I'm new to solar setup so need advice.

[Rocketman]

A 48v 100ah battery is equivalent to four 12v 100ah batteries- but with much smaller wires

A 48v 280ah battery is about equivalent to eleven 12v 100ah batteries.

That is why on large systems (and constant air conditioners needs a large system) 48v is much better.

 

[Toddp]

A 48v 100ah battery is equivalent to four 12v 100ah batteries- but with much smaller wires

A 48v 280ah battery is about equivalent to eleven 12v 100ah batteries.

That is why on large systems (and constant air conditioners needs a large system) 48v is much better.

Four 12v 100ah batteries in series make 48v 400ah. Yes you use smaller wire and less draw and more efficient on a 48v battery and 12v adds more heat and power loss. Most people would love to have 48v 280ah batteries but a $5k and up price tag is to much for most of us when we can get a LOT more power and AH of $5k worth of 12v batteries then ok be $5k 48v battery. Guess a lot of us will be stuck with 12v or 24v batteries.
Thank you all for your help, I would live multiple 48v 280ah batteries but such high price tags it's not feasible for me.

 

[cdherman]

I don't understand how 4 12v 100ah batteries stringed together making 48v 400ah is lower then 1 48v 280ah battery how that same 48v battery is equivalent to 11 12 v batteries. That's where I'm confused.

It don't work that way. 4 12v 100ah batteries in series = 1 48v 100ah battery. NOT 400ah. Now you see why a 48v 280ah battery is should be roughly 3x more expensive than 4x 12v 100ah bats.

To elaborate, perhaps clarify. You could run 4 12v 100ah batteries in parallel. Then you would have 12v with 400ah capacity.

You cannot add both. One or the other.

 

[Tomthumb62]

don't understand how 4 12v 100ah batteries stringed together making 48v 400ah

4x 12v 100Ah batteries in series = 48v 100Ah

4x 12v 100Ah batteries in parallel = 12v 400Ah

 

[Madcodger]

And, you get basically the same amount of usable power either way, as 12 x 400 = 4800, and 48 x 100 also = 4800. The difference is that the 48V system may be a bit more efficient, with less loss to heat and certainly requiring smaller cables, which is a big plus (and cheaper).

I just looked on Amazon, and a 12v, 100ah LiFePO4 battery is about $350 (some a bit more $, some less, but that's a decent average for a quality battery). However, you need 4 of them to get the same usable power as from a single 48v, 100 ah battery, which costs about $1400. So, if you need 4800 watt hours of power, it's about the same price, EXCEPT you'll need larger cables for the 12v system, which costs more.

There are lots of people who think they save money with a 12 volt system, and that's sometimes true for very SMALL systems. But once your power needs start to increase, higher voltage is your friend, largely because it decreases the size of your cabling and will likely take up less space in the battery area. I built my system with 24V for these reasons. Looking back, I wish I had just started at 48V.