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    • ARPOC Awards Scheme

      The ARPOC awards scheme aims to encourage operators to get out in the fresh air with their radio equipment and enjoy portable operating.

      ARPOC has plenty of award certificates that can be applied for and are delivered as a downloadable certificate for members to print at home. Take a look here to see them all.

      Downloadable award certificates are free for all members of ARPOC but it is appreciated if you consider becoming a full member. Full membership costs only 5 per year and helps to ensure that the awards scheme continues for future generations.

    • Portable Power - An Operator's Options

      Everyone knows power considerations are important when working portable and normally this means using some kind of battery.

      Batteries are the source of many debates amongst radio amateurs, but all will agree that different types of operation will put different requirements on a battery, and so a different battery may work better for some types of operations than others.

      For example:

      For table-top operations in a park or other location easily accessible, it is often feasible to use a high powered transmitter, putting out more than QRP watts, and with a power draw to match. These transceivers are often heavier, but as they are not going to be carried for any great distance, this is not a problem. This means the batteries can often be larger both in size and capacity, and heavier, and this is why Sealed Lead Acid Batteries (SLABs) are still widely used. They are reasonably inexpensive, easy to charge and normally have higher capacities.

      However for a mountain top activation, a small, light transceiver, often running at QRP power levels is required, and the battery must be light as it has to be carried in. Often batteries with different chemistry are used in situations like these, such as LiPo (Lithium Polymer) or LiFePo (Lithium Iron Phosphate) battery packs.

      I have both SLAB and LiPo battery packs, as well as a charger to match. I also have a few different sets of cables which allow me make use of whichever battery meets my needs best at the time, but still use the same charger with a standard set of fittings.

      Firstly, my Charger:
      Hi guys-charger-jpg
      This is a charger which I also used for my Radio Controlled Quadcopter battery packs. It can charge NiCd, NiMH, LiPo, LiFe and Pb batteries and is microprocessor controlled, allowing it to charge the batteries in the best way possible for each chemistry type.

      The charge lead has had an Anderson PowerPole connector put on the end, which means I can use it to charge all of my battery packs. I've tried to standardise my connectors as much as possible to keep things simple.

      This charger is available from many places, including online Model Flight suppliers and eBay. It can be bought for as little as £15 if you are prepared to bid on auctions ending late at night!

      Then some cables:
      Hi guys-cables-jpg
      These cables allow me to charge all of my battery packs, as well as use these battery packs in non standard ways. For example, the cable used to charge the batteries can also be used to power items with Banana Plug sockets.

      The cable with the crocodile clips can be used with a battery to power anything which you can connect the croc clips to. Alternatively, this lead can be used with a radio with PowerPole connectors on it to draw power from any battery which has square posts or tabs on it.

      PowerPole connectors are great for standardising power connectors, and they can be fitted into each other only one way if they are made up correctly, avoiding the chances of reversed polarity.

      One of my SLABs:
      Hi guys-slab-jpg
      This is a 12Ah 12V Sealed Lead Acid Battery. It has 4.4mm tabs for it's power connectors, to which I've fitted heavy duty female lugs crimped to to 10AWG silicone covered cables. The crimped lugs are also soldered. On the other end is a 45A PowerPole connector, also crimped and soldered, so that this battery can also be used to power larger radios such as the IC706MkIIG I borrow from my club sometimes.

      One of my LiPos:
      Hi guys-lipo-jpg
      This is one of the LiPos I had left over after getting rid of the Quadcopter. It is a 4000mAh (4Ah) 3S battery, easily capable of powering a QRP radio such as a Xiegu X1M or Yaesu FT817ND. Fully charged it will have a voltage of 12.6V (4.2v/cell), and it should not be discharged below around 9.9v (3.3v/cell) within this range it is easily powerful to run a QRP radio for quite a few hours.

      I did change the discharge plug from the Radio Controlled flying standard one to an Anderson PowerPole. I used a 45A set of PowerPole Connectors to allow for the 10AWG cable supplied as part of the battery. The PowerPole connectors were crimped and soldered, but extreme care should be taken soldering the leads on a LiPo battery.

      It should ideally be balance charged, making sure that all the cells have the same voltage and meaning that none are over or under-charged. The charger noted above will do this, but it should be noted that LiPo batteries should ONLY be charged using a charger designed for LiPo batteries. Failure to do this could lead to a battery catching fire. LiPo batteries should be treated with a lot of respect, but on the positive side provide a great power to weight ratio, making them great for activations where weight savings are paramount.

      I will eventually replace the LiPo batteries using LiFe batteries as these have a flatter discharge curve and are less likely to burn if pierced or shorted.

      In conclusion, when using batteries for powering portable operations, ensure your battery charger is one that can be used for all your battery types, and that your cables and connectors are as standardised as possible. Look after your batteries by not discharging them too far and by balance charging them when appropriate for the battery chemistry.

