Wondering why're many people still building 12/24v system ?

Sparks-n-Splinters said:

...the issues and frustrations with AIO's and inverters, along with buggy firmware updates. Sounds like a lot of headaches I don't want.

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I'm going through just this problem right now. While I admire your solution (and the buy-in from your wife!), my needs are beyond a simple 12v system. I could do without the AIO headache, though.

I use a small 12V system and a medium 24V system. The house has been running on the 12V to 3000W inverter for the last few days including some cooking, hot water and laundry.

12v or 24V you can touch and work on, probably even with wet hands. 58.4V you can probably still touch with dry hands. But if we go above that we need more expensive parts and nothing can be "exposed".

12V/24V components are plentiful and cheap. Many devices are compatible with 24V and even more 12V. A length of 2/0 or 4/0 between battery and inverter is a one-time investment and will never lose it's value so I don't mind spending $100 on cable. An 8S 24V 300Ah LifePO4 is 100LBS so I can still move them around and stack them but a 16S 300Ah is 200LBS so probably has to be built on a shelf or in a cabinet. I don't know why that matters but it might be a consideration for some.

If you have a large home or a large family, 48V with large split phase inverter probably a no brainer. Youd spend less on MPPTs, BMS and cables, but less options when it comes to 48V inverters rn.

SupraSPL said:

I use a small 12V system and a medium 24V system. The house has been running on the 12V to 3000W inverter for the last few days including some cooking, hot water and laundry.

12v or 24V you can touch and work on, probably even with wet hands. 58.4V you can probably still touch with dry hands. But if we go above that we need more expensive parts and nothing can be "exposed".

12V/24V components are plentiful and cheap. Many devices are compatible with 24V and even more 12V. A length of 2/0 or 4/0 between battery and inverter is a one-time investment and will never lose it's value so I don't mind spending $100 on cable. An 8S 24V 300Ah LifePO4 is 100LBS so I can still move them around and stack them but a 16S 300Ah is 200LBS so probably has to be built on a shelf or in a cabinet. I don't know why that matters but it might be a consideration for some.

If you have a large home or a large family, 48V with large split phase inverter probably a no brainer. Youd spend less on MPPTs, BMS and cables, but less options when it comes to 48V inverters rn.

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As someone who built my first system on 12v even though it's designed to sit in a shed, I really would have rather gone with 48v.

It hurts to spend so much money on 4/0 wire when I could be spending a fraction of that if I'd put the extra few hundred up at first to buy a 48v AIO.

In my case, would have been way smarter to go with 48v, I think.

I've been thinking about your lead-in question. After pondering for a while, I will admit that I originally thought 12V was the only way to go. It wasn't until I got more into this forum that I considered other options. Even then, I thought 48V was way beyond my comfort zone. It took a while before I came to terms with my own ignorance and realized that 48V systems were in my future. I ultimately did invest in a 48V system and I'm very happy I did so.

Perhaps others jump into systems and try to maintain their comfort zones (12V). Maybe they figure they'll learn/experience 48V somewhere down the line in the future. Maybe a person that is finally in a place in life to consider a DIY project has more experience in older techniques than newer ones and chooses the "proven path" for their own needs.

I make no judgement accordingly, I just offer this as a response to your opening question.

Some use cases where I still run 24 and 12v
1. Sheds and barns where you have one panel maybe 2 and a single battery for electric fence, a light, etc
2. 15 - 20yr old system where 24V was more popular and cant completely redo/purchase a 48v upgrade. (Although in the works)
3. Running available and cheap 12V components; DC bulbs, Automotive, ...
4. Pre LiFePO4 days, Affordable Lead acid came in 6V and 12V.

On a smaller rv, my only 110 loads are microwave and AC. We try and travel based on temp. Have a generator if I need to run the ac to cool everything down. Fridge, tv, radio, heater blower, lights, are all 12v loads. Our goal was to be able to boondock with what solar we had. Tanks are the limiting factor right now.

If starting from scratch, Id probably just base it on loads and surges. Simply to keep wiring in the realm of "normal sizes"
Less than 2000W inverter - 12V
2000-6000W inverter - 24V
Above 6000W inverter - 48v

Of course, this goes out the window when you buy solar panels by the pallet, and you want to max out charge controllers to their full potential.

seneysolar said:

If starting from scratch, Id probably just base it on loads and surges. Simply to keep wiring in the realm of "normal sizes"
Less than 2000W inverter - 12V
2000-6000W inverter - 24V
Above 6000W inverter - 48v

Of course, this goes out the window when you buy solar panels by the pallet, and you want to max out charge controllers to their full potential.

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2k - 4k : 24v
4k and up : 48v

new off grid said:

Greeting all,
Noticing lots of people here still think about building a new/huge system @ 12 or 24v
is it no debate that 48v is the only way to go ? it's everything better !
unless the new system is very small, sub 500w or upgrading from an even smaller one
Am I missing anything ?
happy harvesting ppl,

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Why the concern about what other people are doing?

I have a 12v system, it works flawlessly.

