Solar busbars...is it a thing?

[thanhrodke]

Howdy all!

I currently have 32 455W panels in two 8S2P arrays into two EG4 6000EX inverters. So that's about 400V name plate VOC, which is just under 500VOC at -10F, the coldest temps in my area.

The inverters have 7,500 watt MPPTs at 500volts which is 15 amps. With the 8S config, I get about 325-350 volts peak on hot days, and with the 16 amp limit, that's about 5,500 watts. Across two inverter/chargers, I can get a peak power of about 11kW out of the two MPPTs, even though I have about 14.5kW of solar power.

I have two spare 6000EX inverters, and am curious if you can just tie all solar to a common set of bus bars, then feed any number of inverter/chargers from the bus bars? On a clear day, it could be an additional 12-15kWh of power, or 25% more than I am currently capturing.

I don't need the AC power from the extra two inverters except on the weekends when I may be running multiple heavy motor loads (3-5hp). On weekdays, I could simply turn those inverters about mid-morning to better capture the maximum available power from the panels, then shut them off mid-afternoon. Otherwise, on cloudy days, when I may only be generating 3-5kW of power, I could just leave the two extra inverter-chargers turned off.

My current plan is to separate each 8S2P array, and end up with four separate 8S arrays feeding the four inverter/chargers, but then got curious about being able to just bus bar all the solar, and then it would not matter how many inverters I had turned on or not, the cabling would all be the same.

Anyhow, just wanted to ask the forum if this was even possible. I can't say that I understand the interaction between an MPPT and the panel array.

 

[burgerking]

MPPTs are wild animals. they need their very own space. You are not to share PV among MPPTs.

However, a SunSynk engineer showed a blocking diode circuit that can be used to parallel MPPTs to a single PV/Turbine source.

(source: www.youtube.com/watch?v=nZ6PGN2L10k )

If you have knowledge in electronics, you know if this will or will not work.

 

[thanhrodke]

Well now that you reminded me here that the key point is "MPPT parallel" and not "solar panels parallel", I can find all sorts of earlier posts about this.

Thanks much for that, and so from reading a lot of other posts, I see that it's a bad thing because MPPTs vary their load dynamically, and will interfere with each other unless you have a sophisticated enough system that the MPPTs have the ability to sync with each other. A few brands were mentioned, but I am just running the EG4 inverters, which are pretty dumb.

Now I just need to find a way to command the inverters to go to sleep early in the evening, then wake back up once solar gets above a certain amount. With my EG4 units, I doubt that's going to be a thing, lol. I might enlist the sneakernet and just go power them up when I need the extra charging capacity.

I am certainly open to any other ideas.