Category: Vehicles

After four months, I finally received the battery I ordered on October 7, 2021. I am currently running it through it paces and recording everything that I find.

I have connected the battery to my FT-991A at my QTH, and am treating it like an off-grid power source. So far, everything looks great, and it seems like it will work pretty closely to the way I predicted.

One of my next steps it to also build a “box” to put the battery into, and make it more versatile.

Updates will be coming, shortly.

In the previous post, I gave the reasons “why” I wanted to go with LiFePO. In this post, I will try to give the details on the calculations that I’ve done, before reaching the decision to buy what I bought.

I ordered a 12V 54Ah Deep Cycle LiFePO4 Battery, a Folding Fast-Charge 12V Solar Panel, and a USB Phone Charger, Voltmeter, & Terminal Adapter Wiring Kit from Dakota Lithium on May 24th. As of May 29th, I have not had all of the items shipped to me, so what follows has not been tested in the real world. These are just my calculations.

Of course, before I start, I will say that I do understand that there are a lot of different factors that will effect these calculations, some of which I may have not even considered. Things like available sunlight, transmit power, transmit frequency (how often… not MHz), other devices connected, are all variable factors that I am aware of.

• The Battery. 12.8 volts / 54Ah / 691.2Wh
  • Size – 9.01” x 5.43” x 8.38”
  • Weight – 17.6 pounds
  • Discharge – 50 A max continuous, 100 A max pulse 10 second pulse
  • Charge – 25 A max

I will just do the calculations for the battery and the radio, without the solar panel connected. The solar panel can be connected while the battery is being used, so I will just be using it as a way to keep the battery “up” for as long as possible. Without any load on the battery, the solar panel will charge the battery in about 19 1/2 hours. Not a lot of input, but enough to help make it through the night, I think. I may end up upgrading the solar part of this in the future, but we’ll see how it works out this way, for now.

• The Radio. Yaesu FT-991A
  • Supply Voltage – 13.8 volts (+ or – 15%) – Calculations will be based on 12.8 volts, which is the battery voltage.
  • RX Power Consumption – 2.2 A
  • TX Power Consumption – 23 A (HF/50 at 100 watts)

Based on a 100 watt output (which is the full power of the radio), here is what I came up with:

Standby only battery run time = 24.54 Hours

Transmit only battery run time = 2.34 Hours – This is obviously an unreasonable number, since there is absolutely no way to transmit at 100 watts for that long. Even if I were to run FT8 or FT4 at a full 100 watts, the duty cycle would be 50%, meaning that I would be transmitting half the time and listening the other half. That would bring it to 4.68 Hours.

When operating portable and on Field Day, I normally use SSB (voice or phone). The duty cycle for SSB is actually much lower than 50%, since the radio is only transmitting while you’re talking. The calculations for this are a little trickier. Simply pressing the push-to-talk (PTT) button, without any talking, the radio consumes about 5 amps. Any time you talk, the radio will draw between 15 to 22 amps at 100 watts. For the sake of my calculations, I based the amperage draw at 20 amps at 100 watts.

Since I am a “search & pounce” type of operator, normally, I also based my transmit time to 20% (the other 80% of the time, I would be listening). I might be wrong on this, but if my “transmit only battery run time”, above, is correct (at 2.34 hours) then only transmitting 20% of the time would work out to about 5 times longer, or 11.7 Hours.

Of course, the other factors that are even harder to calculate (for me, anyway). The 80% of the time that I would be listening. The amount of power that the solar panel will put back into the battery. Any other devices that I connect to the battery (I’m going to try to stay away from doing that, this year). The voltage curve stays pretty flat until about 80% on the battery, too. Does that mean that all of my calculations are off by that much?

Another big thing that I have not figured in, at all is that I can just turn down the power on my radio. If I go to 75 watts, will the battery last 25% longer? If I run at 50 watts, will it last 50% longer? If that’s the case (which I actually doubt), I should be able to run 17.54 hours at 50 watts, even without the solar panel.

