48v battery bank to 12v inverter.

[macy]

Good evening everyone. I have read a ton of great information and so glad I found this site to learn with others. I have a idea in my head that im trying to figure out. If a battery bank is charged to 48v buy 10x 220watt panels is there a way to regulate the voltage feeding into a 12v inverter? My inverters are both 12v 5000watts 10,000 peak. and can take 15v. during the day I can power all my needs just fine with the charge controller steady providing 14.5 volts. In the evening the 8x 12v lead acid battery's Im currently using drop super fast if I use a heater or cooker. I would like to use 2nd life nimh hybrid cells with 4x banks of 48v each that will discharge from 48v to 12v running a heater over night. I have been testing the nimh cells at 12v and plan to use them like that if the 48v is not something that is possible. Step down or "buck" converters will not carry the amount of power needed for a 5000watt inverter. what I am looking for is a devise that will allow me to steady feed the inverter 14.5v from a 48v battery pack hopefully this will make since to people reading. Its hard to explain whats in my head down on paper. thanks

 

[robby]

Sure you can step down the voltage but as you already surmised your going to take a pretty big hit in efficiency. It would be simpler to just rework the batteries into a 12V pack and buy a 12V based charge controller system for those panels.

 

[rmaddy]

You really have a 5000W inverter that runs off of 12V? That's nuts. You need to pull almost 500A from the batteries for a 5000W inverter load. You are not going to find a reasonable way to convert 48V to 12V at 500A.

Why not buy a 48V 5000W inverter? Then it will work just fine with a 48V battery bank and it will only pull about 125A which is much saner.

 

[robby]

You really have a 5000W inverter that runs off of 12V? That's nuts. You need to pull almost 500A from the batteries for a 5000W inverter load. You are not going to find a reasonable way to convert 48V to 12V at 500A.

Why not buy a 48V 5000W inverter? Then it will work just fine with a 48V battery bank and it will only pull about 125A which is much saner.

That was my first thought but I figure he is not going to want to part with those two Inverters. I am assuming he does not even push them close to max and I wonder if that is not peak power figures.
My second issue is the use of NiMH batteries from an old Hybrid.

 

[Rednecktek]

That was my first thought but I figure he is not going to want to part with those two Inverters.

I'd lay money those are the Harbor Freight 5kw Modified sine inverters.

@macy : Chuck those fire hazards please and just go for a 48v 5Kw Pure Sine inverter. At 500a of draw you're talking AWGFRIGGINHUGE wire and a flamethrower.

Inverters are cheaper than fires, and pure sine inverters are cheaper than replacing all your appliances when they burn out.

 

[macy]

I'd lay money those are the Harbor Freight 5kw Modified sine inverters.

@macy : Chuck those fire hazards please and just go for a 48v 5Kw Pure Sine inverter. At 500a of draw you're talking AWGFRIGGINHUGE wire and a flamethrower.

Inverters are cheaper than fires, and pure sine inverters are cheaper than replacing all your appliances when they burn out.

Yes you are correct about the inverters. What brand 48v inverter would you recommend?

 

[Bud Martin]

Good evening everyone. I have read a ton of great information and so glad I found this site to learn with others. I have a idea in my head that im trying to figure out. If a battery bank is charged to 48v buy 10x 220watt panels is there a way to regulate the voltage feeding into a 12v inverter? My inverters are both 12v 5000watts 10,000 peak. and can take 15v. during the day I can power all my needs just fine with the charge controller steady providing 14.5 volts. In the evening the 8x 12v lead acid battery's Im currently using drop super fast if I use a heater or cooker. I would like to use 2nd life nimh hybrid cells with 4x banks of 48v each that will discharge from 48v to 12v running a heater over night. I have been testing the nimh cells at 12v and plan to use them like that if the 48v is not something that is possible. Step down or "buck" converters will not carry the amount of power needed for a 5000watt inverter. what I am looking for is a devise that will allow me to steady feed the inverter 14.5v from a 48v battery pack hopefully this will make since to people reading. Its hard to explain whats in my head down on paper. thanks

So right now you have SCC 12V system.
How are you charging the 48V system right now? You also have SCC 48V system?

 

[time2roll]

Resell the flimsy 12 volters and get a quality 48v inverter. Lower cost than a stack of 48-12 converters.

 

[sunshine_eggo]

I would like to use 2nd life nimh hybrid cells with 4x banks of 48v each that will discharge from 48v to 12v running a heater over night. I have been testing the nimh cells at 12v and plan to use them like that if the 48v is not something that is possible. Step down or "buck" converters will not carry the amount of power needed for a 5000watt inverter. what I am looking for is a devise that will allow me to steady feed the inverter 14.5v from a 48v battery pack hopefully this will make since to people reading. Its hard to explain whats in my head down on paper. thanks

Bad idea from the start. Heaters are devastatingly power hungry and among the most stressful applications for off-grid.

NiMH must NOT be placed in parallel - EVER, unless you know why and design around it.

You must NOT run a 48V NiMH pack down to 12V - bad idea. They are empty at 1.0V/cell.

2nd life NiMH is not good for anything unless you're talking about an EV1 pack (all were crushed) or Rav4 EV pack ( 20 years old and only about 2000 ever made) with the large format NiMH.

I have about 30kWh of NiMH, and I wouldn't dream of using it in a power application.

 

[macy]

Scrapped the idea of charging to 48v. Instead yesterday I used 50 cells together and charge to 14.5v. If each cell is 6.5ah that should make for a 325ah battery. I started testing this morning at 6:30am using a 12v power inverter to run the furnace, coffee maker, lights and charge my lap-top and phones. also used the microwave a couple times for breakfast. Now 5hr later the battery bank voltage is at 14v so in 5hrs it has only dropped .5v. I am very pleased with this system esp. today with the snow is covering my panels.
Most solar yard lights and RC toys have been powered by NiMH for years so I am just doing the same thing on a larger scale. If you research the technology people all over the world are using the 2nd life NiHM batteries for solar and wind storage. as you will see in the articles below.

https://www.motortrend.com/news/toyota-hybrid-batteries-help-yellowstone-national-park-lighten-up/

Islas Secas Island Microgrid | Microgrid Projects

microgridprojects.com