[Elecraft] OT: RF noise in solar photovoltaic system

[Jim Brown]

On Tue,7/19/2016 10:23 AM, Tom Azlin W7SUA wrote:
>
> We put in a 10KW array on our garage roof using two SMA 5000TL-US-22 
> inverters to grid tie. I could not see any difference in noise floor 
> or moving noise bands with the inverters running or with both the DC 
> and AC disconnected. Perhaps just lucky? 

Remember that whether or not you hear more noise with the system running 
will depend on how much OTHER noise there is in your neighborhood. Some 
(many?) of us have background noise in the range of S8, others in the 
range of S3. The difference is 25 dB.

> They also said for just charging my station batteries using the 700 
> watt legacy solar array that came with the house that I should use a 
> PWM charger rather than the noisier MPTT chargers. Have not picked a 
> charger yet. The local solar guy also provided that 700 watt array to 
> the original owners of our house as it was an off-grid solar home. 


It's worth looking for a quiet MPPT charge regulator. Just like any 
other electronics that generate or use square waves, it can be done well 
or it can be done badly. Since badly is cheaper, and done well requires 
more technical design expertise, badly is by far the most common. The 
Genasun regulators are pretty quiet, but so far, they only make units 
for much smaller systems.

73, Jim K9YC