Wiring Diagram

[redrock514]

I am over my head and I would greatly appreciate some help. I am trying to construct a supplemental PV system. I bought the MPP inverter charger, model PIP1012LV-MS. I also bought two 345W Q Cell. I plan on buying a battery, not sure which kind yet. The system is for a house that is also connected to the grid. I would like to connect the PV system to my house system. I know 700W will only power a fraction of the my house load. I do have an electrician willing to do the connection, but he wants a wiring diagram and he will not do any design. I am not really sure how to connect to my house system. I think I need a secondary panel. I prepared a wiring diagram and found a dual switch and circuit on amazon that might work (see attached files). Would anybody be willing to review and offer me some much needed feedback and comments?

Jared

 

[MisterSandals]

I’ll start with the easy battery, how many question.
690w x 5hrs peak sun (ymmv) = 3450wh per day at 100% unrealistic efficiency.
So each sunny day you can charge 3450wh/12v = 287.5 ah of battery(s).

If you plan on using 100% of your batteries everyday, you should strongly consider LiFePO4 battery(s).

 

[Forbisher]

I’ll start with the easy battery, how many question.
690w x 5hrs peak sun (ymmv) = 3450wh per day at 100% unrealistic efficiency.
So each sunny day you can charge 3450wh/12v = 287.5 ah of battery(s).

If you plan on using 100% of your batteries everyday, you should strongly consider LiFePO4 battery(s).

That MPP has a 40A SCC at 12V is 480w
MPP recommends 500w of panels.
690w is over paneled.
Also only has a 1000w inverter.
I have 100Ah LFP on the same unit.
MPP recommends 109A max.

 

[Forbisher]

I bought the MPP inverter charger, model PIP1012LV-MS.
Would anybody be willing to review and offer me some much needed feedback and comments?

Read your tiny printed manual.
16 AWG is the recommended size output from your small 1000w inverter and input from main power.
100Ah is the recommended battery.
You have a 40A SCC so will not get more than about 500 watts.

You were getting answers on this thread so why start another one?

Wiring Diagram

I am over my head and I would greatly appreciate some help. I am trying to construct a supplemental PV system. I bought the MPP inverter charger, model PIP1012LV-MS. Same as the one reviewed and recommended by Will Prowse on this website. I also bought two 345W Q Cell. I plan on buying a...

diysolarforum.com

 

[redrock514]

That MPP has a 40A SCC at 12V is 480w
MPP recommends 500w of panels.
690w is over paneled.
Also only has a 1000w inverter.
I have 100Ah LFP on the same unit.
MPP recommends 109A max.

Thank you for the response. A responder on my previous thread suggested I post in the All-In-One Systems forum as members here would be more familiar with my system.
Attached is a photo of the specs for the inverter. Thank you for catching the overheating issue. Would it overheat only if the electrical load was not consuming at least 190W? Is there any simple solutions to this? or do I need to upgrade the inverter... uugh. I am confused as to why the unit has a 1000W inverter, but only a 500W charger.

 

[Forbisher]

Thank you for the response. A responder on my previous thread suggested I post in the All-In-One Systems forum as members here would be more familiar with my system.
Attached is a photo of the specs for the inverter. Thank you for catching the overheating issue. Would it overheat only if the electrical load was not consuming at least 190W? Is there any simple solutions to this? or do I need to upgrade the inverter... uugh. I am confused as to why the unit has a 1000W inverter, but only a 500W charger.

Yeah I have one so I know what is on the label so they were right.

I never said anything about over heating.
You can attach 690 watts of panels but you will not get more than 500 watts due to the 40A SCC.
You could over panel to 800w.

Where did you get 6 AWG cable from for the inverter output?
You only need 16 AWG as its 8.3A at 120V
Please read your printed manual.

You can not upgrade the inverter or anything on this All in One.

 

[redrock514]

I got the 6AWG cable from the list here. I did not size it (see attached screenshot) or link

All-in-One Solar Power Packages

MPP and a few other manufacturers now sell a "complete off grid system in a box" that has: AC Inverter Solar Charge Controller AC Battery Charger Automatic Transfer Switch (if grid power is...

www.mobile-solarpower.com

I'm not even sure I have the right manual. It says it is for models 1KV to 5KV. Is mine a 1KV? It seems to say a 4 or 8 AWG...

So would I only need one 12V 100amp BattleBorn or equivalent?

