Got electrical questions? I have answers!

[andreap]

Originally Posted by Twigg

Just to add, because I didn't want to ppps

There are a bunch of blogs and websites out there to help you get this right. It's a well-trodden path and what you are asking is standard stuff.

You need help with wire sizing, placement of units, where to use fuses, breakers, shunts. How to join and terminate wires, etc, etc.

None of this is difficult, just make a plan and follow it using the advice for each step.

Wiring batteries together is not as simple as it sounds. There are reasons why you should get your inverter as close to the batteries as you can, and why a Trimetric monitor is a good thing.

Also, which type of solar charge controller and what gauge of wire to use ... the list goes on and none of it is hard.

Basing your system around that AIMS Inverter/Charger was, imo, a smart move.

Thanks so much, Steve! As for the AIMS, our researching proved that to be a good decision.

So appreciate your encouragement to keep at it...we have read many posts and plans but mostly struggling to understand what to do when wires are mismatched, or how the generator interfaces with the inverter, how to put the fuse between the charge controller and the batteries, etc.

My husband laid out all the stuff in our living room and is excited to work on it. Just feels like we literally need someone standing over our shoulder saying, "use this here..., that goes there..., don't do that!!..." Haha!!

We are taking our kids to national parks this summer so have 10 weeks to get this (and a million other things) figured out.

[family wagon]

Originally Posted by Ninjakitty

I'm in the planning stages of my electrical and I'm curious if using a smaller separate AC inverter to power the fridge is a good idea. The fridge will be running 24/7 and with what I've read about inverters, I thought a single dedicated inverter for the fridge might save some power instead of having a large inverter that is constantly in use. Thoughts and opinions are welcome.

The answer depends on the specs for the inverters. The quiescent current/draw (engineer-speak for "the power the inverter itself consumes when it isn't even powering anything") might be the most relevant for your question.

For sake of estimation, suppose the fridge compressor runs 50% of the time. That's 12 hours of compressor run time per day. The other 12 hours the inverter is powered on but not doing anything, so during these hours it's burning battery power at the rate of its quiescent current. If this quiescent draw of your big inverter for 12 hours per day adds up to an objectionable amount of power then it could make sense to look for a different inverter that draws substantially less.

As an alternative, a person could rig a thermostat inside the fridge to activate the remote power-on switch on the inverter. The inverter would power on only when the thermostat in the fridge calls for cooling (another switch in parallel could allow for the inverter to be turned on at other times too).

Originally Posted by andreap

We are taking our kids to national parks this summer so have 10 weeks to get this (and a million other things) figured out.

With that in mind.. you might do well to just turn the inverter on and off manually as needed and not worry about calculating whether a smaller inverter will save you power. You'll have bigger things to spend these 10 weeks preparing!

[Ninjakitty]

Originally Posted by family wagon

The answer depends on the specs for the inverters. The quiescent current/draw (engineer-speak for "the power the inverter itself consumes when it isn't even powering anything") might be the most relevant for your question.

For sake of estimation, suppose the fridge compressor runs 50% of the time. That's 12 hours of compressor run time per day. The other 12 hours the inverter is powered on but not doing anything, so during these hours it's burning battery power at the rate of its quiescent current. If this quiescent draw of your big inverter for 12 hours per day adds up to an objectionable amount of power then it could make sense to look for a different inverter that draws substantially less.

As an alternative, a person could rig a thermostat inside the fridge to activate the remote power-on switch on the inverter. The inverter would power on only when the thermostat in the fridge calls for cooling (another switch in parallel could allow for the inverter to be turned on at other times too).



With that in mind.. you might do well to just turn the inverter on and off manually as needed and not worry about calculating whether a smaller inverter will save you power. You'll have bigger things to spend these 10 weeks preparing!

Thank you for the well thought out answer. I will probably just go ahead and and just run one large inverter

Sent from my Vivo 5R using Tapatalk

[Twigg]

Originally Posted by Ninjakitty

Thank you for the well thought out answer. I will probably just go ahead and and just run one large inverter

Sent from my Vivo 5R using Tapatalk

The inefficiency power used by that AIMS is very low.

