Hello from Missouri

Ronaldrwl

New Member
Joined
Oct 19, 2021
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4
Location
Missouri
Hello everyone. Thanks for all the information on the forums. I've been reading for two days now. Another expensive hobby! With so much to learn.

Here is what I've bought so far. Mostly from a kit.

Monocrystalline Panels 8x200w, 4x2, 24V.
Combiner box, 60A max, 250V max in/out, surge protector, earth ground.
Charge controller 60A 12V/24V PWM
Inverter 3500/7000W 24Vdc-110Vac.
Batteries 8x50 amp LiFePo4 12v, setup as 24V
150amp fuse between batteries and inverter.

Everything seems to be working except the controller gets real hot on sunny days. So, I shut the system down for now. The highest readings I've seen are 28v and 22 amps from the panels. I believe I need to upgrade the controller. It looks like Vectron is the most popular. I'm looking at SmartSolar MPPT 100V 50 amp.

Thanks for any feedback
 

Hedges

I See Electromagnetic Fields!
Joined
Mar 28, 2020
Messages
9,102
Welcome!

Is charge controller in the sun, or just heated by current?
Consider adding a fan, maybe thermostat controlled or PV direct. Some brushless DC motors accept gradually ramped power, some do not. 24V Pabst worked for me.
 

Hedges

I See Electromagnetic Fields!
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Mar 28, 2020
Messages
9,102
Heating is generally proportional to current squared.

PV panels "4x2", meaning 4s2p? All same orientation?
Make that 4s aimed at 10:00 AM and 4s aimed at 4:00 PM, 6 hours or 90 degrees apart.
That will reduce peak current, increase hours of production. Angles other than due South (Noon or 11:00 AM sun) due reduce power captured, a trade-off.
This should level power production to match daytime loads better, enter evening more fully charged, allow more watts of PV for a given SCC.

Review mounting conditions of charge controller vs. manufacturer recommendations - orientation, clearance.
I've had an idea that a chimney would get convection to produce higher velocity.
But forced air from a fan would give greatest cooling. Lifespan of electronics is cut in half every 5 degrees.
 

Ronaldrwl

New Member
Joined
Oct 19, 2021
Messages
4
Location
Missouri
Thanks for the good ideas. I like the idea of orienting some panels more towards morning.
:) I believe that's 2s4p. 4 pairs of 2. I've got to learn the new lingo.
 

Hedges

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Joined
Mar 28, 2020
Messages
9,102
Four parallel sets of 2 series-connected panels? Yes, 2s4p.
Post links to data sheets for panels and charge controller, and I'll double-check voltage and current specs.

Combiner box too; I'll see what I think of the over-current protection.
 

Ronaldrwl

New Member
Joined
Oct 19, 2021
Messages
4
Location
Missouri
I couldn't find links to data pages. I've listed links to each product page and the specifications.

8 x 195W, 12V Monocrystalline Solar Panels
Rated Power: 195W
Open Circuit Voltage (Voc): 21.6V
Short Circuit Current (Isc): 10.83A
Working Current (Iop): 9.02A
Output Tolerance: ±3%
Temperature Range: -40℃ to +80℃

Combiner Box:
6 String PV Combiner Box
Number of Max Connection PV Array: 6
Max Input Current of Single PV Array: 10A
Total Input Current of PV Array: 60A
Max Input Voltage of Single PV Array: 250V
Max Output Voltage: 250V
Protection Grade: IP65
Operational Environment Temperature: -30℃~+70℃
Surge Lightning Protection: Yes

60A Solar Charge Controller
Battery voltage: 12V/24V
Battey Type: AGM,SLA,GEL,Li
Max Charge current: 60A
Discharge current: 60A
Max Solar input Voltage: <55V
Max Battery Voltage: <34V
Over-dischage return voltage: 12.5V/25V(Adjustable)

8 x 50 Ah LiFePO4 Batteries:

Inverter 3500/7000:
3500W 12V/24V/48V to 110V Off Grid Pure Sine Wave Inverter
Continuous Power: 3500W
Output Volt: 110V AC
Waveform Pure Sine Wave
Surge Power: 7000W
Frequency: 110V-60Hz
Input Range: 10-15V DC/21-30V DC
Working Input: 12V/24V/48V DC
Non-load Consumption: <25W
Efficiency: >90%
Fuse: 20A/35A
Over Heating Shut Down:>75℃
Over Load Shut Down: 3600W Over 10 Second
Over Thermal: Shut Down The Output
Working Temp.:-10℃~+50℃

This is a link to the kit. I added 2 more panels, 4 more batteries and the combiner box.
 

Hedges

I See Electromagnetic Fields!
Joined
Mar 28, 2020
Messages
9,102
I couldn't find links to data pages. I've listed links to each product page and the specifications.

8 x 195W, 12V Monocrystalline Solar Panels

Open Circuit Voltage (Voc): 21.6V


60A Solar Charge Controller

Max Solar input Voltage: <55V

That 55V limit is inconvenient.
Looks like 2s is the correct PV array configuration.

I'll dig in more later.

Fuses not (polarized) breakers per string in the combiner; that avoids an issue I would otherwise worry about.
 

Hedges

I See Electromagnetic Fields!
Joined
Mar 28, 2020
Messages
9,102
8 x 195W panels = 1560W (STC)
1560W / 24V = 65A

Charge controller "Max Charge current: 60A"
You could exceed that on a cool day with lower battery voltage.
A charge controller should protect itself,
but all the more reason to orient some strings of panels differently.

PV panel "Short Circuit Current (Isc): 10.83A"
String fuses should be at least 10.83A x 1.56 = 16.9A
Label probably says 20A max, so that would be a good value.

8 x 50 Ah LiFePO4 Batteries:, 12V each so 200 Ah at 24V

60A/200 Ah = 0.3C
The battery should accept that over some temperature range (but not all the way down to zero degrees C.)
Battery page lists under-voltage, but not temperature protection. Find out if it has a low-temperature disconnect, and if it is adjustable.

Based on data published for other batteries in the following link, I would suggest only charging between 15 degrees C and 55 degrees C.

 
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