Solar Panels....

Discussion in 'Ham Radio Discussions' started by KB4MNG, Jun 23, 2019.

ad: L-HROutlet
ad: l-rl
ad: l-BCInc
ad: QSOToday-1
ad: abrind-2
ad: l-gcopper
ad: Left-2
ad: L-MFJ
ad: Left-3
  1. KC8VWM

    KC8VWM Ham Member QRZ Page

    They come in different flavors. This one is a GV-10 10.5 amp designed for charging LiFePO4 batteries, but they are available for charging other battery chemistry.


    These controllers are actually one of the few on the market that are actually FCC certified. I have never experienced any generated RF noise in my radio receiver whatsoever. This is not going to be the case with many other cheaper solar panel controllers on the market so it's a situation where you pay for quality once, the first time.

    I used "Make An Offer" and stole one for $90 bucks with free shipping... I think you can too.

    Genasun GV-10 LiFePO4 Controller

    These are also true MPPT charge controllers which put more energy into your battery when measured on a power curve chart over a day of charging. So what this means is they work to maximize your solar panel charging capabilities even during cloudy overcast and low light conditions. Well worth the cost considering the idea they actually help to increase your solar panel output capabilities.

    Panels with Genasun controller...

    Last edited: Jun 23, 2019
  2. KC8VWM

    KC8VWM Ham Member QRZ Page

    Here's a tip.

    You can make your own DC power extension cable which is perfect for operating an off grid solar panel.

    Easily constructed from around 25 feet of 12/2 low voltage landscaping light cable. This is sold from spools by the foot in the electrical section at any big box hardware store. I played with different lengths and 25' is perfect.

    This is extremely tough and durable, direct bury wire that's UV and chemical resistant.

    Just install 2 Anderson power pole connectors on both ends and install some shrink tubing to help keep water intrusion out.

    cable.jpg panel and wire (1).jpg
    Last edited: Jun 23, 2019
    K7WFM likes this.
  3. AB2YC

    AB2YC Premium Subscriber QRZ Page

    A couple of years ago my son and I got some Goal Zero Nomad 7 solar panels.
    Walmart was selling them as a cell phone charging kit for over $100 but the didn't
    sell so the price got dropped to around $25-30 and we each bought four of them.
    The solar panels daisy chain together for more current and I got a inexpensive
    solar charger module from amazon and connect them to a small gel cell.

    For me I found that what works best is some form of lead acid battery
    gel cell, deep cycle battery etc, and an simple solar charger worked the best.
    I get no RFI from the setup I have and it works well fro QRP.

    For higher power all that needs to be done is to scale it up to larger components.

    My charger is basically a voltage controlled switch that disconnects the solar panels panels when the voltage
    in the battery rises above a preset level to prevent over charging and reconnects when the voltage is below
    that level so they charge. if anything I may hear the click in the radio when it switches but besides that it's quiet.

  4. AI5DH

    AI5DH Ham Member QRZ Page

    Sure, I do this professionally for a lot of commercial applications on a large scale so I have literally most all controllers, any worth having anyway. If you take away anything from this remember this: Virtually all solar charge controllers generate a lot of noise. There is only one certified manufacture for radio use and did not spare the expense on RFI like all other manufactures do. Genasun is a Marine Quality and hardened product made for Navigation and Radio aka NAV/RAD. The issue with all controllers is they are all use a form of SWITCHING TECHNOLOGY and between the two types of controllers; PWM or MPPT, PWM is pure garbage and extremely noisy. Not to mention waste a lot of power. The noise produced is two fold being both Radiated and Power Line line induced.

    So here is some Solar basics and I will will start with PWM controller. Stay the heck awaay from PWM Controllers, they are garbage and in the end cost you more money. They are simple switching devices and operate like an on/off switch. The FET Switch modulates the Duty Cycle from 0% to 100% at full on. They either connect the panel or disconnect the panel. The on/off nature is what generates the noise and makes then extremely inefficient and at best are only 66% efficient. They turn a 100 watt panel into a 66 watt panel or worse. PWM Output Current = Input Current. That may not strike you and most hams, but when you understand it means it is crap. Example if you are foolish enough to use say 100 watt battery panels made for 12 volt batteries a typical spec for a 100 wat panel is Vmp = 18 volts and Imp = 5.5 amps. That means at best only 5.5 amps charge current to a 12 volt battery. Do the math 5.5 amps x 13 volts = WHAT from your 100 watt panel? Additionally using a PWM controller on a 12 volt system forces you to use expensive 12 volt battery panels and wire all of them in parallel which is the absolute last thing you want to do. You cannot use higher voltage/power grid tied panels. Imagine you have a 300 watt GT panel with a Vmp = 54 volts and Imp = 5.5 amps at best you get 70 watts. Additionally once you get to 3 or more parallel strings of solar panels requires you to use combiners and fuses which are a complete waste of money and material only a amateur or DIY would do. If that not enough pain in the wallet running lower voltage panels in parallel means using larger and more runs of expensive wire to overcome voltage loss. Last pain in the wallet is if say you were to need say 500 watts using 5 x 100 watt battery panels requires a lot more racking and hardware over say 2 x 250 watt GT panels wired in series. I repeat myself, stay away from PWM controllers period and do not make a DIY or amateur blunder.

