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Reduced Wattage From Charge Controller

sinner_93

New Member
Joined
Oct 25, 2021
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1
Hi all!

I have a simple off-grid setup consisting of the following as an off grid power system for my house:
  1. 3x135Watt thin film solar panels in parallel
  2. 1x200Ah 12V lead acid battery
  3. 1xMPPT charge controller
  4. 1x900VA inverter
Attaching an image of the panel spec sheet:
246325402_415647056577941_412512443716099420_n.jpg


Everything has been working well since 2016, I did change the battery once after about 5 years as it started giving reduced backup time. Up until a few weeks ago I used to get close to 300W from the solar panels on a bright sunny day as shown in the picture and my batteries would get charged to full every day.
245528860_580492939823264_4398313802582222061_n.png


For some time now the charge controller has only been showing a total input power from my panels at about 100W max even on the sunniest days as opposed to 250-300W previously.

When I check the voltage at panel wires its close to 90V:
246024658_174236511545843_3389544785566351204_n.jpg


When I connect the wires to the charge controller the voltage drops to 13-14V. Earlier it used to go as high as 70-80V on the charge controller display as shown in the second image in this post.
-_4GgwP-6E9bCvegUumw7T60spW3q6uXsao29Q_ZA1HqlaGRbVekS6HwtmhWHvOtFHuPBBM89EcoSOkeVnmWm9CLKy5KQahGqSwLhlJuAR7d6epueOfOZKkcxU-MfEHgnKOsYvnM6RI1nnT3mZkO9vFeRnXDOXqumwSON7AKRDwDUhltktZ7CI7nJ1J0wQhAgZkg8_tQDMMcL1lBvpuktoqLQSGfiYjvzPMd4VYmjMEwjx1Jvhu9TU4vF-LzvT95ib2_RGP4jxRRxpMDC6HbQQpeAsTFGM-c74dMLyU9WcYXjpD5yqKTnIjhorauJjprHhYT32VPNqwh5pl5fxWcDuAX-kqOscRcC7zihzjXHuHcX2TvT53jgCS10zcWDOh8G5hPeWzXPdFXCHnXiBkg2LNMkTdHd12NdpxxMJtbAYtr6UFxl_hT-E1M5PuDmcYEuno10uPwD2ZfOmWBmy8cd3JLpEPlcg5aQqKYWwRPRlFTGsZPVUu2Z1tncyQ6isdF77uXxTKS77asUBDtUQRV-a4Pxsh_fKHqjwSpVsah6arHKejKdCLQpYfGhQxD5rI-eKtyaFbYEXuL1ouzVSAdYMxpi593n6vBmbxmOOB95fY5d4Tdy0Cu0bBFguSB2PI3Q-QFfSbPLGJiM8tS65WSLxg_Bd3ccsAUQIKrvYjA3XMlPx4q3P1vhYsHxRY7BebSJtZeHijRy7YLzosNDM3FTMu2=w666-h887-no


Is this a charge controller issue? It does seem to be working although the voltage level is a lot less than before. Panels seem to be okay as the output at the wires is close to 90V. Looking for any advice or suggestions from the more experienced solar diyers in this forum.

Thanks,
K
 
Since the PV is reading the same as battery voltage, I would assume the MPPT has failed and has simply shorted the panels to the battery. Given the high Vmp and low Imp of your panels, I would never expect more than about 70W of charging in perfect conditions.

Confirm panel voltage and current specifications:


If you can confirm that the panels are performing suitably for the conditions, the MPPT has likely failed.

It's probably worth trying each panel individually to see how they perform on the MPPT.
 
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