My QRP Solar Generator

K7JLJ.com
Published: 11.23.19

While it's not stylish to use SLAB batteries these days for HAM Radio power, they still are my first choice for several reasons.

  1. Affordability
  2. Abuse tolerant
  3. Easy to find in SHTF
  4. Most likely to find a charger for in SHTF

The only downside is they are heavy for their power units (this unit is ~11lbs) and have only a 50% discharge rate, so the combined 18aH supply is effectively only 9aH in use.

One big reason I use them is also that I get them FREE from work. The picture below is a drawer component of a rack mounted UPS system common to Ethernet hubs throughout my workplace.

They are 2S2P 12vdc 9aH batteries that usually have one cell that becomes unbalanced and so the whole tray is replaced. Lucky for me, the other (3) batteries are usually in great shape!

When I was trying to figure out which enclosure to build the Solar Generator in, I laid two of these HR 1234W F2 batteries into a Pelican 1170 and they FIT PERFECTLY, I mean no movement at all!

I decided to try out a new charge controller because I had planned on putting a waterproof one on top of the Pelican case, but when it arrived it was way smaller than the pictures on Amazon.com made me think.

Instead of going on the outside of the case, I was able to fit it inside... perfect!

HUINE 12V 24V Auto10A IP68 Waterproof PWM Solar Charge Controller Solar Panel Battery Intelligent Regulator

All wires are connected with Anderson Powerpoles, and only one (1) need be removed from the multiplier block to completely isolate the batteries for storage.

With an extra opening on the quad block, I can add on more load to the batteries if needed also.

The output of the charge controller feeds the back RED/BLK connections and regulates load with a:

Discharge Stop Voltage: 11.2V
Discharge Reconnect Voltage: 12.6V

The front voltage display is connected directly to the battery to remind me to disconnect completely when not in use.

I can charge the battery via vehicle with a cigarette lighter by plugging into the output terminal or multiplier block.

The yellow connections are for the solar input using my 30W Powerfilm fold up solar panel or other panels. The Powerfilm is always with the FT-817.


Overnight dew has drenched the enclosure, but it's holding up fine. Not IP68 waterproof but definitely splash resistant.

I'm running a test right now 11-23-19 with the panel on the East side of the house and the FT-817 on an FMW radio station at low volume. I will turn the radio to monitor the local FM repeater at night and then back to the radio while the sun is out to see if the system is self sustainable.

I'm confident it will be, but will report back if not.

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