Unsure of a Hybrid inverter that will work for me.

[SolarNewbie2021]

Hey Everyone,

New to the forum as a poster but have been browsing a bit. Building a 9.7kw solar with battery backup grid tie. Not sure what inverter(with charge controller) to use due to my loads. I do know I will need a low frequency inverter because I have a huge 5-ton AC unit to power. At present, my panels provide the following:
Max Power Voltage: 41.60v
Open Circuit Voltage: 49.86v
Max System Voltage: DC 1500v
With 24 panels I'm assuming my DC operating voltage will be (41.60v x 24) for 998v DC voltage on the array.

That being said, I would need a Inverter that can handle the following:

1. 1000+ DC input.
2. Surge protection from the initial startup of the AC unit which is anywhere between 2x - 3x operating KW.
3. Ability to handle high amps. (Just the 5-ton unit is 25amps).
4. 120/240 Split phase 60hz output.
5. Ability to connect to a 48v 45kwh battery storage.
6. Also able to grid tie. (Hybrid)

Would be a great help if someone can point my in the right direction of where to find a good inverter for my needs. Even if I have to hook two inverters up in parallel.

 

[Samsonite801]

I wouldn't do all panels in one series string though. Many inverters have 2 PV inputs on them, and if you use 2 inverters in parallel like my MPP LV6548 pair for example, you have 4 PV inputs (PV input 250v max, 120a each), so you could run up to 4 strings.

You can also wire panels in series and parallel. You try to get the volts where you want, but also keep the max amperage within the range of the PV input you're using, and more than that can go on another string...

On my system, using 24 panels, similar to yours, I am going to do 3 strings, 8 panels each, 4s (x2) and those 2 sets paralleled per string, which will get my volts in good range for my PV input and plenty of amps to spare. So I will use up 3 PV inputs, and have one left as spare or for later expansion if I add another 8 panels.

Better to have separate strings anyways, because if you get shade on one panel it kills performance of the whole string. Not to mention, multiple strings, you could point them at different angles like one string at 10am peak sun and other at 1pm peak sun, and other at 4pm peak sun, if you wanted to get better all day performance (it's a strategy other guys recommend a lot on this forum, I haven't tried that)...

 

[SolarNewbie2021]

I wouldn't do all panels in one series string though. Many inverters have 2 PV inputs on them, and if you use 2 inverters in parallel like my MPP LV6548 pair for example, you have 4 PV inputs (PV input 250v max, 120a each), so you could run up to 4 strings.

You can also wire panels in series and parallel. You try to get the volts where you want, but also keep the max amperage within the range of the PV input you're using, and more than that can go on another string...

On my system, using 24 panels, similar to yours, I am going to do 3 strings, 8 panels each, 4s (x2) and those 2 sets paralleled per string, which will get my volts in good range for my PV input and plenty of amps to spare. So I will use up 3 PV inputs, and have one left as spare or for later expansion if I add another 8 panels.

Better to have separate strings anyways, because if you get shade on one panel it kills performance of the whole string. Not to mention, multiple strings, you could point them at different angles like one string at 10am peak sun and other at 1pm peak sun, and other at 4pm peak sun, if you wanted to get better all day performance (it's a strategy other guys recommend a lot on this forum, I haven't tried that)...

This is perfect and exactly the advice I needed for my setup! Glad you have something similar. Thank you for your help Samsonite801.

 

[Surferdudemi]

I wouldn't do all panels in one series string though. Many inverters have 2 PV inputs on them, and if you use 2 inverters in parallel like my MPP LV6548 pair for example, you have 4 PV inputs (PV input 250v max, 120a each), so you could run up to 4 strings.

You can also wire panels in series and parallel. You try to get the volts where you want, but also keep the max amperage within the range of the PV input you're using, and more than that can go on another string...

On my system, using 24 panels, similar to yours, I am going to do 3 strings, 8 panels each, 4s (x2) and those 2 sets paralleled per string, which will get my volts in good range for my PV input and plenty of amps to spare. So I will use up 3 PV inputs, and have one left as spare or for later expansion if I add another 8 panels.

Better to have separate strings anyways, because if you get shade on one panel it kills performance of the whole string. Not to mention, multiple strings, you could point them at different angles like one string at 10am peak sun and other at 1pm peak sun, and other at 4pm peak sun, if you wanted to get better all day performance (it's a strategy other guys recommend a lot on this forum, I haven't tried that)...

Have not seen any specific clarification of this: does each PV input on multi-input inverter have a separate MPP? I.e., if you use multi-string inputs, will you get the optimum or most efficient conversion for each string, or are they just combined in parallel internally into a single MPP controller, so you effectively sub-optimize each input to get the optimum across all strings?

 

[Dsiee]

Have not seen any specific clarification of this: does each PV input on multi-input inverter have a separate MPP? I.e., if you use multi-string inputs, will you get the optimum or most efficient conversion for each string, or are they just combined in parallel internally into a single MPP controller, so you effectively sub-optimize each input to get the optimum across all strings?

They are generally independent MPPTs so you get the best of both strings. Particularly useful if you have some different arrays like E-W or 2 angles.

 

[Tecnodave]

Sunny Boy (SMA) grid tie inverters do have separate MPP controllers on each string for the exact reason stated....to operate separate strings at their peak power point. I cannot speak for other types, I do have first hand experience with Sunny Boy both transformerless and the older units that do have transformers