Possible to power my shop totally off grid?

[Hedges]

They look like a great bundle.
Some have fresh forklift batteries, some old. I think retail was $5000 each, so it you get good ones you come out further ahead.
Some have a diesel generator. Ideal, since initially you'll just have the amount of PV that comes with the trailer.

Two SI6048 gives you 11.5 kW continuous at 25 degrees C.

If you buy two trailers, you can add one more RJ45 cable and daisy-chain all four SI6048 together.
Right now one is master, one is slave #1, and the AC is wired for 120/240V.
Reprogram the second trailer as slave #2 and slave #3 (simple pushbutton and menu on Sunny Island)
Wire the batteries in parallel.

Connect neutral AC wire together. Connect ground together.
(I would just run a 6 awg cable from each trailer to a 200A panel in the shop, join the two cables either on two 70A breakers or at the main lugs.)

Use a volt meter to see which AC L1/L2 on the two trailers belong on the same 120V leg, then wire those two pairs of hots together.
(Breaker off, measure voltages between inputs of the two 70A breakers. If zero volts between the two poles on same leg, it is correct, close breaker. If 240V, it's backwards. Shut off at trailer. Swap wires. Turn on at trailer, check that you now have zero volts between the breakers but 120V from breaker to neutral.)

You now have four SI6048 wired 2s2p for 23kW continuous, 28kW for 30 minutes, 44kW surge. Same as I have.

The trailers have a relatively small amount of PV, DC coupled with Midnight charge controller.
I think it is 2400W of PV (12 kWh/day) and 48 kWh of battery (two, 500 Ah 48V batteries).
You can use the shop for 1 day, consuming 35 kWh, then leave for 3 days and it will recharge (1 trailer).
With 2 trailers, you can use the shop all weekend, and return the next weekend.

That charge rate is probably less than ideal. The battery wants to be charged at 0.1C or 0.2C (check documentation). So better to have 5kW or 10kW of PV per trailer for best battery life. Or, run the generator (only one generator, no way to synchronize two)

When you want to add more, buy Sunny Boy and add that (AC coupled PV). They can go anywhere on your property the AC wiring reaches, like the roof of your workshop.
Even if battery wants 5 kW per trailer for 0.1C charging, you can put in 10 kW of PV/Sunny Boy. You just program a parameter in Sunny Island for battery charge current. The battery can get a regulated 5 kW (100A at 48V) while your shop tools get 5kW direct from PV.

 

[ruc]

They look like a great bundle.
Some have fresh forklift batteries, some old. I think retail was $5000 each, so it you get good ones you come out further ahead.
Some have a diesel generator. Ideal, since initially you'll just have the amount of PV that comes with the trailer.

Two SI6048 gives you 11.5 kW continuous at 25 degrees C.

If you buy two trailers, you can add one more RJ45 cable and daisy-chain all four SI6048 together.
Right now one is master, one is slave #1, and the AC is wired for 120/240V.
Reprogram the second trailer as slave #2 and slave #3 (simple pushbutton and menu on Sunny Island)
Wire the batteries in parallel.

Connect neutral AC wire together. Connect ground together.
(I would just run a 6 awg cable from each trailer to a 200A panel in the shop, join the two cables either on two 70A breakers or at the main lugs.)

Use a volt meter to see which AC L1/L2 on the two trailers belong on the same 120V leg, then wire those two pairs of hots together.
(Breaker off, measure voltages between inputs of the two 70A breakers. If zero volts between the two poles on same leg, it is correct, close breaker. If 240V, it's backwards. Shut off at trailer. Swap wires. Turn on at trailer, check that you now have zero volts between the breakers but 120V from breaker to neutral.)

You now have four SI6048 wired 2s2p for 23kW continuous, 28kW for 30 minutes, 44kW surge. Same as I have.

The trailers have a relatively small amount of PV, DC coupled with Midnight charge controller.
I think it is 2400W of PV (12 kWh/day) and 48 kWh of battery (two, 500 Ah 48V batteries).
You can use the shop for 1 day, consuming 35 kWh, then leave for 3 days and it will recharge (1 trailer).
With 2 trailers, you can use the shop all weekend, and return the next weekend.

