Over Paneling AC500 - Exceeding wattage but below volt max

I understand I should never go over the 150 Volt maximum and the AC500 will step down Current to 15 Amps, but still have a question about wattage exceeding 1500 watts per DC input. Will it hurt the AC500 if the wattage exeeds 1500 Watts per DC input? In other words, will it damage the AC500 if I am running 120V and 15A = 1800 Watts (300 watts over the 1500W max) for each DC input?

Also, when consider a solar panel, which voltage rating should I look for: VOC, VMP? Same with Amperage?

Hi @SureHope

The only real value which is really important are the 150V. This means you can plug as many Solarpanels as you want on you AC500 as long you dont exceed 150V VOC.

VOC means the solar panel can produce up tp x Volt when there is no load connected. When the AC500 is full, this is the case.

The Current just get cut down. Even when your Panels are produce 30A. AC500 only take what it needs

Hope this helped


Overvoltage is all you need to watch out for, and by that I mean Voc, not Vmp. You want power (Wattage) to spare for cloudy overcast days. Voc rears it’s ugly head when you reach a full charge and the panel wattage drops to zero, but the Voc shoots up to it’s max value.

When shopping for panels you’ll notice only the BIG panels give you high wattage with low Voc.
When you try wiring panels in series-parallel configs to lower the Voc, the current can exceed the 15 amp max input, which means it’s wasted power. The AC500 ignores it.
I built a monster array with 15 100W Renogy panels, 3 strings of 5 panels in series for 121.5 Voc, and those 3 strings in parallel for 15.63 amps. (I didn’t mean to end up like this, but I kept adding panels trying to get to 1500W.) On a good day it can get to 1365W. These 100W panel are only $75 each on Amazon. I’m tempted to add 3 more panels for 3 strings of 6, which would max out 1500W with power to spare for overcast days.

It would be better to have fewer BIG panels than all these smaller ones, but places that sell these charge outrageous truck shipping, costing as much as the panels.

I like to remember it this way:

  • Voltage is defined by the source, so the load has to be designed to manage this as it’s « imposed » onto it.
  • Amps are drawn (« defined ») by the load, so the source needs to be able to handle that amount of electricity.

So if there’s more available, the load won’t just use it. Like unless you floor your car, it’s probably not using all the horsepower it can output.

Now adding my two cents with an experiment done this week-end given the nice sun we had. Done with both AC300 and AC500, using:

  • Trina 405 on MPPT1
  • Longi 405 on MPPT2

They’re both rated at 405Watts. Main difference is in Voc, Vmp and Imp.

While there’s only a 3V difference between both at max power (Longi 31Vmp and Trina 34Vmp), with a limit of 12amps (AC300) or 15amps, this slight difference still plays a role. That’s 9volts - and at 12 or 15 amps, it can mean a lot.

I can’t string 4 Longi panels as it would be 148Voc (at 25°C). So Longi is perfect for rooftops, but less ideal for in this case. Speaking of rooftop hardware, I think of the Victron SmartSolar 250/100 - capable of digesting up to 30amps of inbound DC (with Voc max being 250V).

So regarding your overpanelling setup, while it’s true that rooftop panels are likely to be a better option (Longi 405 is 100eur, Trina 405 is about 130eur), their Voc might be a problem to optimize Voc vs Vmp/Imp.

And the monster « titan » panels like the 450 or 500Wp units can reach Voc of up to 50Volts - this is a total no go as only high-voltage systems would allow this. And again, rooftop fires are a reality with voltages that high. Another reason to go Bluetti (on the go / small-medium offgrid) or Victron (rooftop / larger offgrid).

Thanks for your reply Erik. If I am understanding you correctly, I can run as many panels (I’m considering Series/Parallel wiring) as long as I stay under 150Voc, even if the total wattage output is over 1500W. Is that correct?

Hi @SureHope

Yes, it shouldnt be a problem. The unit will be locked at 1500W i think. But as i said, the only real limit is the 150Voc

Just to be absolute safe, can you confirm @BLUETTI ?

St8kout, thanks for your helpful information. My space is very limited at this point, so I can’t use low wattage panels. And I’ve found that trucking is very expensive as is the minimum panels for each purchase. Thanks for describing what you have done. Is it ground or roof mounted, and what kind of mounts have you used?

Roof mounting involves special permits, inspections, changing my Homeowner’s Insurance info, getting HOA approval, etc. Plus it’s not normally a DIY project. So, forget all that. On the ground you can do what you want, as long as you can’t see it from the street (HOA rule #1).
My pool takes up half the yard, so I had to find the best place by marking morning and evening sun paths, plus avoid the shadow of my chimney, so I really don’t have much room either.
Here’s a pic; 15 panels that see-saws east-west. You’d be surprised how just a little rotation affects output. I used to get a 200 watt difference, but after adding more panels, there’s a 300 watt increase just by aiming it at the sun at 3pm, from a 12 noon position. So you can imagine manually tracking morning to evening. (I actually move it only twice a day, east to west, and back at night.)

Hey, don’t laugh. It’s simple and easy to put together in a day. It survives the high winds we often get in Vegas, putting it somewhat parallel to the ground where the wind hits only the 2” sides of the frame. Built from 5 10’ Superstruts, and 2 20’ long 2x4s. The red posts are in 3’ of concrete.


Wow nice assembly! Can we see the other side?

Well, Hurricane Hilary :nauseated_face: is bearing down on us at the moment. Rain is the forecast for the rest of the week.

It’s simple enough. I had the red “pole” (2 2x4s) already from another project, buried in 3’ of concrete.
A 10’ Superstrut (goes by various names) mounted with one end between the gap in the pole, and the other end on the ground.
Four more Superstruts bolted across the main Superstrut to attach the panels.
When I needed to add more panels, I bolted 2 16’ 2x4s across for the top and bottom rows. (you can see them sticking out a few inches.
It see-saws east&west, balanced so all it takes are a few bungee cords to hold it in one position.
The sun angle can be adjusted by raising the bottom off the ground, but it’s pretty heavy so it just stays put.
The Superstruts are very strong, but they will bend a bit so I propped up the middle underneath with some cinder blocks. When I first bought them they were only about $17 each. They’re almost double that price now.

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good luck with Hilary :muscle:

sounds like a very crafty setup there!

If people ask, I’ll tell them a Chinese balloon must have landed in my yard. :stuck_out_tongue:

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Yes. As long as it does not exceed 150V VOC.

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“When you try wiring panels in series-parallel configs to lower the Voc, the current can exceed the 15 amp max input, which means it’s wasted power. The AC500 ignores it.”

This is not entirely true. Although you may have enough panels to produce over 15 A, it is not wasted. The AC500 takes in up to 15 A. The unused current capacity is not wasted, just ignored.This is like installing a big water pipe but the flow in use is lesser.

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