The crowdfunding campaign has so far raised enough money to buy a small lead-acid battery but hopefully with another four days to go before OSCAL we can reach the target of an AGM battery. In the interest of transparency, I will shortly publish a summary of the donations.
The campaign has been a great opportunity to publish some information that will hopefully help other people too. In particular, a lot of what I've written about power sources isn't just applicable for ham radio, it can be used for any demo or exhibit involving electronics or electrical parts like motors.
People have also asked various questions and so I've prepared some more details about PowerPoles today to help answer them.
In an unfortunate twist of fate while I've been blogging about power sources, one of the OSCAL organizers has a MacBook and the Apple-patented PSU conveniently failed just a few days before OSCAL. It is the 85W MagSafe 2 PSU and it is not easily found in Albania. If anybody can get one to me while I'm in Berlin at Kamailio World then I can take it to Tirana on Wednesday night. If you live near one of the other OSCAL speakers you could also send it with them.
If only Apple used PowerPole...
The first question many people asked is why use batteries and not a power supply. There are two answers for this: portability and availability. Many hams like to operate their radios away from their home sometimes. At an event, you don't always know in advance whether you will be close to a mains power socket. Taking a battery eliminates that worry. Batteries also provide better availability in times of crisis: whenever there is a natural disaster, ham radio is often the first mode of communication to be re-established. Radio hams can operate their stations independently of the power grid.
Note that while the battery looks a lot like a car battery, it is actually a deep cycle battery, sometimes referred to as a leisure battery. This type of battery is often promoted for use in caravans and boats.
Many amateur radio groups have already standardized on the use of PowerPole in recent years. The reason for having a standard is that people can share power sources or swap equipment around easily, especially in emergencies. The same logic applies when setting up a demo at an event where multiple volunteers might mix and match equipment at a booth.
Sites like eBay and Amazon have many bulk packs of PowerPoles. Some are genuine, some are copies. In the UK, I've previously purchased PowerPole packs and accessories from sites like Torberry and Sotabeams.
The PowerPole plugs for 15A, 30A and 45A are all interchangeable and they can all be crimped with a single tool. The official tool is quite expensive but there are many after-market alternatives like this one. It takes less than a minute to insert the terminal, insert the wire, crimp and make a secure connection.
Here are some packets of PowerPoles in every size:
It is easy to make your own cables or to take any existing cables, cut the plugs off one end and put PowerPoles on them.
Here is a cable with banana plugs on one end and PowerPole on the other end. You can buy cables like this or if you already have cables with banana plugs on both ends, you can cut them in half and put PowerPoles on them. This can be a useful patch cable for connecting a desktop power supply to a PowerPole PDU:
Here is the Yaesu E-DC-20 cable used to power many mobile radios. It is designed for about 25A. The exposed copper section simply needs to be trimmed and then inserted into a PowerPole 30:
Many small devices have these round 2.1mm coaxial power sockets. It is easy to find a packet of the pigtails on eBay and attach PowerPoles to them (tip: buy the pack that includes both male and female connections for more versatility). It is essential to check that the devices are all rated for the same voltage: if your battery is 12V and you connect a 5V device, the device will probably be destroyed.
There are a wide range of power distribution units (PDUs) for PowerPole users. Notice that PowerPoles are interchangeable and in some of these devices you can insert power through any of the inputs. Most of these devices have a fuse on every connection for extra security and isolation. Some of the more interesting devices also have a USB charging outlet. The West Mountain Radio RigRunner range includes many permutations. You can find a variety of PDUs from different vendors through an Amazon search or eBay.
In the photo from last week's blog, I have the Fuser-6 distributed by Sotabeams in the UK (below, right). I bought it pre-assembled but you can also make it yourself. I also have a Windcamp 8-port PDU purchased from Amazon (left):
Despite all those fuses on the PDU, it is also highly recommended to insert a fuse in the section of wire coming off the battery terminals or PSU. It is easy to find maxi blade fuse holders on eBay and in some electrical retailers:
If you don't want to buy a crimper or you would like somebody to help you, you can bring some of your cables to a hackerspace or ask if anybody from the Debian hams team will bring one to an event to help you.