Sanity Check on Configuration

[OnWard Family Adventures]

I'm in the process of designing an off-grid system in my RV and just looking for some sanity checks from the hive mind.

I'm buying 16 Grade A LiFePO4 cells and plan to wire them to be 1 large 48V 280AH cell with a 16s BMS.

Plan is for 6 residential 455 Watt panels in a series/parallel config to get my watts/amps to an acceptable level for the connecting wires.

I'm considering the EG4 3kw Off-grid inverter as an all in one solution. 300W output, 5000w PV input/500 VOC Input. Should be good from a connection to PV stance. It's a little high on the idle consumption at 50-60W per hour, but the batter bank should be big enough to support without a huge issue. I'm hoping to install 2 of these, so I can run them in a split phase format, since my RV is 50 AMP and I can run L1 and L2 to the current AC breaker box.

I'll also put in a victron smart shunt, so I can monitor batteries.

First question is, should I just let my existing AC-DC converter in my main panel continue to do the work, or should I disconnect it and run new wires from the battery bank to the DC fuse box. This would also require a step down(probably a victron 48 to 12) so I can change the voltage from the 48 on the battery bank to the 12 needed for the DC connections.

Follow up is, if I run the connection directly to the DC panel, should the step down be as close to the panel as possible so I can take advantage of the 48 volt ability to use smaller wire with less potential issues.

I also have to either run another charge to my current batteries(AGM), or just replace them with a busbar since they are literally 2 75AH 6V wired as a single 12V and going to an inverter that only powers a single outlet for the fridge. I will need to either track back wires, or just drop in a busbar to begin with since the battery box is on an opposite end of the RV(30ish feet) as I want to keep my ability to use house batteries to jump the coach battery in the event it goes dead(lights, dash adapters, etc).

Thoughts from those who know more than me.

Thank you

Scott

 

[time2roll]

Large system for a first go.

I would disable the AC-DC converter but leave in place for unknown situation if needed.
Yes put the 48-12 close to the 12v fuse panel. Although if the existing 12v connection is used it may not matter.
I would ditch the AGM for a small jump box or lithium start battery. AGM float will be an additional large drain on supply. Or see how it goes and adjust as needed. If the AGM stays verify the 48-12 is OK as a battery charger vs just a power supply.

 

[OnWard Family Adventures]

Large system for a first go.

I would disable the AC-DC converter but leave in place for unknown situation if needed.
Yes put the 48-12 close to the 12v fuse panel. Although if the existing 12v connection is used it may not matter.
I would ditch the AGM for a small jump box or lithium start battery. AGM float will be an additional large drain on supply. Or see how it goes and adjust as needed. If the AGM stays verify the 48-12 is OK as a battery charger vs just a power supply.

Thanks for the honest reply. Go big or go home right. I got a bonus from work and about 4 to 6 weeks in Houston and Dallas area sonic seemed right. Plus I can grab the cells in Houston with no shipping. 2100 bucks for 48v 280 amp battery. Think I'm gonna park on the beach in Baja Mexico this winter.

 

[time2roll]

MX runs a bit high on voltage with 127 official and sometimes a bit more from what I read. Consider a small charger to keep the battery up during a cloudy week. Something like Meanwell NPB-48 works on 90-250 volts. Of course if the EG4 is OK with the voltage nothing to worry about. Although could be hard on some items to pass it through.