No I am not saying that at all. The AC70 (I have 2) DC input is 58VDC Max, 10A for 500W. Exceeding rated A and or W will not damage the AC70. Exceeding the 58V will.
However the maximum you will get with 4 x 100W panels in parallel is 200W. That will be less as the Voc of a 100W - 12V panel is around 20-22V, until you exceed 32VDC, the AC 70 will charge at 8A this will be 20% less charge again.
My suggestion is wire 2 panels in parallel, the other 2 in parallel for 2 strings of 200W. Then wire the 2 strings in series to double the Voc. Here you will get over 40V at 10A for near 400W or double what you get now.
There are 2 ways to do this, both have the same output. However if you chose to connect each string in series then parallel them, if one string fails or is shaded the other still works albeit 1/2 output.
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OK. Thank you. Just double checking.
Just wanted to come back and say Thank You Mandp. It was exactly as you said. Wiring as parallel and series, my max solar charging on 4 cheapest Amazon panels went from 160 to 340ish watts (panels are angled oddly, could probably get more if I cared).
Now, 8 months after first purchase and experimentation, I know a LOT more about solar, and various setups, I do think the AC70 is a good little unit for its price point, and has a lot of flexibility for normal uses. I actually needed 12v cigarette outlet power today, and it worked well on the AC70. Something I never thought I would ever use. Everything else works great…
Still, I do wish the AC70 could handle more input voltage. I think 58V is very limiting for solar panel setup options. It would be much more convenient if I could wire my current panels all in series, about 85VoC, so I could have that high voltage straight off the panels for other uses.
Knowing what I know now about solar power, today would have skip the AC70 and do something completely different, and definitely would have put together something that could handle 100+VoC minimum.
Also I’ll never do any solar setup without some kind of freeze protection. Lack of a charging cutoff for low temps I think is a HUGE OVERSIGHT in the AC70 software. It would cost effectively nothing to implement that, since there is already a temp sensor inside the unit, I am surprised low temp protection hasn’t been added in a software update. I was super surprised when I found out I couldn’t charge below 32F, would cause irreparable damage. Almost returned the unit. Nothing about this was mentioned anywhere prior to purchase.
The AC70 was my first stepping stone into solar power… Solar 101. I’m about to graduate, and currently designing a whole house off grid system.