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Author Topic: UltraPack DIY External Battery Pack for Field Comms  (Read 2353 times)

STN

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UltraPack DIY External Battery Pack for Field Comms
« on: July 18, 2016, 05:28:33 AM »
Hi operators.
Just sharing an interesting new project that I'm working on.
I believe my project solves many of the problems that others have had with Lithium-ion LiFePO4 batteries in the past. By introducing a balancing and protection circuit BMS, we can simultaneously charge or discharge the pack without worry of cell damage from under voltage, overcurrent, ...

Description.
The QRP UltraPack External Battery Pack project is an open source project designed to provide radio operators with a low-cost, scalable, and customisable external battery pack solution for modern QRP rigs like the Yaesu FT-817 and Elecraft KX2. It is very much like a QRP Ranger, but smaller, and more configurable. The QRP UltraPack can be built at home as a 4S1P 3.4A (50watt hour), 4S2P 6.8A (100 Watt hour), or 4S3P 10.2A (150 Watt hour) power pack using 18650 cells, by anyone with basic ham radio or ohms law skills.
http://www.survivaltechnology.net/qrp-ultrapack-external-battery-pack-project/

I would very much enjoy feedback on my project, but I ask that you study the attached image, or read the project page before commenting.

OH8STN
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« Last Edit: July 18, 2016, 11:58:03 AM by STN »
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gil

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Re: UltraPack DIY External Battery Pack for Field Comms
« Reply #1 on: July 18, 2016, 02:01:29 PM »
Thanks Julian. I am leaning towards 18650 cells as well. AA cells are great for my MTR but not quite enough for my KX2. I got 3-cell holders for 12.6V so I can use them with both radios. Chargers will be two balanced USB types so I can zip them in a solar panel. A 4-pack at 16.8V would work for the KX2 as the pack will not stay at that voltage long even just sitting there.. I tried the KX2 down to 9V though, so three cells should work for now..

Gil

Hutch

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Re: UltraPack DIY External Battery Pack for Field Comms
« Reply #2 on: August 11, 2016, 09:28:57 AM »
This is an area that absolutely fascinates me.  Thanks.

Also, I just have to chuckle, knowing who the poster is, and seeing him described as a Newbie.

STN

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Re: UltraPack DIY External Battery Pack for Field Comms
« Reply #3 on: August 12, 2016, 02:20:40 AM »
Hi Gil. I know what you mean. I enjoy the simplicity of AA cells. I just wish they had greater capacity.
I've moved forward with this project since I posted this. I did the smoke test for the 4S1P version of the pack and posted the video yesterday. No smoke :D
Last evening I modified my proto for 4S2P, to get the same or a little more capacity out of the pack with minimal use of space. I like the idea of the 4S on the 817 or KX3/KX2. If nothing else this project will push manufacturers to stop building soviet error tank sized packs, and give us the light weight micro packs we want/need.

73 de OH8STN

Thanks Julian. I am leaning towards 18650 cells as well. AA cells are great for my MTR but not quite enough for my KX2. I got 3-cell holders for 12.6V so I can use them with both radios. Chargers will be two balanced USB types so I can zip them in a solar panel. A 4-pack at 16.8V would work for the KX2 as the pack will not stay at that voltage long even just sitting there.. I tried the KX2 down to 9V though, so three cells should work for now..

Gil
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STN

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Re: UltraPack DIY External Battery Pack for Field Comms
« Reply #4 on: August 12, 2016, 02:37:56 AM »
Thanks. I also grin when I see the Newbie label, but its not a bad thing. Ever time we start learning something new, we do so as noobs, so. Its a label I'm proud to wear :D
The search for cost effective, light weight portable emergency power is huge on my list of priorities for emergency communications. I still see operators making "go boxes" with SLABs weighing in at 40kg or more. I think to myself, are those really the best way to go forward in 2016!?
Anyway, this 18650 process is slow going. I wanted to step it up beyond what others were doing with goal zero and zamp solar gear. I mean if we really want "solutions" not appliances, we have to build then ourselves. Until now, nobody is making a pocket sized pack which can run an 897 or 857 at 20 watts.