    MPPT Controller Output Current = Input Power / Battery Voltage. Again that may not strike you but do the math. Use that same 100 watt panel example. 100 watts / 13 volts = what? Did you come up with 7.7 amps? Not all MPPT controllers are created equal and allow you to take advantage. Pay attention to the Voc Input Spec. You want at least 40 volts for a small 200 wat input @ 12 volts and they go up to 600 volts so you can wire your panels in series and keep parallel strings to 1 or no more than 2 parallel strings as no fuses or combiners are needed or required. Example say you need 500 watts. You can use 2 x 250 watt panels in series using 12 AWG wire up to 40 feet one-way distance. Cheap and clean. Remember this you cannot use a prime number of panels except 1, 3, and sometimes 5. Example say you need 5 panels, but you you bought a 100 Voc input controller which means 2 parallel strings. How do you do that with 5 panels? Trust me many DIY's make that mistake.

    Ok that is enough for now because I just made a lot of folks mad at themselves, so lets wrap up. If you insist on solar, use a Genasun Controller. They have two quirks of being expensive and limited power input. The largest they make is a GV-10 or 10 amp controller which means the largest panel you can use with a 12 volt battery is 140 watts. Or 280 watts with a 24 volt battery. You cannot buy them from the factory, you have to use a retail distributor and they will cost you around $135 to $150 and be sure you select the right battery voltage as they make them for all Pb and Li chemistries. so output voltage ranges from 13.2 for a crappy Gel Pb battery up to 16.7 volts for 4S LiCo. So if you use Genasun controller with a 140 watt limit, you will be using a low voltage 12 volt battery panel. A good battery match is a 12 volt 80 to 120 AH Deep Cycle battery. DO NOT USE A CAR SLI BATTERY. Make sure it is Deep Cycle or a Hybrid like a golf cart battery. My advice is forget the solar and sink your money into a good Deep Cycle battery and AC charger at home.

    One last thing, stay as far away as possible Harbor Fright. Pure Chi-Com crap.
    KG4RRH and KD4MOJ like this.
  5. KI3U

    KI3U Ham Member QRZ Page

    Oh for sure ! As you see from the other responses in this thread, setting up a solar power plant is full of technical, practical, economic, and * SAFETY * considerations. I think for someone completely inexperienced it is wise to begin learning the ins and outs with a modest power level system. For reference the best book about it all that I know of is : SOLAR ENERGY The Physics and Engineering of Photovoltaic Technologies and Systems, by Arno Smets et al, published by UIT.

    With a modest "solar starter kit" approach you can experiment and discover the technology's characteristics without spending lots of time and money on the wrong approaches. So for example, it can be advantageous to connect solar panels in series, BUT that will work only when all the panels in the series chain are about equally illuminated, and functional, at all times.

    As for MPPT versus PWM charge controllers, there's no doubt MPPT is better at collecting and delivering power from the solar panels, it is after all designed to be so, but PWM can be pretty effective depending on circumstances, and costs a lot less to experiment with.

    In my experience a pretty good starter kit is the 30-Watt panel kit from Suner Power - well made, and with all necessary components to generate electricity within minutes of unboxing - it was $74.15 from amazon, shipped quickly, and I soon bought a second kit as it was entirely practical for some modest electric energy tasks here - one of the kits is presently powering this reply-post I'm typing. I was quite surprised that its PWM controller is not especially RF noisy. I'm not sure if presently the 30-Watt kit is offered by Suner - amazon seems to be listing only the 20-Watt kit.

    There's a lot to learn with solar power - and as with amateur radio I think it's wise to start with baby steps.

    Berj / KI3U
  6. KN4DQE

    KN4DQE Ham Member QRZ Page

    I bought 2 6v golf cart batteries from Costco - relatively cheap, considering their size (about 250AH from what I recall). They are Interstate Battery brand as well, which are supposed to be pretty good from what I have read. I think they are about $130 each.
  7. AI5DH

    AI5DH Ham Member QRZ Page

    For the application, those will work just fine. The AH spec you mentioned sounds a little high as 6-volt GC batteries, typically are in the 200 to 225 AH range. One thing you did right was purchase a Hybrid Battery as many make the mistake of purchasing a SLI aka Car or Cranking battery, but those are most likely 12 volts.

    You are correct, the batteries are made by Interstate and they make batteries for Walmart, Sam's NAPAA, and a lot of other retailers. Good thing about buying from any of the retailers is if you keep the receipt warranty replacement if needed is a snap. Interstate makes decent entry level batteries. FWIW if you shop around you can find Trojan T-105's for around $125 to $140 range which is Trojan's mid-tier Signature line.

    To extend the battery life keep them on a charger with a Float Function. Don't let them sit, and recharge immediately after any use.
  8. KN4DQE

    KN4DQE Ham Member QRZ Page

    They may be slightly lower AH, but they definitely for the price are great batteries. I also recommend a Battery Minder - which I bought recently (I think it was their 1500 model). This thing is supposed to ensure they don't sulfate.
  9. K7WFM

    K7WFM Ham Member QRZ Page

    I keep an eye out at the big box stores for heavier duty (12ga) 25 foot extension cords. I got a few for like $10. I use one for our portable panels.
    KC8VWM likes this.
  10. AI5DH

    AI5DH Ham Member QRZ Page

    Not sure what wattage the panels are and how they are configured. I suspect like most make the mistake of using 12 volt battery panels configured in parallel with a PWM controllers, a 12 AWG cable is extremely limited before voltage loss eats you up. Depends on wattage.

    With a single 100 watt panel max distance = 20 feet
    200 watt distance = 10 feet
    400 watt is max you can run = 5 feet

    To utilize a 25 foot 12 AWG extension would require you to use less than 100 watt panel. That is the down side of low voltage.
    K7WFM likes this.

Share This Page