 

[Forbisher]

I got the 6AWG cable from the list here. I did not size it (see attached screenshot) or link

All-in-One Solar Power Packages

MPP and a few other manufacturers now sell a "complete off grid system in a box" that has: AC Inverter Solar Charge Controller AC Battery Charger Automatic Transfer Switch (if grid power is...

www.mobile-solarpower.com

I'm not even sure I have the right manual. It says it is for models 1KV to 5KV. Is mine a 1KV? It seems to say a 4 or 8 AWG...

So would I only need one 12V 100amp BattleBorn or equivalent?

Yes 1000 watt inverter is 1Kva
4 AWG is from the MPP to your battery plus and minus terminals.
2 wires x 8 AWG is to confuse newbs like you.
6 AWG on the flyer is just more confusion.
Have you taken the bottom cover off and looked at the connections?

16 AWG is for your inverter to your loads. I use an extension cord.

Yes I use a 100Ah Battle Born.
12 8V x 100Ah is about 1280 watt hours which is what your panels will be charging.

 

[redrock514]

Yes 1000 watt inverter is 1Kva
4 AWG is from the MPP to your battery plus and minus terminals.
2 wires x 8 AWG is to confuse newbs like you.
6 AWG on the flyer is just more confusion.
Have you taken the bottom cover off and looked at the connections?

16 AWG is for your inverter to your loads. I use an extension cord.

Yes I use a 100Ah Battle Born.
12 8V x 100Ah is about 1280 watt hours which is what your panels will be charging.

OK, I've changed the wiring size on the diagram and added the battery size.
What do you think of the transfer switch/panel?
Any other suggestions?
Thank you so much.

 

[Hedges]

... I am trying to construct a supplemental PV system. I bought the MPP inverter charger, model PIP1012LV-MS. ... I know 700W will only power a fraction of the my house load. ...

You haven't said you wanted to power something during grid failure, the only reason to build a battery system.
I wouldn't use that inverter if the goal was simply to reduce utility power consumption and the utility bill.
It is suitable to make a battery backup system, like to keep computer/internet equipment operating during a power failure.
Or for a portable system, like for an RV.

I would use a grid-tie inverter. With PV panels connected, it is just an "appliance" that delivers power instead of consuming power.
And I would put in more than 700W of PV.

 

[redrock514]

You haven't said you wanted to power something during grid failure, the only reason to build a battery system.
I wouldn't use that inverter if the goal was simply to reduce utility power consumption and the utility bill.
It is suitable to make a battery backup system, like to keep computer/internet equipment operating during a power failure.
Or for a portable system, like for an RV.

I would use a grid-tie inverter. With PV panels connected, it is just an "appliance" that delivers power instead of consuming power.
And I would put in more than 700W of PV.

Yes! The primary purpose is to power some LED lights and few electronics (phone chargers, laptop, router) during a power outage. My thought is that I might as well put the system to use when I'm not needing back up power. I've maxed out the budget I want to spend on this. If I am going about this the wrong way, I'm open to suggestions (keeping in mind I've already bought the inverter). Thank you for the comments, very helpful.

 

[Hedges]

Yes! The primary purpose is to power some LED lights and few electronics (phone chargers, laptop, router) during a power outage. My thought is that I might as well put the system to use when I'm not needing back up power. I've maxed out the budget I want to spend on this. If I am going about this the wrong way, I'm open to suggestions (keeping in mind I've already bought the inverter). Thank you for the comments, very helpful.

OK, then this system should be perfect as a UPS with PV to power electronics during an outage. PV may or may not be used for power while the grid is up, but cost-wise that doesn't matter for a small system. You can probably also run a small refrigerator while the sun shines, disconnect in the evening so a small battery lasts the night for electronics. The battery is 100 Ah 12V? 1200 Wh at 100% DoD, maybe 1000 Wh at a suitable DoD. That is about 2 hours PV production out of 5 hours available. You can use about 1500 Wh during the day, 1000 Wh during the night. Over 12 hours, 80W on average.

Try to set it up so it doesn't cycle the batteries except during grid failures. And, doesn't float the batteries at 100% charge. Lithium lasts longer at a lower state of charge, and cycling the battery (e.g. to charge from PV and discharge every night) will wear out a battery that costs more than PV or grid. So you're better off having the PV sitting there doing nothing, keep the battery around 50% charged, and use grid power while it is up.

