combiner box for solar

smkettner wrote:
400+ watts is getting in the zone where 24v panels in series with MPPT controller start to make sense.

$468 gets 520 watts of panels (2)
$350 for 30a Morningstar controller.

I woudn`t go with MPPT until you get at or above 600 watts. Why? For what you are doing its not worth the extra cost. Handy Bob said so!

Well, Handy Bob and a few solar users on this Forum have an agenda--Spend no more than is absolutely necessary for a charge controller. Many of these same users are constantly fiddling with charge setpoints to keep their batteries correctly charged or not getting full charge into their batteries.

FWIW, I have a single 235W module, at present, regulated by a Morningstar MPPT-15. This controller is fully programmable through the software interface. I don't need to change dip switch settings in order to temp compensate or achieve adequate bulk and float settings. The controller is at the heart of the system, a poor place to cheap-out, IMO. Cost was around $200. I also have a roof top combiner box. I made it from a plastic electrical conduit fitting and installed two bus bars. The combiner box allows for upgradeability or replacement of modules, should that be necessary. Cost was around $5. The combiner box has a further function, it allows for heavier gauge cable to be lead from the roof to the controller. Why give away a % of harvest when I can afford the few feet of heavier wire? I use a CB Hiwatt manual circuit breaker between the combiner run and the controller, allows for quick and easy disconnection of modules to controller.

Good luck with your installation. There is probably more discussion in the "Tech Issues" section of the Forum about solar use and installation.