That charge rate is probably less than ideal. The battery wants to be charged at 0.1C or 0.2C (check documentation). So better to have 5kW or 10kW of PV per trailer for best battery life. Or, run the generator (only one generator, no way to synchronize two)

When you want to add more, buy Sunny Boy and add that (AC coupled PV). They can go anywhere on your property the AC wiring reaches, like the roof of your workshop.
Even if battery wants 5 kW per trailer for 0.1C charging, you can put in 10 kW of PV/Sunny Boy. You just program a parameter in Sunny Island for battery charge current. The battery can get a regulated 5 kW (100A at 48V) while your shop tools get 5kW direct from PV.

I going to go take a look at them .
Unfortunately none of these have the generators, only the panels and other equipment on the trailer.
Is there any way to test the batteries and see if they are good...or will I just have to take a chance on the batteries?

 

[Hedges]

Look up the topic on this forum. I think age with the primary discriminating factor.

Bring a voltmeter and check voltage of battery and voltage of each cell. that at least will tell you if they are uneven or drained.
A hygrometer can be used to check specific gravity of each cell (wear goggles)

Plugging in one or two space heaters and turning on the inverters would be a way to apply a load. Check battery voltage under load.

You may be able to print out manual for the battery before going there.

If not dead, they will provide some service. But obviously getting like-new batteries dirt cheap is what you want.

A recent auction, some guys here were unhappy it wasn't the bargain of earlier auctions. But for you the price may be right, a complete system that does what you need. Single trailer and you have power from day one. A bit of work to parallel two of them and it is close to your dream system - just needs more PV. The fact they are all wired up saves you the design, labor, and cost of doing it yourself.

People probably got spoiled by the early prices. I paid $0.25 on the dollar for my Sunny Boys, so the eBay seller probably got them for $0.12 on the dollar at DC Solar auction. After COVID and power failures, likely more people became interested.

I think I've seen these for resale around $8k, but now people are asking more. I see listings in the greater San Francisco Bay Area for $10k to $20k, not clear exactly which versions for which price.

 

[ruc]

Look up the topic on this forum. I think age with the primary discriminating factor.

Bring a voltmeter and check voltage of battery and voltage of each cell. that at least will tell you if they are uneven or drained.
A hygrometer can be used to check specific gravity of each cell (wear goggles)

Plugging in one or two space heaters and turning on the inverters would be a way to apply a load. Check battery voltage under load.

You may be able to print out manual for the battery before going there.

If not dead, they will provide some service. But obviously getting like-new batteries dirt cheap is what you want.

A recent auction, some guys here were unhappy it wasn't the bargain of earlier auctions. But for you the price may be right, a complete system that does what you need. Single trailer and you have power from day one. A bit of work to parallel two of them and it is close to your dream system - just needs more PV. The fact they are all wired up saves you the design, labor, and cost of doing it yourself.

People probably got spoiled by the early prices. I paid $0.25 on the dollar for my Sunny Boys, so the eBay seller probably got them for $0.12 on the dollar at DC Solar auction. After COVID and power failures, likely more people became interested.

I think I've seen these for resale around $8k, but now people are asking more. I see listings in the greater San Francisco Bay Area for $10k to $20k, not clear exactly which versions for which price.

Thanks so much for the help....I will see what I can find out.

 

[ruc]

Look up the topic on this forum. I think age with the primary discriminating factor.

Bring a voltmeter and check voltage of battery and voltage of each cell. that at least will tell you if they are uneven or drained.
A hygrometer can be used to check specific gravity of each cell (wear goggles)

Plugging in one or two space heaters and turning on the inverters would be a way to apply a load. Check battery voltage under load.

You may be able to print out manual for the battery before going there.

If not dead, they will provide some service. But obviously getting like-new batteries dirt cheap is what you want.

