48V vs 24V: why/why not?

[Kwest364]

I have:
-skoolie build
-24V system
-4 x 12V 100Ah Amperetime lifepo4 batteries (5000Wh battery capacity)
-6 x 185W 36V 5A panels ~1100W (either 3s2p @ 108V 10A or 2s3p @ 72V 15A)
-gifted 30A 48V to 12V buck converter (with inline fuse)
-also have 40A 24V, but can buy higher 48-12 capacity converter
-now broken 24V Edecoa 3000W inverter. Came with bus (Edecoa brand), cheap, and temp fan (or something) stopped working recently, so I'm going to upgrade and get a new all in one, which was the plan for some time now.
-lynx distributor


Why not 48V? What are cons of 48V vs 24V besides 24V needing bigger wires and more inefficient? My system is small (1100W + 5000Wh battery capacity), but if 24V vs 48V all in one unit price is the same, why not save $ on wiring and go 48V? Could expand system later on, but will still have plenty as is.

I've decided on a growatt all in one system. Was gonna get 24V but now I'm thinking why not 48V? The only specific thing I had that was 24V specific was inverter and charge controller. I'm replacing both those, so why not 48V? Seems like at 24V, I'm just paying more for wire and I'm replacing all equipment with 48V or 24V all in one, anyways.

4 batteries in series charging issues? Other potential issues?

Buck converter at 30A: I'll never come close to that.
12v loads: 26.5Amps if all on at once
6 gal water heater 12Amps
Water pump 8Amps
Furnace 6.5Amps
Maybe some max air fans I'll install way down road.

Yes, 40A+ buck would be good for extra ceiling and I have a 24V one, but I was given a 48V 30A. I can buy a new one with higher Amp capacity.

Other reason to do 24V vs 48V?

 

[nikitis]

I have:
-skoolie build
-24V system
-4 x 12V 100Ah Amperetime lifepo4 batteries (5000Wh battery capacity)
-6 x 185W 36V 5A panels ~1100W (either 3s2p @ 108V 10A or 2s3p @ 72V 15A)
-gifted 30A 48V to 12V buck converter (with inline fuse)
-also have 40A 24V, but can buy higher 48-12 capacity converter
-now broken 24V Edecoa 3000W inverter. Came with bus (Edecoa brand), cheap, and temp fan (or something) stopped working recently, so I'm going to upgrade and get a new all in one, which was the plan for some time now.
-lynx distributor


Why not 48V? What are cons of 48V vs 24V besides 24V needing bigger wires and more inefficient? My system is small (1100W + 5000Wh battery capacity), but if 24V vs 48V all in one unit price is the same, why not save $ on wiring and go 48V? Could expand system later on, but will still have plenty as is.

I've decided on a growatt all in one system. Was gonna get 24V but now I'm thinking why not 48V? The only specific thing I had that was 24V specific was inverter and charge controller. I'm replacing both those, so why not 48V? Seems like at 24V, I'm just paying more for wire and I'm replacing all equipment with 48V or 24V all in one, anyways.

4 batteries in series charging issues? Other potential issues?

Buck converter at 30A: I'll never come close to that.
12v loads: 26.5Amps if all on at once
6 gal water heater 12Amps
Water pump 8Amps
Furnace 6.5Amps
Maybe some max air fans I'll install way down road.

Yes, 40A+ buck would be good for extra ceiling and I have a 24V one, but I was given a 48V 30A. I can buy a new one with higher Amp capacity.

Other reason to do 24V vs 48V?

So the potential factors and negatives I see with going with 48 over 24v are:
- Bigger wires on a 24v than on 48v.
- Upgrading your MPPT device to handle more amps. (Typically you would need less amps, with a 48v system, but if you want the benefit of faster charging of the batteries, you'll probably need to upgrade this, If you do not, you can still get a better charge rate than 24v but not optimal.
- Will need to buy 48v - 12v transformer to down convert for 12v appliances, and a 48-24v transformer if you had any 24v appliances, but chances are high you may not have anything that's 24v, but you'd need two transformers now if you did.
- Solar panel configuration must change. They don't typically make 48v panels so you have to have more of them in series to up the voltage to reach 48v. The way to think about it is, in parallel you are upping the amps, in series you're upping the voltage. Since the goal is to achieve high voltage at 48v, you need more panels in series keeping the amps the same, and if you want to increase the amps as well you need now more solar panels to achieve this, panels in series and parallel together to raise both. A 12v panel would require 2 panels now to reach 24v, but 48v would require 4 panels in series with no amperage increase. Wattage is higher overall though still.
- Potentially you'll need to re-arrange your battery bank and possibly add more batteries as well for a 48v charge setup, which can also require more wiring.
- Your 120v pure sinewave inverter for home appliances will need to be rated for 48v. You'll have to get a new one of those as well. You'll basically, to get optimal use out of 48v, buy all new equipment if any of your existing equipment was already at 24v to size everything right for 48v. If you are in the market and haven't purchased anything yet for 24v, then just the above considerations should be taken into account. Potentially more solar panels will be needed. I haven't looked lately but maybe you can buy panels that are 48v already within the panel, and wouldn't need as many, but the amps would remain low in such a situation.