Hybrid inverters for off grid

schmek

Hi,

I posted some discussions earlier about using high voltage battery packs with DC coupled off grid systems. It was never suggested to use a hybrid all in one-inverter, and I wonder why that is. I for example found a hybrid inverter from Solax that work with battery packs up to 500 V, and I understand that they can be coupled in parallel. The range is 5-10 kW. https://www.solaxpower.com/wp-content/uploads/2017/10/X3-Hybrid-User-Manual.pdf

Is this an option for a large hybrid off grid system (200 kW), instead of using charge controllers? 
I find very few charge controllers that is compatible with high voltage battery pack and high voltage solar strings, but it seems that a hybrid inverter can do both. I assume a charge controller is integrated into the inverter.

mcgivor

After taking the time to look at the manual, it would appear that there is indeed two solar inputs capable of charging a high voltage battery, specifically lithium ion. The wiring diagrams all include a grid connection, with the battery connected via a DPDT relay to transfer to emergency power, fed from the battery, via an internal DC AC inverter, but it would appear the battery’s purpose is predominantly for load shaving and emergency use only, rationale behind this statement is because all wiring diagrams include grid as a priority. Since there is no information on maximum battery capacity, there has to be limitations due to charge capacity, my thinking is this would not work in a strictly off grid application, naturally I could be wrong. The specifications for the unit would reveal the actual capacity of the DC-AC inverter along with the maximum battery capacity, but the transfer to EPS loads during loss of grid is a dead give away. Look at page 29 of the manual regarding feasible loads for the limitations. I'm convinced this is not designed for an off grid application, but as grid tied battery backup situation, or hybrid system as the name implies.

schmek

Okay, thanks a lot!

MarkC

Very interesting find!  The specifications for the EPS mode show rated VA for each model - essentially the full rating to the sub-panel.  Their web site claims full off-grid capabilities.  The charger specifications indicate a max of 25 amps charge/discharge for all models, so using a nominal 360 VDC lithium battery pack would be limited to about 9000 VA.  Not sure if there are limitations elsewhere. 

However, the bad news seems to be that the web site does not indicate a US support and I cannot find any mention of either a 120 VAC split phase output, nor any mention of an autotransformer set up to establish a neutral line.  

If the charging profiles can be adjusted to meet requirements of various lithium battery types, this would be the first that I've seen to have such capabilities.   

Pika Energy has a similar "hybrid" inverter that works only with it's own battery system - although they offer OEM support via their Rebus protocols for others.  It does support US split phase - typical household panels.

Anyone know of other emerging DC coupled, lithium battery based hybrid systems?