Solar Panel Maximum /24 vt Hybrid 2424 MPP / Big Battery 24vt 170am

[Bob O Adirondacks]

I'm looking to figure out if I can Put (10) 24vt 200watt Rich Solar RS-M200D Solar Panels on My Tiny Home with out damaging anything.

 

[MichaelK]

Can you look on the back of one of your panels and get it's specifications? That is, it's Voc, Vmp, Ioc, Isc?

Is this your inverter? The 2424LV-MSD, on the far right?



I found this rich solar specification sheet.


The key numbers you need to compare here is the Voc of the panel, the mppt range of the charger, and the max PV input of the charger. The max PV input is listed as 2000W, so 10 X 200W = 2000, so that is OK.

Now, move on to the Voc of the panels and the mppt range of the charger/inverter. One panel in series would be high enough voltage to charge a 24V battery, but you want to wire in series to minimize voltage drop and copper wire strings. If you put two of these panels in series, you'd get 75.2V charging, and 90.8Voc. That's significantly lower than the inverter's 145Voc limit, and 75.2V fits right into the 30~80V range.

What about 3 in series? That works out to be 37.6V X 3 =112.8V, higher than the 30~80V recommended range. Much more importantly, the Voc of three panels would be 45.4V X 3 = 136.2V. That is really close to the 145Voc limit of the unit. On a cold, frosty morning, expect the Voc to shoot up past 147Voc, according to Midnight's string calculator. So, strings of three panels will likely fry the unit.

So, wire your panels in a 2S5P configuration. With more than two parallel strings, each string should be fused or have a breaker. Using a combiner box with DC breakers would be ideal. DO NOT use AC breakers.

Assume your 2S5P array will produce (2000W/26V charging) X 0.85 lossfactor = 65amps of charging current. Note that 65A is less then the 80A limit of the charger. This would be enough to charge 520Ah lead-acid battery, a 325Ah AGM battery, or a 260Ah Li battery.

Keep in mind the numbers work for the specifications that I found. If your equipment specifications deviate from these, then the advice would also deviate.

Good luck!

 

[Bob O Adirondacks]

Can you look on the back of one of your panels and get it's specifications? That is, it's Voc, Vmp, Ioc, Isc?

Is this your inverter? The 2424LV-MSD, on the far right?
View attachment 37091


I found this rich solar specification sheet.
View attachment 37092

The key numbers you need to compare here is the Voc of the panel, the mppt range of the charger, and the max PV input of the charger. The max PV input is listed as 2000W, so 10 X 200W = 2000, so that is OK.

Now, move on to the Voc of the panels and the mppt range of the charger/inverter. One panel in series would be high enough voltage to charge a 24V battery, but you want to wire in series to minimize voltage drop and copper wire strings. If you put two of these panels in series, you'd get 75.2V charging, and 90.8Voc. That's significantly lower than the inverter's 145Voc limit, and 75.2V fits right into the 30~80V range.

What about 3 in series? That works out to be 37.6V X 3 =112.8V, higher than the 30~80V recommended range. Much more importantly, the Voc of three panels would be 45.4V X 3 = 136.2V. That is really close to the 145Voc limit of the unit. On a cold, frosty morning, expect the Voc to shoot up past 147Voc, according to Midnight's string calculator. So, strings of three panels will likely fry the unit.

So, wire your panels in a 2S5P configuration. With more than two parallel strings, each string should be fused or have a breaker. Using a combiner box with DC breakers would be ideal. DO NOT use AC breakers.

Assume your 2S5P array will produce (2000W/26V charging) X 0.85 lossfactor = 65amps of charging current. Note that 65A is less then the 80A limit of the charger. This would be enough to charge 520Ah lead-acid battery, a 325Ah AGM battery, or a 260Ah Li battery.

Keep in mind the numbers work for the specifications that I found. If your equipment specifications deviate from these, then the advice would also deviate.

Good luck!

THANKSFOR ALL THE INFO...VERY HELPFUL!
LAST QUESTION
IN A MPPT VT2424 WHAT IS THE MAX 120 AC CAN I PUSH THRU THE ALL IN ONE
INVERTER?
30 AMPS? 60 AMPS?

(The AC output)

 

[iamrich]

I don't think I would push more than 20A through the inverter. The unit will take input up to 60A to charge batteries, but the inverter (even pass through) should be 2400W (20A) max.

 

[MichaelK]

I think it might be be more appropriate to ask, "can more than 30Amps be PULLED from this unit? Just being an ass about semantics!

The rating for your inverter is 2400W, so at 120V, that's 10A, so I would say no. My gut feeling is even 10A is a lot. I always adhere to the 2X guide for everything I design, so if I needed 30A, I would have selected an inverter rated for 8000W; 30A X 120V X 2Xheadroom = 7200W.

That being said, I would only try pulling 10A out of the inverter when there is 2400 of W of raw solar coming in. That's what I do whenever I'm running my well-pump, which pulls about 10A at 240V. For your inverter, I would be leery of pulling out more than 1200W.

 

[iamrich]

For your inverter, I would be leery of pulling out more than 1200W.

Curious why you would say this? I have pulled 1800w continuous off my LV2424 inverter from my batteries.

 

[MichaelK]

Curious why you would say this? I have pulled 1800w continuous off my LV2424 inverter from my batteries.

I'm inherently conservative. Sticking with my own 2X rule has worked well for me over the years. I used to push the limits on the ski slopes when I was younger. Now I go a bit slower.

I'd say if you have easy access to a backup if you red-line and the system fails, then you might be more comfortable with pushing it. I'm 20 miles up a dirt road, so anything failing is not good for me.

 

[iamrich]

Ah! Understand completely. Nothing wrong with running conservative.

 

[MichaelK]

Ah! Understand completely. Nothing wrong with running conservative.

I guessing your system is in the garage, or is this your stand-alone system that you rely on for all of your power?

I my case, the nearest grid pole is 15 miles down the road. If my system (and the backup) fails, I'm back to using the generator, and gasoline lanterns. At least for my power, I take redundancy and extra headroom very seriously.

I just wish I had a second well!

 

[iamrich]

I guessing your system is in the garage, or is this your stand-alone system that you rely on for all of your power?

My system charges Ryobi batteries at this point, so by no means mission critical. I actually have grid power about 75 feet from the garage, but they want $5k to hook it up.