Is this a safe use case for an old inverter / solar panels

[davefromlondon]

I have an old 4500w 12v chinese, inverter from Habor freight, unknown brand. I'm learning from youtube as follows:

I want to run solar panels.

Is this a safe/ correct setup , I welcome any guidance, corrections, additional comments. Dallas, TX location

1) There is no ac input, only 12v so this is regarded as a mobile system.
2) ill put 2 x 12v batteries in parallel on the top set of 12v inputs, and 2 x 12v batteries in parallel on the bottom set . everything remains 12v input per label on the inverter
3) ill test if there is a ground -neutral bond built in to inverter but likely not
4) ill wire my own ground -neutral bond using
4a) the wing nut below the negative battery input , i.e. the case of the inverter
4b) the rubber protective area on the lower left near the ac output, behind there are 2 sets of live , negative, ground poles. I'll wire the 2 neutral poles together and then wire them to the wing nut in 4a) . This bonds neutral to earth
5) ill add 2x GFCI distribution strips to the ac outputs, one each side. note the 2x circuit breakers below the inverter ac outputs
6) ill add solar panels and a controller to charge the batteries.

QUESTIONS
Q 1) do I need a ground rod buried in ground
Q2) if answer to Q1 is yes then what do I connect it to in the system
Q3) what spec solar panel and controller is advised here

 

[davefromlondon]

Correction. 1) this is NOT mobile, it's off grid , independent system

 

[timselectric]

4) ill wire my own ground -neutral bond using

Careful about this one.
Some of the portable inverters can't handle a N/G bond. They will self destruct.
If it doesn't have it internally, I wouldn't add it to this one.
Just add GFCI protection immediately after the output, and move on from there.

 

[740GLE]

@Brucey

He stole your work bench!!

 

[timselectric]

QUESTIONS
Q 1) do I need a ground rod buried in ground
Q2) if answer to Q1 is yes then what do I connect it to in the system
Q3) what spec solar panel and controller is advised here

1. & 2.
No, not for a portable system. Just add GFCI protection for added safety.
3. That depends on how much power you plan to pull from the batteries.
You need enough PV to replace what you use.

 

[Brucey]

@Brucey

He stole your work bench!!

Looks like he has plenty of expansion space actually tearing apart my washer/dryer system today for rebuild.

 

[davefromlondon]

Careful about this one.
Some of the portable inverters can't handle a N/G bond. They will self destruct.
If it doesn't have it internally, I wouldn't add it to this one.
Just add GFCI protection immediately after the output, and move on from there.

Thank you.
I'm unsure if this is classed as portable. weights about 40lbs, measures 16" deep, 14" high, 6" wide.

I was thinking GFCI of little use without the ground neutral bond

 

[timselectric]

Thank you.
I'm unsure if this is classed as portable. weights about 40lbs, measures 16" deep, 14" high, 6" wide.

I was thinking GFCI of little use without the ground neutral bond

GFCI doesn't require a ground to function. That's the benefit of it.

 

[davefromlondon]

1. & 2.
No, not for a portable system. Just add GFCI protection for added safety.
3. That depends on how much power you plan to pull from the batteries.
You need enough PV to replace what you use.

As much solar as this will handle. So 4500 W. maybe limit to 4kw to be conservative

 

[davefromlondon]

1. & 2.
No, not for a portable system. Just add GFCI protection for added safety.
3. That depends on how much power you plan to pull from the batteries.
You need enough PV to replace what you use.

As much solar as this will handle. So 4500 W. maybe limit to 4kw to be conse

 

[TM48]

Do film the initial power up.

 

[Brucey]

As much solar as this will handle. So 4500 W. maybe limit to 4kw to be conservative

So if we assume the inverter will be running at max power of 4kW 24x7, and you have 12 hours of full solar production (this is unlikely to happen except far north in summer etc):

You need 96kW of power.

Half of that will come from solar directly. The other half has to come from batteries. Now in the morning the battery bank will be empty. You then need to produce 96kW of solar the next day (48kW for direct use by inverter, 48kW for battery charging to get you through the overnight).

In reality in winter you may get 2 or 3 hours of full solar production.

Edit I'm not including system losses in these theoretical discussions.

 

[davefromlondon]

Thanks. for my education why does portable negate the needs for a ground rod. what type of systems do in fact need ground rods ?

1. & 2.
No, not for a portable system. Just add GFCI protection for added safety.
3. That depends on how much power you plan to pull from the batteries.
You need enough PV to replace what you use.