      And if we ever meet while out operating, and your battery has gone flat, you'll be glad you've used PowerPole connectors on all your equipment!
      Comments 14 Comments
      1. 2E0LUN/KC2VWR's Avatar
        2E0LUN/KC2VWR -
        I'm building a LiPo Automatic battery reducer for the 4s series which can also support a charger.
      1. M0LMK's Avatar
        M0LMK -
        I ditched the 4s LiPo (3s voltage is to low for the FT-857) and now only use LiFePo4. Stable 13.2v output without the need for a voltage dropper (inefficient), a shallower discharge curve so you get more usage out of the battery and less likely to blow up when being charged!
      1. MI0PYN's Avatar
        MI0PYN -
        Yep, I'll be replacing my LiPo with LiFe batteries too, the price is pretty much like for like now on Hobbyking!
      1. Ni9Y's Avatar
        Ni9Y -
        Thanks for the information. I use a Werker WKA12-7.5F2 12V 7.5Ah AGM Sealed Non-Spillable battery. Saturday my KX3 arrived which is replacing the HB1A. I use end-fed or mobile whips for antennas.
        Will send some photos of my portable operations if you want them.

        72's Dan, Ni9Y
        ARRL Technical Specialist since 2009
        KN9EUV 1955
        K9EUV 1956
        USN Radioman 1958
        First Class Radio Telephone 1961
        Ni9Y 1986
      1. MI0PYN's Avatar
        MI0PYN -
        Hi Dan,

        Thanks for the comment. With KX3, you should be able to have a look at LiFePO battery packs as well for lower weight.

        Why not post a thread in the "Show off your station" forum with some pics of your setup?

        Stefan 2I0SEH
      1. 9H5G's Avatar
        9H5G -
        Thanks for the article Stephan!
        I'm mainly QRO when I go /P since my QTHs are not usually too far away so I can carry the 35Ah slab. However, I would prefer something much lighter like a LiFePo.

        I live 1/2 the year off grid so batteries are important to me and I wanted to point out that when looking at battery capacities, not all batteries are the same.

        A typical leisure slab has a useful capacity of about 1/2 of its rating. That's when the voltage starts to fall, either too low to be useful or so low that the life of the battery would be affected.

        When looking at LiFePo batteries, the story is different. A LiFePo maintains its voltage far better than lead acid batteries. They are, however, sensitive to being over-discharged and the voltage must be monitored to ensure that you do not go below the voltage for your particular cells. Another advantage is that they will give out almost all of their rated capacity before reaching that voltage. So when calculating what size LiFePo you need, it could be a much smaller capacity than your slab was. Alternatively, you could operate for longer, or at higher power from the LiFePo.

        As you rightly say, LiFePo batteries should have the right kind of charger. This is not only for safety but also because they have a far higher charge acceptance rate and purchasing a correctly sized charger would allow you to recharge the battery very quickly indeed.
      1. G8TDU's Avatar
        G8TDU -
        Ive yet to finish project,but at the last Ham rally i went to, i picked up a 12 watt solar panel for £2. This has a nice deep frame to mount some batteries. A quick look on aliexpress and i found some 2900ma AA cells for just over 40p each so i ordered 50 of them.

        The plan is to mount the cells inside the panel frame, add a leg and handle and this should make me a self contained, self charging power source.
      1. G4NRT's Avatar
        G4NRT -
        Sorry if I seem dense but could some kind soul please explain to me why extreme care should be taken soldering the leads on a LiPo battery? I am waiting for delivery of a ZIPPY Flightmax 8400mAh 4S2P 30C LiFePo4 Pack which has 5.5mm bullet connectors. I was planning to install Powerpoles by crimping and soldering!

        Thanks, David
      1. G0DZB's Avatar
        G0DZB -
        If you short out the battery it is capable of delivering 30C x 8.4A = 252A !!! Thats enough to arc weld the wires together !! And shortly after that the whole thing will probably go critical ! Thats why :-)
      1. M0LMK's Avatar
        M0LMK -
        Like Peter said. You can solder them fine but take extra precautions to ensure that you don's short out the battery otherwise things will go very bad, very fast.

        You will also find it difficult to get the solder to take well on the Zippy wires and they are far too big for a 15/30A PowerPole terminal so make sure you have the 45A versions. I just made a 5.5mm bullet to PowerPole adaptor for my packs. Much easier and less chance of a KABOOM!
      1. G4NRT's Avatar
        G4NRT -
        Thanks for your responses. I'm making a short bullet to powerpole lead and I will shrink wrap the bullets and do everything with powerpole!

        73 de David
      1. G4NRT's Avatar
        G4NRT -
        Sorry ... another question ... should I solder, crimp or solder and crimp the powerpoles? I am using 30A ones for everything (and nothing runs more that 10W so I should be fine).

      1. MI0PYN's Avatar
        MI0PYN -
        Sorry it's taken me a while to get back here, but I tend to crimp and solder, nothing beats a belt and braces approach.
      1. G4NRT's Avatar
        G4NRT -
        Thanks ... I will do that on the higher power connectors but probably not bother now that they're all assembled on the low amperage ones!
    • Support ARPOC

      ARPOC is free to join for every licensed amateur radio operator but becoming a full ARPOC member helps us to keep the website, forums and award scheme running and shows your support for portable operators worldwide.

      Full membership costs just 5 GBP per year with discounts for longer memberships.

      You can find out about the different membership levels by clicking here.