raurre
Solar Enthusiast
I have a system you will find helpful. https://diysolarforum.com/threads/m...epo4-battery-14-kw-pv-array.32343/post-486853
MPP LV6548 Ground/Neutral Safety?
- Thread starter Tetawon
- Start date
Jazzmonger
Hacker at heart
Beautiful! (Nice system btw) I thought it was that screw since it was labeled with a ground symbol, I just wanted to make absolutely sure. I literally searched the forums, google images, etc for over an hour and sent emails to Ian@Watts24.
ok, I'm stealing your pic and posting here for others looking for the same info.
Key Search words: bonding, screw, n-g, LV6548, ground, confused, confirmed, dead horse, finally sleeping well.
ok, I'm stealing your pic and posting here for others looking for the same info.
Key Search words: bonding, screw, n-g, LV6548, ground, confused, confirmed, dead horse, finally sleeping well.
I have a video that covers exactly where this screw is with pictures. Starts at 2:17 :
Jazzmonger
Hacker at heart
Great video. Not sure why it didn't come up in my exhaustive search...
here's the image that you show in that video.
here's the image that you show in that video.
@Will Prowse
Is 45.07 still the most recent firmware version (as of today 29 JUN 22)? Where were you able to find that firmware download you supplied in post #186 ?
Thanks!
Is 45.07 still the most recent firmware version (as of today 29 JUN 22)? Where were you able to find that firmware download you supplied in post #186 ?
Thanks!
Yes, and my current understanding after emailing mpp last week is that this is still the latest firmware for LV6548
if there is a bond in the unit, then it is configured to work as "power delivery device" and there should be grounding rod directly at the unit. The connection line between the inverter and the panel has to be treated as power transmission line. Same thing when your house runs the wires from the pole transformer to your house. Usually (in good installations) the transformer will be grounded directly at the pole where it is located, I can show you a picture...
With exceptions. For example, what about systems that are physically connected to the grid but are providing their own power (island mode) unless the battery runs out (presumably meaning the inverter and corresponding output panel have an uninterruptible connection to the ground already provided on-site via the grid connection)? Or mobile installations (obviously RVs don't have an earth ground while islanded)?
you cant have island mode and be physically connected to the grid. there is either an ATS or you have no island mode. RVs have no ground and should not be running devices that are configured to _require_ a ground (do not mix that up! folks may be using devices not made for the purpose, but this does not mean it is used in the intended manner)
timselectric
If I can do it, you can do it.
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RV's can have a ground. If a N/G bond connection is made. But, this connection will need to be broken. Whenever connected to shore power.
This can be accomplished with a simple relay.
This can be accomplished with a simple relay.
easily for example with Victron Multiplus + Victron autotransformer. It is discussed in their manual
timselectric
If I can do it, you can do it.
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Yes, Victron does it for you.
Inverters and ATS' (at least RV ATS) don't make/break upstream ground so while physically connected to shore but providing power, there is a connection to earth ground. That said, it's not typical for an inverter to be the power provider while connected to shore, but I do this sometimes (with Victron's AC input control set to connect to shore if the SoC goes below a threshold).
As for RV's having earth ground (while disconnected from shore) -- yes of course they *can* have it but virtually none do. I'm not talking about NG bond at all.
I'm trying to be clearer about the concept of "you must have an earth ground if the inverter is providing power (independent of the grid)" for other readers here.
Edit: to be sure it's clear, when I say "earth ground" I mean a rod in the ground local to the power source.
I said: you need ATS for island mode. NOT: ATS breaks the ground...
Gotcha; I assume the "ATS" to which you refer can be built-in like it is in the Quattro. It disconnects from L1, L2, and N and bonds GN, inverts, and I become an island, even though I'm physically connected to shore. By doing so, I benefit from having an earth ground. But I don't have to be, and I'd have no earth ground.
Ahh... I think I see the confusion; by "physically connected to grid/shore" I meant that I'm plugged in ... not that I have an electrical connection to L1/L2/N (because the Quattro disconnects).
Whew! Terminology. As my Dad always says, "It's only English...."
timselectric
If I can do it, you can do it.
