Please review my 24v skoolie system

[good sydus]

Hi all,

I would love your help reviewing my first solar setup. I already ordered the panels and battery, but everything in between is still fair game. This will be installed in a school bus conversion, and we spend a lot of time in colder weather (occasionally below 0*F, although the interior temperature should always stay above freezing).

(4x) Eco-Worthy 195W Monocrystalline Solar Panel 12v
Big Battery Hawk 24v LifePo4 170 AH 4.3kWh Battery*
Epever MPPT 40A 150V Solar Charge Controller
Victron Multiplus 3000VA 24-V Pure Sine Wave Inverter 70 amp
Victron Lynx Distributor
uxcell Voltage Converter Regulator DC/DC 24v-12v 40A 480W Buck Transformer
Arterra WF-8930 RV Distribution Center
30 Amp 125V RV Power Inlet
Ampler Battery Switch
Bussman CB185 50 Amp Circuit Breaker
AiLi Voltmeter Ammeter 100V 350A

*One important note: There is a built-in 300A fuse on the battery, which is why I don't think I'll need to fuse next to the battery. Please correct me if I'm wrong.

 

[snoobler]

Welcome to the forum.

2S2P arrays do not require over-current protection.

If used, there should be a breaker or fuse on each string.

If you just want to use the 50A breaker as shown as a disconnect, it is very important that it is rated for the Voc of the solar panels, likely 48VDC or higher for the 2S configuration. Note that breakers have much lower ratings for DC circuits than AC circuits.

MidNite Solar offers inexpensive breakers at various current ratings good to 150VDC.

I recommend you review your design against this Victron schematic for consistency:

https://www.victronenergy.com/upload/documents/MultiPlus-system-example-3KW-24V-120V-AC.pdf

 

[good sydus]

Thanks snoobler, that's a great catch. I will look into MidNite Solar's breakers instead.

 

[John Frum]

That disconnect switch looks scary.
Check the reviews on that buck converter.

 

[good sydus]

That disconnect switch looks scary.
Check the reviews on that buck converter.

Thanks for pointing this out. Most reviews seem positive on both the switch and the converter, but the bad ones definitely are concerning. Do you have any other recommendations?

I'm pretty sure I'll at least need a converter for to get down to 12v for RV lights, appliances, etc., but maybe I can get away with just using the on/off button on the battery and avoid the switch?

 

[snoobler]

Blue Sea Systems makes great switches, breakers and fuses.

 

[John Frum]

Thanks for pointing this out. Most reviews seem positive on both the switch and the converter, but the bad ones definitely are concerning. Do you have any other recommendations?

I'm pretty sure I'll at least need a converter for to get down to 12v for RV lights, appliances, etc., but maybe I can get away with just using the on/off button on the battery and avoid the switch?

Victron Energy Orion 24/12-40 DC-DC Converter with 40 Amp Output p/n ORI241240021