I am finalizing my RV solar design and like many drifted back and forth between 12v and 24v. I was all set on 24v but swung back to 12v for the following reasons.
8x LF304 EVE cells from Amy
2x 4s 150a JBD Smart BMS
Planned:
3x to 5x - 415w Trina Tallmax panels
Appropriate SmartSolar MPPT - Likely 150/100 for 12v or 150/60 for 24v, panels will be flat mounted and used mostly in the northeast so I want to over panel decently.
Victron 12 or 24 / 3000 Multiplus (single leg 30 amp shore service will remain so no advantage for Multiplus II)
- 24v makes each BMS a single point of failure for the whole system. I want to be able to remove the battery bank from the RV during the winter (stored in cold upstate ny) for storage and or maintenance. This means building 2x 4 cell batteries vs a single 8x cell battery which would weigh about 100lbs. I can still wire them in serial or parallel to get 12v or 24v but at 24v if one battery/BMS has an issue the whole system is down. Using DIY batteries mean I cant quickly replace a bad battery while on the road.
- 24v requires a DC-DC converter (Orion 24/12-70) since everything but the inverter would run off 12v. I could buy two to make address this single point of failure but that would wipe out much of the savings on MPPT. I could also leave the OEM 55amp converter installed but disconnected and use 120v from the inverter to supply power to the 12v side of the RV as a fall back.
- I like the decreased current and smaller wire requirements but all of my components will be house right next to each other. No long runs are necessary.
- At 12v or 24v I will be using a small dedicated frame mount emergency brake battery to keep it totally separate from the rest of the system.
8x LF304 EVE cells from Amy
2x 4s 150a JBD Smart BMS
Planned:
3x to 5x - 415w Trina Tallmax panels
Appropriate SmartSolar MPPT - Likely 150/100 for 12v or 150/60 for 24v, panels will be flat mounted and used mostly in the northeast so I want to over panel decently.
Victron 12 or 24 / 3000 Multiplus (single leg 30 amp shore service will remain so no advantage for Multiplus II)