Since one of the main reasons for wanting this battery was for Field Day, since it is a 24 hour event, I wanted to have a battery that would last that long, by itself. I could have went with the 100 Ah battery, but for the price difference, I decided that the 54 Ah battery supplemented with solar would work just fine.

After I test all of this out in the real world, I will post an update.

For quite a while, now, I had been thinking about getting a LiFePO battery for the van. There’s a few different reasons that I’ve wanted to, but the main reason is radio noise. The battery will have almost no interference, compared to the gas powered generator that I had been using. The one thing that really pushed my decision, recently, was when Jason and I went up to the fly-in car show at the airport on May 1, 2021. Jason set up his hambulance and I set up my big ear antenna and generator.

Because of the way the show was set up, I was not able to get the separation between the antenna and generator that I would normally get at a portable operation or Field Day. The generator was set up just in front of the vehicle, toward the driver’s side, and the antenna was set up just behind the passenger’s door. Normally, I set them up as far away from each other as possible (at least 100′ away from each other) to avoid as much noise from the generator getting into the antenna. Normally it works pretty good, but I still get noise (whether grounded or not).

What happened at the airport event was that I was able to operate on 40 meters, but 20 meters was mostly unusable. Since the timing of the event was during the day, it would have been great to be able to get on 20 meters. There were multiple QSO parties happening (7th Area, DE, IN, and New England), so I’m sure there was plenty of signals out there. I just couldn’t hear them on 20 meters (except for a few high powered stations).

On May 24th, I decided, with Field Day coming up, I wanted to get a different power setup, so I finally pulled out the CC and bought a few items from Dakota Lithium. As I write this on May 29th, I have not received everything that I ordered, but I just wanted to go through some of the calculations that I did, before deciding on what I wanted, and making the purchases.

First of all, I will point out that I have never been one for “running a frequency”. I am more of a “search and pounce” operator when it comes to any sort of contest or QSO party. The reason that I am throwing this out there is that depending on how much you transmit, you will use more or less power. I have done all sorts of calculations, and will include those in the next post. Secondly, I will add that they are just my calculations, and I have not yet put any of it to the test, in the real world. I will do an update after I’m able to spend some time testing things out.

I will definitely be getting more things to complete the project, but here is what I purchased, so far, from Dakota Lithium. I ordered a 12V 54Ah Deep Cycle LiFePO4 Battery, a Folding Fast-Charge 12V Solar Panel, and a USB Phone Charger, Voltmeter, & Terminal Adapter Wiring Kit.

In the next post, I will try to detail my calculations.

Well, Winter Field Day 2019 has officially come to a close. We survived, but we also came to a conclusion, and made a decision. As long as we are in North Dakota, we will never again participate in WFD as an outdoor station. We had the experience. And once is all we needed.

We got up to the island (our WFD location) at about 10AM on Saturday morning. Taking care of first things, first, we fired up the generator and the portable heater. If those two things didn’t work for, for some reason, the whole event would have been called off, for us. They fired right up, though.

The next step was to get the antennas up in the air. Using a fishing pole and a 1 oz. weight, I got it over a 40′ tree on the second shot. Pulled the fishing line, pulled the Handy Hundred, then pulled up the end-fed antenna and tied it off. Stretched out the antenna, toward the van and mounted the end about a foot or two off the ground.

We tried to get the “corkscrew” that I use to hold down the Big-Ear antenna tripod into the ground, with no luck. The frozen ground wouldn’t allow it. We ended up using a bungee cord to “attach” the tripod and mast to a 4×4 that a sign was mounted on. It worked pretty well, since nothing ended up hitting the ground.

After running all the coax and extension cord, I tested out the antennas with the analyser. I had the Big-Ear set for 20m, and it tested at 1.15:1 SWR. The end-fed tested below 2:1 on all of the bands that we’d be using, except 75m. If I remember correctly, it was at 4.3:1 at around 3.800. It was better toward the bottom of the 80m band, at 3.600, but that wasn’t where I’d be using it. I decided to try to fix that problem “later”.

Once everything was connected and running, we had about 12 minutes to spare, before the event was set to begin. I was a little surprised that it took us that long, but between and in the middle of the steps involved in the setup, we took quite a few breaks, so we could warm up.

