Batteries for Portable Amateur Radio Use 18

My LiFePo Batteries Side by Side

My LiFePo Batteries Side by Side

One very common question I get about portable Amateur Radio operation is what do I use as a battery? I have answered this question individually more times than I can mention so I thought I’d write it up as a post to help others.

I’ve used everything from car batteries, Sealed Lead Acid Batteries (SLAB), standard AA’s, Lithium Polymer (LiPo) and Lithium Iron Phosphate Batteries (LiFePo). These all work, but all have disadvantages, just some for my type of operation are much larger than others.

My portable operation tends to take two forms:

  1. QRP Operation (10w or less) from a hilltop/SOTA summit for 4 hours of less. This could be a casual SOTA activation or it could be a contest.
  2. QRO Operation (50w-100w) for a short amount of time (2 hours or less), maybe to dip into a major contest to make some DX contacts

My initial SOTA activations used a SLAB battery. These are very common batteries and you can pick them up very cheaply at radio rally’s. The downsides for me were twofold and pretty major. First of all the weight is substantial even for a low capacity battery and secondly it only supplies 12v out which drops off pretty rapidly with discharge. This meant I could only ever run a maximum of 5 watts out from my Elecraft KX3, which under tough conditions is, well, tough!

Sealed Lead Acid Battery

My First Battery – Sealed Lead Acid Battery (SLAB)

My  Choice

LiFePo batteries are my chosen battery based on the current technology available. They hit the sweet spot of lightness vs performance. For the same capacity they are half the weight of SLAB batteries which is pretty significant if you have to walk any distance to your operating location.

LiPo batteries offer similar performance, but with quite a major drawback, they’re quite prone to catching fire while charging! LiFePo batteries are a lot safer in this regard while offering the same level of performance.

Here are the advantages I’ve found:

  • Light – Half the weight of SLAB batteries of the same capacity
  • Supply 13.2v – This is enough to power my rigs at their full output where a 12v battery wouldn’t be man enough
  • Slow Discharge Curve – The high voltage is maintained almost until the battery is depleted, certainly not the case for SLAB’s!
  • Fast Charge – My 4200mAh LifePo4 battery takes less than 1 hour to charge
  • Stamina – I’ve yet to deplete one of these batteries in one session, indeed I ran a pileup for 4 hours on one EA8 SOTA summit and it was still fine running my KX3 at 10 watts.

I own two of these LiFePo batteries:

Side on view for some sense of size difference

Side on view for some sense of size difference

The 4200mAh battery is the one I use most often for SOTA activations and any QRP operation. This must have had over 75 outings to date and is holding up well with no discernible decrease in performance.

I use the 8400mAh battery less often for shorter QRO operations with my Yaesu 897, once again I haven’t had any issues with this battery:

LiFePo4 8400mAh Battery for 50-100w Portable Work

LiFePo4 8400mAh Battery for 50-100w Portable Work

Note: The connectors you get by default on the batteries are meant for radio controlled cars. I replace these straight away for Anderson PowerPole connectors (which I also fit to the charger). Be very careful not to let the exposed positive and negative wires touch when doing this, I did and thankfully still have a working battery, others have not been so lucky!

I made a video explaining the two and comparing them for YouTube if you want to find out more:

Charging

A quick word on charging these LiFePo batteries. You will require a special balanced charger for these batteries. I use the Turnigy Accucell 6 Charger/Balancer (around £25 from hobbyking.co.uk) which can charge a multitude of battery types including Lead Acid, NiCD, NiMH, LiPo and of course LiFePo.

Balance charging is important to keep each cell healthy and evenly charged. LiFePo batteries have a separate balancing cable which you connect to the charger to help with this. Here’s my charging setup:

Balance Charging the LiFePo4

Balance Charging the LiFePo4

Auto Detecting the Cells of the Attached Battery

Auto Detecting the Cells of the Attached Battery

Charging Overview

Charging Overview

Individual Cell Voltage Level During Balancing

Individual Cell Voltage Level During Balancing

Conclusion

LiFePo batteries are justifiably popular with a lot of serious portable operators and seem to be the defacto choice by a lot of SOTA operators. From my point of view their weight to performance ratio is fantastic compared to the other options currently available. They do cost more but this is repaid by better performance.

