Building my first off-grid 24v system LV2424

[hnchen]

Would appreciate this group's help to review the plans for my very first build. I was inspired by Will's videos and the comments from this forum and decided to go for a DIY 24V AIO solar system rather than just buying the Ecoflow Delta 2 Maxes (or equivalent). I have been impressed by all the great advice, sharing of trials & tribulations, and support that this community has given to the craft of solar systems. I didn't realize how accessible it could be until I came across this gold mine of information!

Inspiration / goal:

• Build my own version of Ecoflow's Delta 2 Max w/ D2M Extra Battery (but cheaper, can be upgraded & repaired!)
• Standalone energy storage solution that has the potential to qualify for the federal credit (pending IRS publishing actual details) - sized the system at least 3kWh
• The minimum sizing of the system should be able to sustain a full size refrigerator (avg ~150W) in the event of a power outage, i.e. ~3.6kWh per day.
• Just "portable" enough so that I can either move it around the house or eventually put it into a non-existant camper van in the hopefully near future.
• Leverage the energy storage system to store any "excess" solar generation that my existing grid-fed system generates today. We generate an excess of about 40 to 80 kWh per month during the summer months. (We are on net-metering so the actual "savings" from this will be relatively minimal so this is more "because I can".

Key components:

• MPP Solar LV2424-MSD 24V system (decided to go for 24V instead of the EG4 48V for my first build - due to weight, size, cost & safety)
• 2x Power Queen 12V 190aH w/ 150A BMS - total capacity 4,864 Wh
• 4x 170W Alrska solar panels (Got them for ~$0.67 per Watt so decided to give them a chance even though I can't find much info about the company or their panels. I really like the size and look of the Shingle tech cells - similar to Ecoflow's panels. Couldn't find similar ones from Renogy, Rich Solar, or HQST. Most importantly, they operate at 8.83a. I have a long run so trying to keep my voltage drop to a minimum.)

Total cost of battery system: $1,710 (LV2424 - $610, 2x Power Queen 4,864 Wh - ~1,000)

• 2x Power Queen 12V 190Ah total capacity = 4,864 Wh
• Cost per Wh = $0.35

Comparable cost for Ecoflow D2M + D2M EB: $3,200 MSRP ($2,548 on sale)

• D2M + D2M EB total capacity = 4,048 Wh
• Cost per Wh = $0.79 MSRP ($0.63 on sale)

Feel free to throw any questions, suggestions, comments my way!

Thank you!

 

[hnchen]

I'm about to start my build tomorrow. Appreciate any feedback on the schematic.

 

[Frank F]

I am looking at building something for emergencies power, I ordered a delta 2 max from Home Depot but I may wind up returning it and building a similar system as yours

 

[sunshine_eggo]

I am looking at building something for emergencies power, I ordered a delta 2 max from Home Depot but I may wind up returning it and building a similar system as yours

Is this what you're talking about:

Building an emergency power system with used panels

Looking at options to build a system for power outages during hurricanes that will run a 5000 btu window AC, small fridge and charge cellphones and tablets. Originally was thinking maybe a delta 2 max with 4 200 watt panels... would that be enough to run a small AC through the night? another...

diysolarforum.com

 

[Brucey]

I am looking at building something for emergencies power, I ordered a delta 2 max from Home Depot but I may wind up returning it and building a similar system as yours

I ended up ordering a Delta 2 Max during the prime sales was $1499-8% additional coupon.

Previously I was thinking of a diy system using a Powerurus 12V 200Ah battery for about $750 and then something like a Victron multiplus 12V 2000VA for $1100. But now I'm at $1850 and don't have a scc yet.

Before the Delta 2 max, I had purchased a river 2. This is when I realized that these aren't silent like a candy bar battery. Especially when fast charging (which can be reduced by reducing max charge rate in the app) but also at a lower level when running as a pseudo ups. Anything over say 40-50W constant draw and the fan will turn on at low speed.

One of the big attractions for me with the Delta 2 max is that it's rated at 30db fan noise when running at 500W output or less, and 46dB at full power. The older Deltas were 60dB apparently! Yes maybe quieter than an open frame generator but why should we have to put up with it?

Be careful, from what I've seen those Chinese aios are real screamers in terms of fan noise. That's why I didn't go down that path, tho very tempting from a Watt per dollar perspective.

The additional batteries definitely cost more than a diy option, my thought is to eventually get a 48V server rack battery and use that into the solar inputs of the Delta 2 max (500W x 2) as a 5kw additional for ~$1500-$2000.

 

[Frank F]

Are others charging from 48v batteries into solar inputs? Would you need anything between the battery and the solar input? And how would you charge the 48v battery back up in an off-grid situation? Separate charge controller?

 

[Brucey]

Are others charging from 48v batteries into solar inputs? Would you need anything between the battery and the solar input? And how would you charge the 48v battery back up in an off-grid situation? Separate charge controller?

Something like the eg4 chargeverter would be the fastest way to go for charging the 48v battery. Or scc to the 48v battery.

 

[Brucey]

Normally I think people would use something like a 125A t fuse on a 100ah 100a 48v but the Delta 2 max would be pulling a max of 20A or so?

 

[Frank F]

Normally I think people would use something like a 125A t fuse on a 100ah 100a 48v but the Delta 2 max would be pulling a max of 20A or so?

The delta 2 max solar inputs are 15 amps each I believe

 

[Frank F]

Is this what you're talking about:

Building an emergency power system with used panels

Looking at options to build a system for power outages during hurricanes that will run a 5000 btu window AC, small fridge and charge cellphones and tablets. Originally was thinking maybe a delta 2 max with 4 200 watt panels... would that be enough to run a small AC through the night? another...

diysolarforum.com

Yes that's it

 

[Smeeg]

I’d consider building it on a hand truck YouTube if you haven’t seen it

 

[Brucey]

The delta 2 max solar inputs are 15 amps each I believe

Yes, but with say a nominal voltage of ~50V, each of the two mppts are good for 500W so about 10A for each xt60 connecter.

 

[Brucey]

Ecoflow are now saying they won't be shipping my Delta 2 Max until end of the month so I'm looking again at diy.

Quiet operation is key to me so still thinking of a Powerurus 200Ah and a Victron 1200VA inverter. Just worried about possible humming noise from the transformer. General everyday loading will only be 300W or so.

 

[Electrodude]

Ecoflow are now saying they won't be shipping my Delta 2 Max until end of the month so I'm looking again at diy.

Quiet operation is key to me so still thinking of a Powerurus 200Ah and a Victron 1200VA inverter. Just worried about possible humming noise from the transformer. General everyday loading will only be 300W or so.

I know you didn't mention it in this response post, but the MPP LV2424-MSD isn't the quietest running unit - what, with the fans and all. It's tolerable - especially if it's in a room around the corner, or downstairs in the basement. [Sometimes the sound of operation is a good thing anyway! :D]