Off Grid Ham: Learning From Off Grid Mistakes, 2

This article comes from Chris Warren at Off Grid Ham – Learning From Off Grid Mistakes, Part 2.

I wasn’t planning a “part 2”. learning from off grid mistakes

Last May’s article about off grid mistakes received a surprising amount of attention. Many months later, it’s still a very popular piece. As a follow up, I thought it would be a good idea to revisit the issue and go over a few points that were not discussed last time. I encourage readers to send in questions and comments because most of the articles that appear on Off Grid Ham are derived from reader input. learning from off grid mistakes

Mistake 1: Mismatched batteries.

Batteries are very exclusive. They don’t like other types of batteries. Just because two batteries are of the same voltage, and maybe even the same capacity, doesn’t mean they play well together. If you are using multiple batteries, they should be the same make and model, and roughly the same age. Most batteries will have a date code on the outer casing for determining age. learning from off grid mistakes

When I went shopping to replace my large storage batteries two years ago, I brought my battery analyzer with me to the store. They had a huge pallet of deep cycle batteries, so I had plenty to choose from. I dug through the pile and picked out a few that were manufactured within a month of each other. From that cohort, I tested each until I found a few batteries that had the same or very close to the same internal resistance. That was the matched set I ultimately bought and took home. Yeah, I must have looked a little weird picking through batteries and running tests, but I got what I wanted. learning from off grid mistakes

When you mix dissimilar batteries or batteries of different ages, the weak one will pull down the strong one. Always Install and remove your batteries as a set. If you must mix dissimilar batteries, wire a battery combiner between them.

Mistake 2: Mismatched solar panels.

This mistake needs some clarification. You should not mix/combine solar panels of differing voltages at any time. Solar panels that produce the same voltage but not the same wattage can be used together, but only if they are wired in parallel. Solar panels are often wired in series to increase efficiency and make better use of MPPT solar controllers. This works only if all the panels in the series are the same voltage and wattage.

If you wire solar panels of the same voltage but different wattage together in series, you will not damage anything or create an unsafe condition. What will happen is that the total power output of the system will not exceed the capacity of the smallest panel. For example, you have one 100 watt panel and one 50 watt panel wired in series. It might seem reasonable to think you’ve got a total of 150 watts capacity. Sorry, but you’ll never get more than 74 watts out of this system.

The reason why is fairly simple: Kirchoff’s Law states that current will always be the same at all points (nodes) in a series circuit. A 100 watt panel will produce about 5.75 amps. A 50 watt panel maxes out around 2.85 amps. Our 12 volt example panels below are wired in series for a system total of 24 volts (in reality, it would be closer to 26 volts).

Since Kirchoff says the current is the same at all points in the series, and the 50 watt panel will never exceed 2.85 amps output under any conditions, the system total is limited to 2.85 amps. Doing some basic math, 2.85 amps x 26 volts= 74 watts. These numbers will vary due to differences between loaded and open voltages, what specifications are used for your calculations, etc., but this gets us pretty close. Think of it like a convoy of ships: The entire convoy cannot go any faster than the slowest ship.

learning from off grid mistakes


Mistake 3: Using automotive batteries.

If someone gives you a car battery, or a car battery is all you have (such as in a SHTF situation), then certainly go with it for your off grid ham radio power needs. But no thoughtful ham would purposely choose a car battery.

Car batteries are designed to deliver a large burst of current over a short period of time, which is needed to start a car. Off grid hams need batteries that can deliver smaller, steady amounts of current over a long period of time. Using a car battery will not hurt your equipment and is not a safety hazard, but you will not see the the level of performance that a correct battery would provide, and the car battery will have a shorter service life too.

Mistake 4: Using automotive “jump boxes”.

Those inexpensive portable battery boxes made for jump-starting cars seem like an easy, ready made power system for ham radio. They are not recommended for ham radio use for the same reason as standard car batteries. They are made for a short power burst, not for a lighter, continuous load. Some hams do use them with modest success, especially for QRP, but they’re not a serious way to power your radio.

Mistake 5: Buying the best, most expensive gear available.

Just as buying cheap junk because it’s cheap is a mistake, so too is insisting on only “the best”. More expensive does not necessarily mean a device has better build quality or will last longer than a less expensive device of the same type. In many cases it only means you get more cool switches and pretty lights. If you cannot justify the extra cost with some clear purpose or practical benefit, buying “the best” is a journey of vanity.

