MPP Solar LV6548 split phase supply side tap details

dragontea

New Member
Joined
Mar 29, 2021
Messages
8
Location
Markham, Ontario, Canada
Hi,

I'm just finishing up installing 2 x LV6548 for split phase and looking to tie it into my main panel to supplement my utility usage. Is there are details or diagrams on how to tie it into the main panel either via a supply side tap or connecting it to the main or sub panel? I have 200 amp main. panel.

Thanks in advance.
 

Sanwizard

Photon Sorcerer
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Feb 2, 2021
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Main panel or sub panel? The LV6548's are not grid tie capable. If you are totally off grid, just connect the AC out of the inverters to the main L1 with inverter A, and L2 with Inverter B. The nuetrals are tied together in the panel.
If you have grid coming in to that panel, DO NOT connect your inverters to it.

You can use your main panel to supply AC IN to your inverters, and then use the inverters to supply AC OUT to an isolated sub panel.
 

dragontea

New Member
Joined
Mar 29, 2021
Messages
8
Location
Markham, Ontario, Canada
Main panel or sub panel? The LV6548's are not grid tie capable. If you are totally off grid, just connect the AC out of the inverters to the main L1 with inverter A, and L2 with Inverter B. The nuetrals are tied together in the panel.
If you have grid coming in to that panel, DO NOT connect your inverters to it.

You can use your main panel to supply AC IN to your inverters, and then use the inverters to supply AC OUT to an isolated sub panel.
Thanks @Sanwizard ! Figured it out and added a subpanel and relocated a lot of the loads to it before connect the inverter to the subpanel.
 

mrzed001

Voice of reason
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Apr 10, 2020
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Location
Hungary - EU

Can I suggest some improvements on your system ?

1, BMS. Active balancer is not protecting your cells and pack.
2, Battery fuse and/or disconnect switch. You have switches before each inverter (I can not identify them) that is good.
3, Are those water pipes ? Then I suggest at least IP55 protection for the inverter, the battery, and the not waterproof switches and breakers (AC and DC)

Nice setup btw.
 

dragontea

New Member
Joined
Mar 29, 2021
Messages
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Location
Markham, Ontario, Canada
@mrzed001 Thanks for the input!
1. I was under the impression the 2 x LV6548 has BMS built in or at least monitors the battery pack voltages?
2. I have a terminal fuse block on the positive post of battery bank.
3. Drain pipes. no pressure in the drain pipes but i plan up putting some clear acrylic over the battery bank and wall wiring

New pics below of added subpanel, double throw switch, Inverter AC disconnect.
 
Last edited:

mrzed001

Voice of reason
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Messages
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Location
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@mrzed001 Thanks for the input!
1. I was under the impression the 2 x LV6548 has BMS built in or at least monitors the battery pack voltages?
BMS is always part of the battery, not the inverter :)
Inverter only knows the sum V of all cells. There will be cell with too high V (overcharging) and inverter would not know it.
Also too low V cell ...
Did you do a proper top balance ?

2. I have a terminal fuse block on the positive post of battery bank.
I am not sure that is enough. It was designed for lead battery. But LFP has a much higher short circuit Amp.
So ... not secure. If it melts then arch can remain. Thats bad.
Class T fuse is the minimal (or NH).
I also like to put a fuse on the other line too (overkill or not, you sleep better).


3. Drain pipes. no pressure in the drain pipes but i plan up putting some clear acrylic over the battery bank and wall wiring
You know Murphy's law?
A pipe can break, leak, ....
Imagine what would happen if water leaks from it into the inverter, or into the PV DC panel between the two inverter ... or on top of the batteries shorting them out.
If water pipes around ... you need to think of it like it can rain in there.

Use an IP55 enclosure for the inverters and breakers like here:


And something similar, or something like Andy did for the batteries:
 
Last edited:

dragontea

New Member
Joined
Mar 29, 2021
Messages
8
Location
Markham, Ontario, Canada
BMS is always part of the battery, not the inverter :)
Inverter only knows the sum V of all cells. There will be cell with too high V (overcharging) and inverter would not know it.
Also too low V cell ...
Did you do a proper top balance ?


I am not sure that is enough. It was designed for lead battery. But LFP has a much higher short circuit Amp.
So ... not secure. If it melts then arch can remain. Thats bad.
Class T fuse is the minimal (or NH).
I also like to put a fuse on the other line too (overkill or not, you sleep better).



You know Murphy's law?
A pipe can break, leak, ....
Imagine what would happen if water leaks from it into the inverter, or into the PV DC panel between the two inverter ... or on top of the batteries shorting them out.
If water pipes around ... you need to think of it like it can rain in there.

Use an IP55 enclosure for the inverters and breakers like here:


And something similar, or something like Andy did for the batteries:
Great thanks for all the tips!
Will implement them as I want the whole setup to be as safe as possible.

I have an external DC disconnect as well for the solar panels.
 

jasonhc73

Cat herder, and dog toy tosser.
Joined
Oct 1, 2019
Messages
1,640
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Wichita, Kansas
I have my 2 LV6548 plugged into a NEMA 14-50 outlet.
I have the outlet turned on at the loads panel. At the loads panel, I turn off the GRID "line"(main circuit breaker).

I am thus isolated from the grid.

My plan however is to run my system like this, as soon as I can convince an electrician to do it.

GRID(LINE) --> METER --> FUSABLE SAFETY DISCONECT --> (AC IN) INVERTERS/INVERTERS (AC OUT) --> LOADS PANEL --> HOUSE

As it is now;

(off grid configuration)
INVERTERS(AC OUT)--> LOADS PANEL --> HOUSE

I can switch the ac line to the (AC IN) with the use of a knife switch and flipping the circuit breakers. The only reason to do this is to run the house from the grid, and charge the batteries if needed.

(on-grid configuration - NOT grid-tied)
GRID(LINE) --> METER --> LOADS PANEL --> HOUSE --> (AC IN) INVERTERS/INVERTERS (AC OUT) --> NEMA 14-50 for car EVSE only.
 

Sanwizard

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Feb 2, 2021
Messages
1,294
I have my 2 LV6548 plugged into a NEMA 14-50 outlet.
I have the outlet turned on at the loads panel. At the loads panel, I turn off the GRID "line"(main circuit breaker).

I am thus isolated from the grid.

My plan however is to run my system like this, as soon as I can convince an electrician to do it.

GRID(LINE) --> METER --> FUSABLE SAFETY DISCONECT --> (AC IN) INVERTERS/INVERTERS (AC OUT) --> LOADS PANEL --> HOUSE

As it is now;

(off grid configuration)
INVERTERS(AC OUT)--> LOADS PANEL --> HOUSE

I can switch the ac line to the (AC IN) with the use of a knife switch and flipping the circuit breakers. The only reason to do this is to run the house from the grid, and charge the batteries if needed.

(on-grid configuration - NOT grid-tied)
GRID(LINE) --> METER --> LOADS PANEL --> HOUSE --> (AC IN) INVERTERS/INVERTERS (AC OUT) --> NEMA 14-50 for car EVSE only.
I am confused. Your ac in and ac out use the same panel?
 
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