A recent auction, some guys here were unhappy it wasn't the bargain of earlier auctions. But for you the price may be right, a complete system that does what you need. Single trailer and you have power from day one. A bit of work to parallel two of them and it is close to your dream system - just needs more PV. The fact they are all wired up saves you the design, labor, and cost of doing it yourself.

People probably got spoiled by the early prices. I paid $0.25 on the dollar for my Sunny Boys, so the eBay seller probably got them for $0.12 on the dollar at DC Solar auction. After COVID and power failures, likely more people became interested.

I think I've seen these for resale around $8k, but now people are asking more. I see listings in the greater San Francisco Bay Area for $10k to $20k, not clear exactly which versions for which price.

I did buy one of the trailers. I think I may have a chance to get another one.
I am having a little issue. I first hooked it uo to the shop using one of the 50 amp external connections and connected directly to the breaker box in the shop. Lights came on and everything was good. I didn't have air compressor or anything big hooked uo, just the lights which are 20 8ft led's. I checked..they were pulling 15 amps. ran like that for about 2 hours, then the "slave" sunny island kicked off and showed message "F117 malfunction". It kept trying to restart but would not. I turned the inverter off and restarted everything and immediately did the same F117 code. I can unplug the power cord and it is ok. AS soon as I connect the cord it faults again, even with out the lights being turned on. Any ideas??

 

[Hedges]

Manual:

"F117 AC current limit (short-circuit control active for too long)"

"Why is it that shortly after startup, the slave switches to standby with the error
message F117, but the master continues to operate?
• Are the line conductors within the cluster or from the cluster to the Multicluster Box connected
the wrong way around? This causes a permanent short-circuit in the cluster, and the slave reports
this to the master."

You don't have a "multicluster" box.
Examine AC wiring.
Are your loads 120V or 240V? On both phases?
Try running the trailer with 50A plug disconnected, with 120V loads connected directly to it.

I don't understand what it is doing.

Other references to "short-circuit" say,

"12.4 Overload and Short-Circuit Behavior
The Sunny Island can be temporarily operated under overload conditions. and is able to supply
short-circuit current.
In the event of overload, the Sunny Island 4548-US supplies a power of 5,300 W for 30 minutes at
77°F (25°C) and the Sunny Island 6048-US a power of 7,000 W. Both Sunny Island inverters can
deliver a power of 7,200 W for 5 minutes at 77°F (25°C). The available power can even reach
8,400 W for 1 minute at 77°F (25°C).
In the event of a short circuit, the Sunny Island provides a maximum current of 180 A (for 60 ms). This
is sufficient to trip commercial 20 A circuit breakers."

The enclosure on the DC Solar trailer doesn't follow instructions for 12" clearance on all sides of the inverters. They did install a fan to vent the enclosure.
I assume you had the doors open (probably can't have plug connected when closed), but see if they are getting hot.

 

[ruc]

I going to try to work on it today....maybe a little tuff with Christmas going on, but I am excited about the trailer. I agree with you, I really like the Sunny Islands although I am having some issues at the moment.
The plug is actually on the outside, but I did have both doors open so I don't think it got to hot.
The only load was the lights which are 120V
I used a 8-4 wire to connect to the plug. It was color coded L! & L2 were red and black with green for ground and white for neutral. I don't see how anything could be short circuited.
I attached a photo of the plug

 

[Hedges]

If lights are 120V and plugged into a single phase (not two lights on the two phases), then only 1 Sunny Island was powering them.
20 lights, 15A if on one phase is 0.75A each, 90W each is reasonable. Some are listed as 54W, some 110W.

Turning off after 2 hours could be heating. Operating no load but instantly tripping with load doesn't sound quite like that, would expect some delay.

Sunny Island cools by convection, then turns on two fans at the bottom.
Does the enclosure have vent openings under them, or does air have to come in through a narrow gap?

See if you again get a couple hours operation, and if the heatsink gets hot. Maybe the fans don't come on for some reason.

