Solar powered Ham Radio station

[KA1J]

Some history and future thoughts/plans: I want to in the short term power my Ham radio only with solar power. I have no intention at this time to connect my solar system to the grid. If, after obtaining sufficient solar power to run my station, I would like to power refrigerators in an emergency if there is enough solar energy available to do so.

Currently, I have cobbled a UPS using two Trojan SPRE 06 415 6V batteries in series, running to a Dimensions 12/3000N, 3000 WATT, 12V True Sine wave Inverter. There is currently a 75 amp charger maintaining the batteries. I want to charge these batteries via solar and not require the battery charger. I have been considering using one of the Victron controller units which will allow me to series three panels ground mounted for this winter, and when relocated on the roof next year, which has a fair amount of sun-facing space, series-parallel those & additional panels. At that time I would obtain more batteries, obtain a 24V inverter, and then also power the television & entertainment area.

I have a limited space next to the garden for 2-3 full-size solar panels, there will only be direct sun on them for 3-4 hours/day during the summer due to shade from the house in the morning & leaves in the afternoon. At the moment I have two 12V Sunpower 110W flexible panels, one still unopened in the box. I want to utilize full-size panels to capture as much energy as possible as my window of direct light is limited. The full-size panels I am considering are 480W Q Cell. Rather than buy multiple controllers I would rather purchase a single controller, with an eye to the future in mounting 5-6, possibly more Q Cell or equivalent panels to the southern side of the roof which would give much more exposure to the sun. I've been considering the Victron 250/100 controller in that of Victron's offerings it will allow me the greatest flexibility for adding solar panels in the future, understanding it is overkill for my immediate needs. I do not foresee ever using greater than a 5000-watt power requirement with this solar system. The controller I've been considering is the Smart MPPT 250/100 - Tr which is seen here: https://www.altestore.com/store/cha...ar-charge-controllers-p40910/#VICSSMPPT250100

The Q Cell panels data I am considering is here: https://www.energysage.com/solar-panels/q-cells/2766/DUO_XL_G10_BFG_480_Watts/


Considering the above I have a few questions which I'd like advice on. In no particular order:

1. Does a solar system that is not connected to the grid or house and is a single point of service, require a permit?

2. I haven't been able to find out what else I need with this controller to properly see the state of my charging system and batteries. Does the Bluetooth Victron App give me this info natively from this controller, or do I need to buy add-ons to monitor the system?

3. Has anyone used this controller and knows how shielded it is regarding its generating RFI that will affect my radio reception?

4. According to what I have entered in the Victron calculator (link below) if I series parallel two banks of 4 panels (8 panels in all), it looks like this controller is not being pushed unreasonably. Perhaps I have not considered something I should have. Any thoughts as to this being a good choice of controller for my future stated plans? https://mppt.victronenergy.com/#djI...sMTEuMTIsNDgwLDQ1LjMzLC0wLjM1LDUzLjM5LDEwLDQ=

5. RFI for me is a deal breaker, I will be powering radio communications with this assembly. Is there another solar controller that will adequately suit my needs which is known to generate low RFI that I should look into?

Thanks!

 

[Substrate]

I'll let others comment on the suitabilty of your arrangement. However we don't know what, and how much, and for how long you are using the equipment. Specifically, the 90/10 rule can come into play (90% receive 10% transmit) etc.

Are you low power like 100 watts, or running a full kilowatt with an amplifier? Have you measured your actual current draw taking into accound the 90/10 rule. Do a lot of transmitting - then maybe 90/10 needs to be modified.

As for rfi, we kind of covered this topic elsewhere (i'll have to find it, or search for it). Some SCC's that are considered to be rfi-generators, are actually coming from noise being conducted onto the dc-rails of the battery, which transceivers aren't expecting nothing but pure-dc, so they may not be filtered on the dc side for that. SCC's are also designed solely for charging batteries, and not designed to be necessarily quiet on the dc output rails - expecting their loads to be solely a battery, and not a highly sensitive receiver hanging off that (with the battery too of course).

