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Inheriting a Off Grid Cabin Solar Setup. What would you change?

Bullshit. They can be made to work with lithium fine.

In 99.9% of cases, if it works with lead acid, it works with LFP. Period. LFP operating voltage range is nearly identical to FLA. There are some additional considerations, like you'll need to buy LFP batteries that have their own low temp charge protection, and disconnect all the temp sensors to your chargers (you don't need temp compensation on LFP), but that's about it.

Back in the day, Volvo had a crazy reputation for reliability. Let's say that's still true... they're crazy reliable.

No one in their right mind would replace a Volvo with a Yugo. Please don't replace your Volvo with a Yugo.
I was thinking this too, but wasn't sure enough to post it.
 
I'd suggest running thru the "clean sheet" design effort anyway, just to see what parts need rework, *and* answer these q's:
- have loads changed from original design, plus new stuff you want to do
- what's out of warranty right now (most likely, *everything*)
- do you need more capacity than the FLA can support (remember, it's capacity is half of it's rated aH's)
- the new design would flip you to LFP (you *really* don't want to do FLA maintenance), and, it would be 48v
- can you stand to be "down" for days/weeks, because some piece failed
- who does the resurrection of the failed system, and how long will it take?
- if fuel generator backup isn't there, add it in

If you are fully capable of fixing anything that goes wrong with the current 24v system, and/or some installer will guarantee 24h to 48h resumption of service, there might be an argument to keep it (to save money). But you, and certainly your wife/family, aren't going to understand being down for days/weeks because of a failure anywhere. The power has to keep flowing ...

My family doesn't understand or appreciate a power outage, but if something goes south in any component, I can swap in any number of backups immediately (from fuel-generator to entire replacement system, utilizing the existing LFP battery-bank, and moving between 12v/24v or whatever), while I see if my old Magnum 24v system can be resurrected. Perhaps the original installer can do this for you as well, but ... best to plan on newer tech and redundancy in backups, than rely on the older stuff that may not be resurrectable any longer.

I'd do the design work, answer those q's, and then figure out which way to jump ...

Hope this helps ...
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I'm facing similar battles to what OP might be facing ... Magnum has gone south, no longer sells my 24v (or any) inverter. Don't know where Xantrex is, but I imagine the marketplace (of AIO's) won't do them any favors ... I think the only decision point left for (magnum, xantrex, whomever) inverter companies is ... will they produce their own AIO?

Magnum didn't flip to AIO designs, so they bailed and are shutting down the Magnum line (as best I can tell).

Midnite *is* producing an AIO ... I'd think they are a safe bet, for something to last as long as a Magnum or a Xantrex did. Can't (yet) tell about the other AIO's ... however, this forum is full of exciting discussions about AIO issues, horror stories, etc. In the face of this, I'd have to have two (or more) AIO's, at least one online, and one as nearline spare.

Again, have backups to the backups ... if nothing else, get a fuel generator in there (some way to ensure the power keeps flowing), while you figure out which way to jump.
 
Don’t be tempted to buy slapdash-new when you have really solid existing components. Ask folks on this forum how to test that battery, but just use it and keep it watered. Technology marches ever onward. Some evolved battery chemistry (American made?) in the future might tickle your fancy, when that forklift beast fades into uselessness for your application.
 
Hello,

We are purchasing a property that has over 6000 watts of solar and a dedicated insulated shed for everything. It is an older system that includes a large 1000ah 24 volt Forklift battery. I am reading through all of the manuals. Everything works but it is an older setup. Shed has a exhaust fan but no heat or AC. If anyone has a similar setup I would love to hear your experiences with it.

My first consideration would be to swap out the monster lead acid battery for lithium. I believe 600 ah worth would be plenty for what we are using. 400 ah might even be fine and we would probably start with that. I can't decide if it makes sense to buy some 24 volt 200ah LifePo4 batteries or go with the rack mounted stuff. What are the pros and cons? Then replace other parts as needed when/if they fail.

Here are some photos:
3 solar controllers - each handles 10 - 230 watt panels than can be switched to charge lithium batteries
2 inverters but I believe only one is in use on the building. With the other as a backup
Building has a breaker box and has been wired for power with outlets and some basic lighting.

We plan on installing a 110 v solar mini-split but may have that use its own set of new panels.

This was professionally installed years ago. I have the company information if I ever need to reach out to them.

Any advice is appreciated! Thanks!

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Hey thats a nice setup. My advice is to use it for a while. Learn about charging lead acid batteries in the meantime. Take note of any shortcomings with this setup, then you will have clear direction on what you need. Being its already installed your best choice is let it ride.

230W solar panels are definitely dated but if they work, watts are watts. Upgrading panels might be the most cost effective improvement, but again not necessary until you determine your usage.