Check with a different load, like portable heater directly plugged into trailer or one of your branch circuits. Perhaps a fault developed in your wiring or a light.

Sunny Island has a relay function "Overload" which can be used to control loads, disabling optional loads to reduce heat buildup in the inverter. Once you have these issues worked out, that could serve to shed excessive load on hot days.

If all your lights happen to be on one phase, you could test by swapping to the other at your load panel, so Master Sunny Island powers them. If on both phases, try moving all to one phase (not if your neutral wire if shared, to avoid overloading) or turn off lights on Slave.

"AS soon as I connect the cord it faults again, even with out the lights being turned on. Any ideas??"

!!??

With nothing turned on??
Either something like a large well pump is connected and won't start, or you've developed a short. Get out the ohm meter and chase it down.
Perhaps a poor connection overheated wire until insulation melted and it shorted. Obviously on the generator side of the light switch.

 

[Japera]

Batteries cost so much more than PV panels (about 10x the price, comparing $/kWh of battery life to $/kWh of PV amortized over a decade) that I'm inclined to over-panel and use-it-or-lose-it. PV panels cost $0.025/kWh, batteries $0.20/kWh or more.

As Jmac786 said, can't run PV direct to loads if the sun doesn't shine.
Are you willing to forego work on a rainy day?
Or how about a generator for those times?

I would suggest either:

Split-phase 120/240V, four Sunny Island 6048, 400 Ah (or more) 48V battery, Three or four Sunny Boy 7.7 kW PV inverters, each with 12kW to 20kW of PV panels in arrays aimed at 9:00 AM summer sun, 3:00 PM summer, Noon winter.

Current prices $2500 x 4 + $5000 + $2000 x 3 (or 4) + $5000 to $16000 (varies with brand and condition if used)

Or, 3-phase 120/208Y, 3 Sunny Island, 400 Ah or more, 3 Sunny Boy each with 12kW to 20 kW PV.

Generator would be either split-phase or 3-phase. You expect to consume 35 kWh over the day, so at least 5kW generator. Batteries hold 20 kWh (14 kWh usable), enough to smooth that out, and can take about 4 kW charging. 4x Sunny Island is 23 kW continuously, 28 kW for 30 minutes, 44 kW surge. 3x Sunny Island would be 3/4 of that. PV, when available, is added.

System cost $25k to $45k plus generator.

Enable loads like HVAC, water heater, air compressor and well pump only when battery SoC > 80%, or otherwise when surplus PV generation is available.

Do you workin the solar industry or are you just that good. You are breaking it down like it aint nothing.

 

[rin67630]

Batteries cost so much more than PV panels (about 10x the price, comparing $/kWh of battery life to $/kWh of PV amortized over a decade) that I'm inclined to over-panel and use-it-or-lose-it. PV panels cost $0.025/kWh, batteries $0.20/kWh or more.

Yes PV panels are ridiculously cheap. But that is not the bottom line.
I am currently a bit pissed off about the prices companies are asking for frames, tile fixtures and all the mechanics around.
The price for these ancillary items are exceeding by wide the price of the panels.
Unfortunately I am living in a shared property, so I have to use certified solar frames on the roof and must let professionals do the erection, else I would never get the approval from the community and no insurance would cover any possible damages.
In the total cost, the price of the panels practically weights peanuts.

 

[Hedges]

Do you workin the solar industry or are you just that good. You are breaking it down like it aint nothing.

I'm just that good.
I put in my first grid-tie PV 17 years ago, a package designed by Real Goods.
Dreamed for years about putting in Sunny Island, although it hardly made financial sense.
Finally did this year, due to bargains out there, and the Devil finding work for idle hands (got canned, 3 months until I found other work).
I only work with SMA equipment, so that's what I know and can talk about.
My professional field is EE, have degrees from U.C.B. and S.J.S.U.
I've worked for big and small name electronics companies, DoD/military, and federal research lab.
Along the way I've learned to work with transistors (integrated in custom silicon), board level, and systems engineering.
I also have a contractors license, have done a bit of PV install for others but mostly my own.