I thought about doing that for our internet/VOIP, but have put in a whole-house UPS at much greater expense. It is still subject to low-battery disconnect, so I may set up a 12V system of AGM battery and PV panel. All that equipment uses 12 VDC adapters, so I would make several fused taps off the battery and use an AC charger for float plus PV. I have a spare 100 Ah battery which would supply multiple days operation.

 

[redrock514]

OK, then this system should be perfect as a UPS with PV to power electronics during an outage. PV may or may not be used for power while the grid is up, but cost-wise that doesn't matter for a small system. You can probably also run a small refrigerator while the sun shines, disconnect in the evening so a small battery lasts the night for electronics. The battery is 100 Ah 12V? 1200 Wh at 100% DoD, maybe 1000 Wh at a suitable DoD. That is about 2 hours PV production out of 5 hours available. You can use about 1500 Wh during the day, 1000 Wh during the night. Over 12 hours, 80W on average.

Try to set it up so it doesn't cycle the batteries except during grid failures. And, doesn't float the batteries at 100% charge. Lithium lasts longer at a lower state of charge, and cycling the battery (e.g. to charge from PV and discharge every night) will wear out a battery that costs more than PV or grid. So you're better off having the PV sitting there doing nothing, keep the battery around 50% charged, and use grid power while it is up.

I thought about doing that for our internet/VOIP, but have put in a whole-house UPS at much greater expense. It is still subject to low-battery disconnect, so I may set up a 12V system of AGM battery and PV panel. All that equipment uses 12 VDC adapters, so I would make several fused taps off the battery and use an AC charger for float plus PV. I have a spare 100 Ah battery which would supply multiple days operation.

This is interesting. First, what is UPS?
So what I am getting is that I'm only going to be saving pennies if I connect the system to the house because it is so small.
The battery suggestion is very insightful. Should I not connect the battery? Just put a trickle charger on it and then only connect it during an outage?
What is the best way for to power house lights off the PV? Should I plan on using a power bar connected to the inverter and plug in some lamps? Or is the secondary panel with the transfer switch an option (shown in my wire diagram)?

 

[Hedges]

This is interesting. First, what is UPS?
So what I am getting is that I'm only going to be saving pennies if I connect the system to the house because it is so small.
The battery suggestion is very insightful. Should I not connect the battery? Just put a trickle charger on it and then only connect it during an outage?
What is the best way for to power house lights off the PV? Should I plan on using a power bar connected to the inverter and plug in some lamps? Or is the secondary panel with the transfer switch an option (shown in my wire diagram)?

"UPS" is short for Uninterruptable Power Supply. You can buy those to keep your PC or other equipment running for a short while on batteries.

Batteries should be stored at optimal state of charge and temperature. Cool but not freezing is best for most batteries. 100% full either floated at a low voltage or periodically recharged is best for lead-acid (AGM can go 6 months or more between recharging), but lithium should not be fully charged except if you need maximum capacity and will use it immediately. You shouldn't fully charge a car the night before a long drive, it should reach 100% just before you leave in the morning. For shorter trips, should only be partially charged.

Keeping the batteries connected lets you have UPS operation, so internet stays up. When we have a grid failure and I manually transfer the house from grid to battery backup, our VOIP box gets hung. I need to power-cycle it again after U-Verse is back up to get the phone working. Once I have it all set up as UPS we should have uninterrupted communications. Your inverter may have a "PV priority" or "grid priority" option, so it could be set to just pass through grid most of the time and switch to PV/battery during power failures.

Best way to get light from the sun is open the shades. Oh, you mean from battery? For a small system, just hook up a lamp with LED bulb, turn it on when you need it. Panels and transfer switches connected to the house are an expensive option, not cost effective when you have limited capacity. Just run an extension cord to the refrigerator and plug it in during the daytime (or get an electronic timer from Harbor Freight) for extended outages.

What I've done for an economical whole-house transfer switch is install a Square-D interlock (piece of sheetmetal) on my breaker panel. That lets me turn on a branch circuit breaker connected to output of inverter after I turn off the main. It prevents both breakers from being connected at the same time.

