Sourcing information on MPPT controllers and specifically, their make-up with regard to the ‘blocking of cells’.

The background involves a decision on whether to use these MPPT units. Our system has 4 panels - 360W strong, option of 12/12, 24/12 or 48/12 (depending on the controller type), in warm climate area and space critical.

Our situation presents shadowing of panels by yacht mast and booms and general movement and heeling. I have been advised that certain MPPT controllers use 15-minute electronic ‘checks’ and others use ‘inbuilt- tables’ for assessing their optimum power generation settings at that particular instant of the day. As has been brought to my attention, this check could easily occur while a cloud is passing or the boom is swinging past, setting inappropriate power generation data for the next 15-minutes that is different to the sunshine that followed. This would then negate the use of MPPT and its positive aspects. The units being looked at are:
> MX60,
> SB 3024, and
> SB 50.

Any guidance appreciated. Thank you in advance

Your are correct in your findings

The MX60 is a sweep and sleep technology, that’s the 15 minute one but the interval is user programmable

The Blue-Sky controllers are even simpler, they use a percentage of the voltage on power-up to guess at the voltage maximum power (vmp) point

Neither will work well for a sail boat that is randomly placing shadows on the panels

Xantrex has announced their new Mppt controller, which will be shipping in early 2007. It’s similar in size and specs to the MX60 but is a true dynamic Mppt controller, like the Grid-Tie inverters are, it also is FCC Class B and the EU equivalent compliant so no interference with the radios

I should disclose I was the primary hardware and Mppt firmware designer for the product. Not sure exactly what there calling it, it was the SC-60 but I think now is called the WX-60 to match with the new inverter system they are releasing

http://www.xantrex.com/forum/forum_post ... D=327&PN=1, is the xantrex site where they have started leaking information on the unit

Solar Guppy

Thank you for your informative response and grateful for a new link to some great gear.


In your opinion (and any others who can help us), should I be looking at a simpler unit. I have to admit that advice from others in other Forums ask “Why MPPT on a sailing-boat in a warm climate?â€￾ We are restricted to the 4 panels and (like everyone I suppose) trying to get every bit out of the system. This obviously needs to be weighted against a practical budget of which the MX 60 was definitely the limit (if not over), for this small system.


While I understand you may no longer be involved, do you know off-hand if the unit will carry a 'conformal coating'?

Thank you once again