I am powering an offshore buy with 3 Sanyo HIT panels connected in parallel to a Morningstar SunTracker MPPT charge controller. As the seasons change two of the panels are not getting the same sun exposure as the third one. Am I loosing power generated by the one panel into the other two? Should I have blocking diodes on each of the panels?
Regards,
Al
Submitted
13 years 2 months ago
Comments
Al,
Technically, you are not blocking, you are isolating. Each module is its own string in your case because they are all in parallel.
Most Sanyo HIT modules have 4 internal Bypass diodes. These resist backflow current.
The bypass diodes should cover you. Your risk of power loss is much higer from corrosion in a marine environment. Make sure you have full ecapsulation of any exposed conductor - even a tiny opening will allow moisture to travel along strands of wire to corrode components and J-boxes (capillary action).
Thank you SF_Solar.
Yes, corrosion is an uphill battle with anything marine.
Will currnet flow backwards through the solar cells themselves, not the blocking diodes?
Thank you,
Al
Al,
Current will not flow from the battery to the low power module. Nor will it flow from the powered module(s) to the low powered one(s). However, I don't know what will happen to the MPPT algorthm in the charge controller. It may see the three modules as a composite - influenced heavily by the low power one. I don't think a diode will help with that.