开云体育

One of my larger projects has been to convert my QTH ham radio station to run on solar power.
My station's layout has the HF is on one end of my house and the VHF/UHF the other.
I use two identical 12 volt 4 x 100 Watt solar panel arrays, each having a 100 Amp hour lithium iron phosphate (LiFePO4) storage battery.
These type of batteries cost more than lead acid deep cycle, but totally out perform them with usable voltage.
Each set up is located near the radio it serves. This minimizes cable loss.

You are probably wondering what this cost. Since I built two identical systems, I'll laundry list one.

$240 ? ? 4 - 12v 100W solar panels with weatherproof MC-4 connectors on leads (400W max output).

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$235 ? ? ? ?1 - 100 Amp Hour Lithium Iron LiFePO4 storage battery.

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$60 ? ? ? ? ?1 - 12v Solar charge controller with 30A capacity and lithium battery support.

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$65 ? ? ? ? ?1 - 4x6" treated timber and 5 - screw style dog anchors with tie down line and 2 noodles cut to fit panel tops.

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$100 ? ? ? ?3 - Wye 2 into 1 MC4 connectors, 10ga x 20' power cable MC4 on one end. Use for solar to controller and controller to battery connections.

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$40 ? ? ? ? ?2 - 4 bolt 5/16" power distribution bars, one red & one black. The radio and accessory power leads connect here, safely and neatly.

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$20 ? ? ? ? ?2 - 10ga - 40A inlineline fuses, 5/16" ring terminals, butt splice, misc shrink tubing.

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Installation notes.

Mounting-
The panels are located about 18" away from a south facing wall with their bottoms set in the grooved landscape timber. The timber is anchor nailed to earth.
Split swim noodles are used to protect the siding from the solar panel tops. Slit length way and paint with latex to protect from sun damage.
The panels have a pair of mounting holes on each side. Two lines are threaded across the top and bottom holes then tied to the anchors on each side.
Four panels requires 5 anchors to securely tie them down.

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Electrical-
There are 3 pairs of 2 into 1 weatherproof wye MC-4 connectors allowing the panels be connected in parallel.

10 gauge cable connects the 4 panels to the battery charge controller located indoors near the storage battery.
There are many solar chargers to choose from. I use the one in the picture with very good results. It also has stout wire terminals compared to others.
The charge controller's output connects via 10 ga cables and a 30A in line fuse in the positive lead to the battery terminals.

The battery is also connected to the 12 volt distribution bars with the positive lead fused at 30A.
I recommend buying a good crimping tool. ?A tight, gas free crimped connection seldom gives any trouble. Poor connections will get hot and waste Watts.
American made connectors tend to be stouter in my experience.

Contact me at N0QBH@... for details.

73
Mike N0QBH

Mike, I’m very impressed with your solar set-up! ?On our Alaska farm, being totally off-grid, we installed solar back in about 2004. Ours is a 48 volt system with 16 130 watt solar panels connected in series and parallel to give 2080 watts at 48 volts and we have 24 6 volt lead acid batteries also in series and parallel. ?We have a 48 volt charge controller/inverter that provides power to the house. ?Our radio set up runs off house power and what we found was the inverter caused significant RF interference on HF radio, probably in part due to the system being 20 years old. ?I tried the usual methods to control the interference but without wanting to spend too much time or money on it we instead would turn off the inverter and run the radios off a 12 volt battery instead. The result was almost zero noise.

We plan to install solar at our house in Stewart as time permits and your set-up seems to be a good example to follow. Without needing to provide 120 volt power to a whole house, the need for a large inverter is eliminated. ?We did determine the solar panels themselves provide no detectable noise.

I will be interested to follow updates on the performance of your system!

73,
Roger

Some "after" pictures of my set up.

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73
Mike N0QBH

The biggest lesson I learned over the past year with one 400W system was to move away from using lead acid deep cycle batteries for this application.

I had 2 - 90 Ah 12v lead acids in parallel and my charge controller has great metering. I found, after drawing the first 20 Ah, was the batteries were dipping well below 12 volts during 10A transmit.
When I pushed it further, the HF rig would reset due to low voltage.? Without a load, those batteries would float back up a half volt or more.

The Lithium Iron phosphate chemistry cells have a much lower internal resistance and much higher energy density, yet are much safer than Lithium ion.
They can be shipped and the quoted price is to your door.
With a single 100 Ah LiFePO4 - even drawing 25A while transmitting 100W - the voltage only drops to 13 volts. The radio is much happier.

The only downside I have encountered happened when I had adjusted my charge controller to charge to 14.6 volts.? The Lithium's protection circuitry opened the battery connection and the radios were floating momentarily at panel level - almost 20 volts!? My own fault.? A Internet "experts" advice that was years old. Controller default is 14.2 volts.?

73
Mike N0QBH

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Operating temperature and LiFePO4 batteries.

This is a good place to remind potential LiFePO4 users of the battery's chemistry limitations.
LiFePO4 batteries cannot be charged when the battery is below freezing.
Their protection circuitry will open, turning off the power.
This means they have to be located indoors where it's warm or kept warm for operation.
They can discharge at temperatures down to about 5 deg F.
I mention this for folks thinking about using LiFePO4 as batteries for remote solar power supplies.

73
Mike N0QBH