Can you use a cheaper SLAB for portable use? Sure you can. But when you walk up a mountain for 3 hours you will pay that little bit more for something half the weight!

Got any further questions? Let me know in the comments below and I’ll try and answer.

18 thoughts on “Batteries for Portable Amateur Radio Use

  1. Reply wb7ond Aug 30,2016 13:29

    Banggood.com has a little “low” voltage alarm that plugs into that little 4 pin “leveler” connector. Good for 1S to 8S. It sound when the voltage falls to 3.3 volts, Its alarm voltage is settable. They are only about $3 or $4 USD.
    http://www.banggood.com/2-x-2-in-1-Lipo-Battery-Low-Voltage-Tester-1S-8S-Buzzer-Alarm-p-973987.html

    I tend to forget about the battery until the KX3 shuts down by itself, it might then be too late.. The battery vendor warns about letting these batteries drain too low.

    • Reply James Stevens Aug 30,2016 19:01

      Thanks for the great link Richard, I’ve not seen these before and have just ordered two. Very useful devices!

      I have also previously read warnings about not running these batteries too low and now I’ll have a way of telling if I’m in danger of this 🙂

      73, James M0JCQ

  2. Reply Jim K9YC Aug 30,2016 16:51

    I’ve had similar excellent results with LiFePO4 batteries. The best vendor stateside (quality, price, attitude) is Bioenno Power. https://www.bioennopower.com/

    More than a year ago, my neighbor and I each bought a 20Ah LiFePO4 battery pack with the primary goal of supporting AF6RT, who was going to hike several miles and climb 1,000 ft to activate a rare grid on 6M. We also loaned him a KX3 and KXPA100 amp. At the end of a day of operation he still had power left in the first battery!

    For nearly two months, I’ve been powering the radios in my shack from a 100Ah LiFePO4 battery. So far, I’m a very happy camper. I had previously been using a pair of 220Ah 6V golf cart batteries. My reason for changing to LiFePO4 was primarily the much better discharge characteristics. I feel the far longer life of LiFePO4 chemistry justifies the much greater initial cost. I got less than 2 years from those golf cart batteries, and they were below 12V for most of their discharge curve. That’s the kicker for me — higher voltage means a cleaner signal. For backpacking, of course, the advantage is weight.

    The other good NA vendor I know of is batteryspace.com They offer a far wider range of batteries, but you must order battery, charge balancing system, and charger separately (they sell them all), so comparative pricing is confusing. Bioenno Power batteries all come with the balancing system built in. Both companies have people who know what they are talking about responding to email and landline questions.

    73

    • Reply James Stevens Aug 30,2016 18:57

      Thanks Jim, I’m sure other US readers will find the stateside suppliers useful!

      Interesting to hear about the larger capacity LiFePo5 batteries you’ve used. I’ve not seen them offered in the 100Ah capacity, impressive!

      73, James M0JCQ

    • Reply wb7ond Sep 2,2016 20:24

      I have had good success with HobbyKing.com here stateside.

      http://www.hobbyking.com/hobbyking/store/uh_listCategoriesAndProducts.asp?idCategory=86&LiPoConfig=4&sortlist=&CatSortOrder=desc

      They seem to have good prices, and a great selection of all types, you can filter by how many “cells” you want, 3S, 4S, ah, type battery, and accessories and chargers. I use their 4S 5000ma rc battery with the KX3 with a metered bucking device, equip both ends with Anderson Power Poles(APP), set the “cell” voltage alarm and I am ready to go..
      As you say, they really last a long time…

      Don’t forget your accessory “fire bag”… (:-)

      Dick

  3. Reply Pete Sep 10,2016 20:33

    Thanks.
    My gaggle of SLAB’s just went flat.
    Now after reading this I will get LiFePo’s.
    Great newsletter, will subscribe.
    Keep it up!
    Pete / W6LAW
    ==========

    • Reply James Stevens Sep 12,2016 08:37

      Glad you found it useful Pete, you won’t regret the decision to switch. I’m sure you’ll be pleasantly surprised at the size/weight difference 🙂

      73 James M0JCQ

  4. Reply Curt KB7CJA Sep 10,2016 20:39

    This is topic of great importance to me, as I live in a tsunami zone and must prepare to leave on foot.