 

[Forbisher]

So what I am getting is that I'm only going to be saving pennies if I connect the system to the house because it is so small.
The battery suggestion is very insightful. Should I not connect the battery? Just put a trickle charger on it and then only connect it during an outage?
What is the best way for to power house lights off the PV? Should I plan on using a power bar connected to the inverter and plug in some lamps? Or is the secondary panel with the transfer

First decide if you are buying a LFP battery or initially cheaper AGM.
A LFP does not need a trickle charger.
There are cheaper 100Ah LFP batteries than a $950 Battle Born.
Low $600 right now.

Your MPP needs a battery connected to accept solar power or use the inverter.
The few lights etc you are powering do not need a 1000 watt inverter but you could run your fridge during a power outage.
And make coffee, toaster but 1000 watts will not run your microwave.

 

[redrock514]

"UPS" is short for Uninterruptable Power Supply. You can buy those to keep your PC or other equipment running for a short while on batteries.

Batteries should be stored at optimal state of charge and temperature. Cool but not freezing is best for most batteries. 100% full either floated at a low voltage or periodically recharged is best for lead-acid (AGM can go 6 months or more between recharging), but lithium should not be fully charged except if you need maximum capacity and will use it immediately. You shouldn't fully charge a car the night before a long drive, it should reach 100% just before you leave in the morning. For shorter trips, should only be partially charged.

Keeping the batteries connected lets you have UPS operation, so internet stays up. When we have a grid failure and I manually transfer the house from grid to battery backup, our VOIP box gets hung. I need to power-cycle it again after U-Verse is back up to get the phone working. Once I have it all set up as UPS we should have uninterrupted communications. Your inverter may have a "PV priority" or "grid priority" option, so it could be set to just pass through grid most of the time and switch to PV/battery during power failures.

Best way to get light from the sun is open the shades. Oh, you mean from battery? For a small system, just hook up a lamp with LED bulb, turn it on when you need it. Panels and transfer switches connected to the house are an expensive option, not cost effective when you have limited capacity. Just run an extension cord to the refrigerator and plug it in during the daytime (or get an electronic timer from Harbor Freight) for extended outages.

What I've done for an economical whole-house transfer switch is install a Square-D interlock (piece of sheetmetal) on my breaker panel. That lets me turn on a branch circuit breaker connected to output of inverter after I turn off the main. It prevents both breakers from being connected at the same time.

Thank you for your time.
I still need a little more info. What I am hearing is that I can connect the battery, but use the grid priority setting (which the inverter has). Now, any suggestions on how to cheaply connect to the grid? Is that where the Square-D interlock comes in?

 

[Hedges]

To feed the inverter cheaply from the grid, just attach a cord (14 AWG) with standard plug and plug it into a wall outlet.
To power appliances, plug them into the inverter.

If you want to power any and all 120V appliances in the house, that is where the interlock comes in. Has to be the right one for your particular breaker panel. You would use/install a breaker adjacent to the main breaker. Turn off all double-pole breakers so they and 120V appliances on the other half don't experience brownout. I think you could also use the 120V inverter to feed both halves of the panel (both legs of the breaker.) Ordinarily, doing that is bad because neutral wires on some circuits could carry too much current. But if your inverter can't even put out 15 or 20A it won't be a problem.

For batteries, if you want AGM I see SunXtender 1040 for (100 Ah 12V) for about $325. That's cheaper than lithium but won't last as many cycles. For standby and only draining to 70% DoD a few hundred times it should last 10 years. Lithium can be cheaper if you drain it daily because AGM would have to be replaced more often.

 

[redrock514]

To feed the inverter cheaply from the grid, just attach a cord (14 AWG) with standard plug and plug it into a wall outlet.
To power appliances, plug them into the inverter.

If you want to power any and all 120V appliances in the house, that is where the interlock comes in. Has to be the right one for your particular breaker panel. You would use/install a breaker adjacent to the main breaker. Turn off all double-pole breakers so they and 120V appliances on the other half don't experience brownout. I think you could also use the 120V inverter to feed both halves of the panel (both legs of the breaker.) Ordinarily, doing that is bad because neutral wires on some circuits could carry too much current. But if your inverter can't even put out 15 or 20A it won't be a problem.

For batteries, if you want AGM I see SunXtender 1040 for (100 Ah 12V) for about $325. That's cheaper than lithium but won't last as many cycles. For standby and only draining to 70% DoD a few hundred times it should last 10 years. Lithium can be cheaper if you drain it daily because AGM would have to be replaced more often.

OK, I think I'm getting this. I will work on revising the diagram. Thank you!