Just a warning that there is a difference between running from an entirely isolated battery, and a station that has an scc controller attached to the dc rails and battery. Running in isolation may reveal that some controllers are extremely quiet (ie not *radiated*) if used in isolation. Put one on your dc rails, and different story because it is *conducted* noise onto that path. Sometimes the use of a pair of .1uf caps in series across the dc output of the controller, and a ground going from in between those two caps, has pulled this noise conducted onto the dc rails down.

 

[KA1J]

Good questions. I'm a DXer and contester but I have 332 of the 340 checked off and the last 8 I need won't generate much activity going forward. During contests, it's a mix of transmit & listen. I would like to run the amp from solar but it's an Alpha 77SX and I rarely use it but when I do it's a 220V drain. Sometimes I contest as QRP and for this discussion of solar power, that's almost the same value as the Rx drain is. IF someday I relocate to a place with more unobstructed space, I'd like to power 100% solar but till then I'll use the main for the amp.

I've been searching for as much as I can find about RFI and controllers and it's hard to find a good thread with useful info about which controllers are known to be low RFI generators. Most people don't care if their equipment is junk RFI-wise, all they care about is if it is cheap, works for them, and doesn't break down. With that, most of the threads I have found relate to how people cured their RFI issues, or they didn't, not about which controllers are designed well to not splatter RFI as a by-product.

Relating to your last paragraph; that is exactly what I am trying to find out so I don't end up buying $1,000 worth of a controller just to find it is an RFI generator in a pretty box that I must return.

 

[TorC]

I forget the link off the top of my head, but there's a ham who has made small SCCs (one per panel, essentially) for either 12 or 24V that are engineered to be zero (or very nearly) RFI on ham bands. I looked at them, but don't have them for the system I'm preparing to install as it's 48V and, at least when I bought, he didn't have them for 48V.

Ah, here it is: https://www.diysolarforu.com/products.html
I haven't tried them, so I can't vouch personally, but from what I've read it looks top notch if you can afford it for your setup.

 

[Substrate]

With that, most of the threads I have found relate to how people cured their RFI issues, or they didn't, not about which controllers are designed well to not splatter RFI as a by-product.

Exactly. Part of the reason is that some don't differentiate between a totally isolated battery system, or one that has a controller hanging off it.

Now there is a difference between those that actually radiate from the plastic front panel, or are clean radiation wise, but very tiny amounts of switching noise are superimposed on the dc-line conducted to the rig through the common ground connection. And then what looks like radiation, is actually a common-mode path to the feedpoint.

I wish I could tell you, but my situation is very low power, so I am running TWO battery setups in a hot-swap fashion so I can be isolated. One bank is discharging, while the other is charging. Keeping them isolated lets me run small pwms, mppts and so forth, with nary a problem. Within about 3 inches of my transmission line, or even brought near my feedpoint! The trouble begins when I'm not isolated, and the scc is sharing the ground, so I run a two-bank hot-swap.

Looking at your power needs, I'm thinking an isolated two-bank system is not in the works. Good luck - I know the frustration.

 

[KA1J]

TorC: Thank you for that link. I suspect his controllers are truly ideal, he's approached the controller design from someone making functional excellence available, for everyone in general, and for people who require low EMI/RFI emissions. Unfortunately, I would have to get many of these controllers for the # of panels and voltage range I want to eventually use.

Substrate: Although cobbled together, this 12V system is really RFI-wise, fantastic. The ancient Sensata Dimensions 12/3000N inverter I have in my system is without any detectable RFI in my radios as far as I can tell. The spectrum analyzer shows no increase when it is turned on. There is no decrease when it is not only turned off but it is disconnected from the battery. With that I have to figure it does not splatter RFI/EMI. I understand this same inverter has been used in ambulances in many locales for its purity & won't affect lifesaving machines negatively. I'd like to find one of these made for 24 or 48V for my next stage, it would be perfect.

This means IF I get RFI with the controller, whichever one it will be, it will be on that end of the system. While this removes 50% of the issue, it isn't a free pass; I'll either have to return a noisy controller within their time limit, or I'll have to figure out how to get around doing what their engineers didn't feel it was worth doing in the first place.

Yeah, a two-bank system is something I might have considered at one time, it has its value. For me though, I want to just work out something that doesn't require me to keep troubleshooting. I just want to get a low RFI solar system right the first time & go with that.

