Combiner Sizing

[Diemjoe]

I have 6x 200w, 20.4Vmp, 9.8a Imp and 6x 100w, 18.5Vmp, 9.8aImp. The online calculator for 3s4p shows that there will be 1687W, 55.5V and 30.4 amps going to the MPPSolar LV2424 once I combine it all. I am trying to size the combiner to support it. It would be easier to buy pre made but I am not seeing any that match what I think the entire system voltage (1687v) will be.
For example, an Eco-worthy combiner has this description ......."As long as the current and voltage of a single PV does not exceed 10A/250Vdc, you can connect the combiner box.(E.g. If use the 195W 12V Eco-worthy solar panel, it can support solar panel system up to 780W in 12V system, 1560W in 24V system ,3120W in 48V system.)".

If I build my own, what do I need to consider to hit my max wattage.

Thanks

 

[FilterGuy]

You might find this usefull in sizing things correctly

 

[OffGridInTheCity]

Since you have 6 x 200w panels and 6 x 100w panels - I'd think in terms of strings that include equal numbers of 200w + 100w panels so that when you parallel, the strings will be nicely compatible. Assuming no shade, then I see these 3 basic choices....

2s6p parallel strings of 1 x 200w and 1x 100w (2s) would be around 40v @ 59a - 6p is not the most common combiner box scenario. You could use Y MC4s and bring this down to 3p at the combiner box but 40v is too low for a 48v battery. 40v * 59a = ~2300w.

4s3p parallel strings of 2 x 200w and 2 x 100w in series (e.g. 4s) would be 78v @ 29a - 78v is high enough for a 48v battery and 3p is a more common combiner box setup. 78v * 27a = ~2300w

6s2p parallel strings of 3 x 200w and 3 x 100w in series (e.g. 6s) would be 117v @ 20a. 117v * 20a = ~2300w.

The watts are the same for any of these options. The 4s3p or 6s2p would likely match you're combiner box / charge controller / battery situation better. Even if you don't currently have a 48v battery you might at some point so why not put the panels up so this is an option. 4s3p could be the best choice if you have partial shading and you're controller goes up to 150v input kind of thing.

 

[FilterGuy]

Crap!!! I forgot to add the link.

Fusing & Wire Sizing guidelines for solar panels

This resource is intended to help the user understand when they need to add Over Current Protection Devices (OCPDs - Fuses or Breakers) to the solar panel array and what size the OCPDs need to be. There is also guidelines for wire sizing for the...

diysolarforum.com

 

[GXMnow]

4s3p parallel strings of 2 x 200w and 2 x 100w in series (e.g. 4s) would be 78v @ 29a - 78v is high enough for a 48v battery and 3p is a more common combiner box setup. 78v * 27a = ~2300w

I agree. This is probably how I would go as well. Even a 100 volt controller would be safe, but a 120 or 150 volt would give some room to grow later. But you want this to feed into the LV2424? That unit has a single MPPT tracker that can handle 145 volts, and it can track from 30 to 115 volts, so you are all good there. But it can only make use of 2,000 watts of PV. You need to check through the manual to see if this much over panel is acceptable.

Looking at your PV panel specs, something is not right. The 200 watt panel numbers look ok. 20.4 volts x 9.8 amps = 199.9 watts. But the 100 watt panel numbers can't be right. 18.5 volts x 9.8 amps = 181 watts.

Before you complete this plan, make sure you have all of the right specifications. If it is a wrong current number, this series idea won't work properly. Also you really need the VOC voltage to make sure the 145 volt rating on the MPPT is high enough.

 

[Diemjoe]

I agree. This is probably how I would go as well. Even a 100 volt controller would be safe, but a 120 or 150 volt would give some room to grow later. But you want this to feed into the LV2424? That unit has a single MPPT tracker that can handle 145 volts, and it can track from 30 to 115 volts, so you are all good there. But it can only make use of 2,000 watts of PV. You need to check through the manual to see if this much over panel is acceptable.

Looking at your PV panel specs, something is not right. The 200 watt panel numbers look ok. 20.4 volts x 9.8 amps = 199.9 watts. But the 100 watt panel numbers can't be right. 18.5 volts x 9.8 amps = 181 watts.

Before you complete this plan, make sure you have all of the right specifications. If it is a wrong current number, this series idea won't work properly. Also you really need the VOC voltage to make sure the 145 volt rating on the MPPT is high enough.

You're right, its 5.4amps. Was looking at the 200w sticker. Thanks for the info.

 

[Diemjoe]

Here are the spec stickers from my panels.....

 

[GXMnow]

That is going to make it difficult to get them al to play nice on a common MPPT input.