Blueprints for backup battery power at home

[richardw]

I am in the process of putting together a battery backup solution for my home. Listed below are the items which I have purchased so far. I am looking for the best blueprints to properly connect everything together and to learn what I am missing. I have looked at many videos of people building batteries and many solar systems use the all-in-one inverter/charger/controller systems so I haven't really seen a video or article that shows all the items put together which I will be using at this time. I am interested in possibly adding solar panels in the future, but I am not ready for it yet. I want to be able to charge my batteries from the grid under normal circumstances and from one of my generators in an extended power outage situation. I want redundancy in my solution so that is why I am starting with 2 batteries each being 12v. I have seen where it is possible to use multiple chargers and multiple inverters. To start with, I will only have one inverter and one charger, but I want to have at least 2 of each in the future. In the future, I may transition to a 24-volt solution, but I will use 12v for learning. It may be all I need, and I can use the two 12V batteries in different locations, if needed, and they would be easier to transport.

• (8) VariCore LiFePO4 cells of 280 AH capacity (will make 2 batteries of 4 cells each)
  • Purchased from AliExpress LiitokalaVariCoreFlagship Store earlier this year per the link on Will's site
• (2) Overkill Solar 12v 4S 120A BMS
  • I added the Bluetooth option to both.
• (1) AIMS Power CON120AC1224DC AC Converter & Battery 12V or 24V Smart Charger 75 amps Listed to UL 458 & CSA
• (1) Renogy 3000W 12V Pure Sine Wave Inverter RNG-INVT-3000-12V-P2
• (1) 4 Stud Bus Bar Power Distribution Block with Cover (Red & Black)
  • https://www.currentconnected.com/product/bbl46/?attribute_color=Bundle:+Black+&+Red
• (1) Kungber DC Power Supply Variable with Memory, 30V 10A Adjustable Switching Regulated DC Bench Linear Power Supply
  • for top-balancing the cells, etc.
• (1) APT, 1 mil Thick Polyimide Adhesive Tape, HighTemperature and Heat Tape
• (1) NTE Electronics 25W030 Cermet Wire Wound Resistor, 5% Tolerance, Axial Lead, 25W, Flameproof, 30 Ohm Resistance

In an emergency power situation, my goal is to power our 2 refrigerators and 1 freezer for 12 - 24 hours so that I only have to use the generator to charge the batteries. I would also want to be able to run some LED lights, a 1200W microwave, TV, radio, water pump, etc. temporarily. When all 3 refrigerators and freezer are running at the same time, they use about 427 watts as measured using a clamp meter and Kill-O-Watt meter devices. They are the most important items to keep running.

Any assistance is greatly appreciated!

 

[12VoltInstalls]

Tell us about your water pump specs
I’m not sure that renogy fits your plan very well.

As a matter of fact, I think you’re spending wrong for your description. An all-in-one auto-switching inverter/charger is about the same money up front SO while one would be fully automatic it also has the benefit of expanding and/or adding solar down the road without any the failure concerns of renogy.

Folks who know more than I can affirm this or shoot it down. (It says PowerMr which is the cards that came in the boxes of two of my Epever purchases so maybe the same company?) This makes too much sense in so many ways but maybe you should get a 24V version. (that’s 48V)

All-in-ONE Hybrid https://www.amazon.com/dp/B0969YRPKF/ref=cm_sw_r_cp_api_glt_fabc_WSAZS8WHCJ9DXP6G0W5P?psc=1

There’s better units but that’s a start. I don’t think your selections are going to meet your expectations short- or longterm.

 

[John Frum]

I am in the process of putting together a battery backup solution for my home. Listed below are the items which I have purchased so far. I am looking for the best blueprints to properly connect everything together and to learn what I am missing. I have looked at many videos of people building batteries and many solar systems use the all-in-one inverter/charger/controller systems so I haven't really seen a video or article that shows all the items put together which I will be using at this time. I am interested in possibly adding solar panels in the future, but I am not ready for it yet. I want to be able to charge my batteries from the grid under normal circumstances and from one of my generators in an extended power outage situation. I want redundancy in my solution so that is why I am starting with 2 batteries each being 12v. I have seen where it is possible to use multiple chargers and multiple inverters. To start with, I will only have one inverter and one charger, but I want to have at least 2 of each in the future. In the future, I may transition to a 24-volt solution, but I will use 12v for learning. It may be all I need, and I can use the two 12V batteries in different locations, if needed, and they would be easier to transport.

