk crate, with the inverter's chassis ground connected to the negative bus bar inside the crate, and I put the milk crate inside a tent (so no trailer chassis) and I plug a metal bodied microwave into the inverter (let's ignore why we're camping with a metal bodied microwave for the moment). Because the microwave has a metal chassis, do I now need to ground the negative bus bar some how? Or do I separate the inverter chassis ground from the negative bus bar and just ground the inverter chassis somehow? (not sure if that's what you meant by "THE EQUIPMENT GROUNDING") Or is it still fine all connected to the negative bus bar because unless my tent is sitting in water I, the microwave operator, am not at risk of electrocution if something goes wrong with the milk crate / microwave in my tent? Or have I misunderstood this all still?

And if I may ask a cheeky second question how 'large' a portable system can we have before it becomes medium or heavy duty? The Jackery 1000 appears to have a 1KW inverter and is plastic bodied and not externally grounded. So I take from that that a 1KW inverter in a plastic milk crate with its chassis ground connected to the negative bus bar is ok. How about 2K? When do I start to have to worry about having a proper external ground? Or do I need to worry at all if it's all contained in a figurative plastic milk crate? Some of the diy emergency "portable" systems (on trolleys as they'd be way too heavy to carry by hand) I've seen around the internet are pretty large and none of them seems to be externally grounded.
 
Sorry to hijack but this thread is as close as I've found to my own confusion and anxiety with grounding a small off-grid portable system. If I could take the thought experiment one step further...so I have my plastic milk crate, with the inverter's chassis ground connected to the negative bus bar inside the crate, and I put the milk crate inside a tent (so no trailer chassis) and I plug a metal bodied microwave into the inverter (let's ignore why we're camping with a metal bodied microwave for the moment). Because the microwave has a metal chassis, do I now need to ground the negative bus bar some how? Or do I separate the inverter chassis ground from the negative bus bar and just ground the inverter chassis somehow? (not sure if that's what you meant by "THE EQUIPMENT GROUNDING") Or is it still fine all connected to the negative bus bar because unless my tent is sitting in water I, the microwave operator, am not at risk of electrocution if something goes wrong with the milk crate / microwave in my tent? Or have I misunderstood this all still?

And if I may ask a cheeky second question how 'large' a portable system can we have before it becomes medium or heavy duty? The Jackery 1000 appears to have a 1KW inverter and is plastic bodied and not externally grounded. So I take from that that a 1KW inverter in a plastic milk crate with its chassis ground connected to the negative bus bar is ok. How about 2K? When do I start to have to worry about having a proper external ground? Or do I need to worry at all if it's all contained in a figurative plastic milk crate? Some of the diy emergency "portable" systems (on trolleys as they'd be way too heavy to carry by hand) I've seen around the internet are pretty large and none of them seems to be externally grounded.
In he case of a jackery, there is no grounding potential, because there isn’t a grounding conductor present in the device.
With a milk crate diy build, it gets tricky… because the components of the build are unknown. If he inverter chosen has neutral and ground requirements, then the ground terminal of the device if installed in a tent, etc with shock hazard of moisture, from the metal bodied toaster, here should be a ground conductor isolation protection… not necessarily a ground rod, but GFCI safety for sure.
 
In he case of a jackery, there is no grounding potential, because there isn’t a grounding conductor present in the device.
With a milk crate diy build, it gets tricky… because the components of the build are unknown. If he inverter chosen has neutral and ground requirements, then the ground terminal of the device if installed in a tent, etc with shock hazard of moisture, from the metal bodied toaster, here should be a ground conductor isolation protection… not necessarily a ground rod, but GFCI safety for sure.
Ah...so in the UK a GFCI is an RCD. So plugging an RCD plug into my inverter and then plugging my metal bodied toaster into that RCD plug would be the general advice if no ground rod were available. Makes sense.

One of these: Masterplug ARCDKG-MP Single Socket RCD Safety Adaptor,
 
For my generator, the grounding solution was a sum of each individual's grounding requirements. Once this was understood, a system-wide grounding solution was implemented.
There is the DC grounding side of things, and AC:
Is equipment DC side of charge controller "negative" ground? "Positive"? Floating?
What about DC grounding of inverter?
Is AC-out ground bonded to case of inverter?
Is there a neutral-ground bond inside inverter? Will there be a bond in your power panel?
I built the generator in a metal cabinet, so unless I isolated metal cases of of components, the DC ground bus bar and AC ground bus bar are bonded.
 
I am starting to build a diy solar generator also. I am patterning it after the Renogy Lycan 5000 and had similar questions about grounding. It's going to use the EG4 3000 all in one inverter. A review of the technical data for those systems indicate that you need to create a ground (i.e. a rod, cold water etc) under battery use with PV charging. While grounding is handled via the line/service ground if operating on grid or charging (i.e. shore power). I'm definitely going to put a grounding lug in my setup to attach it to something appropriate (like the Lycan).
Hope that's helpful.
 
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