My COVID Project LOL - 1.4KW Off-Grid Garage

[wade0000]

Hello everyone,
New to the forum.

Back in March when it was apparent we were going to be in a long lock down mode and would be stuck at home a lot, I decided to put in an off-grid system for my detached garage.

I wanted to design, purchase and install everything in order for me to 1) have enough to do thru the summer and 2) save money.

It certainly was a learning experience and I was happy that I passed city electrical inspection since a building permit was required.

It's 1.4 KW
Four(4) 350W panels connected in series-parallel
EPEVER MPPT 40A charge controller
Four(4) 12V 200AH AGM batteries connected in series-parallel
3000W 24V pure sine wave inverter
Run to 2 120V AC gang boxes and out to pond (running 100W pond pump, pond lighting, garage lighting, garage receptacles, garage security cameras)

Here are some photos... I'd love to hear your questions!!

 

[Hedges]

Earthquake territory? If so, secure the batteries. At least a binder strap around them.
Good to see battery cables tap opposite corners of the two strings, to balance.

Any fuses, or just breakers? We're not sure about the quality of that style breaker from some questionable sources. There are good names too.
What is interrupt rating (thousands of amps) for those breakers? I've seen 4000A quoted for short-circuit current of 100 Ah AGM, so yours might have 16,000A short circuit current. For my 405 Ah 48V battery I used a class T fuse (20,000A interrupt capability)

40 A charge controller, 400 Ah battery. Probably 0.1C is a good maximum figure. What does battery documentation say?

Controlling loads to activate when battery is full, avoid discharge at night, should extend battery life. The ones I'm using would be expected to last a couple years with 70% DoD every night, 10 years with 15% DoD.

Did you adjust charge parameters to match battery recommendations? My VRLA defaults were close, but I adjusted voltages slightly.

 

[wade0000]

Earthquake territory? If so, secure the batteries. At least a binder strap around them.
Good to see battery cables tap opposite corners of the two strings, to balance.

Any fuses, or just breakers? We're not sure about the quality of that style breaker from some questionable sources. There are good names too.
What is interrupt rating (thousands of amps) for those breakers? I've seen 4000A quoted for short-circuit current of 100 Ah AGM, so yours might have 16,000A short circuit current. For my 405 Ah 48V battery I used a class T fuse (20,000A interrupt capability)

40 A charge controller, 400 Ah battery. Probably 0.1C is a good maximum figure. What does battery documentation say?

Controlling loads to activate when battery is full, avoid discharge at night, should extend battery life. The ones I'm using would be expected to last a couple years with 70% DoD every night, 10 years with 15% DoD.

Did you adjust charge parameters to match battery recommendations? My VRLA defaults were close, but I adjusted voltages slightly.

No big earthquake threat here in Virginia. I might strap them around table though now that you mention it.

yes fuses on the battery and inverter sides. 60A and 150A respectively. Will have to check on the interrupt capacities. I did change the default AGM sealed settings to match what the battery mfg specified.

 

[Hedges]

Wire resistance will serve to limit short circuit current (depending of course on where you short it.)
Although I'm estimating 16kA for my 400 Ah, or 2 x 8kA for your batteries, my scaling from a 100 Ah measured as 4kA could be incorrect due to battery internal lead busbars.

Class T is good for 20 kA (at 125V), ANL only 2700A at a lower voltage which is about an automotive starting battery. Not sure about other popular ones.

Your batteries have bolts that stand up. Might want to put a cover over them to prevent anything metal from landing on top.
Mine are recessed in pockets. I laid a piece of corrugated plastic roofing over them to keep water and cats off (outside under a deck, and up to 60V present.) I plan to add a fan; the inverter/charger has default 40 degree C to enable it.

I see a cable from the charge controller disappear behind the batteries. Temperature sensor?

Looks like your batteries:

Deep Cycle Series

nppbatteries.com

15 year float life, 2 years at 50% DoD nightly.
Recommended for shallow cycles, but the total Wh you'll get out of its life is about the same regardless of DoD. You just get your use and money's worth out sooner if you wear it out sooner.
Still, running loads off surplus PV is better than curtailing PV production because battery is full, then cycling battery at night.

 

[rhino]

Very commendable having everything labeled and well laid out.. and nice diagram!

 

[wade0000]

Very commendable having everything labeled and well laid out.. and nice diagram!

I did this with the purpose of the electrical building inspector's visit... knowing full well he/she would frown knowing a do-it-yourselfer was putting in his own solar power system. The inspector said I 'obviously knew what I was doing" which made me proud. He said that it would very well labeled. thanks

 

[wade0000]

a couple of more...

 

[MadMax03]

How cool! Nice work. Is inverter one of these?

275.4US $ 19% OFF|Off Grid Pure Sine Wave Inverter Power 3000w 24v Dc To Ac 220v Solar Inverter Generator Converter 12v/36v/48v To 120v/230v/240v - Inverters & Converters - AliExpress

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[wade0000]

How cool! Nice work. Is inverter one of these?

275.4US $ 19% OFF|Off Grid Pure Sine Wave Inverter Power 3000w 24v Dc To Ac 220v Solar Inverter Generator Converter 12v/36v/48v To 120v/230v/240v - Inverters & Converters - AliExpress

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Yes it is.

In hind sight, it is probably too big. Uses about 30W just by itself. Based on me running <200W on average and only needing the extra oomph when starting high surge tools like circular saws, etc...., 2000 would probably have been plenty.

Works great though. I got it as a return for $199 I think.

 

[MadMax03]

Awesome! Was thinking about putting one in my car (I'll have lots of LTO and LFP in it). I can set up flood lights when I'm broke down and need to change a tire at night.

 

[wade0000]

Also, I connected the two standard electrical plug-in outlets exiting the inverter to an AC breaker box and breakers... so that I could tie into a ground and have GFCI circuits.

I made it this way because the floating ground issue had concerned me...especially running to an outdoor submerged pond pump. (Middle right of photo are the AC breakers)

(Mi