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diy solar

Home System - Getting It Started

Just pulled the trigger on (8) of the CHINS 12v 100ah batteries.
Building an identical system for my father next door so we are buying all of the components together.

Buying the panels next.
Most Likely either 6 or 8 - 250w panels (Per System)
Each panel is 37.6 VOC / 8.27 A
Will wire them 3s2p or 4s2p depending upon how many we get.

Final decision will be which 48v All-In-One to purchase.
I'm down to these 2:

*Growatt 48v SPF 3000TL LVM (Max PV is 4000w / 145 VDC)
*PowMr 48v 3500w Hybrid (Max PV is 4500w / 145 VDC)

The PowMr is almost $250 cheaper but the reviews are still good on those.
Can anyone tell me why not to get the PowMr?
 
Just pulled the trigger on (8) of the CHINS 12v 100ah batteries.
Building an identical system for my father next door so we are buying all of the components together.

Buying the panels next.
Most Likely either 6 or 8 - 250w panels (Per System)
Each panel is 37.6 VOC / 8.27 A
Will wire them 3s2p or 4s2p depending upon how many we get.

Final decision will be which 48v All-In-One to purchase.
I'm down to these 2:

*Growatt 48v SPF 3000TL LVM (Max PV is 4000w / 145 VDC)
*PowMr 48v 3500w Hybrid (Max PV is 4500w / 145 VDC)

The PowMr is almost $250 cheaper but the reviews are still good on those.
Can anyone tell me why not to get the PowMr?
I think the bad spelling would put me off. PowMr? ?
 
I think the bad spelling would put me off. PowMr? ?
I'm with you there, but if that were the case, very few solar products would be legit.
Even domestically named products are made in China, so I care more about what's inside the case than the name on the case.

What I find interesting is that PowMr was also the agent for Growatt and EPever for 5 years according to their website before the came out with their own product. You can actually buy Growatt on their website.

I've heard very positive things about the response of their customer service which is huge for me.
 
Growatt 48v SPF 3000TL
(8) 230w Panels (SST) - 2 Strings (4 Panels in Series on each String)

Am I missing anything?
I would seriously consider going with 250w panels from Santan. Figure $200 in shipping for a pallet, you can still get each panel for $58 (maybe less if you time it right). I am running 9 of these panels (3S3P) and they are working great on my LV2424 (similar to the Growatt you picked).
 
I would seriously consider going with 250w panels from Santan. Figure $200 in shipping for a pallet, you can still get each panel for $58 (maybe less if you time it right). I am running 9 of these panels (3S3P) and they are working great on my LV2424 (similar to the Growatt you picked).
Actually already made that decision. The only reason I considered the 230w panels is that they are also SST panels like SanTan's but I can pick them up locally for almost the same price.
 
Here is my initial schematic after all of the input.

I've attached a jpg as well as a PDF.

Realized I don't have room on the roof for more than 6 panels total, so I am maxed out at 6. If it doesn't cut it, I could build a tower on the corner of the house and add another 3 panels to make it 3s3p potentially.

Here are the specs of all of the components below:

SanTan 250w Panels
  • Rated Power: 250W
  • Open circuit voltage (VOC): 37.6 V
  • Max power voltage (VMP): 30.3 V
  • Short circuit current (ISC): 8.85 A
  • Max power current: 8.27 A
PowMr 48v / 3500w All-In-One
  • Rated Load Power: 3500w
  • Max PV VDC: 145v
  • Max PV Wattage: 4000w
  • AC Charge Current: 40a
  • PV Charge Current: 80a
CHINS Batteries:
  • Life P04 Lithium
  • 12v 100ah
  • 100a BMS
OK everyone...tear me up here and tell me where I need improvement.
 

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Here is my initial schematic after all of the input.
I would add:

Fuse between battery and inverter
Maybe a shutoff between battery and inverter (I don't have one, but been thinking about it)
PV shutoff between inverter and panels (I really urge you to get this)

You show 250w panels in your pdf, but you mentioned 230 in your post.
 
CHINS are showing up today.
What are everyone's feelings on the best way to series connect?
Just trying to decide between using bus bars or 2awg like I did for my cabin build.
 
Packaged very nicely.
Surprised at how light these are!
 

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OK...Getting ready to order the rest of my components.
I've decided to switch from the PowMr to the MMP Solar 3048.

I've attached the latest and greatest updated schematic.

Questions:
* Do I need a combiner box to connect the 2 strings of panels? If so, any recommendations?
* Recommendations for an inline fuse between the Batteries and the MPP?
* Recommendations for a shut-off switch for the battery bank to the MPP?
* Recommendations for a circuit breaker (Running 2 circuits off of the MPP. Most likely 20amp breakers.

Ordering the panels from SanTan soon.
Cabling will be ordered from Windy Nation.
Going to use bus bars for the series battery connections instead of cables, then cables to the inverter.

