[RE-wrenches] MPPT on a MX60

[Ray]

Depending on the light conditions, that could be a normal reading.  I've 
seen the MPPT voltage approach battery voltage in low light/ cloudy 
conditions.  If this was in full sun, I would start isolating the 
strings, and see what their individual performance is.  Also as 
mentioned, it could be a loose connection, so a thermal imaging camera 
is great to "see" those bad connections.  That should be a good system, 
I don't know of any problems with the Shell modules from that time period.

Ray

Remote Solar


On 10/2/17 9:21 AM, Steve Bell wrote:
> Hi Bill,
>
> The original Voc of the array was probably about 91 volts, the original Vmp
> of the array was probably about 68 to 70 volts. The 58 Vmp from the array
> still seems somewhat low.  I would check for bad/corroded connections
> causing a voltage drop while under load.
>
> Best Regards,
>
> Steve Bell
>
> On Mon, Oct 2, 2017 at 8:27 AM, frenergy <frenergy at psln.com> wrote:
>
>> Off-gridders,
>>
>>              Checked in on a 13 year old system and something caught my
>> eye. Yes, everything is 13 years old.  First off: PVs: 14 (7 strings of 2
>> PVs each), Shell 150's, batts: HUP 845 AHR, 48 volt system, MX60 CC.   So
>> the MX60 was reading (mid day) ~1500 watts or ~27 amps (somewhat low for
>> the array but acceptable considering age, soiling, tilt, etc.  Regardless,
>> Volts "IN" were 58, batt volts were ~53.5.  This info was taken from the MX
>> display.
>>
>>              For PVs that have an MPPT rating of 45.5 volts ( X 2 per
>> string = 91V), that 58 volts seems especially low.  Normal?? Possible one
>> string is pulling down the rest?  Feedback welcome.
>>
>> Bill
>>
>> Feather River Solar Electric
>> Bill Battagin, Owner
>> 4291 Nelson St.
>> Taylorsville, CA 95983
>> 530.284.7849
>> CA Lic 874049
>> www.frenergy.net
>>
>>
>> ---
>> This email has been checked for viruses by Avast antivirus software.
>> https://www.avast.com/antivirus
>>
>>
>> _______________________________________________
>> List sponsored by Redwood Alliance
>>
>> List Address: RE-wrenches at lists.re-wrenches.org
>>
>> Change listserver email address & settings:
>> http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org
>>
>> List-Archive: http://www.mail-archive.com/re-wrenches@lists.re-wrenches.or
>> g/maillist.html
>>
>> List rules & etiquette:
>> www.re-wrenches.org/etiquette.htm
>>
>> Check out or update participant bios:
>> www.members.re-wrenches.org
>>
>>
> _______________________________________________
> List sponsored by Redwood Alliance
>
> List Address: RE-wrenches at lists.re-wrenches.org
>
> Change listserver email address & settings:
> http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org
>
> List-Archive: http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html
>
> List rules & etiquette:
> www.re-wrenches.org/etiquette.htm
>
> Check out or update participant bios:
> www.members.re-wrenches.org
>