My guess is the only thing youll ever need is a battery bank, someday... with 6k in solar i bet that battery lives in float mode most of its life and will likely last 10+ years. There are lots of 24v battery options and LFP choices that can run without comms. The inverter wont care about battery type, especially if you are not using a generator to charge. Classic charge controllers can be set for LFP just fine. Or you may be happy with Lead acid batteries. Myself, i prefer lead acid.

If you decide to take it all down, call me, ill be there in a jiffy with an empty pickup truck 😅
 
Other than age and maintenance I don't think so. My concern is lack of visits to the property might mean we would damage the battery. Not sure how often it needs water added. I believe it is at least 4 years old. Possibly as much as 6 years old.
Lithium has a far better chance of being destroyed by cold weather than what you currently have.

I have 6 flooded lead acid golf cart batteries at a weekend cabin in central NY. They see temps well below 0*f many many times a winter. My maintenance is putting a bit of water in them 2x a year. They are left on a CC 365 and have been for 4-5yrs.
 
Replacing the inverters only - off-grid setup context.

AIOs are common these days but there is the alternate (individual component) design approach which is what you have now. I have Midnite Classics and I use them (via the AUX1 external relay) to turn my inverters on/off by battery voltage. Several good inverters have external on/off switch capability - same as toggling the on/off switch on the unit. It's just a pair of wires over to a remote on/off switch or relay.

When I hit 49.5v low for my battery bank the inverter(s) are turned off via the AUX 1 relay, no more load on the battery. When the PV charges the battery up to 55v, I turn the inverters on via the AUX1 relay. The gap is to simply to avoid rapid on/off. The voltages are just 'what I picked' and the concept works with all battery types. For LifePo4 you'll need to do full range (low/hi) because the middle voltages aren't meaningful for SoC but as @Will points out - it's fine to do 100% for LifePo4 so this would be OK.

These on/off voltages are easy to set via internet using Midnite software and you can change them to suite whatever battery bank you wind up with.
1738636068852.png

This let's me use 'dumb' inverters for 240v/120v such as the AIMS and SGP 12,000w shown here..
1738636351884.png

I understand this is not a common approach but it's simple and works well for me so I thought I'd just throw it out there that you could view you're system as 'components' rather than force-fit an AIO and this would let you 1) keep the Midnites and 2) expand you're options to include well priced (dumb) inverters.
 
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Other than age and maintenance I don't think so. My concern is lack of visits to the property might mean we would damage the battery. Not sure how often it needs water added. I believe it is at least 4 years old. Possibly as much as 6 years old.

That's just a Spring Chicken. It could live to be 20.

Check voltage of each cell, to see how well balanced.
Determine what charge voltage and absorption time it is getting.
Determine what equalization schedule, voltage, time has been used.
Check specific gravity of each cell with hygrometer.

Well, I reached out to the original installer. The inverters are no longer supported and can’t handle lithium batteries. So once the beast of a battery dies I will look at replacing things.

LiFePO4 can be operated with voltage settings for VRLA. The inverter and SCC will be none the wiser.
You just don't get closed loop communications, which could have slowed charging to allow for balancing.

Certain LiFePO4 has some advantages (doesn't need long absorption, greater round-trip efficiency, zero maintenance).
And some disadvantages.

If you do upgrade, consider 48V system; many components available. But also consider just battery replacement keeping 24V.
For 48V, Midnight Rosie as suggested is one idea. 2x Sunny Island would be another. Schneider (presently being closed out) is yet another.
 
Nice setup.
I agree with the others in that I would not change anything unless it's no longer able to meet your requirements.
Be warned that once you start to change stuff you might as well change everything and just go with a 48V system.
The reality is that even the solar Panels will need to be upgraded once you go down that road.
 
Stick with your current inverters, they will work fine and dandy on lithium whoever told you that they would not is full of a foul smelling brown substance.

if they die, then consider replacing them. same for the battery when the battery dies then go lithium you will not be able to close loop the system with battery comms but that is not a prerequisite for a good quality battery system... its about the bells whistles and the pretty graphs you can generate. (that and getting the last nth out fo the batteries capacity wise)

If you have a 1000 aH lead acid, replace it with 1000 aH lithium, it will give you extended run time without the need for a generator, remember the lithium's do not get a memory like FLA or AGM... the batteries sitting at 30% for a month or two will not harm them... so you can put in your split pack use the snot out of it for a long weekend stay once or even twice a month and the system can slowly charge over the remaining days... no genset required no problems. if you down size the battery bank when replacing you may or may not run the whole weekend with the A/C you want to install.

most importantly have fun with your little getaway place... go up and use it on a regular basis for three or four months to learn the systems current limits of battery life. (FLA so 50% or 500ah is your limit and you must charge it back up within a week or less to maintain capacity.
 