• (8) VariCore LiFePO4 cells of 280 AH capacity (will make 2 batteries of 4 cells each)
  • Purchased from AliExpress LiitokalaVariCoreFlagship Store earlier this year per the link on Will's site
• (2) Overkill Solar 12v 4S 120A BMS
  • I added the Bluetooth option to both.
• (1) AIMS Power CON120AC1224DC AC Converter & Battery 12V or 24V Smart Charger 75 amps Listed to UL 458 & CSA
• (1) Renogy 3000W 12V Pure Sine Wave Inverter RNG-INVT-3000-12V-P2
• (1) 4 Stud Bus Bar Power Distribution Block with Cover (Red & Black)
  • https://www.currentconnected.com/product/bbl46/?attribute_color=Bundle:+Black+&+Red
• (1) Kungber DC Power Supply Variable with Memory, 30V 10A Adjustable Switching Regulated DC Bench Linear Power Supply
  • for top-balancing the cells, etc.
• (1) APT, 1 mil Thick Polyimide Adhesive Tape, HighTemperature and Heat Tape
• (1) NTE Electronics 25W030 Cermet Wire Wound Resistor, 5% Tolerance, Axial Lead, 25W, Flameproof, 30 Ohm Resistance

In an emergency power situation, my goal is to power our 2 refrigerators and 1 freezer for 12 - 24 hours so that I only have to use the generator to charge the batteries. I would also want to be able to run some LED lights, a 1200W microwave, TV, radio, water pump, etc. temporarily. When all 3 refrigerators and freezer are running at the same time, they use about 427 watts as measured using a clamp meter and Kill-O-Watt meter devices. They are the most important items to keep running.

Any assistance is greatly appreciated!

You should have made a plan(including blueprint) before you bought stuff.
Its too late for you but me saying this might help the next person.
3000 ac watts / .85 conversion factor / 10 volts low cutoff = 352.941176471 service amps
Your 2x 120 amp BMSs are over matched.

I'm not saying this to offend you.

My system is a 24 volt on-line backup rig.

smoothJoey

diysolarforum.com

 

[richardw]

Tell us about your water pump specs
I’m not sure that renogy fits your plan very well.

The water pump I was referring to above is that I might look at using an RV-type water pump to pump water from our IBC totes to smaller containers or directly into the house. I do, however, have a sewage pump in my basement that I did not mention above. It is a 120v pump, but I don't know anything else about it. It runs when the water level rises to a set point in the reservoir and then it empties the reservoir. It just runs on an as needed basis.

 

[richardw]

You should have made a plan(including blueprint) before you bought stuff.
Its too late for you but me saying this might help the next person.
3000 ac watts / .85 conversion factor / 10 volts low cutoff = 352.941176471 service amps
Your 2x 120 amp BMSs are over matched.

What does over matched mean? The stuff I have purchased will work okay for now. The regular power draw is not going to be that high to run the refrigerators, freezer, etc. I will be watchful of what is running when we are using the batteries. I do not have easy access to my breaker box or external power box for doing an all-in-one system at present. My garage is on the opposite side of the house. There is concrete along the back of the house, and I do not have anywhere outside to place equipment, such as in an external shed or garage. However, I was wondering where I may need to add fuses, make sure I can connect both the charger and the inverter at the same time, etc.

 

[John Frum]

What does over matched mean?

Your inverter can pull >350 amps and your BMSs can only supply 240 amps.

 

[richardw]

Your inverter can pull >350 amps and your BMSs can only supply 240 amps.

Ah, yes. Once I have some time to test my LiFePO4 batteries (maybe today - definitely over the next week or so) and confirm that they are good, I may go ahead and purchase 4 to 8 more cells to add another battery and have some for replacements in case a cell were to go bad. Or I may decide to move up to 24 volts and make a larger system in the near future to add solar, etc. I may try to build a shed/workshop in my backyard next year where I could place solar panels and the battery backup equipment.

 

[richardw]

I would still like to see some kind of blueprint or point me to someone who has connected these kinds of components together to see how things are arranged and where to place fuses or other safety devices, as needed. My system will be offline, except when charging. I will get it out and connect devices to it when needed for emergency power situations.

