Building a new 16p 48v battery + solar for my RV, some (a lot) questions

[BartonB]

Hey all!

I'm going to build a 15KWH system for my RV, so I can work remote reliably
I'm a beginner, and have a few questions,

Battery:
1. What are the current most recommended diy box? laying flat
2. BMS - why is the new Inverter JK-BMS such a big deal? until now BMS warnet able to communicate with the inverter? even though they have the com ports?
3. Recommended BMS? What BMS does the EG4 PowerPro has? Should I maybe just use the Victron BMS? I'm planning on a Victron inverter
4. Active balancer? our good dude Andy from Off-Grid Garage said something about them always working and that it's counterproductive or something? see here
5. Should I rely on the DIY BOX supplied fuse? should I get a circuit breaker? the total emergency stop of the EG PowerPro looks cool
6. Fan in the cabinet it will be in yay/nay. (fan will make things a it more complicated for me in the RV)
7. How does EG4 PowerPro enable 8000 cycles? I've only seen 6000 cycles batteries

Solar:
1. My roof is 6.5m long, 2.3m width - what is the most optimal solar configuration to get the most juice out of this area?
2. Is there a way to have a setup when solar power is used directly and only excess goes to the battery? to save cycles. all the current configurations I see are just mppt -> battery -> inverter
2.1 - Hear me out guys - Enphase micro inverters + shore charger that goes into the battery and get it's input from the micro inverters, what do you think of this monstrosity?
3. Type of solar? Ideally I would want to extract the most, even in low sun light, is making my system 48v will prevent that?

That's all the dilemmas I currently have, hope it's ok that I asked all of the questions and appreciate your help in advance!

 

[thebeavesknees]

I'll reply with what I'm fairly confident are correct answers.

Hey all!

I'm going to build a 15KWH system for my RV, so I can work remote reliably
I'm a beginner, and have a few questions,

Battery:
1. What are the current most recommended diy box? laying flat
2. BMS - why is the new Inverter JK-BMS such a big deal? until now BMS warnet able to communicate with the inverter? even though they have the com ports?

The ports aren't as important as the protocols. Having more built in protocols means you can just connect more things without having to do silly things to get everything talking.

3. Recommended BMS? What BMS does the EG4 PowerPro has? Should I maybe just use the Victron BMS? I'm planning on a Victron inverter

I am going to use JK, though I'm waiting to see if it's worth using the newer version. It might not be since my AIO doesn't have battery comms built in.

4. Active balancer? our good dude Andy from Off-Grid Garage said something about them always working and that it's counterproductive or something? see here

Yes, but only if you can set when it activates.

5. Should I rely on the DIY BOX supplied fuse? should I get a circuit breaker? the total emergency stop of the EG PowerPro looks cool

It depends on the box. Having a breaker is good since you can use it to disconnect the battery from your system. That's usually a very good feature to have.

6. Fan in the cabinet it will be in yay/nay. (fan will make things a it more complicated for me in the RV)

I'm not planning to use additional fans, though I could.

7. How does EG4 PowerPro enable 8000 cycles? I've only seen 6000 cycles batteries

Solar:
1. My roof is 6.5m long, 2.3m width - what is the most optimal solar configuration to get the most juice out of this area?

It depends. Heh. You probably need to be able to tilt to get the most out of your panels, and that's only if you aren't parking under shade. In many cases, a remote set of panels you can optimize will do better than a roof full of panels in the shade.

2. Is there a way to have a setup when solar power is used directly and only excess goes to the battery? to save cycles. all the current configurations I see are just mppt -> battery -> inverter

Yes, but it depends on the AIO or system.

2.1 - Hear me out guys - Enphase micro inverters + shore charger that goes into the battery and get it's input from the micro inverters, what do you think of this monstrosity?

Probably not worth it, but that's an opinion that I don't have experience to base it on

3. Type of solar? Ideally I would want to extract the most, even in low sun light, is making my system 48v will prevent that?

I'm not sure what you mean by this.

That's all the dilemmas I currently have, hope it's ok that I asked all of the questions and appreciate your help in advance!

 

[BobH]

Have you done an energy audit to see how long that 15KWH will last? Do you have enough open roof area without obstructions to mount enough solar to replenish the 15KWH of batteries in your expected time frame? If not, are you supplementing with a generator? Do you have a rough diagram of what you're considering? Building DIY batteries is pretty straight forward given all the resources available. I currently have older versions of JK BMS's on my 24v system and I really don't miss the comm's to the inverter feature. It would be nice, but is not a show stopper. My victron shunt provides the key data I need, so far.