Watching prices and utility rates/schedules over the years, I update my math on what makes sense.
The individual 280 Ah LiFePO4 cell prices people here talk about are making that look more cost effective than LA.
Also gaming time of use rates could make sense with those cells, but I think extra PV panels is still preferable.

 

[Hedges]

Yes PV panels are ridiculously cheap. But that is not the bottom line.
I am currently a bit pissed off about the prices companies are asking for frames, tile fixtures and all the mechanics around.
The price for these ancillary items are exceeding by wide the price of the panels.
Unfortunately I am living in a shared property, so I have to use certified solar frames on the roof and must let professionals do the erection, else I would never get the approval from the community and no insurance would cover any possible damages.
In the total cost, the price of the panels practically weights peanuts.

My first panels cost $6/watt, then $5/watt.
Inverters cost me $0.80

You can get good panels these days for $0.33, or bad/used as little as $0.12
I figure inverters are available $0.10 to $0.30
Rack hardware is probably in the $0.12 to $0.30 range. As you say, costs as much as panels.
Now Rapid Shutdown adds cost, some $0.10, some less.

Is community solar something you can buy into, use to offset your bill? I know the new California laws require homes either have PV installed or participate in such a program, but I'm not clear if utility rules now allow credits from a remote system.

Better yet, buy yourself an unfettered single-family home (after prices fall back down from the current bubble).
If your "community" has significant costs like HOA it is probably better as a rental unit than a residence.

 

[ruc]

If lights are 120V and plugged into a single phase (not two lights on the two phases), then only 1 Sunny Island was powering them.
20 lights, 15A if on one phase is 0.75A each, 90W each is reasonable. Some are listed as 54W, some 110W.

Turning off after 2 hours could be heating. Operating no load but instantly tripping with load doesn't sound quite like that, would expect some delay.

Sunny Island cools by convection, then turns on two fans at the bottom.
Does the enclosure have vent openings under them, or does air have to come in through a narrow gap?

See if you again get a couple hours operation, and if the heatsink gets hot. Maybe the fans don't come on for some reason.

Check with a different load, like portable heater directly plugged into trailer or one of your branch circuits. Perhaps a fault developed in your wiring or a light.

Sunny Island has a relay function "Overload" which can be used to control loads, disabling optional loads to reduce heat buildup in the inverter. Once you have these issues worked out, that could serve to shed excessive load on hot days.

If all your lights happen to be on one phase, you could test by swapping to the other at your load panel, so Master Sunny Island powers them. If on both phases, try moving all to one phase (not if your neutral wire if shared, to avoid overloading) or turn off lights on Slave.

"AS soon as I connect the cord it faults again, even with out the lights being turned on. Any ideas??"

!!??

With nothing turned on??
Either something like a large well pump is connected and won't start, or you've developed a short. Get out the ohm meter and chase it down.
Perhaps a poor connection overheated wire until insulation melted and it shorted. Obviously on the generator side of the light switch.

Well, I did find my problem.....It was me, not the sunny islands. I had two wires switched when I wired up the plug.
It seems to be working fine now, but the batteries do seem to be slow to charge back up.

 

[Hedges]

Slow in voltage? See what watts or amps is reported by Midnight.
Do the DC Solar trailers have data cable between Sunny Island and Midnight Classic, with a card to translate protocol? That would put Sunny Island in charge of voltage and charging phase. Or, does the Midnight use its own charging parameters? (in that case there is probably a shunt)

 

[ruc]

Slow in voltage? See what watts or amps is reported by Midnight.
Do the DC Solar trailers have data cable between Sunny Island and Midnight Classic, with a card to translate protocol? That would put Sunny Island in charge of voltage and charging phase. Or, does the Midnight use its own charging parameters? (in that case there is probably a shunt)

Pouring down rain here today, but tomorrow supposed to be better so I will check it out.
Something strange that happened the other day. When I left for the day I checked and the battery soc was at 90%
I always unplug the trailer from the shop when I leave. When I came back the next day I checked and the soc was down to 76%. That was without any usage. The trailer was not connected. That is strange.