 

[John Frum]

I would still like to see some kind of blueprint or point me to someone who has connected these kinds of components together to see how things are arranged and where to place fuses or other safety devices, as needed. My system will be offline, except when charging. I will get it out and connect devices to it when needed for emergency power situations.

smoothJoey

diysolarforum.com

click on "my system"
There is a hidden hover menu at the bottom of each page to navigate to other pages.
Many of the objects also include links

 

[richardw]

smoothJoey

diysolarforum.com

click on "my system"
There is a hidden hover menu at the bottom of each page to navigate to other pages.
Many of the objects also include links

Thank you! I may have some further questions about this diagram.

 

[John Frum]

Thank you! I may have some further questions about this diagram.

Will be glad to answer.

 

[richardw]

What is the purpose of the Class T Fuse where the yellow area is on the screenshot just so that I completely understand the principles behind the design?

 

[12VoltInstalls]

In case of a fault or A Bad Event you won’t have a gazillion amps burning the cables or throwing arcy-sparkies and catching things on fire. Emergency line of defense.

 

[Bud Martin]

The loads' negative should be connected to 'D.C. Neg'. of the BMS, am I correct? The drawing shows the load negatives are connected directly to the battery negative so the battery is not being protected by the BMS.

 

[richardw]

Well, after testing with my current 8 cells purchased from Aliexpress and having good results so far (except for a GFCI issue with my Renogy 3000 watt inverter), I have decided to expand. I am now in the process of purchasing 16 new EVE 304AH cells from Docan and will put together a 24v system of 604AH capacity for my home. I will continue to use the other cells in 12volts for backup and mobile uses, etc. I have not yet decided what I will connect these new cells to for purposes of charging and generating 120v AC power. However, I will have a lot of energy available for home use! My current scenario is using the solution for emergency power.

 

[HARG Hunter]

Well, after testing with my current 8 cells purchased from Aliexpress and having good results so far (except for a GFCI issue with my Renogy 3000 watt inverter), I have decided to expand. I am now in the process of purchasing 16 new EVE 304AH cells from Docan and will put together a 24v system of 604AH capacity for my home. I will continue to use the other cells in 12volts for backup and mobile uses, etc. I have not yet decided what I will connect these new cells to for purposes of charging and generating 120v AC power. However, I will have a lot of energy available for home use! My current scenario is using the solution for emergency power.

I am in the process of putting this together for a home back-up system as well.
Might at least give you some reference. I'm also in the process of adding fuses in the right spots.

Not quite running as much as you. 1 fridge, 1 freezer, internet, my wife's work computer set-up and about 10 led lights scattered around the house.
Eventually I hope to expand it to run the well pump and furnace. We have a wood fire place, so heat wouldn't be high priority if we can't run the furnace.

 

[richardw]

Now that I have decided to pull the trigger on the new 16 cells, I am seeing less options for 24v inverters. I want to be able to use 4,000 to 5,000 watts from my battery bank. It will be capable of up to 4,800 watts of output, at least. What do you all recommend for 24v? I want good quality, but lowest price I can get. I probably won't splurge for a Victron at this point. Renogy doesn't have any 24v options.

 

[richardw]

I am in the process of putting this together for a home back-up system as well.
Might at least give you some reference. I'm also in the process of adding fuses in the right spots.

Not quite running as much as you. 1 fridge, 1 freezer, internet, my wife's work computer set-up and about 10 led lights scattered around the house.
Eventually I hope to expand it to run the well pump and furnace. We have a wood fire place, so heat wouldn't be high priority if we can't run the furnace.

Thanks for sharing! I guess I could configure my cells into a 48v bank of four 12v batteries. Have you actually used that PowMr device yet to get a feel for how durable and well it works?

 

[John Frum]

The loads' negative should be connected to 'D.C. Neg'. of the BMS, am I correct? The drawing shows the load negatives are connected directly to the battery negative so the battery is not being protected by the BMS.

Only the inverter bypasses the bms but is controlled by the bms using remote switching.

 

[HARG Hunter]

Thanks for sharing! I guess I could configure my cells into a 48v bank of four 12v batteries. Have you actually used that PowMr device yet to get a feel for how durable and well it works?

I haven't even received the PowMr yet, but I've received a lot of positive input on that unit. I was going to go with a Growatt, but the PowMr version is $250 cheaper. I will pm you the website, because I'm not sure the link will be welcome here not being an endorsed product. I have heard mostly good reviews and better yet the customer service is responsive.