Pre-flight Peer Review - 16kw System

[nscottsdale]

Hi all,

I am down to connecting batteries and a load to call the city for a permitted off grid inspection. Appreciate a second set of eyes before flipping any switches.

Here is my plan using two MPP LV 6048 and thirty six Solarever 460 Watt panels:




The panels were installed on steel roof with slick mounting pads from S-5!



Because of my mistake, and parts were already ordered, - the LV 6048 has a max PV voltage of 115v , and my panels open voltage Voc 49v, so i had to add a lot of combiners and a lot of PV wires ... (instead of serial each row)



Every two panels in the 36 panel set is wired down to the combiners. All pairs reporting around 90 volts, and the combiner is alo reporting the same (i didn't throw the switch on these) . Inside i have this setup:

The two inverters are wired to receive the feed from the four combiners...





The two inverters AC out are paralleled as the feed into the AC cutoff switch and the output routed to my dedicated load subpanel.



I still need to:
[ ] Study the serial / connections between the MPP's and any startup details
[ ] Build the battery cables and parallel output of the MPP's to a terminal strip (bus bar) and that terminal strip for now will have a pair of matched length wires to only two 48v EG4 batteries as a starter battery pack.

 

[nscottsdale]

here is how i used a Bus Bar to tie the DC in parallel. I had a 100' roll of 3/8 flex for the project so i kept using that for the lines. The battery cables are 2AWG



In my new (to me) server cabinet i did my starter set of batteries. I was able to use a But connector to transition from the 2AWG to a pair of the Signature Solar EG4 leads. As i add batteries i left some slack to deal with in cabinet bus bar later.





So this still leaves

[ ] researching what the inverter to inverter connections are needed

[ [ For the batteries i understand the EG4 and MPP Inverters don't communicate for BMS control from the inverter and need to be set to AGM so i need to read the threads on how to set the battery level. In (https://diysolarforum.com/threads/mpp-lvx6048-communication-with-eg4-lifepro4-48v-100ah-bms.34692/ ) Eber says 56 bulk and 54.5 float.

[ ] Hopefully no new is good news from the forum as feedback on the design or install, but i will still re-read the manuals related to because this seems like risk points
(1) parallel of the L1/L2/Neutral
(2) parallel of the batteries
(3) Do i need a fuse in lines with batteries?
(4) Startup process

[ ] I now need to study startup and any firmware updates

[ ] MPP included wifi add on's , I need to add that in i gues..

 

[Sanwizard]

Hi all,

I am down to connecting batteries and a load to call the city for a permitted off grid inspection. Appreciate a second set of eyes before flipping any switches.

Here is my plan using two MPP LV 6048 and thirty six Solarever 460 Watt panels:

View attachment 133675


The panels were installed on steel roof with slick mounting pads from S-5!

View attachment 133676

Because of my mistake, and parts were already ordered, - the LV 6048 has a max PV voltage of 115v , and my panels open voltage Voc 49v, so i had to add a lot of combiners and a lot of PV wires ... (instead of serial each row)

View attachment 133677

Every two panels in the 36 panel set is wired down to the combiners. All pairs reporting around 90 volts, and the combiner is alo reporting the same (i didn't throw the switch on these) . Inside i have this setup:
View attachment 133678
The two inverters are wired to receive the feed from the four combiners...

View attachment 133679

View attachment 133680

The two inverters AC out are paralleled as the feed into the AC cutoff switch and the output routed to my dedicated load subpanel.

View attachment 133681

I still need to:
[ ] Study the serial / connections between the MPP's and any startup details
[ ] Build the battery cables and parallel output of the MPP's to a terminal strip (bus bar) and that terminal strip for now will have a pair of matched length wires to only two 48v EG4 batteries as a starter battery pack.

Nice setup! Not sure about your location, but my local code failed me on the exposed MC4 connectors on my outside combiner box. My town required all external DC wiring to be in conduit. I know Amazon sells many variants with external MC4 connectors. I hope your area does not have that rule (not sure about NEC code).

 

[nscottsdale]

Thanks - i will post a photo soon but i did make a sheet metal cover for that 7" gap. The city specifically approved those combiners (with MC4 external) but i am aware steel raceways or condit for all dc. So my cover attempt for preventing any UV or birds nests may work out.

 

[nscottsdale]

This covered the connectors

 

[fatdaddy]

im pretty sure you cant double tap your AC connections from your disconnect switch. ive seen distribution blocks like these used before: https://www.grainger.com/product/MERSEN-Power-Distribution-Block-3-25CC40

parallel battery cables are ok, just make sure the cable can handle the combined amp load

those EG4 batteries have breakers on them, but its nice to have a 400amp fuse in between your batteries and inverters to protect the total amp draw of your battery rack

 

[nscottsdale]

Thanks, you seem to be correct on the double tapped lugs. I have an inspection next week so i need to source a solution locally. It seems as is would be electrically fine but a split lug connector which seems like a legal option?

 

[fatdaddy]

Thanks, you seem to be correct on the double tapped lugs. I have an inspection next week so i need to source a solution locally. It seems as is would be electrically fine but a split lug connector which seems like a legal option?

yeah i think its just AC code to have every wire have a separate connection. im sure there is a good reason for it. thankfully you have the whole phoenix metroplex to source materials from!

i dont know about the split lug connection. if its safe and the inspector approves it, go for it!

 

[Sanwizard]

yeah i think its just AC code to have every wire have a separate connection. im sure there is a good reason for it. thankfully you have the whole phoenix metroplex to source materials from!

i dont know about the split lug connection. if its safe and the inspector approves it, go for it!

I used Polaris connectors for the shared neutrals.

Polaris Insulated Multitap Connector, 2 Ports, 14 AWG to 4 AWG Range, L Shape, Aluminum, Plastisol, Black IT-4B | Zoro

Order Polaris Insulated Multitap Connector, 2 Ports, 14 AWG to 4 AWG Range, L Shape, Aluminum, Plastisol, Black, IT-4B at Zoro.com. Great prices & free shipping on orders over $50 when you sign in or sign up for an account.

www.zoro.com

 

[fatdaddy]

I used Polaris connectors for the shared neutrals.

Polaris Insulated Multitap Connector, 2 Ports, 14 AWG to 4 AWG Range, L Shape, Aluminum, Plastisol, Black IT-4B | Zoro

Order Polaris Insulated Multitap Connector, 2 Ports, 14 AWG to 4 AWG Range, L Shape, Aluminum, Plastisol, Black, IT-4B at Zoro.com. Great prices & free shipping on orders over $50 when you sign in or sign up for an account.

www.zoro.com

nice! are those up to code to use on the hot lines also?

 

[Sanwizard]

nice! are those up to code to use on the hot lines also?

I believe so. They are typically used to tap the lines in the main panel. I will try and find some examples.

 

[Sanwizard]

I believe so. They are typically used to tap the lines in the main panel. I will try and find some examples.

 

[fatdaddy]

thanks! ill check it out

 

[nscottsdale]

I ended up using a split bolt for a splice and covered in electrical tape.

Lets see what inspector says on Monday.

 

[nscottsdale]

Woohoo.. passed inspection !

 

[Sanwizard]

Woohoo.. passed inspection !

The tape may dry out and unravel over time. That concerns me if the split bolts are not insulated like the Polaris connectors. Glad you passed though!

 

[fatdaddy]

Woohoo.. passed inspection !

Congratulations!!

 

[1201]

How's the setup working so far? Have you had any problems with the 6048?

If you could do it over would you do the direct attach mounts, or roof rails?

Thanks