 

[Hedges]

When I first commissioned mine I saw lower SoC like that. Maybe it takes time for Sunny Island to learn about the battery, or to do a compete absorption charge. My main setup is grid tied with AC coupled Sunny Boy. Right now mine shows 94%, float, zero time remaining. 7.7 kW from Sunny Boys feeding the grid.

I have a second system with DC coupled Sunny Island Charger. I switched on the breaker of Sunny Island but I don't think I have it running its inverter to produce AC. I just check its report of external charger (which is connected by data cable.)

Maybe battery was drawn down a bit by the idle consumption 2 x 25W overnight. That should only be 600 Wh out of 50 kWh of battery.
PV probably peaks around 2kW or so, might be putting out 500W or just 50W right now (which would only be treading water if inverters are still on.)

Check what SI reports for battery voltage and bulk/absorption/float, time remaining.

Meanwhile you can have fun shopping for Sunny Boys, maybe some bargains will show up. Having AC coupled Sunny Boy and a load-shed relay will let you connect a bunch more PV and have the system manage things better.

 

[ruc]

When I first commissioned mine I saw lower SoC like that. Maybe it takes time for Sunny Island to learn about the battery, or to do a compete absorption charge. My main setup is grid tied with AC coupled Sunny Boy. Right now mine shows 94%, float, zero time remaining. 7.7 kW from Sunny Boys feeding the grid.

I have a second system with DC coupled Sunny Island Charger. I switched on the breaker of Sunny Island but I don't think I have it running its inverter to produce AC. I just check its report of external charger (which is connected by data cable.)

Maybe battery was drawn down a bit by the idle consumption 2 x 25W overnight. That should only be 600 Wh out of 50 kWh of battery.
PV probably peaks around 2kW or so, might be putting out 500W or just 50W right now (which would only be treading water if inverters are still on.)

Check what SI reports for battery voltage and bulk/absorption/float, time remaining.

Meanwhile you can have fun shopping for Sunny Boys, maybe some bargains will show up. Having AC coupled Sunny Boy and a load-shed relay will let you connect a bunch more PV and have the system manage things better.

Now I have GNB Flooded Classic Platinum industrial batteries 468 AH capacity 48 volt (2 of them), which I think are just fork lift batteries, but I was thinking about switching over to lithium ion.
Will the sunny islands work with LifePO4

 

[Hedges]

If the forklift batteries are healthy, possibly just need equalizing and watering (should be able to charge each 2V cell individually without overcharging the other cells as usually done for equalization), keeping them could be best and most cost effective. That pair of batteries is probably worth $10,000 new.
Sunny Island is optimized for maintaining lead-acid batteries. SMA has decades of experience. People say forklift batteries can give 15 years of use. They will accept charge when below freezing. Just get an automatic or semi-automatic watering system. I think it is float valves and central squeeze bulb to add water to any low cells with a single action.

https://www.powerstridebattery.com/...atering-kit/gnb-forklift-battery-watering-kit

If the FLA batteries are so large they only cycle 10% to 25% most of the time (exception being occasional times of bad weather when they supply power for multiple days), the higher cycle life of lithium isn't needed, so cost parity or cost advantage is lost. Some cheap sources or DIY may put lithium at same capital cost as lead-acid. But that of course is only if you would have to buy lead-acid.

Sunny Island has been used by some forum members for lithium with lead-acid settings and voltages adjusted for the batteries. This was only with DC coupled PV, no AC coupled and no generator or grid charging through Sunny Island.

REC has a BMS which speaks Sunny Island's language. That lets BMS control all charging, so Sunny Island's charger function and AC coupled Sunny Boys can be used. There may be some other brands available.