 

[TorC]

@KA1J, yes, I looked at and rejected his for similar reasons. Also hence the "if you can afford it." I suspect I made a suboptimal choice with the Outback FM-80 SCCs I have - that seems to make quite a bit of noise during the day. I'll be seeing what I can do about it, I guess.

Sounds like you've already got an inverter, but in the scale you're looking for, Samlex makes some good stuff. Both their PST and Evo series are specifically advertised as being low/no RFI. I haven't run detailed tests, but things look quiet at night on my IC-7300 waterfall, when my Evo is running. Just bought a small PST for a portable 12V battery, in part on the theory it would be useful if I wanted to take my rig portable to have a quiet inverter.

 

[KA1J]

TorC, thanks. I've written to the maker and asked if he has any further offerings in the near future, ones capable of fully utilizing the wattage these larger panels put out. I'm hoping to hear back, he's a Ham and I'd rather support him and give him the sale rather than go to a large corporation's product.

PST for portable? I'm not sure what that acronym is for. I can offer if you're looking for a 12V RFI quiet solar inverter you might look into the flexcharge. I have one for the camper and it's RFI silent. It isn't what I care to use on the home system though it works wonderfully if you parallel 12V panels. There's a micro relay in it that makes very light clicks once full battery charge is achieved but it's perfect for portable work & a solar panel to keep the battery charged.

Another great inverter company is Exeltech, I had one of their very first 500W inverters and it was perfect zero issues, zero RFI, and on the scope generated a perfect sine wave. Pricey though but reliable and worth every penny.

 

[TorC]

On the inverters I mentioned, PST is Samlex' higher end inverter only series. I don't know if that is or was an acronym. Their Evo series is inverter/charger combined.

Thanks for the notes on those inverters. I've put it in my source list file should I ever be looking for it.

 

[Nevadablue]

Just curious… lazy old non-on-the-air ham here…

Why wouldn’t it work just to turn off/isolate the noisy equipment while on the air? Do you work at night or? If so, it would be a very simple solution to just turn off the dirty equipment.

 

[KA1J]

Just curious… lazy old non-on-the-air ham here…

Why wouldn’t it work just to turn off/isolate the noisy equipment while on the air? Do you work at night or? If so, it would be a very simple solution to just turn off the dirty equipment.

My goal is to avoid all dirty anything. There's so much available that's less expensive and most people go for what is the cheapest that works without regard to side effects they won't notice themselves. As in a controller that is say, 30% cheaper than a competitor's version that does the same job and has few longevity issues. Most people would say "Bargain! Deal done" but by choosing the cheapest solution, they inadvertently have bought something that destroys radio communication anywhere near them, including emergency communications. The buyer may not know or even care as long as they got a deal.

For me, true quality as in no RFI generated by the equipment, and a long life expectancy of 100% service is what I require. $ are important & many companies with recognizable names I think, overcharge for their products. Because of that high $ for what you get, a knockoff-designed company will advertise the same ideal specs for much less money, but when you put it into use, the RFI invariably comes through because they skimped with pennies of properly utilized components instead of properly having designed it to have the lowest footprint of impact.

As to when I work on the air, I shouldn't have to be concerned about what time I am on the air, the equipment I purchase should be of high enough engineering quality I shouldn't have to even consider when I use my equipment.

 

[Substrate]

Well, I can say that with all the lower powered stuff, like from Genasun, and nearly ALL small pwm controllers - zero rfi. Hang one onto your dc rails, and things might be different, as it is no longer an rfi issue, but a conducted-via-the-dc rails issue.

So yeah, don't be too upset. Charge controllers are only expecting a battery to be a load. Not a battery AND and hf transceiver, whose input is only expecting a pure-clean dc in the first place. Just a hint to keep radiated RFI, and conducted noise in the dc-rails as two distinct environments.

One thought we be to talk to Kenwood, Yaesu, Icom, and others to beef up their dc-input filtering to handle noisy DC. Like that's going to happen.

Instead, keep in mind the series-connected pair of 0.1uf caps, with a ground going in between the two across the dc source. Perhaps on the input to the transceiver/receiver, or on the dc output of the charge controller itself. Or both. Try it - it's what we're supposed to do as amateurs.

 

[ko6kL]

my ham solar project is up and running, highly endorse this SCC , much lower noise level , just a little around 60mhz.