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

[JRH]

I love my 24V system. Wouldn't change a thing.

If youre not using LFP batteries it gets expensive to go 48V.

I love my 24V system too…chose it for several reasons… wouldn’t change a thing except I’m adding more panels now ..all else does will do everything I planned to do… wire costs are not important as I oversize everything anyway.
Everyone likes their steak cooked “their” way. There is rarely one size fits all in life ….…
J.

 

[SupraSPL]

Fwiw I just squeezed a 58V wire, hard with a dry hand to verify that I couldn't feel any kind of shock, so just as easy to work on as 24V.

 

[scubadoo]

I will stick with 12V for a while yet thanks.
Our 10 year old 4 cell LiFePO4 battery both powers our MH and starts the 3.9l turbo diesel engine often several times a day.
A 48V - 12V 730A peak current converter could be tricky.
The 255l 230V fridge, TV, coffee maker, toaster, jug, Instant Pot, induction cooker, excess energy 1000W water heating etc. and etc. run just fine from our 12V inverters.
All the thick gauge wiring involved in our entire setup for charging, inverter, solar controller output etc. would amount to perhaps 3m (10ft.) in total.
Converting to 48V would save us essentially zero.

Others obviously use or want far more energy.

 

[DPC]

Fwiw I squeezed a 58V earlier wire hard with a dry hand to verify that I couldn't feel any kind of shock, so just as easy to work on as 24V.

Never the less the experts consider that extra low voltage ends at 30 volts and thats because there touch potentials they are concerned about.
There was time when that was considered the best and safest voltage for a DC lighting systems
That's why something like this delco 850 was designed to run at 32 volt.

I often wondered why cars never went to 32-36 volt..
But in the same breath a lot of people had cars that ran at 6 volt and they starters and lights and radio worked and no one complained.

I'm going to correct myself now..
The threshold for low voltage AC is 30
Its 42 for DC.

I worked on higher voltage DC and AC systems and personally I can tell you its much worse getting a poke off a live higher voltage DC system
At one time we didn't have as many rules around working on them or ways to bring them to a zero energy state.
I hope people are careful ...

 

[SoggyShoes]

RVs can be tricky. Many small RVs cant fit enough Solar to runs 48 volt system. The large ones that can, have to run 2 or 3 48/12/30 amp converters to run jacks and levelling systems. But can run panels in series make 48v work.

I'm running 24 volts, easier to convert back down to 12 for jacks. I have one 330 watt panel so far, with plans to add some small panels but will never exceed 40 volts of solar. Hoping to fit another 3-400 watts of mixed small panels on the truck camper roof.

I agree with @Dooug.
For RVs, the sweet spot seems to be 24V. Many RVs have 3 battery systems (motor, house, and storage bank) two of which are almost guaranteed to be 12V. There seem to be so many more options for chargers and converters if you are just going back and forth from 12V & 24V.

As others have already mentioned, for RVs, the size and weight of batteries are an issue. A 304amp 48V battery is going to be pushing 200lbs. That is a lot to be lifting and squeezing in the crawl space of an RV.... if it fits.

 

[seneysolar]

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.

Is your current charge controller only capable of 12V? Most nowadays can do all 3 voltages (12,24,48).

If i was to upgrade your setup, simply hook your 4 batteries up in series for 24v. Find a 24v AIO inverter /charger /larger mppt. So $600 (ex. Growatt 3000?) and now you can double your panels (watts) to meet your needs. Done.

But 12v or 24v, watt/hours leaving the battery doesnt change. Perhaps more solar would get you to a higher SOC before nighttime. I personally use 4 of the trojan L16s and i can go a few days on a full charge. I suspect you arent getting a full charge if you are draining those overnight.

Jumping to 48V really forces you to buy new batteries, generally the most expensive part of any system.

 

[time2roll]

I'm going to correct myself now..
The threshold for low voltage AC is 30
Its 42 for DC.

30 Vac is the RMS. Divide by .707 gives peak at 42.4 volts. Nominally the same as 42 Vdc.

 

[hwy17]

Fwiw I just squeezed a 58V wire, hard with a dry hand to verify that I couldn't feel any kind of shock, so just as easy to work on as 24V.

I did it the other day with sweaty fingers and felt a nibble lol.

 

[Supervstech]

Fwiw I just squeezed a 58V wire, hard with a dry hand to verify that I couldn't feel any kind of shock, so just as easy to work on as 24V.

The difference is, 12V is nigh impossible to cause shock injury, 48V needs little to be deadly. Sure, it is safe under most conditions, but tired, mistakes, in a hot room, and it can be deadly.

As long as you treat it with respect, it is very hard to die from a 48V dc system, but it CAN happen.
Use safety, don’t die.

 

[gotbeans]

A lot of people started systems before 48v consumer stuff was even around

Fwiw I just squeezed a 58V wire, hard with a dry hand to verify that I couldn't feel any kind of shock, so just as easy to work on as 24V.

I did it the other day with sweaty fingers and felt a nibble lol.

yea be careful, for DC it's ~30v wet and ~60v dry for average person to get shocked.. depends on skin thickness and body resistance at that point.
bit lower voltage for AC
You can test your finger and put a buck booster on it and crank it up until you're getting zapped

 

[crossy]

Fwiw I just squeezed a 58V wire, hard with a dry hand to verify that I couldn't feel any kind of shock, so just as easy to work on as 24V.

IIRC the first RN sailor recorded to have died from electric shock was killed by a "48V" bus-bar.