I left my 12 volt system intact. I do however have my ac system running through a Samlex EVO 4248 48v inverter/charger/auto transfer with 200ah of batteries. I can pull the shore power and the wife be watching tv/ using her hair dryer etc... and not know anything has changed. Best of both worlds.

new off grid said:

Greeting all,
Noticing lots of people here still think about building a new/huge system @ 12 or 24v
is it no debate that 48v is the only way to go ? it's everything better !
unless the new system is very small, sub 500w or upgrading from an even smaller one
Am I missing anything ?
happy harvesting ppl,

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Some of us can no longer pick up 100# batteries or handle 4ft x 4ft 50# panels.

scrubjaysnest said:

Some of us can no longer pick up 100# batteries or handle 4ft x 4ft 50# panels.

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Haven't done solar on the fifth wheel yet. I agree on not being able to lift 100# bateeries. That's why I did 100ah mini batteris for the rv. 8 in 4s. I save the heavy suckers for my home system.

pollenface said:

Why the concern about what other people are doing?

I have a 12v system, it works flawlessly.

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seeing a baby on the cliff edge and turn a blind eye...
seeing a poor set up and the lips are zipped....
is that you sir ?
lol.....,

My first system I installed at the family cabin back in 2020 was a 12v system and I almost immediately regretted going with 12v.

Originally I had planned on going 24v with 4x6v S550 batteries and an outback charge controller. But couldn't find a good deal on a 24v inverter or water pump at the time(I'm in Canada). So I ended up configuring the batteries in to a 12v configuration, going with a 12/24v DC fridge, 12v water pump and 12v lighting. Original plan was the inverter would only be on to watch TV and the system would only be used in the summer.

Then last year my parents got Starlink and have pretty much moved to the cabin full time year round. We upgraded from a 1000watt big box store inverter to a 3000 watt inverter with built in charger. Now the inverter is never turned off. So over half of the year the generator is run every evening to top of the batteries and they are barely getting to sun rise without over discharging the batteries. It doesn't help that the original panels are angled for summer and are facing south east.

So now rather than trying to upgrade that 12v system, I'm building a whole new 48v system to supply 120v to the cabin. The 12v will stay for now and run the water pump, fridge and lights. But it just isn't practical nor economical to try and grow a bigger 12v system. When the batteries hit their end of life I will likely put in a DC to DC converter for the lights and one for the fridge. The water pump will likely get upgraded to a 120v.

This time around I was able to get AOLithium 48v batteries with free shipping and no duties at an amazing price. I bit the bullet and got an EG4 inverter from the US and had to pay an extra $100 in UPS brokerage on top of the taxes. The panels I'm getting locally for an amazing deal. Things have changed in the past 4 years.

Yeap a pair of 220W 12V water pumps are a good part of the reason I left the 12V and added a separate 24V. I also run fans, modem, router, hard drives, drone chargers, LED strips, USB chargers, power station charging etc directly on the 12V

LordGarak said:

My first system I installed at the family cabin back in 2020 was a 12v system and I almost immediately regretted going with 12v.

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For comparison sake, convert everything to watts in/out. If youre using more watts than your solar is bringing in, youre bound to be disappointed no matter the system voltage

pollenface said:

Why the concern about what other people are doing?

I have a 12v system, it works flawlessly.

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+1

My 12v is also flawless and works perfectly. 24/48 would just add complications I don't want and don't need.

Going over 33 volts means your system falls under a different set of regulations in some places ( maybe not in some or all of the USA )
You may not be able to get insurance unless you pulled a permit and had it inspected.
You may run afoul of local electrical authorities with a grid tie system as well

There are still a lot of real advantages to a low voltage small system.
Like 24 or 12 volt solar fridges and appliances that run direct off batteries.
Don't forget low voltage lighting...

DPC said:

Going over 33 volts means your system falls under a different set of regulations in some places ( maybe not in some or all of the USA )
You may not be able to get insurance unless you pulled a permit and had it inspected.
You may run afoul of local electrical authorities with a grid tie system as well

There are still a lot of real advantages to a low voltage small system.
Like 24 or 12 volt solar fridges and appliances that run direct off batteries.
Don't forget low voltage lighting...

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Yeah, except low voltage lighting is also low wattage lighting, and works wonderfully on a buck converter.

If BUILDING a new system over 2000W, 48V just makes the most economic sense.

If upgrading existing equipment, it is painful to sell for pennies what you have, and reinvest in 48V stuff.

48V LFP requires high arc fault tolerant fuses, relays, and switches.

Sure, the wire sizes are smaller, and lighter, but safety hazards go up exponentially.

5kWh of 12V is simple to handle.

5kWh of 48V, especially in a mobile setup means fusing and control issues abound.

I'd wager most are simply concerned with potential issues.

seneysolar said:

For comparison sake, convert everything to watts in/out. If youre using more watts than your solar is bringing in, youre bound to be disappointed no matter the system voltage

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The comment is more to how difficult it is to grow the system larger. At 12v charge controllers get expensive. An 80A charge controller cost about the same at 12v or 48v but the 48v one can handle 4x the power. Similar story for inverters and AC chargers. The 48v all in one I just bought cost about the same as the 12v charge controller alone and significantly less than the 12v inverter/charger.