12 volt battery for ham radio power

12 Volt Battery Power For Ham Radio

ByKen J. Last Update
16 Comments

Particularly from a preparedness point-of-view, a preferred power source for a ‘ham radio’ (amateur radio transceiver) is a 12 volt battery. That is, compared with using a plug-in power supply such as a 120 VAC to 12 VDC converter.

Why do ham radios have a dc power input?

Well, there are a few reasons… So they can be operated in a vehicle. So they can be run on emergency power (e.g. 12 volt deep cycle battery). A DC battery is ‘pure’ and clean power. Or add a power supply (AC to DC converter) and the radio can be conveniently run from AC power in your home.

Ham radio DC voltage specification

Amateur Radio equipment is usually specified at 13.8V DC. Why that voltage? Because the charging voltage in the average vehicle is typically very close to that. A fully charged lead acid battery (at rest) will measure ~ 12.7 volts. Most Amateur equipment is marked with a tolerance figure for its DC voltage. You might typically see +/- 10% (12.4 – 15.2), so there’s a range.  

Advantages of using 12 volt battery for ham radio power

Although modern well designed AC-DC converter power supplies can be very good, a 12 volt dc battery is literally pure-clean power. A 12 volt battery is portable (though on the heavy side) – operate from anywhere. A 12 volt battery can be recharged from a variety of sources, including solar (making the 12 volt battery an attractive option for prepping/preparedness in this regard).

Disadvantages of using a 12 volt battery for ham radio

To be fair and objective, you do need to be mindful that the battery will need recharge, whereas a AC-DC power supply works ‘forever’ (as long as there’s grid power). Therefore you should periodically monitor the battery voltage (while it’s at rest for awhile) – see link at end of article for voltages.

Transmit uses LOTS more power from the battery than Receive. So the longer you transmit, the quicker the battery drains. This is where the size (amp hour rating) of the battery becomes more important.

I really like the following 4-stage charger / maintainer because it’s rated 5 amps (much faster charging than a small trickle charger). Though float trickle charge will maintain for extended periods of time.

Battery Tender 5 AMP, 12V Battery Charger, Maintainer
(Battery Tender on amzn)

12 volt battery size

A preferred size is a ‘deep cycle’, which are typically rated at ~ 100 AH (Amp Hours).

However I recently purchased an inexpensive ($39) 12 volt battery for my Yaesu FT-450 HF ham radio (pictured above). Got it at Walmart. It’s not a big deep cycle battery. Instead, a Lawn & Garden ‘Group Size U1’ EverStart (300 CCA), typically used for mowers. I preferred it’s smallish size to set on my bench next to the radio.

It’s not a deep cycle battery so there’s no official AH (Amp Hour) rating (which is very different from CCA Cold Cranking Amps). Best I could determine while searching online, this battery might be equivalent to ~ 35 AH. While I’m using this radio for ‘Receiving’ (measured at 1 Amp), I might get about 12 to 18 hours of operation until reaching 50% state-of-charge (the point at which you really need to recharge a lead acid battery).

I would get about 50 hours of receive time (until discharging 50%) with this radio if using a typical deep cycle battery (for example).

Transmitting, however, is another story. At 100 watts (~ 8 amps), my small U1 battery size will deliver maybe 2 hours. But who talks that long anyway?? The 100 AH deep cycle will provide ~ 6 hours before needing recharge.

Conclusion

If you’re into prepping & preparedness, and into amateur radio, you might consider a dedicated 12 volt battery for your ham radio power (be it HF, or VHF/UHF). It’s comforting to know that you could recharge the battery without grid power.

Renogy 200 Watt 12 Volt Portable Solar Panel with 20A Charger Controller
(Renogy on amzn)

[ Read: Battery State-Of-Charge Chart – 12 Volt Battery Voltage ]

16 Comments

  1. My VHF/UHF Yaesu FT-736R is 120v so for backup I have a Voltworks 1000w Pure Sine Wave inverter with a Renogy 100ah Sealed lead acid battery (on a Battery Tender) and a Renogy 100 watt solar panel to recharge.

    Also have a Patcomm PC-9 HF radio that is 12v and I use a TekPower converter to run it on 120v. I also have a small Generac Inverter generator 1000w in my HAM shack if needed.

    The ability to gather information will be priceless in a total telecomm/power grid down situation and I believe they will be the first to go if things continue to escalate.

  2. Romeo Charlie and Ken covered most everything very well. Literally every battery or combination of batteries will work with ham. Yes, as mentioned ya need 12 vdc with a little lee-way. 13.6 would be optimum, but hey, in a grid down…..? 11.5 vdc is the low end, according to the specs with the radio(s).

    I got into ham as a result of prepping. VIPs too. I don’t have a “power supply” other than a marine battery. From the very start I’ve utilized battery power. Prepping again. Needed to have real world experience with how much draw down. I’m small potatoes with ham radio. Mostly, I use 50 watts to xmit with my ‘big’ radio. Also have an old 2m all mode from the 1980’s. It’s 10 watts, but I have an amp to boost it to 140 ish watts.

