On a strict interpretation of the subject line, I would argue that any SCC that does not natively support cold-temp charge protection is out of the running. Victron does. Others might, but I'm not familiar with them.
I’ve been assuming that any SCC that comes with a battery temperature sensor includes cold-temp charge protection, but if that is not necessarily the case, I’ll look into that spec more closely, thanks.
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The best way to save on SCC cost is to increase bank voltage. If you need 4X SCC, you really need to ask yourself if 24V is right for you. [/quote]
First, I’m dealing with severe shading issues on this new array, so the more MPPTs the better (I’d be going with Microinverters if I could).
And second, I’ve got 16 cells and can go either 24V or 48V and ideally want SCCs that support either option. 24V is better for 1S strings of half-cut-cell panels when dealing with shade, but I’m still evaluating both options.
And going 2S / 48V is not going to change the picture dramatically. I’ll still need at least 3 MPPTs in any case. But I’ll keep your input in mind and price it out - if going 48V / 2S cuts my MPPT cost in half (or allows me to afford Victron over cheaper Chinese 2nd-tier options), that might cause me to forgo some potential energy lost to shading in favor of a more capable solution...
I have 6kW of panels, and I have one SCC. The cost was about 35% of the cost of the panels. 48V system.
Those were NEW prices of course. I'm not comparing a new SCC to cheap used panels.
What do you base that on? $150 for the full 4500W of panels?
Apologies for the he typo (since corrected). I meant $450. 5 $90 30A Epever MPPTs serving a 2P string is that baseline.
And the panels I’m talking about are new, not used. I just purchased 3 new PhonoSolar 380W panels for $0.39/W and by the time I purchase 10 450W panels, I expect them to be ~$150 each (already under $200 each today).
So yeah, $1500 for 4.5kW of new panels and hope to get charge into the battery for no more than 30% of that ($450).
Because of the shading, I’ll struggle to use a single large MPPT chargecontroller like yours, but I’ll look into it. What brand/model do you have?
You need to ask yourself if you're being rational and not letting your desire to pay less influence your thinking. You state that you can get 60A for $150, which will only get you about 1600W. But you somehow conclude that you would be able to get 3X that for the same price?
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Again, apologies for the typo, but I believe I’m being realistic (correcting for that).
60A for $150 (Reliable 60A) would cover 4 panels or 40% of the full 4500W array (with a bit of overpanelling).
Complement that with 3 30A Epevers costing $90 and handling 2 panels (20%) each, and the full 4.5kW is handled for $420 (not $150 as I typed by mistake).
You need upwards of 165A to ensure you can utilize the 4500W for charging a 24V battery. I'm using 3.4V/cell as the bulk of the charge will occur in that range.
My existing 4kW array peaks at under 3.3kW or 83% of rating, so I’m planning for some overpanelling. Applying that same -17% of rating peak translates to a maximum of 3.375KW from this new 4.5kW array, meaning under 140A @ 8S 3.4V / cell.
One 60A 2S2P MPPT and 3 1S2P 30A MPPTs provides a total of 150A, so a bit beyond this.
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Your thinking is skewed by the $600 you paid for 4500W of used panels. You're not buying used MPPT at less than 50% of new price.
I think I understand how you got to $600. You took my typo of $150 got total MPPT coat and my 30% of-panel-cost target to get to $600 (or $500??!).
Anyway, I’m not buying used panels. I could purchase 10 new 450W panels for under $2000 today and am pretty certain I’ll be able t get them for under $1500 by the time I install the full array in 2023.
Panel prices are dropping more quickly than charge controller prices, but aiming for 30% or $450 seems realistic.
I might pay more for better battery-centric capability and protection (Victron).
I appreciate everyone’s contributions on the thread (and apologize yet again for the confusion I caused with my bone-headed typo).