REC BMS's

Smart CANBus Integration of your off grid, marine or ESS energy system using REC BMS, Victron and Wakespeed WS500 products

offgridsoftwaresolutions.com

 

[ruc]

If the forklift batteries are healthy, possibly just need equalizing and watering (should be able to charge each 2V cell individually without overcharging the other cells as usually done for equalization), keeping them could be best and most cost effective. That pair of batteries is probably worth $10,000 new.
Sunny Island is optimized for maintaining lead-acid batteries. SMA has decades of experience. People say forklift batteries can give 15 years of use. They will accept charge when below freezing. Just get an automatic or semi-automatic watering system. I think it is float valves and central squeeze bulb to add water to any low cells with a single action.

https://www.powerstridebattery.com/...atering-kit/gnb-forklift-battery-watering-kit

If the FLA batteries are so large they only cycle 10% to 25% most of the time (exception being occasional times of bad weather when they supply power for multiple days), the higher cycle life of lithium isn't needed, so cost parity or cost advantage is lost. Some cheap sources or DIY may put lithium at same capital cost as lead-acid. But that of course is only if you would have to buy lead-acid.

Sunny Island has been used by some forum members for lithium with lead-acid settings and voltages adjusted for the batteries. This was only with DC coupled PV, no AC coupled and no generator or grid charging through Sunny Island.

REC has a BMS which speaks Sunny Island's language. That lets BMS control all charging, so Sunny Island's charger function and AC coupled Sunny Boys can be used. There may be some other brands available.

REC BMS's

Smart CANBus Integration of your off grid, marine or ESS energy system using REC BMS, Victron and Wakespeed WS500 products

offgridsoftwaresolutions.com

I think the batteries are good. The water is good on all cells. I will check the voltage on each cell. How would I go about charging the cells individually? Are there any other test that I can perform to verify the health of the batteries?
As you know this is the solar trailer that I bought at auction. What I would like to do is mount the solar panels on the roof, and add maybe 10 more panels to the array. I would also move the sunny islands and the midnite charge controller inside and mount everything on the wall. So I would be taking everything off the trailer and moving it inside the shop. I just thought the LIFePO4 batteries might be a better option, but if I hear what you are saying it may be better to stay with FLA batteries I have.

 

[Hedges]

Check voltage of each cell. They should be similar. During charging they should reach absorption voltage and remain there a couple hours, then drop to float voltage. Exact voltage is computed based on temperature.
Use a hygrometer. That gives specific gravity.
Check settings in Midnight and compare to GNB specs. Does the trailer have a shunt to inform Sunny Island about battery current?
Or, does it have a data cable and interface board between Sunny Island and Midnight so Sunny Island controls?
If using an AC source (Sunny Boy, generator), Sunny Island would control that.
Check settings and adjust if needed for both Midnight and Sunny Island.
I expect maximum charge current to default to an excessive value (0.55C) which wouldn't matter unless you added lots of AC coupled PV like I did.

If some cells are lower voltage than others, I would get a bench supply with constant voltage and constant current. That would put in constant current (say 10A) until absorption voltage then sit there. Monitor it and after appropriate absorption time, disconnect and move to the next.
Ideally this would occur while other cells were fully charged, so this one doesn't get ahead of others.

I have a "DAS", bench meter with relay cards. I would consider that plus a power supply for an automated BMS/balancer. But just going through occasionally with a bench supply should be good. Some people suggest equalization is hard on the cells that get overcharged, so I figure individual charging would be better.

Why disassemble anything? You could leave all as is, but add a large quantity of panels on a Sunny Boy. Up to about 24 kW of Sunny Boy.
But I guess having it on a trailer isn't helping if you don't need mobile, and you could free up the trailer.
DC Solar's box doesn't provide proper space for convection cooling. Read up on that before making your setup.

The tilt-mount could be convenient. Maybe you could double the number of panels per tilt. Orient one tilt SW, one SE, and their combined output will have lower peak. More watts would fit the charge controller. Your rooftop panels may all be a single fixed orientation, so using these racks for tilt-able and catching sun other hours could improve the system.

Batteries outgas and are corrosive, so should be walled off and vented. But they would prefer more controlled temperature.