It's only going to be an issue if you undersize your battery bank and regularly run into the 50% state of charge limit. Add two more batteries and don't worry.

[Ninjakitty]

Originally Posted by Twigg

The inefficiency power used by that AIMS is very low.

It's only going to be an issue if you undersize your battery bank and regularly run into the 50% state of charge limit. Add two more batteries and don't worry.

Thank you for the reply.

[Mgulley82]

I’m having a difficult time determining what these two earth wires (I assume earth based on yellow/green color coding) are for on my AIMs 2k watt pure sine inverter charger.



On has a male spade connector the other a female spade connector

Any ideas? I’m finding nothing in the literature or AIMS provided schematics or wiring instructions

[Drew Bru]

Originally Posted by Mgulley82

I’m having a difficult time determining what these two earth wires (I assume earth based on yellow/green color coding) are for on my AIMs 2k watt pure sine inverter charger.

Attachment 22410

On has a male spade connector the other a female spade connector

Any ideas? I’m finding nothing in the literature or AIMS provided schematics or wiring instructions

Link to the pdf: http://www.aimscorp.net/documents/PI...0W24V240VS.pdf

Page 22 in my Aims Inverter manual

[Mgulley82]

So if I’m understanding that correctly connecting the two spades together enables the automatic neutral switch feature

Disconnecting them from each other disables it?

[Drew Bru]

Originally Posted by Mgulley82

So if I’m understanding that correctly connecting the two spades together enables the automatic neutral switch feature

Disconnecting them from each other disables it?

Yup, that's correct.

[Mgulley82]

Awesome!

I’ll definitely connect them together so I’ll be safe when connected to shore power

Also I’ll bond my generator to bus chassis for when I use that in place of shore power

[Drew Bru]

Originally Posted by Mgulley82

Awesome!
Also I’ll bond my generator to bus chassis for when I use that in place of shore power

Something I'd been wondering about. I have zero idea what I'm supposed to do about that. There's a grounding terminal on the Harbor Freight generator and the manual says I should drive a copper grounding rod into the earth and wire it to the grounding terminal on the genny. That doesn't seem practical?

[Mgulley82]

Originally Posted by Drew Bru

Something I'd been wondering about. I have zero idea what I'm supposed to do about that. There's a grounding terminal on the Harbor Freight generator and the manual says I should drive a copper grounding rod into the earth and wire it to the grounding terminal on the genny. That doesn't seem practical?

That only makes sense if your AC system your powering is ALSO grounded to earth?

[Mgulley82]

My understanding is that within the Bus neutral and ground should NOT be bonded together in any panel or sub panel

With shore power neutral and ground should be bonded in the main service box on the campsite

For a generator I’m guessing neutral and ground would be bonded at the generator?

[Drew Bru]

Originally Posted by Mgulley82

That only makes sense if your AC system your powering is ALSO grounded to earth?

Yeah, that's what I thought. The AC is grounded to the chassis. No matter how much I read about it, I can never seem to grasp the concept of grounding, neutral-ground bond, floating neutral, etc. etc.

I've got a weird mental block I think.

So far as I can tell, I'll ground my inverter to the chassis and my conduit to the chassis. Shore power *should* be grounded at the post. I don't plan on using the generator all that much, but who knows?

[BlackJohn]

Here is my 2 cents again....

The ac service cord contains your ground when plugged into the source of the ac. No if and's or buts there.
Your ac panel has a ground lug that the incoming green service cable connects too. The branch circuits in the bus have grounds also which run or should run back to that same panel and attach to the ground busbar provided. They have nothing to do at all with the neutral bar. The neutral should never be switched in an ac service.
When using the generator as the power source for the bus, the neutral floats if you do not ground the generator itself to the lug provided. That means it can have a potential on it that can create safety issues of the worst kind up to and including death.
I do ground my generator to a ground rod when not on the ac service. It's not something to joke about like one here thinks. (The one who knows everything about everything there is to know!) He wouldn't know how to get off his bus if it was hot due to a generator fault. If your bus shows signs of being at potential and the genny is not grounded then stay in it rather than getting off and away from the problem getting off the bus. As soon as you set foot on land if not grounded you are going to get a helluva lift if not electrocuted instantly. Some joke eh?
If you have to leave the bus, jump well clear and with both feet coming off the bus at the same time. Do not hold the door or any metal and you should be fine. If not you are not going camping ever again.
So get it right folks for you and your loved ones.

