(Continued from Part 4. This concludes the article.)
There is a serious weakness in the Baofeng UV-5R and several other similar radios, since there is no off-the-shelf charger made to charge these radios from a standard 12vdc source. Fortunately, we can make our own 12vdc step-down charger power supply by putting together the parts that I list below. It can charge up to four Baofeng UV5R radios, or any brand handheld radios, and even some Kenwood and Midland radios (transceivers), or any radio that requires 9vdc to 10vdc at its charger base. It can charge more than 4 handhelds at a time. However, with four transceivers charging, the charge times would be extended to a point that is impractical for most typical use.
The 5.5mm barrel connector, or appropriate connector fits many charging docks. The converter provides up to 2 amps, and 9.14vdc that the Baofeng charging base then steps down to 8.3vdc as a maximum allowed voltage. This duplicates factory performance and allows the factory circuitry to regulate the charging process, and avoids overcharging.
Solar Direct Charging
If we can charge radios “solar direct”, then we have eliminated the need for a battery bank and charge controller. Charging solar direct is roughly 30 percent more efficient if a PWM charge controller is eliminated. We avoid the loss of power during the conversion into a chemical form as when a storage battery is used –with the loss of power when the chemical process is reversed to transfer power.
As tested with a constant 5aH 19.5 vdc power supply, the converter steps down the voltage to 9.22 volts instead of the previously mentioned 9.14vdc, and the charging base limits the maximum charging voltage to 8.3 vdc as it does when the original power source is between 12 and 13 vdc, the voltage of a typical lead acid battery.
This test at 19.5vdc simulates the level of power that would be supplied by a nominal 12vdc 100-watt PV panel at VOC that the maximum voltage during peak production as occurs during bright sunny conditions in very cold weather. Therefore, I estimate that this step-down conversion device can be used to charge 1 to 4 handheld radios in the same time period that the manufacturer expects when directly connected to a single 40-watt panel as minimum during ideal solar conditions. Or to a 400-watt 12vdc panel during cloudy conditions, or during ideal conditions.
During cloudy conditions, the 400-watt panel array would be expected to produce only 10 percent of its maximum output rating, or only 40 watts. Each handheld needs a maximum 500 maH. A 100-watt panel produces at a maximum, 550 maH during cloudy conditions. Even if there was not enough insolation (that is a term for hours of sunshine) during the winter months to recharge a completely dead battery to a fully-charged battery in a single day, we can use the minimal power available to transmit during a commo window that would of necessity be during peak solar conditions.
Although my testing is satisfactory for my own needs, it is not time-tested nor tested in the field, and your results can be different and dissatisfactory resulting in the loss of equipment — but likely only the loss of the transformer.
Therefore, purchase many spare transformers just in case, and whether you decide to experiment or not.
Only one 12vdc cigarette outlet and plug, or set of Anderson Power Poles (or other similar connector) are needed, and one voltage converter, and 4 barrel connectors are needed for the assembly to charge up to 4 Baofengs at the same time. I prefer soldering and shrink-tubing the connection points. We could also cut costs and forego the connectors and wire the device with an inline fuse directly to a 12vdc battery. The same assembly, or device, can also be used on other brands that have the same voltage requirements. However they may draw additional power, therefore the number of radios that can be charged simultaneously is reduced, or more time is needed to fully charge all handheld batteries attached to a single converter limited to 2 aH/9.0vdc of power out. The unit cost to build can range from $5 to $30 for a first-class example.
A Game-Changing Charger
Once spring is underway, and the sunshine returns, as a real-world field test, I will test my charger to destruction if necessary, and attempt to safely charge Baofengs with this device directly from a 12vdc PV panel. As an example, a Baofeng battery eliminator can use 12vdc PV power directly. In direct sun, a Baofeng UV5R can transmit with 4 watts of power using only one 10-watt PV panel. In my opinion, my prototype transformer is a better choice as a power supply than the flimsy Baofeng battery eliminator. With this device, we eliminate the need for a storage battery and charge controller when used as a remote repeater power supply during the six months of the year when sufficient sunshine is available. Yet more importantly, a device such as this can allow survivalists to keep their communications up with a minimal amount of investment.
