Expanding my original solar plan

[VideoLenser]

As mentioned in my prior post , my original plan (which is up and running) involves 8 100w HF solar panels w/sae to MC4 adapters w/15amp fuses each to a 50ft MC4 10awg cable(w/ a breaker box) to my Renogy 100a CC to 4 Weize 100ah agm batteries in parallel to bus bars & T fuse to a Renogy 3000watt inverter. I was going to add 4 Renogy 100w Solar panels going 4S 3P. But due to all the great holiday deals I also bought 4 Eco Flow 100W Solar panels and 2 more Weize 100ah agm batteries. That would give me 16 100 watt solar panels and 6 100ah agm batteries. Most of these types of systems seem to stop at 12 100w solar panels. I could do a separate system with the Eco Flow panels and another 40a CC I have lying around for our rain barrel watering system in a greenhouse. But I'd like to hear your thoughts on using the 16 panels and 6 100ah AGM batteries in one system. 4S 4P possibly but that may be too much. The 6 batteries can be in parallel.. Thanks

 

[Rocketman]

What are the specs on the solar panels? Do the HF and Eco Flo have the same:
Voc
Vmp
Imp

If they are different how different?

What are the specs on your SCC? Both the one in use and the spare one.

Make sure the batteries are connected to a “Battery bus bar” with all equal cables - length, size, lugs, etc.

PS - you really should do the math and verify stuff will work together before buying.

 

[MichaelK]

I think you are making poor choices as to what you can shop for only online. The best deals for solar panels are shopping locally, with cash and carry pickup. Part of the problem is sticking with 12V panels. That is a mistake. You get more bang for your buck with larger residential panels. Shopping locally, you are likely to get 300-400W of panels for the price of one single 12V panel.

Rather than adding more and more parallel strings of small batteries, I'd look at a single string of much larger batteries. Six parallel strings of batteries is almost certainly going to damage some of them, as they become hopelessly unbalanced. You will be further ahead with just a single string of bigger Trojan L-16 batteries.

 

[scrubjaysnest]

At 78, a 4x4 foot panel weighing around 47# is difficult to handle so I prefer the 12 volt 100 watt panels. Now if I could lift them used Trina panels at $30 each is definitely cheaper then a pair of new 100 watt panels at $128.

 

[VideoLenser]

Your both are absolutely correct. My original intent, approx. 4-5 years ago, was to have a small emergency solar backup if I lost grid power to handle the bare basics, 1-2 100 watt panels with 1-2 100ah agm batteries. I'm sure I'm not alone in thinking if I just add a little bit more I can power a few more things. That grew into 12 panels over time. I think both of you are correct in advising people just beginning, that plan to go full off grid, to start out with one plan, and do your math. I think the larger wattage panels are a wise idea. I have looked and I didn't find these local deals in my area that you were mentioning. Over the last few years my plans have changed as my circumstances changed. I think I'll stay with the 4 100ah batteries in parallel & 12 100 watt solar panels. 4s 3p. The battery cable sizes & lugs are all equal.
I bought the 4 eco flow panels & 2 more amg 100ah batteries to go with my old MPPT 40a controller to use in my 10 by 20 greenhouse and garage.
My original intent of this post was to see what others thought I would need to do if I went with more than the 12 100 watt panels. I believe I got some of that answered.

Thanks

 

[Rocketman]

Going from four to six batteries is a big deal. Like I stated above, I would change out the battery section- install a good copper bus bar and have each battery directly wired to the bus bar with equal cables (equal length, size, lugs,etc.).

Also according to the way I read your posts you now have 2 different solar panels- are they electrically the same - the same specs?

If they are different specs there will be a penalty for connecting them together. If you post the Voc, Vmp and Isc of each panel - I can show you how to calculate it. If the panels are the same on those specs - the penalty will be zero. Usually it’s not bad if it’s under 10% - but it may be more advantageous to purchase a second solar charge controller.

 

[VideoLenser]

At 78, a 4x4 foot panel weighing around 47# is difficult to handle so I prefer the 12 volt 100 watt panels. Now if I could lift them used Trina panels at $30 each is definitely cheaper then a pair of new 100 watt panels at $128.

Going from four to six batteries is a big deal. Like I stated above, I would change out the battery section- install a good copper bus bar and have each battery directly wired to the bus bar with equal cables (equal length, size, lugs,etc.).

Also according to the way I read your posts you now have 2 different solar panels- are they electrically the same - the same specs?

If they are different specs there will be a penalty for connecting them together. If you post the Voc, Vmp and Isc of each panel - I can show you how to calculate it. If the panels are the same on those specs - the penalty will be zero. Usually it’s not bad if it’s under 10% - but it may be more advantageous to purchase a second solar charge controller.

Once I find those panel specs , I'll post them. For some reason Harbor Freight doesn't list them in their manual. I've noticed that other people have had a hard time finding that info. I'll check on the panels tomorrow. I thought using 6 batteries and changing to 12 or 16 panels was a big deal. That's why I made this post before I did it. Thanks your input.