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Earth connection is an addition to the grounding system. The grounding system is created by, and originates at the N/G bond. The purpose of the grounding system is to create a low impedance path back to the source of power. So that a breaker or fuse will clear a fault. While it's better to also have an Earth connection. Not having an Earth connection on a mobile installation, is better than not having any grounding system.
"physical connection" has no meaning if there is no electrical connection. same if you just plug in an empty plugGotcha; I assume the "ATS" to which you refer can be built-in like it is in the Quattro. It disconnects from L1, L2, and N and bonds GN, inverts, and I become an island, even though I'm physically connected to shore. By doing so, I benefit from having an earth ground. But I don't have to be, and I'd have no earth ground.
Ahh... I think I see the confusion; by "physically connected to grid/shore" I meant that I'm plugged in ... not that I have an electrical connection to L1/L2/N (because the Quattro disconnects).
Whew! Terminology. As my Dad always says, "It's only English...."
you should familiarize yourself with the grounding requirements:
www.ecmweb.com
The Basics of Bonding and Grounding Transformers
Clearing up confusion on bonding and grounding solidly grounded transformers
www.ecmweb.com
MartianFarmer
New Member
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- 1
I have read this whole thread and it was a fun trip. I put of up a couple LV6548's split phase with 280AH/48v of battery more or less as a UPS. The solution for grid attached (not as in feeding the grid but as in having grid priority) seems to just be to remove one bonding screw and make sure you're running on the latest firmware (if you don't give a crap about warranty). I don't think warranty is an issue because I'm not shipping one back to Taiwan if it breaks anyhow. I won't be using any solar right now but if my power outage stretches too long I'll just charge the batteries off a gen. I'm building a wood gasifier for the generator, that might end up being my eco friendly solar equivalent.
My thoughts if you do it like am... clearly label the inverter with the ground neutral bond removed and tape the screw on the side with guerilla tape in a ziplock with the printed location picture in case some poor bugger comes along behind you and wonders what's going on or tries to change/use them as standalone units or what have you. Test the unit standalone to make sure it's working out of the box before even bothering to mount or open it. Trust no commentary, test everything for yourself - clamp meters and multi meters are dirt cheap.
Everything else is already in the electrical code.
I'm running a sub panel with my critical loads (water pump, propane furnace, pellet stove, random household circuits for lights and light appliances like coffee maker and microwave , TV and networking). As a bonus I actually get some upgrades like AFCI to the bedrooms and such from the subpanel. (It was cheaper to buy an entrance panel and just remove the ground neutral bond because it included all the breakers I wanted anyhow). My clothes dryer and convection oven (I have a propane range) aren't really very critical to me considering our outages are a day or less on average with the most annoying ones being five seconds in the middle of day several times a day for no known reason. Peak loads I have measured (not including the dryer and oven) do not ever get close to what this layout can deliver during our daily use.
I sure appreciated everyone who had something to say here. Took a while but I feel very clear on the issue so thanks to everyone who added to this discussion.
YMMV
Mark
My thoughts if you do it like am... clearly label the inverter with the ground neutral bond removed and tape the screw on the side with guerilla tape in a ziplock with the printed location picture in case some poor bugger comes along behind you and wonders what's going on or tries to change/use them as standalone units or what have you. Test the unit standalone to make sure it's working out of the box before even bothering to mount or open it. Trust no commentary, test everything for yourself - clamp meters and multi meters are dirt cheap.
Everything else is already in the electrical code.
I'm running a sub panel with my critical loads (water pump, propane furnace, pellet stove, random household circuits for lights and light appliances like coffee maker and microwave , TV and networking). As a bonus I actually get some upgrades like AFCI to the bedrooms and such from the subpanel. (It was cheaper to buy an entrance panel and just remove the ground neutral bond because it included all the breakers I wanted anyhow). My clothes dryer and convection oven (I have a propane range) aren't really very critical to me considering our outages are a day or less on average with the most annoying ones being five seconds in the middle of day several times a day for no known reason. Peak loads I have measured (not including the dryer and oven) do not ever get close to what this layout can deliver during our daily use.
I sure appreciated everyone who had something to say here. Took a while but I feel very clear on the issue so thanks to everyone who added to this discussion.
YMMV
Mark