Nice setup, I'd run it as is. Tech keeps advancing in this arena, what you install today might be considered outdated a year or two from now. Your system was built with solid components, run it until it dies. As mentioned, new or more panels wouldn't hurt. If the battery has decent capacity, run it. I wouldn't change inverters or charge controllers at this point.
 
You can purchase replacement similar batteries when needed without a problem.

If your loads exceed the system to run the air conditioning, I would just add a generator to support the load vs changing.
The real problem is going to be the pellet stove the OP wants to run. Generaly people run them in the winter and that time of year has the least sun.

Also that battery being a forklift battery and how cheap lithium has got could cost 2x to replace vs lithium. But i also wouldnt change it.
 
The real problem is going to be the pellet stove the OP wants to run. Generaly people run them in the winter and that time of year has the least sun.

Also that battery being a forklift battery and how cheap lithium has got could cost 2x to replace vs lithium. But i also wouldnt change it.
I did not catch the part about the pellet stove but if the cabin isn't heated when they are not there the lead acid should remain.
 
The battery is worth the same now as at end of life, so run it till it dies and then simply sell for $0.20/lb and replace with 24V LFP. Replace NOTHING else unless the system isn't meeting your needs.

Those inverters (previously Trace brand) are still the best in the world.
SORRY missed your 2nd reply. Ignore.... :_)

If the inverters are only running as inverters and not chargers is there any reason why they cannot use LFP batteries? As long as they are 24 volt?

Thanks!
 
I did not catch the part about the pellet stove but if the cabin isn't heated when they are not there the lead acid should remain.
All the solar equipment is in a dedicated insulated shed. It is not heated but I am sure I could fix that if required down the road. Southern AZ is the location. You have about 2-3 months of below freezing temps at night.
 
Location? FLA are a LOT more tolerant of cold than LFP batteries.
Southern AZ at around 5000 ft. It does get below freezing at night be rarely below freezing during the day. Dedicated shed is insulated but not heated. I am sure I could fix that if need be.
 
Make them work... seems like they should have a manual mode so you can program the charge curves
The Inverter/Chargers are only being used as inverters in this setup. The only difference would be if I ran a generator to charge the system. I have no plans to do this. IF we ever spent longer weeks and weekends with this setup that might be useful. With that said it would be easier to just make it possible to plug a generator into the panel on the barn and not worry about charging the batteries. Anyway, all TBD down the road.
 
Thanks again everyone. I have PDF manuals for most of the equipment and I am reading through them.

The solar equipment is in a dedicated unheated but insulated shed. It has a temperature controlled exhaust fan for heat. It is an 8x8 shed. Thus it would be pretty easy to heat and cool it if required.

We take ownership in a couple of weeks. Then I will get to spend a few days watching the system and see how it does.
 
SORRY missed your 2nd reply. Ignore.... :_)

If the inverters are only running as inverters and not chargers is there any reason why they cannot use LFP batteries? As long as they are 24 volt?

Thanks!

I wouldn't hesitate to use them as chargers with LFP either. It's simply about selecting a suitable charge voltage, which you need to do for lead acid too.

The nice thing about LFP is you barely need absorption to get them fully charged. When you hit your absorption voltage with LFP, you're typically above 90-95% SoC, so there's really no point in charging past that as you want to run your generator at about 80-90% of it peak continuous power. The absorption phase means you're running at a progressively lower load and higher fuel burn per kWh.

Southern AZ at around 5000 ft. It does get below freezing at night be rarely below freezing during the day. Dedicated shed is insulated but not heated. I am sure I could fix that if need be.

We're between Show Low and Concho at about 6500 feet, so we get a little colder there... weather station logged -3°F a couple weeks back.

My lithium battery is manageable in an UNinsulated shipping container, so I suspect you'll not have many issues with an insulated shed. If you further insulate the battery in a box, it will be even better. I would do that before I consider adding shed heat.

The Inverter/Chargers are only being used as inverters in this setup. The only difference would be if I ran a generator to charge the system. I have no plans to do this. IF we ever spent longer weeks and weekends with this setup that might be useful. With that said it would be easier to just make it possible to plug a generator into the panel on the barn and not worry about charging the batteries. Anyway, all TBD down the road.

I vigorously recommend you make provisions for running a generator and charging. It will be needed at least one day a year. Running a generator directly powering a house is horribly inefficient as your baseline loads are usually a very small portion of the generator's capacity where it's VERY inefficient. Better to run your generator at 80-90% of rated to charge the battery bank only when needed rather than run it for many hours just powering loads. You burn a LOT more fuel that way even with the supposed "ECO" efficient inverter generators.
 

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