Re: Davits & solar panels

Dean Gillies

Hi David,
The choice is indeed endless.

The structural decisions you make will go a long way to determine the power rating you end up with. Larger heavier panels mean more power, but you need to consider the mounting structure carefully, particularly if you are hoping to mount onto the davits. (as I did) My three panels weigh around 50kg, my stainless tubing weighs about 15kg. 
This weight is not supported at the lifting points of the davits, and so can likely be deranged when comparing to the 300kg weight limit.
I have a 45kg dinghy and 28kg outboard motor.
I am quite happy with these numbers.

Dealing with the non-mechanical factors... 
The key things are reliability, efficiency, access to data and of course safety.

I used the Victron MPPT solar controller with bluetooth interface.  Victron is a reliable brand, (most would agree), and the BT interface gives good access to the system data and allows control without needing access to the hardware.
The Victron unit is efficient, and regardless of brand you choose, you must get an MPPT controller for efficiency. 
Serial or parallel connection is a ubiquitous debate. In a perfect environment, serial connected panels are more efficient due to lower power loss in the cabling and also require lighter (cheaper) cabling due to lower currents (higher voltage).  However, series connected panels are degraded much more by partial shading of the panels.  This is a choice you must decide upon. I chose parallel. 
To tick the safety box you need to make sure you have good quality, properly rated breakers on both battery and panel connections. Properly sized cable with good quality interconnections is also critical.

I used 3x 240W Panasonic HIT panels.

Feel free to ask any specific questions you might have along the way. Good luck.

SY Stella

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