Two MPPT 250/60 vs SmartSolar MPPT RS 450/100

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paulcooper asked Mar 30, '21

Two MPPT 250/60 vs SmartSolar MPPT RS 450/100

I will have two PV strings of 8 panels in each, one string facing east and the second facing west. Each panel will be about 320 W. I don't know whether it would be better to use the SmartSolar MPPT RS 450/100 or two MPPT 250/60. With the SmartSolar I would connect two strings with all eight panels in each string in series. With the two MPPT 250/60 units I would have each string connected in a 2x4 configuration (2 parallel sets of 4 panels in series).

Both options cost about the same but I would like to know the advantages and disadvantages of each option.

MPPT Controllers MPPT SmartSolar

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Answer 1 · 2021-04-04T11:51:49Z

Lyndsay Cotton answered · Apr 04, 2021 at 11:51 AM

From previous answers both here on this forum and from a research paper I read - there is only a VERY MARGINAL benefit to have a separate MPPT - one for East and one for West.

I put one of my East/West installations on one 250/85 MPPT due to the cost saving of one Smartsolar over two.

If cost were not the driving factor as it seems from your explanation - Then I would rather install two MPPT's - one for east and one for west

Take special note that if using ONE MPPT on a East/West scenario - the modules on east and west must be identical in output and qty

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Answer 2 · 2022-03-23T18:03:43Z

johnsmith answered · Mar 23, 2022 at 06:03 PM

I indeed have done the same, using MPPT 250/70 MC4 ve.can and will add my other string in parallel to this before I buy another controller. Its the only choice you have when running 48V battery. As the startup V is too close to the array Voc if you don't go above 2 panels per series in parallel array and 3 panels will exceed the MPPT 150 so its either MPPT250 with 3 panels series minimum or RS with minimum 5 panels in series. I didn't get the RS as its startup is 120Voc and the I don't think the invertor is as heavy duty as the Multiplus(II) and Quatro as it weighs nearly half. Just my observations. Also the MPPT in the RS doesn't talk to the network.

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