We started making contacts, almost right away. Ran a couple pileups (the first of them was my first experience at running a pileup, which lasted about an hour). We operated on 20m, 40m, and 75m. On 75m, we were very limited, and just barely got the contacts that we needed, to count for the multiplier for the extra band. We also had a lot of (generator?) noise on 75m, but managed to get IL, TN, and WI.

In the end, we wound up with 208 SSB contacts. We didn’t work any digital or CW. At 3:43AM, I got a notification that a Blizzard Warning had been issued. It was expected to move into the area at about 9AM. I decided, at that point, that we wouldn’t be staying until 1 in the afternoon, and we would start tearing things down at dawn. We actually started tearing down at about 8:45AM, and the wind and snow was already there. Luckily, the tear-down went a lot faster than the setup, and we were off the island by 9:30AM.

Things that I’ve learned by doing Winter Field Day, this year.

1. Never put yourself into an uncomfortable situation, if you don’t absolutely have to.
2. Conversion vans are definitely not as insulated as they might seem.
3. Heat rises (I actually knew this). Don’t sit on the floor.
4. 9-10 hours is the amount of time it takes for the generator to go through a full tank of gas (it ran out at about 4AM)
5. Whenever I get a chance to work a pileup, do it! I need the practice.
6. “Foot Warmers” would have definitely helped.
7. No amount of “pre-sleeping” can prevent you from getting tired.
8. Get pictures. Sadly, this year, I did not get any pictures or video. It was the last thing on my mind, actually.

I want to send out a great big thank you to Jason Linz (ND0JL) for checking in on me via 146.52, every few hours, while he was awake. I really appreciate it!

There was one other thing that did happen, while we were up there. A county sheriff stopped up to see what we were up to. He told us that somebody had reported that it looked like somebody was living on the island. This happened just a few hours into the contest. We explained to him what we were doing, and that we had permission to be there, and everything was alright.

About 8 days from the time that I’m writing this, Winter Field Day will begin. I’ve been watching the Facebook page that’s been set up for WFD, and making sure that I am ready to go get things set up on the morning on January 26th. Some others in the Facebook group have explained how they already have antennas set up on their fish houses, etc.

I am of the thought that this should be an exercise in actual preparedness, and how quickly I can respond, if needed. To put my “getting ready” process into perspective, I’ll explain it, a little bit.

• The area where I’ll be setting up has been picked out. I have no “Plan B”, so if my first location won’t work out, I’ll need to come up with something else, quickly.
• Nothing has been set up or installed, but most things are ready in the “go bag”.
• I have a checklist of all the items that I’ll need, which will be completed about 3 hours before WFD starts.
• The radio that I’ll be using is still connected at my home QTH.
• Other needed items, such as tools, antennas, wire, heater, generator, fuel, flashlights, etc. are inside my hamshack (where they normally are), and will be loaded into the vehicle at the last minute.

In other words, when WFD comes, I will be grabbing everything that I need and double checking my checklist. The plan is to go from my normal operation at my home to operating in the field in under 2 hours (hopefully less). This is how I would normally do any portable operation, and is a major factor in the Winter Field Day operation. The statement on the front page of their website explains the importance of preparedness.

For Winter Field Day, I will be uploading my logs, live, to Contest Online ScoreBoard. I have a link to the WFD contest on the front page of my site. This is so you can follow along, if you’d like, and see where I’m at on the leaderboard.

I am also testing out what I’m calling a “Live Log”, which is linked in the right-hand column of the home page. That Live Log will NOT be updated during WFD, since I’ll be linked to the Contest Online ScoreBoard. It’s not that I “can’t” do it… I just don’t see the need to use any more bandwidth than I have to, while tethering during the event.

In the same respect to limiting bandwidth, I will also not be running any spotter network, either. Since I mostly plan on calling CQ, and not answering, I don’t see a real advantage in running it.

My QRZ page has been updated with the information about the fact that I will be participating in WFD, and all of the other information that I thought may be important. Since most people that I will talk to likely refer to my QRZ page, first, I thought that was important to put, there.