48V vs 24V why/why not?

[littleharbor2]

I recently installed a 3000 watt 24 volt AIO. Love it. I made it a point to get a high VOC input rated unit. Mine is 450 volts max. This makes wiring your array very simple. All panels in series, no combiner or fused strings and one small gauge pair of wires coming from the array. Just something to consider. I have a friend who has a 6000 watt 48 volt AIO and I was shocked to see it has a 140 volt dc input limit.

 

[12VoltInstalls]

How can I use my current bank of 4 x 12V @ 100Ah in series at 48V to periodically and easily charge batteries individually at 12V?

I think you want something like this:

https://www.aliexpress.us/item/3256805704027252.html

Shop around

There’s good units “domestically available” that while more expensive will take care of. I’ve seen specific lead acid BMS’s as well.

Do the BMS and never think about it again. ?

 

[kwest364]

Any problems with 36V panels charging 48V/60V system? Will be series connected up to 216V, so assuming doesn't matter. Will I have to wait longer in the day, when better sunshine achieved, till panels start pulling panel V closer to battery bank V of 57.6V and then starting to charge bank? 57.6V battery bank ÷ 216V PV array = 27% of panel capacity Voltage necessary to start charging battery bank.

Essentially, I'll get better "performace" out of panels by all series connect. I'll be able to have a more optimal charging range for the mppt cc (new concept to me), and pick up more power more efficiently at sun rise and sun set. Do I have that all correct? Series panels = bigger V range for more optimal mppt CC to battery bank charging and better low light performance? I'm not worried about shading.

My 6 x 185W 36V 5A panels all in series to ditch the combiner box, fuses, and x into 1 parallel wire combiners too.


So I'd be running:
1100W PV input (and can expand)

216V @ 5A

5000Wh battery capacity (and can expand)




Brand comparison:
-The eg4 all in one accepts higher PV input V vs growatt: 500V vs 150V. For similar price $675 vs $660, might as well get the EG4 for higher PV input capacity. It's smaller and less idle draw too.


-Reviews said fans are constantly running, is that true? It will be towards front of skoolie, away from bedroom, but maybe fans are quiet enough?


-Idle consumption says <50W. Any practical experience with real numbers here?

 

[Brucey]

Any problems with 36V panels charging 48V/60V system? As in, will I have to wait longer in the day, when max sunshine achieved, till panels start working more optimally and then starting to charge bank? Shouldn't matter, though, I'll have them all series connected to up V to 216V. And I'll get better "performace" out of panels by all series connect, I'll be able to have a more optimal charging range for the mppt cc (new concept to me), and pick up more power more efficiently at sun rise and sun set. Do I have that correct? Series panels = more optimal V range for charging batteries and better low light performance? I'm not worried about shading.
I could run my 6 x 185W 36V 5A panels all in series to ditch the combiner box, fuses, and x-1 parallel wire combiners.
So I'd be running:
1100W PV input (and can expand)
216V @ 5A
5000Wh battery capacity (and can expand)

The eg4 all in one accepts higher PV input V vs growatt: 500V vs 150V. For similar price $675 vs $660, might as well get the EG4 for higher PV input capacity.


Reviews said fans are constantly running, is that true? It will be towards front of skoolie, but maybe fans are quiet enough?

A lot of the aios have rather loud cooling fans going on. Definitely be aware and research sound levels because most won't accept a rack computer fan noise 24*7.

 

[12VoltInstalls]

Will be series connected up to 216V, so assuming doesn't matter

If the SCC allows the voltage that is acceptable.

For similar price $675 vs $660, might as well get the EG4 for higher PV input capacity. It's smaller and less idle draw too

I would

 

[seneysolar]

90% of what i do is 24v systems. I primarily use L16 batteries (6v) and use 8 in a system. So 2 strings of 4. I have not seen any balance issues using 4/0 wire and occasional equalization charges (2/year).

For the scenario of living off grid, the main benefit of being 24v is the ability to isolate 1 of the strings if you ever do have a battery issue and continue for a few days on half of your battery bank. If the system was 48v , your system is dead until get a replacement battery. I like having this backup plan.

 

[pollenface]

I have a 48v system with two Victron 100/20s. My highest recorded VOC is 90.14v (144 cell)

 

[time2roll]

My 12v system is maintained with 90 volts of solar.