bp sx-170b or sharp nt-s5e1u 185

I just got a quote from an installer for 2 options to connect to 2 Xantrex GT 3.0, which would be the better choice to go with:

1. 42 bp sx-170b which produces 5.98kW system
2. 38 sharp nt-s5e1u 185 which produces 5.86kW system

The price difference between 1&2 is about $4k.
So, would it be worth it to go with the BP panels, or would the Sharp panels
be a better choice? Is quality an issue between the 2?


  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: bp sx-170b or sharp nt-s5e1u 185

    maybe wind-s2's comments will help you to decide.
  • System2System2 Posts: 6,290 admin
    Re: bp sx-170b or sharp nt-s5e1u 185

    I have the Sharp NT-185U1's and am quite pleased with them, wish I'd bought more while they were in production.  If I'm not mistaken, the NT-S5E1U's were replaced by the model I have now so you may be considering some even older panels.  Those panels aren't listed on Sharp's website, nor do they have documentation (current or archive) for them.  Sharp's documentation for my  panels  doesn't have a temperature/power coefficient but using the more or less standard .5%/degree Celcius and a nominal 47 degree celcius cell operating temperature at 800w/m2, my panels seem to perform at spec.  Using the BP-5170 specs for NOCT: HERE and Standard Test Conditions (STC), 25C cell temperature at 1000w/m2,

    Normal Operating Cell Temperature (NOCT) for the BP-5170 specify 47C cell temp at 800w/m2

    On a typical 95 deree F day for an hour or so on each side of solar noon, I usually see ~ 130 watts per panel.  If I assume that I'm experiencing NOCT conditions, then:

    47C - 25C X .5%/degree C = 11% reduction in performance due to cell temperature alone
    185w - 11% = 164.65w

    Factoring in the 800w/m2 instead of the 1000w/m2 STC figure (using 80% irradiance for the calculation):

    164.65w temp corrected X .8 irradiance = 131.72w expected output

    So I'm putting out about 1.72w less than expected or less than 1.5% off spec.  That isn't even close to the -10% power rating the warranty specifies.  Of course, this is a calculation and may not be the actual conditions that produce 130 watts for me.  For a 95 degree day it seems like they are working fine.  I must admit that I'm curious how other people's systems perform on a hot summer day.

    PV Brand, model, STC rating, guess-timated summer temp and observed output would make an interesting comparison.  Any takers?


    Bad Apple
  • WindsunWindsun Solar Expert Posts: 1,164 ✭✭
    Re: bp sx-170b or sharp nt-s5e1u 185

    The problem we had with the old Sharp (not the new ones now in production) is that the specs were all over the place from lot to lot.

    One pallet load would be right on, the next one from a different lot would be 5-6& less amps, measured side by side.

    Sharp has supposedly gotten that issue fixed, but we still don't like their warranty. We can get them, but generally prefer Evergreen, Kyocera, Solarworld (ex Shell), Mitsubishi, or Sanyo.
  • marksmarks Registered Users Posts: 17
    Re: bp sx-170b or sharp nt-s5e1u 185

    I have to preface my input, in that I'm new to this pv process. However I too was struck by the pricing of the Sharp panels. Initial research on Sharp revealed that they claim to the be Number 1 producer of panels, and that they've only been marketing in US for three years. Hence, the discount pricing would make economic sense as they establish their position in the US market.
  • WindsunWindsun Solar Expert Posts: 1,164 ✭✭
    Re: bp sx-170b or sharp nt-s5e1u 185

    When Sharp first came into the US market, they were priced very competively. In fact, I suspect that they might have been dumping them - or selling below cost to gain market entry. However, that did not last. In the last 18 months we have seen no less than 9 price increases on Sharp - they are now one of the more expensive panels - I think only BP is higher at this point. And the Sanyo HIT, of course, but those are different animals.

    What made us mad at Sharp was that we had panels on order for over 4 months at a price quoted by their importer/distributor. Before we even got the panels we got notice of 3 price increases, and when the panels finally arrived, there was yet a 4th increase in the bill, so we sent them back. Been over a year, but their price went from the original quote of around $3.30 per watt to over $3.90 per watt while on backorder.
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