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Expanding System


stoic

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Hi There,

My Current panels and MPPT setup is as follow:

MPPT: Victron SmartSolar 250/100 Tr
Panels: 18 * Canadian Solar 275w

My panels are set up in 3 sets of 6 panels

My first question: I cannot get the same panels, but i can get these JA 280W their specs are fairly similar. Can i expand using these panels?

Second Question: How can i configure my panels to add the most possible of these new panels to my existing setup, all within the limitations of the MPPT though.

 

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12 minutes ago, stoic said:

My first question: I cannot get the same panels, but i can get these JA 280W their specs are fairly similar. Can i expand using these panels?

Second Question: How can i configure my panels to add the most possible of these new panels to my existing setup, all within the limitations of the MPPT though.

First Question: I'd say Yes.

Second Question: I'd need more info:

1. What is your present noon peak current when you are tracking?

2. Are all the existing string the same tilt and direction?

3. Will any extra strings be at the same tilt and direction, or do you have other directions and tilts available to you?

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39 minutes ago, phil.g00 said:

1. What is your present noon peak current when you are tracking?

Max recorded peak is 5.1kw

39 minutes ago, phil.g00 said:

2. Are all the existing string the same tilt and direction?

yes, all facing north :) and all at an angle of 28 degrees

 

39 minutes ago, phil.g00 said:

3. Will any extra strings be at the same tilt and direction, or do you have other directions and tilts available to you?

I can have any tilt and direction. I would prefer a direction more east though so i can get more of the morning rays.

Edited by stoic
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If you have Pylontechs at 52.5V, then your MPPT is limited to producing 5250W.

Which would suggest you are already pretty much maxed out with a 5.1 kW peak, with your panels in their present position.

I pair combinations of E and W and N strings to moderate the noon peak and then I find I can have quite a lot more panels before the MPPT is maxed out.

Purely E and W pairings (at the non-ideal roof tilt,) it seems to be about double the number of panels of an ideal tilt North facing array..

Aesthetics is also a consideration, when pairing panels of different  manufacturers. I'd like to have same panel type grouped together on one side of the roof and use the other make as a group on another side of the roof. That way people only see one type of panel at a time. This may not bother you though.

Then again if you are considering this, then the cost and hassle of re-fitting existing panels would start me evaluating the cost of another MPPT. 

Depending on your planned expansion, it doesn't have to be the expensive Victron flagship MPPT this time.

 

 

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I have a very large flat roof... panels are barely ever seen.

so basically.. i can add 6 facing due east or west and i should still be in the green .... 

49 minutes ago, phil.g00 said:

f you have Pylontechs at 52.5V, then your MPPT is limited to producing 5250W.

But this is if i only draw from battery, which the multiplus is not at the moment.. it draws from array and if array is not supplying enough it draws from battery. Which means if i over panel i can still pop the poor MPPT cause it will simply try and supply more than what it can :( 

I know one can daisy chain victron MPPT's but do they all have to be the same?  maybe @plonkster knows?

cause another mppt is the difference between 2 or 3 additional pylontechs for me :) 

if i read the specs of the mppt it can theoretically go up to 5.8kw  - 70A (max 30A per MC4 conn.) ... what confuses me is the 70A, is that the max it can take cause it is also rated @ 100A on the same sheet? 

I dont have MC4 on my MPPT. I have a combiner box. where my 3 strings of 6 connects to.

Edited by stoic
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7 minutes ago, stoic said:

But this is if i only draw from battery, which the multiplus is not at the moment.. it draws from array and if array is not supplying enough it draws from battery. Which means if i over panel i can still pop the poor MPPT cause it will simply try and supply more than what it can :( 

No, not so. The maximum allowable voltage on your Pylontechs dictates the maximum allowable voltage of the entire DC side, including your MPPT output voltage.

On the other hand if you over panel your MPPT (within reason, I suppose), it won't pop it will just clip the output power to its rating. So you will get very limited benefit from the extra panels.

11 minutes ago, stoic said:

know one can daisy chain victron MPPT's but do they all have to be the same?  maybe @plonkster knows?

cause another mppt is the difference between 2 or 3 additional pylontechs for me :) 

You don't need identical sized MPPT's. 

13 minutes ago, stoic said:

if i read the specs of the mppt it can theoretically go up to 5.8kw  - 70A (max 30A per MC4 conn.) ... what confuses me is the 70A, is that the max it can take cause it is also rated @ 100A on the same sheet? 

The 100A is the output current at the DC voltage. And because your DC voltage is 52.5V, your output power is limited to 100A x 52.5V = 5250W.

The 70A will be on the input side at whatever the Vmp voltage is.

20 minutes ago, stoic said:

so basically.. i can add 6 facing due east or west and i should still be in the green .... 

I never said that, I said with your panels positioned as they are your MPPT is essentially maxed out. You would need to re-position your existing panels, to allow the "electrical room" for more panels.

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