[RE-wrenches] Outback AC coupling Sunpower?

[jay peltz]

Hi Corey,

Did you mount the SS relays to a good heat sink with heat compound?
They are quite sensitive to heat damage and also like a lot things optimistically rated.
I use a 2X oversize ratio for SS relays if they are used very much at all or for longer periods of time.

And I think  you are correct to install a back up to the frequency shift that may or may not work.


jay

peltz power


On Jul 31, 2013, at 11:24 AM, Corey Shalanski wrote:

> Mac,
> 
> We have installed about ten AC coupled Magnum systems over the past year.
> 
> Overcharge protection is accomplished by frequency shift, but Magnum recommends an auxiliary form of battery management. The cheapest way to do this is to program the relay driver on the Magnum advanced remote control (ARC) to open/close a solid state relay at specified battery voltage setpoints - similar to what Kelly mentioned. Unfortunately the "cheapest way" sometimes comes back to haunt us in the form of unanticipated extra costs. We had two customer callbacks indicating their inverter had mysteriously shut down - site visit revealed a fried relay in each case.. so I would recommend at least investing in a good quality relay if you choose this route.
> 
> One other thing we have learned is that not all grid interactive inverters are compatible with the Magnum inverters. Specifically Power One Aurora string inverters cannot seem to synchronize in off-grid mode - we have had to switch out Auroras on two projects because of this. We have had no such synchronization issues with SMA inverters so far.
> 
> --
> Corey Shalanski
> Joule Energy
> New Orleans, LA
> 
>