Portable Off Grid Power for Amateur Field Communications

First, thanks for the cool comment and kindness. Apologies for taking so long to reply, my wife was on holiday this week and we enjoyed lots of family time.
I agree, we have similar issues. Carrying a kit would be ideal, but I have not figured out how yet. I have thought of 3d printing a "rack" for the radio battery and audio interface. Something which fits in a backpack. One thing which makes life easier is the ski pulk sled. Using the sled, I can load the gear up in a pelican case without caring about the weight. I'm doing the same thing for the non-winter months. A hiking trailer, either Monowalker or Wheelie trailer. I just can't imagine carrying everything I would like to carry, all on my back. The days running through Camp Whereverstan are long gone.

The LiFePO4 inside a pvc pipe is a brilliant idea! What cells did you have in mind? I can easily imagine the Headway 38120 cells in a pvd pipe, including the charge controller. Btw, a small company has reached out and asked about a collaboration on a 3d printed case for the Headway pack. Let us see what comes from it. The parts of the next battery build are already one the way. It is 30A 18650 4S4-6P LiFePO4 build. Perhaps after that, and the next series coming up (x days off grid in the field station), I can build a prototype.

I have been using dry bags to protect my gear. My wife says I have agear bag fetish, so I try to keep the bags and pouches down to minimum.

You've given me lots to think about, and some very cool ideas.
73
Julian oh8stn

 

Hi John. many thanks.
Yeah, people are turned off by LiFePO4 because of the reduced density/capacity. I think it is a small price to pay for longer life and increased safety. About the BMS, I always use a charge controller. If nothing else it is a second line of defense to protect the pack. I've heard some companies say the BMS is just like a charge controller, but I want to insure the voltages going to the cells are what they should be. I do charge from time to time using an 18v laptop power supply, but in that case, I use an adjustable buck to set voltage and amperage for a gentle charge.

Thanks for the tips, and please show off your battery builds. More hams showing the LiFePO4 builds will help inspire more of us.
73
Julian oh8stn

 

Thanks Dan. These comments are so amazing! It's like fuel for the fire.
I am no expert at this so please do the research. Even if not always perfect, the projects on the channel are well researched, and can be improved upon.
When you are ready to upgrade, consider documenting it. There is a gap in knowledge in regards to off grid portable power for amateur radio. Every new article helps.

73
Julian oh8stn

 

That is right Carl.
Although not a big fan of reusing lithium-ion battery packs, one of my YouTube buddies (Jehu Garcia) did a DIY Tesla Powerwall build on his channel using reclaimed 18650 cells from laptop battery packs. I can't afford it this year, but I have also considered a DIY Powerwall for the fixed location. Are you considering a scrap Tesla pack?

73
Julian oh8stn

 

Hi Bud
It is a PF 20w FM16-1200 panel. I have a second one on the way. One is able to power the FT-817, the QRPver 10w amp, and my tablet. The second one will allow me to power the Asus laptop as well.
Cost might be an issue, but if portability is your priority...

73
Julian oh8stn

 

You are definitely too kind, but it is appreciated.
Water Lilly? Perhaps you can post a picture of it. The wind gene is tempting, but I don't know how portable it would be, and still be effective. Would really enjoy reading more.

73
Julian oh8stn

 

I seem to recall seeing links to heftier BMSs in one of Julian's LiFePo pack builds---probably the 10ah one. Take another look and a short list of 20-30 or 40-amp capable BMS units should show up (perhaps Julian will correct me or enlighten us if I'm mistaken).

I watched all of them more than once as I was seriously considering building my own. However, after adding up the various individual parts costs (and the higher amperage BMS units are a little more) and then stumbling onto an article about 100-watt portable ops using an Icom 7300 and a nine-pound Bioenno 1230 30ah pack with built-in BMS---I made the decison to go the "off-the-shelf" route. (I also took advantage of an Amazon credit card deal to save $50 which made it all the more tempting). I like to DIY wherever possible but in my particular case this was the way to go.

I am planning and putting together my nearly ideal portable system for beachside/saltwater portable operations. I have a good twenty-year-old 83-watt Solarex panel that I will pair with the Gennasun 10amp MPPT LiFePo controller that KC8VWM recommended as well as the Bionenno 6 amp AC charger for home use. I have three different HF/VHF rigs that I can use but will likely strap my Icom 706MkIIG to the Bioenno pack with Velcro One Wrap and mount the Gennasun controller on the side of the battery with 3M Lock strips. The 1230 battery will allow 50TX/50RX contest-style 100-watt SSB operations for at least 7-8 hours on one charge (!) which is pretty amazing, in my opinion.

I happened across a really nice canvas carry-all bag at a garage sale down my street recently that this assembly will all fit into nicely (minus the solar panel, of course) and now I am only awaiting the arrival from China of a cheap voltage/amperage monitor via ebay to complete my system. Since I live on the Gulf Coast (which is flat as a pancake) I will not be lugging things up and down hills or tramping far into the bush---just loading up my car and taking a 2-mile drive to our local beach with a long wooden fishing pier where I hope to catch some big DX Fish once in a while. (Also building a 20M vertical dipole and an adjustable ground plane for 10-20M to act as "bait.")

I also really enjoyed all of Julian's videos (even though I haven't yet built any packs) as they opened my eyes to the wonderful world of LiFePo4 batteries. I used to operate portable on 6M with a 52-pound marine gel cell and my aforementioned solar panel back in the mid-1990s and now look forward to having more fun in a similar but less back-breaking fashion soon.

73,

Jeff NH7RO/5
Rockport, TX EL18

 

Julian,

Four Electrical Engineers formed a company called Seaformatics. They built water turbines that can withstand a depth of up to 10 Kilometres. These amazing devices can sit on the seabed and power themselves for months. Very interesting stuff.

