A somewhat hybrid solar question

[wb8erj]

Hello,

I am interested in input from the experts. This is probably not the most cost effective solution, but honestly being a tinkerer, that is not really much of a concern.

This spring I completed an install of a 2.5 KW grid-tied system on the roof of my house. I am quite pleased the performance, and would like to add more panels. I am using Enphase M-215 microinverters with (12) 255 watt panels. My installer told me that the Enphase trunk cable could handle 5 more panels before it is maxed out.

With the layout of my 12 panels in a 3 vertical X 4 horizontal panel arrangement, and adding 5 panels it would leave me an axtra space for one more panel, but it would not be able to be connected to the Enphase trunk. (I hope I made this clear enough..)

So here is the deal. I am a ham radio operator, and I have run my ham station for many years with a 12 volt deep cycle battery and charging it with a DIY charger via 120 volts. Yes being a grid-tied solar system it is charging my ham station, but what if I used that "extra" solar panel to that is physically next to the other grid-tied system, but it would be a second system that was off-grid specifically to run my ham radio station. In doing so, when I lose power, my ham radio station would still be able to have the battery charged.

All panels are up on the roof, and grounded per NEC codes. This would just be a second much smaller off-grid system (one panel 255 watts..) that is for my ham radio station.

Thoughts?

-- Mike

[inetdog]

I see no problems at all in doing that.
The "extra" system might technically need to have a permit, depending on your local regulations, but the wiring should be simple and there will be no interaction between the two systems.
The only downside I see is that if your regularly operate your shack off battery power you will be taking cycles of the batteries and shortening their shelf life.
If you use the system only when the grid is down you can float your battery bank most of the time and get longer battery life.
The solar component would give you more operating time if the grid goes down for days. But so would a small generator.

[Sunking]

Whiskey
Bravo
8
Echo
Romeo
Juliet

I copy you five niner ++

OK I am a ham operator and have done this a few times and my own rig. Might I dare suggest another approach? One that is more effective and reliable? Here is what I have done and many more have done the same or similar.

You really do not want to integrate your GT system and shack. Nor do you want to do away with AC Power or your 12 volt DC Power Supply. Sounds like you are not considering using the most reliable and economical sources as a Primary Source. You want to relegate the panel and somewhat the battery to Emergency when commercial power is out. You do not want to risk or trust Solar to keep your expensive batteries charged and maintained if there are ways not to. Good thing is you already have most everything except the Solar and batteries. I know you have a DC Power Supply, and should still be used.

Assuming your DC Load Amps is that of a standard 100 to 200 watt transceiver, and some aux equipment, the battery should be no less than 200 Amp Hours. Best bang for the buck is a pair of Golf Cart Batteries. Look into US BATTERY 6-VOLT batteries.

A 200 to 250 AH 12 volt battery requires a minimum 200 watt Solar panel, with a 15 amp MPPT Charge Controller.

So here the how part. You are still going to use your DC Power Supply. Assuming you use some sort of DC Power Pole to distribute 12 volt power, connect the DC Power Supply output, battery, and Solar Charge Controller to the DC Power Pole positive and negative buses. Set you DC Power Supply Voltage to the battery manufacture Float Voltage Specification. If that is US Battery would be 13.02 volts.

Under normal operating conditions you DC Power Supply does all the work. It charges the battery, keeps the battery charged and ready to go, and powers all the 12 volt equipment just like you do right now.

When you hear BOOM BOOM OUT GO THE LIGHTS, your 12 volt equipment never hears it or knows it happens because the batteries are on-line all the time and now supply power. If it is day with bright sunshine the panels will keep the battery charged. If it is at night, and the power comes back on, your DC Power Supply recharges the batteries. All automatic, you do not have to do a thing.

But know this, those two Golf Cart Batteries will last 2 days up to a week depending on how much you jack your jaw, mode, and power at TX before they need recharged. In fact I know from experience 2 days of Contest. What that means is unless your Power is out for more than 3 or 4 days, the solar really does nothing except something for you to rag-chew about.

Hope that helps.

73's

Kilo
Foxtrot
5
Lima
Juliet
Whiskey

[wb8erj]

Thanks Sunking for your input - You basically covered my core question, and that is concerning grounding. Good stuff here, and I will be going this direction. Thanks for your help!

73's

-- Mike

[SolarFox]

This is similar to what I did with my brother inlaw's garage but we didn't check for permits. I am not sure even where to check for those. Probably a good idea to do so though.