    Figure out what ya need and go from there. That’s the most important thing with getting the license, You’ll have all the help you will ever need. Other hams will help you. You can concentrate on whatever your needs may be. Listening will be the biggest thing.

  3. I have a few baofengs, though I don’t use them much at all. Question on the batteries for these little radios: Best way to go with rechargeable batteries; AA, AAA, lithium? All I’ve ever used is the battery that came with the uv5r. Has it’s own charger thing. Some of the chargers have usb for charging. Others have 120vac. If shtf, these little radios will get a work-out. Only so many charges in the came-with batteries. Mostly, they live in faraday.

    What are you guys doing? Hands-on real world experience is often the best teacher. Should I purchase the added battery packs? Make-up my own using rechargeable AA or AAA?

    1. Plainsmedic,

      Consider a battery eliminator for your Baofeng’s. Basically a battery shell with a converter from 12v to 7.4v that replaces the standard battery and has a cigarette-lighter plug pigtail. I have two I use when I use the radios as a mobile unit tied to a rooftop antenna in the cars/trucks. They work great.

        1. Ken J.,

          Yep, that’s the one I use. Had read that you need to watch out for counterfeits, so I checked mine out with a multi-meter before I used them, getting a 7.4 volt output reading.

  4. Plains – I just got the empty battery packs for Baofeng that can be stuffed with AAA cells, the radio clips right in it as a normal pack. Maybe you could make a custom ‘D’ cell pack, tap it in parallel and Velcro it to the back of the ‘AAA’ pack. You’d end up with something like a Motorola 800 brick phone from the 80’s but it would run for weeks.

  5. Tmac, Dennis,
    I’m looking waaay down the road here. Convertor could work really well in a vehicle, 4 wheeler, golf cart, etc. Way down the road, most of us will be on foot. I’m thinking of posting look-outs. Two look-outs could handle all ways in here. 99% of the time, very boring. Thought about a small solar panel/battery at each spot for charging baofeng. Might be easier/better to charge at home? These radios could be passed around a lot.

    The store-bought AAA packs work well? Have a decent stash of rechargeable batteries (AA and AAA). Trying to figure out the logistics. Seems crazy to consider these things, but ….? May be necessary in the near future. Maybe a 1/4 wave ground plane at each spot? Good neighbors will be important.

    1. Plainsmedic,

      I’m sure you are aware, but I’ll remind folks…most rechargeable AA & AAA batteries are 1.2 volt, regular alkaline non-rechargeables are 1.5 volt. These battery packs require 5 batteries. Baofengs need 7.4 volts. 5×1.2 (rechargeables)= 6 volts … 5×1.5 (alkaline non-rechargeables)= 7.5 volts.

      I use a variety of the cheap micro-walkie talkies around the homeplace. I use the rechargeable AAA’s in them and they are fine for relatively short ranges for our daily regimen, but simply replacing the rechargeable batteries with alkaline increases their range substantially.

      While I have no experience with the AA loaded replacement packs, I would expect a loss in power and range using rechargeables rather than alkaline or lithium AA’s.

  6. Plainsmedic,
    Lots of options. Oem battery runs about $6 each (less than 6aaa rechargeables). Cigarette lighter plug for the desktop charger that comes with the radio is less than $10.

    1. Dennis,
      Yep, lots of options. I have stash of “stuff.” Cigarette plugs, female side too. Of course any kind of plug would work. Lots of wire and fuses. Several homebrew antennae, you know, stuff. I think there’s a convertor around here somewhere. Used it for lights on an electric golf cart. Back before LED. Probably not the right voltage though, can’t remember.

      Long term I’m thinking keep it simple for multiple users. AAA may be as simple as it gets, once the original batteries give out. I know you utilize your baofengs a lot. Have ya worn out any of the original batteries? Guess I need to do some shopping. Exposure to emp is always a concern, especially with balloon world.

      BTW, really good results with using baofeng and 1/4wave ground planes 2m. Hang the antenna in a tree, up around 10-12 feet. Short piece of coax and it makes a ton of difference. Played around last summer a little bit. Baofengs back in faraday. Hope we never need ’em. They work surprisingly well.

  7. Plainsmedic,

    Original batteries are probably 3 years old and still working fine. While I haven’t tried, I feel they would do 24 hrs standby w/o a problem. I bought a 4 pack of spare oem batteries with the radios and have never unpacked them. The original antenna is their weak point, but aftermarket antennas are very reasonably priced, homebrew 1/4 wave even better.

  8. my aa battery pack will hold 5 aa non rechargeable batteries with a dummy spacer for 7.5v or 6 rechargeable batteries without the dummy for 7.2v, both work!

    1. radio man,

      Good to know. Like I said, I don’t have any experience with those packs, my post was based on my thinking from reading other posts they held 5 batteries. Thanks for the correction.

  9. One last thought on the baofeng batteries. Lately, I’ve been using 18650 batteries for various things. Very good battery tech. Happened to notice they’re 3.7 volts. Hmmm, two of those = 7.4 volts. 3000mAh each battery. Just a thought. Heck, that may be what’s in the original batteries???

    If I should ever wear one out, may as well take a look. I’m not great with soldering, but I bet I could cobble something that would work. My motto: if it’s already broken, ya can’t hurt it.

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