24V or 48V

[burtinator]

Hi,

I'm planning on building a semi-offgrid system in my future shed that i'm building next year, and i'm already trying to plan a bunch of stuff in advance.
One thing i'm not sure about however is if i should go for a 24V or 48V system.
The pro's of the 48V system
- Amperage divided by 2 so thinner wires required (at todays copper prices)
- Solar charge controllers can deliver higher wattage for the same price, or you can use a cheaper model for the same wattage (using victron datasheets as reference)
The con's
- Way less hardware that supports 48V
- You need 16 batteries in series (not really a big con)
- More expensive because less hardware to choose from (somewhat, because of the lower amperage you can save some money on other things)

What are your opinions? Knowing that the system will have to power 4-5Kw

 

[Craig]

I say go for the 48. My system is 24 and if I was not so commuted to 24 already I would go 48. Mainly because of wire size and I think 48v inverters get more efficient.

 

[jobu01]

If you plan on drawing 4-5kW, I'd go with 48V. Amps will also limit what hardware will work in your system.

Some math for 5kW estimated power draw at lower end of battery (the lower the battery voltage, even more amps):
5000W / 24V = ~208A (continuous draw at 208A means wire needs to support 125%*208A = >260A)
5000W / 48V = ~104A (same as above, continuous needs 130A capable wires)

Knowing your amp requirement, the amount of hardware that will support a 24V system is also limited.

 

[Bluemalibu]

What are some reliable inverters for the 48v system in this 4-5kW range?

 

[burtinator]

I'm planning on going for the victron phoenix inverters, these can be parallelled (or even put in 3phase which i might also do, not sure yet)
I'm going to start off with one inverter and see how far i'm going to get with one, if it isnt enough i'll parallel a second one.
But first i need to build the shed ofcourse but thats for springtime