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Ham friendly small (500W) 24V inverter recommendation needed

AlpineJoe

AlpineJoe

Solar Enthusiast
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Jun 13, 2022
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I've been playing with solar for about 30 years, but never made anything permanent. Looking for a recommendation for an electrically quiet 24V to 120VAC, ~ 500W inverter to power stuff that runs 24/7 (cable modem, router, access points, ubiquiti air links, PC running Blue Iris, security cameras, voip phone). Tired of paying the electric company $0.34/KWh all-in and would like to offload this continuous load.

Anyone have any recommendation for something that doesn't mess up the HF bands?

Going with 24V to reduce cable size, plus my MPPT controller is limited to 20A and would top out with my used 24V residential panels I already have. Batteries are 4 qty 100AH AGMs from a decommissioned network UPS.

Thanks
 
There is a similar thread on this forum here

diysolarforum.com

What inverter wont wipe out ham radio?

Today I got on the radio during the day. I normally don't use the radio while everything is running. This reliable 24v inverter is wiping me out on the bands. Bad. Is there something I can do ? I shorten the dc power leads so far with the tiny cables that came w it. I'm not sure they will...
diysolarforum.com diysolarforum.com
 
Look for FCC Class B compliance ( not just inverter ), almost everything is noise hell for Ham electrically speaking. The mppt unit is especially important as it has long wires to the array. The Schneider XW-MPPT60-150 MPPT is one such unit.
 
Well, how about a refurbished APC UPS 1500 - $135 (no battery) - https://www.ebay.com/itm/304986878631 . They're 24v, quiet at 500w load, and have ~50w built-in charging. No problem to parallel in panels -> charge controller -> 24v battery. They need 120v to turn on easily, but if you take advantage of grid assist - e.g. leave it plugged in when grid is available - then this won't be an issue.
 
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DIYrich said:
No recommendation, but you may be able to power the stuff directly with DC-DC converters.
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I'm looking into that option to help with the conversion efficiencies. The Ubiquiti stuff is 24V, voip is 48V, PC is 120V, router, cable modem is 12V. So I'm up to 3 dc-dc converters and still an inverter for the PC. Will start with an inverter first as a lower cost of entry.
 
chrisski said:
There is a similar thread on this forum here

diysolarforum.com

What inverter wont wipe out ham radio?

Today I got on the radio during the day. I normally don't use the radio while everything is running. This reliable 24v inverter is wiping me out on the bands. Bad. Is there something I can do ? I shorten the dc power leads so far with the tiny cables that came w it. I'm not sure they will...
diysolarforum.com diysolarforum.com
Click to expand...
Thanks, I did read through that yesterday before posting today. That guy gave up.

I do see that they mention an Exeltech 1100 as being quiet, and I too bought one 25 years ago. Never used it as the quiescent power consumption is high, even though I bought the low power consumption model. I should drag it out and see if indeed it is quiet, and re-measure the self consumption.

edit: Drat! I just remembered I bought the 12V version back then.
 
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Samlex PST series is reportedly the best and I have personally had good experience with Cotek on 160m-70cm since I was too frugal to buy the Samlex.

Both explicitly state FCC Part 15 compliance in the manual last time I checked.

One example :

www.donrowe.com

Samlex PST-600-24 600W, 24V Pure Sine Inverter | DonRowe.com

The Samlex PST-600-24, 24 Volt, 600 Watt Pure Sine Wave Power Inverter features a commercial grade design for extreme reliability and is designed to accommodate tools and appliances in vehicles, RVs, boats, solar systems and more.
www.donrowe.com

Be sure to put a few twists on the supply wires and add mix 31 or 43 ferrites if needed. Choose according to your frequencies of interest. See here :

palomar-engineers.com

Ferrite Mix Selection - Palomar Engineers®

Ferrite Mix Selection Guidelines Quite often we are asked which mix is best for a certain application or frequency range and there is a lot of misinformation on the internet and elsewhere regarding the selection of proper mix for a given application. Material Types There are two basic ferrite...
palomar-engineers.com palomar-engineers.com

Your MPPT is more likely to create RFI so I would choke the p!ss out of those wires. The inverter likely won’t need it.

My Victron MPPTs are noisy buggers without choking and proper grounding.
 
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JoeHam said:
Samlex PST series is reportedly the best and I have personally had good experience with Cotek on 160m-70cm since I was too frugal to buy the Samlex.

Both explicitly state FCC Part 15 compliance in the manual last time I checked.

One example :

www.donrowe.com

Samlex PST-600-24 600W, 24V Pure Sine Inverter | DonRowe.com

The Samlex PST-600-24, 24 Volt, 600 Watt Pure Sine Wave Power Inverter features a commercial grade design for extreme reliability and is designed to accommodate tools and appliances in vehicles, RVs, boats, solar systems and more.
www.donrowe.com

Be sure to put a few twists on the supply wires and add mix 31 or 43 ferrites if needed. Choose according to your frequencies of interest. See here :

palomar-engineers.com

Ferrite Mix Selection - Palomar Engineers®

Ferrite Mix Selection Guidelines Quite often we are asked which mix is best for a certain application or frequency range and there is a lot of misinformation on the internet and elsewhere regarding the selection of proper mix for a given application. Material Types There are two basic ferrite...
palomar-engineers.com palomar-engineers.com

Your MPPT is more likely to create RFI so I would choke the p!ss out of those wires. The inverter likely won’t need it.

