FilterGuy
Solar Engineering Consultant - EG4 and Consumers
Unfortunately no, it does not work that way. Lets talk about some basics.
* When putting the cells in series, the voltage adds, but the Ah stays the same. So four 400Ah cells wired in series would 12 Volt but only 400 Ah.
* When putting the cells in parallel, the Ah adds but the voltage stays the same. So four 400Ah cells wired in parallel would be 1600Ah but only ~3.2 volts.
Amp-hour is a useful measure, but it does not tell you energy storage. To get the energy storage, you must multiply it by the voltage to get Watt hours (Wh).
You might want to review the notes in this resource about wiring up cells
https://diysolarforum.com/resources/cell-configurations-for-12v-24v-and-48v-lifepo4-batteries.42/
First, lets be clear about the energy storage
1600Ah @ 48V: 48V x 1600Ah = 76800Wh
1600Ah @ 28V: 24V x 1600Ah = 38400Wh
1600Ah @ 12V: 12V x 1600Ah = 19200Wh
What is the energy storage (in Wh) that you need?
Note: One of the air conditioners you discussed before will draw 6.8Ax230V=1564W. So it takes 1564W to run it for one hour. Lets assume they are on a thermostat and don't run continuously.
For a quick calculation I will assume they are on 50% of the time, so in a 24 hour period it is 12 hours of running. That means it will consume 18768Wh in a day.
Back to your question. Yes, there are advantages to running higher voltages. The primary advantage is that the current is much lower so your wires can be much smaller.
Going back to your air conditioner. On the DC side of the inverter, to get the 1564W, you will be drawing much less current for the same power
@ 12V: ~1564W / 12V = 130.3A
@ 24V: ~1564W / 24V = 65.2A
@ 48V: ~1564W / 48V = 35.6A
