Shuttle Bus Conversion - New Installation with an EG4 3000EHV-48 - Looking for some guidance on design and installation please.

[DioRox]

Hello there. Looking for some assistance with our shuttle bus solar installation. We are not utilizing anything from the bus, so everything we will be using is new. Here is a list of our parts that we intend on using...

• EG4 3kW Off-Grid Inverter | 3000EHV-48 | 3000W Output | 5000W PV Input | 500 VOC Input
• (1) EG4 LifePower4 Lithium Battery | 48V 100AH | Server Rack Battery
• (4) SunPower 360-Watt solar panels | VOC – 69.5 | Impp 6.09A for a total of 1,440 watts
• BZONE DC 48V Step Down to DC 12V 30A 360W Voltage Reducer Converter Golf Cart Voltage Regulator
• WUPP Boat Marine Fuse Block Panel with LED Warning Indicator Damp-Proof Cover - 12 Circuits with Negative Bus Fuse Box Holder Screw for Car Marine RV Truck DC 12-24V (just in case this was needed)

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Our usage at the moment consists of -

• LF Bros Professional 110V/12V 5KW Diesel Heater (the amps are a mystery at this point, I've emailed them)
• CONTOURE 10.7 cu. ft. 12V DC Power Frost-Free Compact Refrigerator rated at 9A
• SEAFLO 12V Water Pump with a max draw of 6.74A (when Amazon can get it to me without getting lost in transit)
• We have no AC at this time but in the future would like to add a hybrid mini-split

I guess I'm feeling a bit intimidated with how/where to wire up the voltage reducer/transformer. Unsure of parallel vs serial. We don't need 48 volt, just 12v across the board. Any guidance would be appreciated very much. Thank you.

 

[HRTKD]

For the amount of solar you plan and the low load requirements, a 48 volt system is overkill. But, since this is a from-scratch build, you can go with whatever voltage you want. I have a 48 volt Victron system in my camper, but only because I'm going to have 2500 watts of PV on the roof.

For your PV configuration, you can do 2s2p or 4s. Your solar charge controller can handle either. You could do 4p also, but that's a lot of extra connections and fuses.

The 48-12 converter will need fuses or circuit breakers on both sides.

 

[DioRox]

For the amount of solar you plan and the low load requirements, a 48 volt system is overkill. But, since this is a from-scratch build, you can go with whatever voltage you want. I have a 48 volt Victron system in my camper, but only because I'm going to have 2500 watts of PV on the roof.

For your PV configuration, you can do 2s2p or 4s. Your solar charge controller can handle either. You could do 4p also, but that's a lot of extra connections and fuses.

The 48-12 converter will need fuses or circuit breakers on both sides.

Thank you for a response. Yes, a 48v system is overkill, that's why I was wanting to transform it down to 12v. But I was going off a suggestion from Prowse on getting the 48v battery even for a 12 volt system. I got the inverter for it's small form factor. We might add another panel or 2 later on, but for now, this will be sufficient. I think we will do all 4 in series for simplicity sake right now.

Thank you for the fuse comment for the converter. I picked up some inline fuse holders, but I'm not sure how to size what size of fuse I would need in them.

So the best way to pick up my 12v fridge/heater/water pump would be just running wire from my fuse block to the items/appliances, correct? I'm thinking 16 gauge wire would be sufficient?

 

[HRTKD]

Wire gauge depends basically on three things: voltage, amperage and distance. Take those three values and plug them into a wire gauge calculator. My preferred calculator is linked below.

Interactive Wire Size Calculator

Battery Chargers, Inverters, Solar Components, and Wiring Supplies for Boats, RVs, and Off-Grid Applications.

baymarinesupply.com

The wire gauge answer can change based on temperature (engine room) and conduit.

The general "rule" here on the forum is that the over current protection device (fuse or circuit breaker) is there to protect the wire. So each wire needs to be protected. A fuse block like the ones linked below will accept 12v from your 48-12 converter and allow you to distribute 12v to your fridge/heater/water pump while protecting each wire. This is similar to how most RV's distribute 12v power.

 

[DioRox]

I got it all connected and it's working. Fine tuning it, but it'll work for our Friendsgiving trip at the dunes this weekend. I'm pretty happy with it already. I found the instructions for the fridge and it called for 14 gauge wire for a 3' connection or less, so that's what I used.

 

[MattMan119]

Hello there. Looking for some assistance with our shuttle bus solar installation. We are not utilizing anything from the bus, so everything we will be using is new. Here is a list of our parts that we intend on using...

• EG4 3kW Off-Grid Inverter | 3000EHV-48 | 3000W Output | 5000W PV Input | 500 VOC Input
• (1) EG4 LifePower4 Lithium Battery | 48V 100AH | Server Rack Battery
• (4) SunPower 360-Watt solar panels | VOC – 69.5 | Impp 6.09A for a total of 1,440 watts
• BZONE DC 48V Step Down to DC 12V 30A 360W Voltage Reducer Converter Golf Cart Voltage Regulator
• WUPP Boat Marine Fuse Block Panel with LED Warning Indicator Damp-Proof Cover - 12 Circuits with Negative Bus Fuse Box Holder Screw for Car Marine RV Truck DC 12-24V (just in case this was . Unsure of parallel vs serial. We don't need 48 volt, just 12v across the board. Any guidance would be appreciated very much.

I like the 48v, most people that have problems with it in mobile is because they can get to high enough voltage to charge.. but you got enough of the right sized panels . This allows you all the advantages of using 48v … one good sized 100ah 48v battery is so much easier to manage then all series or parallel balancing … also make it real easy to expand

Overkill… I don’t think so, just good planning … smaller cables, less connections… I did a 24v trailer hook up, now that I have it done I wish I had just did the 48v thing, it would be so easy to expand to allow bigger devices.. so no I don’t think it is over kill… but that’s just me I could see how it would be seen that way .