 

[hybe022]

Man i'd be careful doing electrical work near the washer and dryer

 

[davefromlondon]

Do film the initial power up.

Do you have a concern

 

[davefromlondon]

Man i'd be careful doing electrical work near the washer and dryer

Thanks. It's been stored there for years. It won't be used there at all

 

[halexudson]

Careful about this one.
Some of the portable inverters can't handle a N/G bond. They will self destruct.
If it doesn't have it internally, I wouldn't add it to this one.
Just add GFCI protection immediately after the output, and move on from there.

Is there any more literature on why having a NG bond on the output of the cheap inverter would kill it? Same result if it's in the "main" panel for this setup? This would also mean the inverter would explode if you used it on a genny input on a transfer switch, since the main panel has a bond.

 

[740GLE]

Do you have a concern

Internal components (lesser grade caps in particular) can fail, and you’d only know they failed on initial power up.

 

[davefromlondon]

Internal components (lesser grade caps in particular) can fail, and you’d only know they failed on initial power up.

Thanks. I did use this years ago, system totally "as is" in the pictures to drive outside sound equipment from fully charged batteries, no solar, no recharging. Worked well.

 

[timselectric]

As much solar as this will handle. So 4500 W. maybe limit to 4kw to be conservative

The inverter doesn't use solar. It's powered from the batteries. The solar will replace what you take from the batteries.

If you really intend to use 4500w for 24/7. That will be 108kwh per day.
Which would require 25kw (25,000w) of solar on a sunny day to replace it. And about 20kwh of batteries to sustain it through the night.
But I'm sure that you can get by with less. You just need to calculate what you actually need.

 

[timselectric]

Thanks. for my education why does portable negate the needs for a ground rod. what type of systems do in fact need ground rods ?

Permanently installed systems. (Mounted and incorporated into your electrical system)

 

[timselectric]

Is there any more literature on why having a NG bond on the output of the cheap inverter would kill it?

The warnings are usually found in the owners manual.

Same result if it's in the "main" panel for this setup? This would also mean the inverter would explode if you used it on a genny input on a transfer switch, since the main panel has a bond.

Correct, they cannot be connected to your bonded electrical system.
They don't explode. Just a bang, and a puff of smoke. And then it's a paper weight.

 

[davefromlondon]

On this thread I'm seeing multiple opinions if GFCI does / does not require Ground-Neutral bonding. perhaps it's a different use case. any additional guidance ?

W

Thread 'Running a GFCI outlet from inverter.'

Jul 13, 2023

I have a mini campervan and would like to add a single 120v GFCI outlet by running a circuit no more than 9' in length from my 1500w inverter to the outlet. Here is where my question comes in, I would be plugging this circuit into the inverters 3 prong outlet, this seems simple enough but would like to get confirmation that this is an acceptable installation.

• WNCGUY
• Replies: 51
• Forum: Vehicle Mounted Systems

 

[timselectric]

On this thread I'm seeing multiple opinions if GFCI does / does not require Ground-Neutral bonding. perhaps it's a different use case. any additional guidance ?

W

Thread 'Running a GFCI outlet from inverter.'

Jul 13, 2023

I have a mini campervan and would like to add a single 120v GFCI outlet by running a circuit no more than 9' in length from my 1500w inverter to the outlet. Here is where my question comes in, I would be plugging this circuit into the inverters 3 prong outlet, this seems simple enough but would like to get confirmation that this is an acceptable installation.

• WNCGUY
• Replies: 51
• Forum: Vehicle Mounted Systems

This isn't about opinions. Many are misguided.
A GFCI doesn't require a ground, because of how it works.
It measures the current going out and returning. If they don't match (power going somewhere it shouldn't be) , it trips.
In the NEC (National Electrical Code) a GFCI is the only acceptable way to install a 3-prong receptacle without a ground connected. Due to the way it functions.

 

[davefromlondon]

Thank you. forgive me as I'm learning before I go ahead with this project and would welcome more detail.

I had thought , and I totally could be wrong, that the purpose of a ground-neutral bond in an inverter was to immediately allow a ground fault (a live wire is loose and accidentally touches the metal case of an appliance ) to complete the circuit back to source via the appliance ground cable that then connects to the neutral via the bond , and trips a breaker to disconnect the power quickly.

Are you saying an inverter with no bond, but with a GFCI at the ac out, offers the same protection in the event of a ground fault as described above. ?