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 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:
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 Â£15 if you are prepared to bid on auctions ending late at night!
Then some cables:
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:
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:
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!