My Victron MPPTs are noisy buggers without choking and proper grounding.
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VERY much appreciated! I haven't heard about Cotek inverters. Will give them a look later tonight (have to run a net at 0230 UTC)
 
Victron Phoenix line of inverters. Uses big iron toroidal transformer for voltage step up. RF quiet due to not having high voltage switching stage. If you search for 500VA 24V version on google there is one for $150.

I have 48V 800VA version, it peaks at 93% efficiency 260w or 30% of rated power.
I also have 24V 1200VA model i am looking to get rid of since I switched to 48V. It starts 5k BTU window AC and Makita LC1230 metal saw while 800VA cannot.

Victron MPPT charge controllers on other hand do make RFI on ham bands. My 150/60 MPPT has many pulsating spikes across 40M band. Took a lot of mix 31 toroids to knock that down 25 dB.
 
AlpineJoe said:
inverter to power stuff that runs 24/7 (cable modem, router, access points, ubiquiti air links, PC running Blue Iris, security cameras, voip phone)
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I would look into setting up 12V DC solar system and powering all these electronics directly from battery to avoid inverter and power supply losses. You can power your ham radios too. My main 44V solar system powers my 12V stuff via Victron 75/15 MPPT used as DC step-down converter keeping 4S LFP buffer battery at 13.6V at all times. Both my PCs, network gear, PC monitors, DVR and IP cams, speakers, ham radios, LED lights run on 12V. My inverter stays off most of the time. I keep cable modem on grid power via UPS to prevent galvanic connection to my PCs in case of lightning strike. Data is ran via RJ-45 to Fiber converters to avoid having metallic path to my computers.
 
AntronX said:
I would look into setting up 12V DC solar system and powering all these electronics directly from battery to avoid inverter and power supply losses. You can power your ham radios too. My main 44V solar system powers my 12V stuff via Victron 75/15 MPPT used as DC step-down converter keeping 4S LFP buffer battery at 13.6V at all times. Both my PCs, network gear, PC monitors, DVR and IP cams, speakers, ham radios, LED lights run on 12V. My inverter stays off most of the time. I keep cable modem on grid power via UPS to prevent galvanic connection to my PCs in case of lightning strike. Data is ran via RJ-45 to Fiber converters to avoid having metallic path to my computers.
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Much appreciated. Especially about the Victron MPPT causing hash. I think that was the source of our 80M RFI at Field Day last weekend from another ham and his setup.

I wish all my stuff were 12V. The Ubiquiti stuff for my AREDN and my AP is 24V. The voip phone is 48V as is the POE switches. Gigabit network switch and PC are 120VAC.

Thinking of going with Victron isolated 24 to 12 V converter so as not to deal with ground loops. I really should start with that and get the benefit of peeling some of the stuff off.
 
We hosted the ham Winterfest 2023 at our lake pavilion, near our off-grid solar system, and some of the hams had an issue on the 6 meter band whiich they believed may be our solar system since there was no other source for interference nearby. The group was using their own generators and not our solar system. We have a Renogy sine-wave inverter which should be clean power. We tried to make our solar system ham friendly and we have Anderson plugs to facilitate Go-boxes but those were not used.
 
Here's an update on where I'm at.

- I found that Samlex makes a 24V input 600W pure sinewave inverter that meets FCC class B emissions. I just received one yesterday but haven't fired it up yet to check its output. I have high hopes that it will be clean.
- Separately I've purchased both a Victron 24V to 12V/9A isolated converter, and a Victron 24V to 12V/20A non-isolated converter. Both of these will be tested to run my rigs straight from the 24V packs, and maybe the cable modem/router/AP. Though if my system fails and I need to go back to AC mains, it would be easier to keep everything BUT my ham gear on the inverter AC so switching over is fast and easy enough for the wife to do if I'm not home.

My current MPPT solar controller is an EPEver from 15(?) years ago? It was the only inexpensive MPPT at the time. I have yet to fire it up and see how noisy it is. IIRC my panels are less than 72 cell panels, so not quite enough to use a PWM controller straight to my AGM batteries. Plus I'd like to run the panels in a string to minimize I2R losses and cheapen the price of the wiring I need.

This weekend I'll give the Samlex inverter a try.
 
Good news! The Samlex inverter I bought is quiet on the HF bands! I'm sitting here running my HF rig, 2M rig, and a dual monitor PC and I'm not seeing any increase on the S meter on 160 through 10 meters.

Samlex SA-600R-124

And it's cheap. Looks like the US Gov't bought a lot of these and then sold them off as there are sellers on Ebay selling them new, still sealed in an ESD bag with dessicant and with a US Gov't Cage code tag on the box.

It's not enough to start my fridge though, so I'll still need another inverter for that for when the power is out and I'm not on my rigs.

I'll ask in another thread for a inverter for the fridge with high surge capability.
 
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