Apparently, he got trapped between the bars and had broken skin (reducing his body resistance), cooked slowly!

Take care with any 'lectric and remember all those amps lurking inside even a 12V pack.

 

[pollenface]

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.....,

what's your objective here? Troll and make fun of 12/24v users?

 

[JJJJ]

Very happy at 24v. Meets the needs and allows flexibility if fewer panels are used. It is also easier to move the DIY battery cases LOL.

If one were starting from scratch I could see how 48v could be appealing. Each level 12/24/48 has its own unique challenges.

 

[Madcodger]

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,

When I built my 24V system, I didn't know any better and thought I was saving money and being safer. I love my little 24V system and plan to use it for years, but if I could do it all over again I'd go straight to 48. Neither of my earlier beliefs were really true, for me. Live and learn...

 

[Woody]

Why 12V….because solar parts are everywhere! From Walmart, HD, Lowe’s, Autozone, Oriel’s, NAPA, Harbor Freight, Tractor Supply, Bass Pro,….

12V systems in a disaster situation can help more people. Solar arrays based off 12v nominal panels even configured for other voltages (24, 36, 48,…) could be disassembled and a single 12v based panel could be given to someone to recharge their car battery so that they can power all sorts of 12v items. Ideally they should have a charge controller but they can be the controller and manually connect/disconnect the panel to the battery. Point the panel to the sun….Yeah lots of potential problems but one could. Not saying it’s a perfect solution but is a MacGyver fix.

24v or higher voltage makes it more difficult in finding replacement items quickly and easily. The local US stores typically don’t carry much inventory for 24v or higher products. Sure you might be fortunate to have a local solar supply shop where you are, otherwise you’ll have to “order” them. No problem, you just wait for the delivery to implement your repair. You can do without power for awhile. If it was a 12v based piece of equipment, you could just go to the local auto parts/box store for a replacement part and have the repair done.

12v is for DC based loads (radios, lights,…) and in general for micro solar systems with low to moderate alternating current (AC) power needs. Higher voltages are better for higher power consumption systems that have standard appliances, irrigation pumps, back feeding the grid, …. This is where higher voltages fit the design curve.

 

[SupraSPL]

IIRC the first RN sailor recorded to have died from electric shock was killed by a "48V" bus-bar.

Apparently, he got trapped between the bars and had broken skin (reducing his body resistance), cooked slowly!

Take care with any 'lectric and remember all those amps lurking inside even a 12V pack.

Yeap if you have wounds that's a game changer. I felt a small jolt from a live telephone wire that poked through the skin and I believe that is 48V DC

 

[OffGridForGood]

I say, all the voltages are welcome at my place, come one come all, 12v, 24v, and 48v all live and co-exist in my shop, and get along (tip use different colours for the Anderson Plugs! yeah.
The large stationary system running my business (and my home next door) is 48v, and lower voltages were not going to cut it. But my large mobile is 24v and it is about the same as a 120v 20A source rolling around on wheels running anything a 20A plug can run. But it is a bit heavy, and sometimes I don't need 120-20A, sometimes 6-8Amps is enough.
So for those smaller tools, that don't need more than 8Amps - yup I have a 12v super mobile, can carry it easily anywhere set up and do 'stuff'.
It all depends what your needs are.

 

[ohmboy]

Building first system at 24V. Mainly cost. This build will be half the cost of a 48V system.

 

[JRH]

I say, all the voltages are welcome at my place, come one come all, 12v, 24v, and 48v all live and co-exist in my shop, and get along (tip use different colours for the Anderson Plugs! yeah.
The large stationary system running my business (and my home next door) is 48v, and lower voltages were not going to cut it. But my large mobile is 24v and it is about the same as a 120v 20A source rolling around on wheels running anything a 20A plug can run. But it is a bit heavy, and sometimes I don't need 120-20A, sometimes 6-8Amps is enough.
So for those smaller tools, that don't need more than 8Amps - yup I have a 12v super mobile, can carry it easily anywhere set up and do 'stuff'.
It all depends what your needs are.

You are correct… what’s being suggested by some is like saying. “ no more 22LR ..ever” …

” no 9mm “ for nothing ….

use a 300 win mag for everything… that would be quite silly and expensive.

different needs would suggest different answers.

I have a small 12 volt set up in my shed for certain portable needs on my land, for jumping cars and equipment and outside 12v lights….had it for years… , a 24 volt main system on my mobile trailer system for powering the RV and bigger loads …

…and perhaps will have a 48V system one day if I build a new house up on the hill…..possibly by then higher voltage will be the cool way to go …

Who doesn’t remember when Mikita brought out the expensive ( Blue) 9.6 volt batt drill in the 80’s / 90’s … fantastic… game changers for working fast… and easy… at the boat yard we all thought they were a miracle when going up the mast to install stuff.

Soon no one wanted them as Dewalt came out with the 18v …then the XRP stuff ….and the others and others …and so on and so on……

Look where we are now with 60v+ batt powered table saws … maybe even more ….!
I don’t follow it much today.

Nothing is for very long anymore.. use what works for ya now..

A Lowly hillbilly opinion….J.

 

[JLD]

I have about the largest system that you would ever want to build in a 24v system. I have 4 Magnum ms4024 PAE stacked,
for a 16kw system with 122kwh battery and 29kw array. Ac coupled by transfer switch to either a 5k SMA OR 7.7 SMA that are
normally grid tied unless I need the extra power on cloudy days.