In my experience, mid-grade equipment has always given me the most bang for the buck. Early in my off grid career I spent over $500 on an ExcelTech inverter. They are made in USA. They are practically indestructible. The American military and US embassies around the world use them. They’re the Rolls Royce of inverters. I didn’t know it at the time, but it was unnecessary overkill. As nice as my ExcelTech is, my Samlex inverter is just as suitable for my application. It cost half as much as the ExcelTech and gives excellent performance. I still use both inverters, but if I were doing this over I’d get two Samlexes and spend the extra money on other useful upgrades.

Never buy any piece of off grid amateur radio equipment based solely on high or low price point…(continues)

Off Grid Ham: When Things Go Wrong, What Type of Ham Are You?

Chris Warren of Off Grid Ham asks When Things Go Wrong, What Type of Ham Are You?

It’s all fun & games until the electrons stop flowing.

Operating amateur radio is a load of fun. Operating amateur radio off grid is extra fun, but adds a layer of technical complexity to your station. Have you ever thought of what you would do if your off grid system itself went off line? Do you have the skills, spare parts, and tools to correct the problem and get the electrons flowing again? Troubleshooting solar power system may or may not be hard depending on what type of ham you are.

What kind of ham are you? Troubleshooting solar power

There are basically three kinds of off grid hams. “Type 1” hams do not get very involved with the technical aspect of the hobby. Maybe they just want to run contests. Perhaps they got into ham radio only because their kids are doing it, or to be part of a community service group. Type 1 hams don’t see amateur radio as a stand-alone hobby, but rather, as a tool, a means to achieve some other goal. They have some basic tech skills but want everything to be as plug-and-play as possible.

“Type 2” hams see radio as an end in itself. They love to tinker and experiment and would enjoy radio even if it had no ancillary practical purpose. Type 2’s enjoy messing around with radio/electronics and have a high skill level but don’t necessarily do a lot of on-air operating. They will pursue all kinds of projects, many of which never work and might seem a little crazy. They have a great time anyway. Troubleshooting solar power

“Type 3” hams are a combination of the first two. I place myself in this category. I love DIY and home brew projects and that’s what attracted me to ham radio back in the day. Yet, I see that ham radio has real-world applications. Type 3’s have figured out the magic combination of skills and utility. Troubleshooting solar power

Why this matters. Troubleshooting solar power

The type of ham you are will determine what happens when your off grid system goes down.

For Type 1’s it’s straightforward. Unless it’s a blown fuse or similar simple fix, they either call a pro or replace the entire suspect device.

Type 2’s know their off grid systems forward and backward because they probably built the system themselves. They can resolve even complex problems and have a large personal inventory of spare parts. Many Type 2’s will use the opportunity to reconfigure and make major changes and may spend a lot of time dabbling with different ideas beyond the initial problem.

Type 3’s, like type 2’s, can handle nearly any malfunction themselves because they have extensive technical knowledge of their off grid systems. They also have an inventory of spare parts, but only as it relates to their needs. They do not keep a lot of extra unrelated supplies around just for the heck of it like Type 2’s do. Type 3’s are practical and goal-oriented. They will quickly correct the immediate problem and save the tinkering and experimenting for another time. Troubleshooting solar power

Attention to detail.

Hopefully you occasionally take time to verify everything is in order. This means checking cables and connections, topping off electrolyte levels and density in flooded batteries, looking for damage with outdoor components, etc. By the way, when is the last time you cleaned your solar panels? Troubleshooting solar power

If you’re a Type 1 you’re probably not doing any of this. You probably don’t keep any spare parts around either. If you don’t plan on fixing anything yourself then at least plan for the time and resources for someone else to do it for you. Type 1’s are seldom preppers/survivalists (and if they are, they’re delusional) so being independent in SHTF situations is not a priority to them. I’m not trashing on Type 1’s. We all gotta do our own thing, right? It’s all good. I just want them to understand that they will have very limited options when things go wrong.

Types 2 and 3 are best set up to go it alone if needed. Still, there are always areas of improvement. For example, do you have printed technical data and manuals for your equipment? Are your tools neatly arranged and easily accessed, or are you the kind of person who spends thirty minutes tearing through a heap of junk to find a screwdriver? Do you proactively maintain your system, or do you only react when something goes wrong?