    • Reply James Stevens Sep 12,2016 08:35

      Wow, thanks for your message Curt. I’m glad it was of some use, obviously my uses are much less serious, but glad you found it useful none the less!

      73, James M0JCQ

  5. Pingback: Batteries ? Learning from the amateur radio operator that have the experience… | CT1DBS/CU3HF

  6. Reply Steven Kiel Feb 20,2017 15:50

    Hi James, as I await the result of my exam to see if I get an M0 call sign or not, I’ve bought the lipo version of this battery to use my FT857 portable. Now if you wouldn’t mind can you possibly guide me through how you linked the radio and battery please? I’ll be honest if not feeling a little daft, but not sure what the best way to go about it is!!!

    Regards
    Steve 2E0WEO

  7. Reply Thomas, F4HPX Apr 9,2017 18:41

    Hi James
    How do you manage transport of LifePo batteries when travelling abroad ?
    or you buy them locally once arrived ?
    I am going on holidays on Indian Ocean’s islands
    I am stuck with that issue….

    Regards
    Thomas F4HPX

    • Reply James Stevens Apr 28,2017 09:58

      Hello Thomas,

      I’ve transported them a few times to EA1, EA8 and CT7. There’s some basic advice, it’s allowed in hand (carry on) luggage only by the airlines. Make sure the ends are terminated properly so they can’t be shorted. LiFePo batteries aren’t susceptible to fire like LiPo batteries but you could also get a fire proof bag to add a bit more safety. Also make sure the battery is less than 100Ah, this was the limit at my last check.

      To be honest my small 4200mAh LiFePo never gets picked out during security screening, my SLAB on the other hand attracted quite a bit of attention!

      73 James M0JCQ

      • Reply Thomas, F4HPX Apr 28,2017 12:41

        Thanks

        I eneded buying LiIon set from Elecraft for KX2 as it is getting inside and is compliant with current regulations
        My LiFeFo is 22AH and so more than 160WHr thus no way to pass it through since the recent stories with Galaxy Note… and Acid Lead are officially forbidden too.
        I will buy one 12A/7Ah once on site – they are cheap so will recycle before going back

        Thomas

  8. Reply Damian Apr 14,2017 09:36

    Steve here’s a video on connecting Anderson power
    pole connectors, my advice when connecting
    to lipo batteries is cut, strip and solder only one lead at a
    time.

    https://youtu.be/hUPWKxPGRGI

    In depth solder technique.

    https://youtu.be/JwvUaP2tbgY

    Regards Damian G4LHT.

    • Reply James Stevens Apr 28,2017 09:47

      Thanks Damian, only stripping one lead at a time is a good plan. I once accidently let the two exposed battery wires touch, it was quite a frightening experience! In this instance the battery continued to work afterwards but others have not been so lucky..

  9. Reply Rob Janoska Apr 27,2017 22:13

    Hi James, when using the 8400mAh battery, how long does it last and what power do you use?
    Cheers
    Rob
    VK4AAC

    • Reply James Stevens Apr 28,2017 09:49

      Hi Rob,

      When using this battery I tend to operate at 50w rather than the full 100w, this will keep the battery going for longer without sacrificing much in terms of S points.

      I’ve run it at 100w for around 2 hours, but not sure how much was left in the battery, as I wasn’t (at that point) using a voltage monitor.

      Hope this helps!

      73 James M0JCQ

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