[RE-wrenches] Low Voc for effective string?

[Ray]

A 2nd option: A pair of 72 cell modules should be enough.

Ray Walters
Remote Solar
303 505-8760

On 9/12/18 9:21 AM, Mac Lewis wrote:
> Hi Bill,
>
> I agree with Allen. We get similar peak temps here and two 60 cell 
> modules doesn't charge a 48V battery bank adequately. This effect 
> would become worse over time with voltage degradation. I try to be at 
> least 15% above highest expected battery voltage with Vmp of the 
> strings. With 150V input limit on the Outback controllers, that leaves 
> you with only one option, strings of 3, with our low temps.
>
> On Tue, Sep 11, 2018, 4:24 PM Sindelar Solar <Allan at sindelarsolar.com 
> <mailto:Allan at sindelarsolar.com>> wrote:
>
>     Bill, I wouldn't, especially with FLAs. I have seen this situation
>     here, where the summer highs are similar, with a few
>     homeowner/hack installations and no, 60-cell modules will not
>     finish the charge in hot weather. Strings of three work just about
>     perfect with modern charge controllers, especially in winter, as
>     they range high enough but well below 150VDC limits.
>
>     Allan
>
>     On 9/11/2018 4:04 PM, Bill Battagin wrote:
>>
>>     I've been on hold with OB for about 40 minutes now and I need to
>>     know if 2 SW PVs with a Voc of 39.9 and a Vmpp of 31.3 will do an
>>     effective job of charging a 48 volt LA battery especially with
>>     temps of 95 degrees.  Anybody have experience with this or
>>     similar,  Appreciate the feedback.  It just seems I'm a little
>>     low in Vmpp if I want to equalize when its hot.  Will it be even
>>     more questionable in 10 years as PVs age?
>>
>>     OB did just pickup only to tell me I need Java for the string
>>     sizing tool and he can't help me with this configuration.
>>
>>     Bill
>>
>>     -- 
>
>     *Allan Sindelar*
>     allan at sindelarsolar.com <mailto:allan at sindelarsolar.com>
>     NABCEP Certified PV Installation Professional
>     New Mexico EE98J Journeyman Electrician
>     Founder (Retired), Positive Energy, Inc.
>     *505 780-2738 cell*
>
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