It happened to me. Troubleshooting solar power

troubleshooting solar power


A few weeks ago I noticed that my home solar was producing hardly any watts during strong sunlight. Still, the batteries were fully charged at sundown. I didn’t think much of it until the next morning morning when the batteries were much more deeply discharged than they should be… (continues)

OH8STN: How to Ham Radio Off Grid

Julian, OH8STN, has another video on How to Ham Radio Off Grid.

Hello Operators. Todays video is very special, since it answers many of the questions we’ve asked about portable ham radio off grid. Operating a ham radio station off grid and or in the field is not something to be taken lightly. We need to look at our field communication goals, how long we’re going to be out there, the type of equipment we need in the field, and battery power for our ham radio, when off grid or in the field. If you’re a ham radio beginner or seasoned veteran adding additional skills and capabilities to your station, you’re going to love this series.

OH8STN: Portable Power and Field Communications

Julian, OH8STN, has another good post up about using portable power during field operations and a couple of radios with versatile power options – Portable Power and Field Communications.

Hello Operators.

This is just a short post about the relationship between field communications, and portable power. Ham radio manufacturers would have us believe our goal is to go out and operate a couple of hours at a time, then recharge our batteries back at home. This may be true sometimes, but it’s not always true.

Ham radio manufacturers don’t recognize the importance of a decent operating run time from internal batteries, or the ability to recharge those batteries, without grid power. For example Elecraft offers one of the most amazing portable radios on the market, the kx2. Did you know it’s impossible to recharge the kx2 in the field without the Elecraft proprietary smart charger, connected to AC mains? This means if you’re off grid without additional batteries, or the ability to plug in a smart charger, you’ll have to use an external battery anyway. Despite how awesome the radio is, having to use that external battery diminishes its lightweight field utility of the radio.

The Yaesu ft-818 is another example. Its internal AA battery pack can power the radio for about an hour or two. Unlike the Elecraft kx2, the ft-818 can be recharged in the field from any DC power source 9 to 15 volts, (AWESOME). It’s Achilles heel is that it takes 8 to 10 hours to recharge its internal battery pack. What the heck is the point of having 2 hours runtime, and 8 to 10 hours recharge time? It’s freaking ridiculous! This means in practice, we need to use an external battery pack anyway.

Some operators have offered alternatives to these problems.

  • Carrying additional battery packs.
  • Using an inverter to power the smart charger.
  • Ration the radios usage so batteries last longer.

All of these ideas come from operators without a solid understanding of communications off grid. Off-grid communications requires us to be grid and energy independent. So when manufacturers tell us the only way to recharge the internal battery of their radio, is using their proprietary AC powered smart charger, we should tell them to go lay an egg. We should also tell manufacturers who have an 8 to 10 hour charge time on a relatively small internal battery, to do a little bit more engineering.

From where I’m standing, it looks like popular ham radio manufacturers have become complacent. We have become such Fanboys, that we continuously make excuses for why these functionalities are not built into their radios. Why don’t we demand amateur radio manufacturers create radios, which are grid independent!? Why do we still accept double AA packs inside our rigs, when a lithium ion or lithium iron phosphate pack are a fraction of the physical size, weight, and offer much higher capacity!? These ultra energy dense packs are standard in everyones mobile phones, tablets and laptops, so why not ham radio!? Why should I buy an Elecraft smart charger, when it’s simply a 3s lithium ion battery pack inside the radio!?

Most of the battery research and projects done on the channel, are in response to ham radio manufacturers not stepping up to offer viable solutions for the off-grid operator. Certainly Elecraft gives us low current draw, but what good is that when your battery is dead, and there’s no way to recharge it?

Although much of the research going into off-grid portable power on the channel, has been done for off-grid and field communications, some of the previous and upcoming projects, exists purely because ham radio manufacturers don’t understand our needs.

Yesterday I tried a new radio for the first time. It’s only the second time I’ve seen this functionality in a commercial radio. The functionalities are

  • Powering the radio from external power supply while
  • Simultaneously recharging the internal battery pack in a reasonable amount of time.

The two radios I’ve seen with this capability are the Icom IC-705, and the Xiegu X5105…(continues)

Click here to read the entire article at OH8STN.