As usual, please tear this apart before I order all of this stuff!
 

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Questions:
* Do I need a combiner box to connect the 2 strings of panels? If so, any recommendations?

With 3s2p, no fuse is required.
Some kind of disconnect is appropriate, so when making final connection in the sun it doesn't arc and burn connectors (will charge capacitor).
2-pole disconnect is nice because then no chance of it driving voltage to any wires while you work on it.

8.85A Isc, x2 = 17.7A, x1.56 design factor = 27.6
Use at least 10 awg after strings paralleled. A 30A 2-pole breaker would be once choice for disconnect.
Could be this one, just remove jumper from one end so two separate poles for (+) and (-)

Alternatively, there are some 250V AC/DC rated 2-pole knife switches. Those should be cheaper than the Square-D 600V AC/DC 30A "heavy duty" switches I've used.

* Recommendations for an inline fuse between the Batteries and the MPP?

Is there an internal resistance spec for the lithium cells?
3.4V / IR = possible short circuit current
Fuse should have an "AIC" rating to interrupt short circuit current at least that high (at 48VDC). For larger cells, I've seen 0.00025 ohm rated, 0.00017 ohm measured, which suggests 20,000A possible so "class T" fuses would be a good fit. Yours may be less.

Amperage:

3000W / 46V low battery / 80% efficiency x 1.12 ripple factor x 1.25 margin = 114A, so 120A or larger fuse rating.

Blue Sea is one vendor, resells LittleFuse or other quality brands.

Here's a breaker a somewhat larger than you need, 175A. It has 50,000 AIC.


Here's one 125A rated. AIC is 10,000 which may be sufficient.


* Recommendations for a shut-off switch for the battery bank to the MPP?

Any rated for expected operating current (actually for fuse amperage rating) and not an off-brand.
If you use breaker not fuse, then no separate disconnect needed.

* Recommendations for a circuit breaker (Running 2 circuits off of the MPP. Most likely 20amp breakers.

Any AC breaker and panel you choose.
There are DIN rail breakers from Midnight; if you wanted you could put DC and AC breakers in a single panel.

I use Square-D QO AC breakers. I prefer the panels which are 125A busbar or higher (12 slots, some are 24 circuit) because they have copper busbars; the smaller panels use aluminum.
There are cheaper models such as Homeline, may come in a bundle with panel and several breakers. Aluminum bus. Several brands of breakers are compatible.
 
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With 3s2p, no fuse is required.
Some kind of disconnect is appropriate, so when making final connection in the sun it doesn't arc and burn connectors (will charge capacitor).
2-pole disconnect is nice because then no chance of it driving voltage to any wires while you work on it.

8.85A Isc, x2 = 17.7A, x1.56 design factor = 27.6
Use at least 10 awg after strings paralleled. A 30A 2-pole breaker would be once choice for disconnect.
Could be this one, just remove jumper from one end so two separate poles for (+) and (-)

Alternatively, there are some 250V AC/DC rated 2-pole knife switches. Those should be cheaper than the Square-D 600V AC/DC 30A "heavy duty" switches I've used.



Is there an internal resistance spec for the lithium cells?
3.4V / IR = possible short circuit current
Fuse should have an "AIC" rating to interrupt short circuit current at least that high (at 48VDC). For larger cells, I've seen 0.00025 ohm rated, 0.00017 ohm measured, which suggests 20,000A possible so "class T" fuses would be a good fit. Yours may be less.

Amperage:

3000W / 46V low battery / 80% efficiency x 1.12 ripple factor x 1.25 margin = 114A, so 120A or larger fuse rating.

Blue Sea is one vendor, resells LittleFuse or other quality brands.

Here's a breaker a somewhat larger than you need, 175A. It has 50,000 AIC.


Here's one 125A rated. AIC is 10,000 which may be sufficient.




Any rated for expected operating current (actually for fuse amperage rating) and not an off-brand.
If you use breaker not fuse, then no separate disconnect needed.



Any AC breaker and panel you choose.
There are DIN rail breakers from Midnight; if you wanted you could put DC and AC breakers in a single panel.

I use Square-D QO AC breakers. I prefer the panels which are 125A busbar or higher (12 slots, some are 24 circuit) because they have copper busbars; the smaller panels use aluminum.
There are cheaper models such as Homeline, may come in a bundle with panel and several breakers. Aluminum bus. Several brands of breakers are compatible.
Thanks as always for the tips. Much appreciated!
 
CHINS batteries have arrived - CHECK
PANELS have arrived from SanTan - CHECK

Now I've been waiting forever for the MPP Solar all-In-One to show up. Can't wait anymore.
Seems like everyone's opinions have changed constantly on Growatt, PowMr, etc...
Anyone have any opinions as of late?
Looking for a 48v system - 3000/6000 watt range.
 
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