48V Electrical Concept

Assumptions

• 48V 200AH LFP
• 24V Fridge and Freezer
• Quattro 48/3000/35-50/50 120V ($1855)
• 48V Alternator
• 1 48V to 24V converter (1500W) Candidate ($99) (or skip 24V all together)
• 1 48V to 12V converter (? W) Candidate ($37)
• Smart Solar 100/20-48 ($166)
• Need HV Solar panels so would use Panasonics (Victron MPPT "chooser" says they should work)

Open Questions

• Does REC BMS that supports 48V also support Victron? Yes

• Does Wakespeed 500 support 48V? Yes according to Nation's? Yes according to Nations and Wakespeed manual.

Benefits

• MPPT is 0.65 kg and 678000 mm³ and $166 for 48V vs 3 kg and 4393750 mm^3 and ~$450 for 24V vs 4.5 kg and 6563160 mm^3 and $700 for 12V
• Alternator line temperature rise will be 1/16 of 12V for equivalent wire.
• Second Quattro AC input can be used for Orton Method charging with an independent current limit.
• Much smaller wire and forgiveness on lugged connections

Downsides

• Known latching relays are limited 12V and 24V (Gigavac)

• Known high efficiency (~1W) non-latching relays are limited to 12V and 24V (Gigavac) vs ~8W

• BlueSea Remote Battery Switch is limited to 12V or 24V

• Not all MEGA fuses are rated beyond 24V

• Inverter is same size, 5W higher no load, and same weight for 24V and 12V (but more expensive)

• Extra parasitic draw for 12V (and 24V if optioned) conversion

• Extra loss for 24V conversion

• This post from forum user Van Gohg sums it all up

Similar/Equavalent Wire Comparisons:

12v to 48v Equivalent Voltage Drop % and Equal Loss for the Same Transmitted Power

V=IR. Because I has decreased by 1/4 and Vsource has increased by 4, to achive the same fraction of Vsource/Vdrop, Vdrop must also double. This implies R must increase by a factor of 16.

P = R*I². I has decreased by a factor of 1/2, thus I² has decreased by a factor of 1/16. This implies R must increase by a factor of 16.

4/0 becomes 8 AWG [TODO: Check the math on all these]

2 AWG becomes 14 AWG

12v to 48v Equivalent Ampacity for Same Power

4/0 becomes 6 AWG

50 ft 4/0 Ancor = $290

50 ft 2/0 Ancor = $215

50 ft 2 AWG Ancor = $119

50 ft 4 AWG Ancor = $85

50 ft 8 AWG Ancor = $52

48V Contactor Options:

GigaVac Minitactor - NO, I=80A, P_{coil_at_54v}=2.7W

GigaVac HX22 - NO, I=300A, P_{coil_48V_listed}=7.8W

GigaVAc HX200 - NO, I=350, P_{coil_48V_listed}=2.1W

GigaVAc HX21 - NO, I=350A, P_{coil_48V_listed}=2.1W

GigaVAc HX241 - NO, I=400A, P_{coil_48V_listed}=2.0W

Most GigaVac MX series are generally 7.6W at 48V

GigaVAc MX23 - NO, I=300A, P_{coil_48V_listed}=2.0W, P_contact@300A=45W

GigaVAc MX14,MX64,MX15 - NO, I=400A, P_{coil_48V_listed}=2.0W, P_contact@400A=60W, R_{contact_max}=0.375ohm

Most GigaVac GX series are 7.6W at 48V

GigaVac GV200 - NO, I=500A, P_{coil_48V_listed}=2.0W, P_contact@500A=38-100W

GigaVac GX14,GX23,GX24,GX34,GX54 - NO, i=350A, P_{coil_48V_listed}=2.0W, P_contact@350A=18-49W

Most GigaVac GV series are 7.6W or 6W at 48V

GigaVac GV240,GV140 - NO, I=400A, P_{coil_48V_listed}=2.0W, P_contact@400A=48-54W

TYCO makes an attractive option - KILOVAC EV200:

P_{coil_48V_listed}=1.44W, P_{contact_typ@400A}=32W