So, they took that technology and miniturized it into a man-portable format. It is a very solidly engineered piece of equipment. I am very lucky to have their first production run. They will also custom manufacture to a specifc range of voltage. Have a look for yourself. They have a number of videos and information on their website.

https://waterlilyturbine.com

Julian, I hope this helps.

73,

Mark

 

I went with a more expensive approach in the interest of saving time. Right before I left for Puerto Rico, I bought a Bioenno Power Pack 400 that has a 35Ah LiFePO4 battery in it. It also comes with a solar charge controller specifically for the internal LiFePO4 battery, sine wave AC and DC outlets, and a wall wart for charging with wall power. I got a 105W folding solar panel that folded into thirds (rather than in half) so it was just barely skinny enough to fit into a rolling duffel bag that I checked as baggage. I took the Bioenno with me as a carry-on since they don't allow lithium batteries in the checked baggage anymore.

When I got down there and tried everything out in full sun, the solar panel was putting about 81 watts into the Bioenno. That's not the max power output because the solar charge controller will throttle what's coming in based on the charge level of the battery - the closer to fully charged it is, the less current is allowed to flow in. The other day I pulled out my larger 200W folding panel and hooked it up. Battery was only about 25% down so the panel was giving it about 121W. If the weather holds up this weekend, I'll drain the LiFePO4 battery down to maybe 25% left then hook up and see what the "max" the panel can do.

The folding solar panels also came with chargers for 12V lead-acid batteries so if I need to, I can charge those as well.

I'm looking forward to Field Day this year so I can try to operate fully off solar. (I'll still take my Honda genny just in case, though.

 

I really enjoyed this video and had to rewind in a few spots to catch something I missed the first time. I even took notes!

One question: You say your 10 amp hour lithium battery will power a 100 watt radio. That sounds like quite a stretch if you're doing anything more than a quick QSO.

Does this battery really support all that stuff for any length of time, or is it because it's getting help from the solar panels? How long could you operate from just the battery alone, for example, at night?

Lastly, this guy does a lot of what you're doing and you might want to check out his website: http://offgridham.com

 

Thanks Mark, I'll check them out.
73
Julian oh8stn

 

Thanks for your experience with the Bioenno battery and charge controller. Did you know that they don't actually make that charge controller? Their name is on it, but after a little research, you'll likely be disappointed with where it was manufactured, and the voltages (which don't play nice for the long-term happiness of the cells in your lithium iron phosphate battery pack).

Choosing the correct solar charge controllers is extremely important. If you really want to get the 2000 Cycles out of that awesome pack, you should choose a charge controller which doesn't try to stuff 14.6v xA into your pack. It should also shutdown long before the battery is depleted. Bioenno never actually tells you that. By the time most people figure it out, it's too late. If I were you, I would switch over to a Genasun controller for your battery chemistry.

I don't want to sound like I'm blasting all of your equipment, but throw away the lead acid charge controllers for your solar panels and just use them as great folding solar panels. Then separately purchase for yourself a charge controller with good reputation and quality.

73
Julian oh8stn

 

I absolutely love it when people call me out, because I do so much research and testing long before you ever see the video

The 10Ah Headway cells can put out 100 amps continuously. So I'm using them at half of their rated capacity. So short answer, yes! So the 15 to 30 amps of an HF radio is absolutely nothing for this pack. Btw, the BMS is rated for 50 amps and does it easily. We're not talking about 30 seconds or a minute, then backing off. I mean full continuous workload. It's only a stretch if one has put cost over functionality. As an example, the closest equivalent pack from Bioenno (9Ah) has 12A continuous current draw rating. Their 12Ah has 20A continuous and 40A (2sec.) Peak. This is the problem with buying things off the shelf. When you bespoke build, and come up with your own requirements, one can source the cells with the proper current draw, the BMS with the proper voltages and current capacity, you can use the wire with the correct current rating, and the correct charge controller as the interface between your solar panel, battery, and rig.

There seems to be some misconception. I build these battery packs to be used simultaneously with a solar panel. The misconception might be what the job of the solar panel is. When the radio is sitting idle, or radio and laptop, the solar panels job is to supply voltage and current for those devices. When the radio transmits, the batteries job is to give the radio and laptop the current it can't get from the solar panel on its own.
I also deploy this battery pack as Standalone without a solar panel, for example, 5-6 hours on a summit, or out in the park. When one is done, it is brought back home for a recharge, ready for the next time. Honestly, I rarely use it that way. I want ham radio operators venturing out in the field, to get in the habit of deploying lightweight foldable solar panels whenever they deploy their Rigs. The reason we do this is for a sustained field communications. Without the battery pack working with the solar panel and charge controller, the entire portable gokit becomes a boat anchor once the battery is dead.

I know the off-grid ham and I follow his blog.

73
Julian oh8stn

 

Hi,
Just wanted to drop a note that in large part, due to your video, I now have a 40Ah Lifepo4 pack ready for my mobile operating. I have been lugging around a pair of 35Ah SLA that weigh about 56lb in the box. The new 16 cell pack weighs about 18lb. I had some issues initially with the BMS, but I think I have those worked out. I also have a flexible 100 watt solar panel that I will be running into a Bienno charge controller. I will be taking this out this weekend on a camping trip and will be on the air portable. I also looked at the Alpha and Chameleon antennas, but chose to go with a Wolf River Coils instead. I could not justify the $400-ish price of the other solutions. The WRC has performed very well. With 6 radials, I have made DX to Japan, Russia, and Poland over the past few weekends.
Keep making your great videos!

73
Ray N6DZK

 

Thanks Julian, a bit of a grave dig for the forum. But a timely reminder of the worth of great contributors like yourself... thank you!