I suspect that this charger, and a 100-watt PV panel, are all that is needed to keep a single retreat using one to 4 handhelds operational, and connected to a local radio network, 12 months a year.
400 watts of PV power would be needed to keep four Baofeng UV5Rs operational during the dark winter month in the American Redoubt region. The import of this capability can give us several advantages as well, including a method where carrying storage batteries would otherwise be necessary. And storage batteries are a capital investment — an expense that could preclude us from making other investments. And storage batteries in a long-term event will eventually lose capacity, or in the case of lithium batteries, the microcircuitry involved in the charging process could be damaged by EMP, or simply fail.
This step-down transformer is very compact, and light for carry in the field. All that would be needed would be a 10-watt flexible, or glass-faced panel to charge one Baofeng UV5R in the field. Or if my friend in need needs a radio, but cannot afford a solar system at this time, all he needs is a 100-watt panel and this transformer to keep his radios charged.
Essential Components For The Step-Down Charger:
An Experimental Homemade Audio Amplifier for Transceivers
Recently, I used a Baofeng as a receiver, and a modified amplified desktop computer speaker system purchased at a thrift store for only $2.50. When a ‘call’ alert is transmitted by the Midland GXT950 to the Baofeng, the amplified audio is loud enough to awaken anyone sleeping in the room, or an adjacent room in another part of the house. It is that loud. A sleeping radio attendant assigned to a graveyard shift would certainly wake up. Another advantage of an amplified speaker system is that weak signals are easier to hear, and the attendant might hear a weak signal whilst they are not in front of the receiver as they might be making another pot of coffee, or otherwise be away from the radio and distracted. This would be a secondary means of contact for a base station, to be used only when someone unsuccessfully attempts to make contact via the primary channel.
The audio quality of this system also greatly improves the tone and volume level of the audio over that of the tiny handi-talkie transceiver speaker. Those who are losing part of their hearing due to old age might appreciate the difference. A similar amplified computer stereo speaker system can be purchased new on eBay for as little as $21. Replace the 3.5mm plug with a 2.5mm plug that fits into the Baofeng UV5R speaker outlet. The 2.5mm plug will work in other handhelds as well. The amplifier is designed to operate directly from 12vdc.
For the sake of longevity of the transceiver used, I suggest that this amplified system be reserved for emergency radio alert signals, instead of routinely used. Use at your own risk. I have not yet conducted long-term testing to determine how long the Baofeng would remain operational in this kind of improvised setup. That said, it has utility, and is definitely a part of my radio shack. I have yet to explore its other potential uses such as a long-range wireless P.A. that can be used to assist at a lightly manned checkpoint, or to deliver commands to would-be trespassers at a comfortable safe distance. I now have two of these. And if I can dig up another $2.50 for another thrift store find, then I’ll have three of them.
Those who are closest in proximity will be far more important to us than those who are more than a few miles away. HF has limited importance when compared to local communications and a community connected by a single road, and not one separated by mountains. Guerilla-style communication are not for everyone. But those who are so motivated need to be creative. Be bold and experiment outside of the box of what are acceptable practices, and be prepared create something that works, if need be. Even if it is “stupid simple”, then try it. Innovation created the powerhouse that the U.S. once was.
Edison is often quoted as saying: “Genius is one percent inspiration, and 99 percent perspiration.” I am not sure who actually said that, but I love the humility implied by a report where Einstein was supposedly asked, “What it like to be the smartest man on Earth?”, and he replied, “I wouldn’t know, go ask Tesla.”
The fictional character, Forest Gump might be considered the wisest man on Earth if he was the one who originally said: “If it is stupid, but works, it ain’t stupid.”
Down and dirty commo could keep us on the air, and alive. So stuff your head with knowledge and experience, and load up the toolbox accordingly for what I expect will likely be the most epic period in the history of Western Civilization. But for the Good Lord’s intervention, without commo, we haven’t got a chance, alone. We will need each other’s help, and that will mean we will need reliable commo.