John

John

[Drew Bru]

Originally Posted by BlackJohn

Here is my 2 cents again....

The ac service cord contains your ground when plugged into the source of the ac. No if and's or buts there.

Ok. So far, so good there.

Originally Posted by BlackJohn

Your ac panel has a ground lug that the incoming green service cable connects too. The branch circuits in the bus have grounds also which run or should run back to that same panel and attach to the ground busbar provided.

I had planned on using the EMT conduit to ground to the chassis of the bus, at one point only. Also grounding the inverter to the chassis.

Originally Posted by BlackJohn

They have nothing to do at all with the neutral bar. The neutral should never be switched in an ac service.

Got it.

Originally Posted by BlackJohn

When using the generator as the power source for the bus, the neutral floats if you do not ground the generator itself to the lug provided. That means it can have a potential on it that can create safety issues of the worst kind up to and including death.
I do ground my generator to a ground rod when not on the ac service.

What type of grounding rod do you use? I've seen copper grounding rods at the hardware store, but they're about 5' long....far too long to drive into the ground. How deep does this grounding rod go, in a generator-based situation?

[BlackJohn]

Most residential grounding rods are at least 10 feet in length to pass inspection. What you are seeing locally is likely for lightning protection and would be better than nothing at all to ground your generator.
I carry a piece of steel rebar, 1/2" x 4 feet and drive it in till it's firm and not going to fall over accidentally. With the ribs on the rebar it is very easy to pull up out of the ground too when you move the bus.

When you mention the EMT conduit I have to ask does than run from the connection/entrance point to the main panel? Inside or underneath the bus?
Can't picture what you have built with the description or lack of.
If it's fastened to the frame somehow then that is your ground for that pipe only and not the chassis. That would need another ground to the frame itself.

John

[family wagon]

Interesting little factoid about the ground lug on the chassis of portable generators: in many units it isn't electrically connected to anything in the generator head. Though the generator likely features 3-prong sockets, and the ground prong will be wired to the chassis, it's left for the user to sort out whether or not they should install a jumper between the generator chassis and the neutral.

Moral of the story: always test with a meter. Don't assume that because a 3-prong plug (or hard wire) was used that the genny will be providing the ground-neutral bond.

[Mgulley82]

Originally Posted by family wagon

Interesting little factoid about the ground lug on the chassis of portable generators: in many units it isn't electrically connected to anything in the generator head. Though the generator likely features 3-prong sockets, and the ground prong will be wired to the chassis, it's left for the user to sort out whether or not they should install a jumper between the generator chassis and the neutral.

Moral of the story: always test with a meter. Don't assume that because a 3-prong plug (or hard wire) was used that the genny will be providing the ground-neutral bond.

Am I correct in my assumption that the proper way to hook up a bus frame mounted generator is to bond ground to neutral in the generator (similar to how you would bond ground to neutral in your shore power post) also keeping ground and neutral separate in all your breaker/distribution panels on the bus?

[family wagon]

Originally Posted by Mgulley82

Am I correct in my assumption that the proper way to hook up a bus frame mounted generator is to bond ground to neutral in the generator (similar to how you would bond ground to neutral in your shore power post) also keeping ground and neutral separate in all your breaker/distribution panels on the bus?

Make the connection "at" the generator, anyway ("in" to me implies possibly buried inside the unit somewhere, even though that may not be how you meant it).

I like this installation approach because it sets things up for easy addition of a transfer switch and shore power cord down the road. A person then doesn't have to remember "oh yeah, I put a ground-neutral bond in the circuit breaker panel and that needs to come out before shore power is used."