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Power supply for base station.


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I want to power a 25 watt radio I already have a power supply for my radio . I just want a back up supply that way I have a way to run my radio when the electric goes out. I have thought about using a power bank such as jump box or something like the Jackery 160 or similar. Then I thought about just a 12 volt marine battery and running cables from the radio to the direct to battery. Of course fused. It would be a semi permanent set up . At some point solar to charge the battery.

Is there any of those jump boxes or power banks like the Jackery able to produce the ample amount of amps to power a 25watt mobile radio?

What do you guys recommend. New to radio and GMRS. WRQK522

 

 

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I would recommend a LFP, Lithium Iron Phosphate, battery pack over a cheap Lead Acid type.

https://www.bioennopower.com/collections/12v-series-lifepo4-batteries

Lead Acid batteries, gell, glass matt, marine etc. all suffer from the same short comings. 

First they don’t like sitting for extended time periods in a partial state of charge. When they discharge lead sulfate forms on the plates. Newly formed its porous allowing the acid to penetrate so on charge it is changed back to lead or lead dioxide, depending on which plate it is like the positive or negative one. Allowed to sit the porosity decreases and the areas where the acid can’t penetrate results in a permanent loss of capacity. The common practice of using a trickle charger is employed to combat this.

The next problem is the terminal voltage during discharge. It starts off around 12.6 volts and drops fairly steadily as the battery discharges. Mobile radios are typically designed to operate on a 13.8 volt electrical system, which is what you have when the car’s alternator is charging the battery. The range is usually plus or minus 15 percent of that 13.8 volts, so the low side is around 11.73 volts. That’s about 50 percent, more or less depending on discharge rate, of the battery’s capacity used.

http://scubaengineer.com/documents/lead_acid_battery_charging_graphs.pdf

At the low voltage spec radios may behave erratically, shut down and or loose significant output power.

LFP batteries largely avoid the above problems. You can leave them sit around for months in a partial state of charge without damage. The terminal voltage starts out around 13.3 to 13.4 volts and remains around 13 volts for 70 to 80 percent of the discharge capacity. That makes for a better match to the typical specifications for mobile radio gear.

https://footprinthero.com/lifepo4-battery-voltage-charts
 

The LFP batteries are significantly lighter than similar capacity Lead Acid types. Much better for backpacking etc.

Now the major negative of LFP battery packs is the cost. 

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7 hours ago, WRQK522 said:

Is there any of those jump boxes or power banks like the Jackery able to produce the ample amount of amps to power a 25watt mobile radio?

 

Can it be done? Sure. Besides voltage, the other big factor is what it can handle for draw and what the radio wants for current. 

IIRC, my mxt115 showed a 3.5a draw on high power, and I wouldn't expect a lot more draw for 25 watts. Ive done some limited testing running the anytone 779uv off of a small jumper pack that has a 12v socket accessory (I'd have to look at the brand and rating, I want to say 8a) for a short time, and it worked fine.

Also been meaning to test it with the big power bank (ecoflow river max) that has a 10a rated 12v socket, and also rated for something like 600 watt draw on the ac outlets (or 1200 in "boost" mode).

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I have a Jackery 1500 Explorer. Under no load (I've not measured under a load) I was seeing 13.3V output. For my higher power radio (KG-1000G) I just use the AC output to my SamlexPower SEC-1235 power supply that is stable at 13.8, even under the load on H power while transmitting. Also, note, the KG-1000G has 15A fuses, the DC output on the Jackery is rated at 10A, another reason I didn't direct DC connect this radio to the Jackery.

With my smaller first radio (Midland MXT275) I regularly powered directly from the Jackery DC power with no issues while camping.

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4 hours ago, Screech said:

I have a Jackery 1500 Explorer. Under no load (I've not measured under a load) I was seeing 13.3V output. For my higher power radio (KG-1000G) I just use the AC output to my SamlexPower SEC-1235 power supply that is stable at 13.8, even under the load on H power while transmitting. Also, note, the KG-1000G has 15A fuses, the DC output on the Jackery is rated at 10A, another reason I didn't direct DC connect this radio to the Jackery.

With my smaller first radio (Midland MXT275) I regularly powered directly from the Jackery DC power with no issues while camping.

yeah, i think all of my 45/50 watt radios have shown between 10 and 11 amp draw transmitting on high, i wouldn't want to test the 12v socket with that...if i want to run one off the power bank, i'd go the same route; use the AC outlets with a PSU.

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I estimated at least 5 amps for a 25 watt radio and about 9 amps for around 50 watts. I think the minimum you should look for is a 15 amp power supply.

https://www.hamradio.com/detail.cfm?pid=H0-003728

While this one is a bit more expensive than the one you looked at it does have ample current capacity to power your radio or a 50 watt model, many use this for 100 watt Ham radios, if you choose to move up for more power. The extra outlet and power connections are handy for powering other devices at the same time.

One nice feature is the noise offset adjust. Every switching power supply will generate high frequency trash, some more than others, that may show up on the frequency you want to operate on. The adjustment allows you to change the internal switching frequency by a slight amount, usually enough to get the garbage off the frequency you are using.

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36 minutes ago, WRQK522 said:

Thank you Lscott . Will look into a higher amp power supply. I have the pyramid PS9KX. I really don’t think it really was that good for my radio.


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(had a post half-typed earlier, but lost it to a page refresh)

I was thinking a similar estimate to @Lscott, at around 5 amp draw for a 25 watt radio, based on what i've seen from 15-20 watt rated (around 3.5 amps) and the 45-50 watt stuff (in the 10-11 amp range). Looking at what your PSU is rated for, you're probably right on the border between 'enough' and 'not quite enough', with 5 amps continuous rating.  that said, running it at the limit all the time isn't usually a recipe for long life.

Alinco is a good suggestion on upgrade as well; I've been running my 'shack' off of a Alinco DM-30TR for a little over 2 years, though i don't leave it on continuously.  It's a bit less expensive ($135, currently, vs $190), and has a correspondingly lower power rating (20 amp continuous, 30 amp peak), along with powerpoles rather than the bare wire connectors (i made my own powerpole to 12v socket connector from a couple other pieces).  Still has a switch to set it to 13.8v, or adjustable voltage, and the noise offset knob.  Currently have 3 radios connected, sometimes use a 4th with that 12v socket/powerpole for testing, and it's holding up fine.

 

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My 100 watt Yaesu radio draws an honest 23 amps when transmitting digital (which is a worst case mode) at 100 watts.  I have a Samlex 1235PM power supply.   If you don’t need the illuminated voltage and current meters you can find this 35 amp power supply for about $140 or so, I think.  It’s nicely built but you do hear the fan when it turns on. It doesn’t bother me, but it might bother you.

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