Here is a playlist I made for the battery
UltraPack 18650 Batteyr pack for emcomms https://www.youtube.com/playlist?list=PLKMrdrsNkFA6X3j0KJ3WDdKfxuGeLOZWy

there is a hidden video of the last proto dev. Actually, I'll share lots of hidden vids in that playlist as not to terrify the less technical :D





This is an area that absolutely fascinates me.  Thanks.

Also, I just have to chuckle, knowing who the poster is, and seeing him described as a Newbie.
« Last Edit: August 12, 2016, 03:57:06 AM by STN »
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gil

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Re: UltraPack DIY External Battery Pack for Field Comms
« Reply #5 on: August 12, 2016, 03:51:30 AM »
Quote
I still see operators making "go boxes" with SLABs weighing in at 40kg or more.

Yep, it amazes me to see the size and weight of those go-boxes. I'd rather call them stay-put-boxes. To be fair, the builders probably envision short duration local emergencies where they can show up with their SUV, open the hatch, put up an antenna and "save the day." No problem with that, but it is a different mindset and mission.

What we see in large scale long lasting disasters is vast migrations of people on foot. There could be many reasons for having to leave an area; some sort of contamination, radiation, chemical or viral, gangs roaming, etc.  Why not be ready for the worst? I believe most amateur stations would be out within a week without grid power. Solar power is the only and best way to go.

Which brings us to the single most important factor for a portable radio IMHO, current draw. The only reason I spent 200 (500 inc. taxes) more Euros for the KX2 is not the superior Elecraft receiver or the large screen, but a lower current draw on receive than the FT-817nd. The Yaesu is a fine radio mind you, actually more practical than the KX2, but for that one factor. I hesitated for a long time before pulling the trigger on the Elecraft. Had I known that the French customs were going to steal 300 Euros from me on delivery, I would have bought the FT-817. My MTR draws 35mAh on receive, and I believe the MTR5b draws 15mAh! Those are CW only, so not for everyone, and you can't listen to anything else but Morse code, but still.. Today manufacturers can make low current draw radios, but the market just doesn't care. Lots of radios used in those go-boxes draw 2Ah. Even eight 18650s wouldn't last long.

Now I look at military manpack radios for meaningful numbers, such as with the RT-320: 30W output power and 175mAh on receive. Too bad they are so heavy, but the specs are right on the money.

The 18650 is a great cell, more reliable than LIPOs. I should have used them instead of AAs. Now I probably will have to leave the KX2 at home for my camping trip and only use the MTR. The chargers I have only go up to 1.2V, even though the AA cells can take a bit more. I was counting on that little extra for the KX2. I could use alkalines, but that would cost me a bundle.

Julian I am following your project with great interest. I will go with 3S and probably put the whole thing in a Hammond cast aluminum case. No display since my radios display voltage. The issue remains how to charge the cells. The fact that you need to supply 16V is a bit of an issue, but a solar panel will do that. Too bad that DC regulator was RF noisy. BTW I have used Genasun controllers and they work great. I had two GV-4.

My idea was to use USB chargers like the Nitecore UM10 and Xtar VC2 to charge three cells with my Choetech panel. You do have to remove the cells from the holder every time though, so better have a good one..

Gil.

STN

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Re: UltraPack DIY External Battery Pack for Field Comms
« Reply #6 on: August 12, 2016, 04:46:28 AM »
Hi Gil
I'll go straight to it.
I totally agree about the low rx current. Like you I also beleive we are going to be on foot (at some point) during a disaster. People just don't get that! At some point what we can carry will become critical enough for us to start choosing what to leave behind. Food or go-box!? Anywa, I really love the KX2 size and rx current. I also knew about the +300euro tax, so I have passed on that radio for now.

BTW, the Genesun GV-5 controller for lithium ion works perfectly for the UltraPack project. If you use that, there is no need for the DC/DC +16v converter for charging. I will sort out the noise issue in time. I have parts now to make filters on the outputs. for a budget solution. I also have quiet DC/DC converters which are more expensive and are completly rf quiet.

I'm afraid you wont be very happy with the Choetech charging 18650 batteries in multiples. One at a time perhaps, so please test before heading out to the field. I did a video review of the Choetech 19w last year. I used the Choetech to charge AA batteries during last years arctic circle excursion. I'll add a link to the video in your CHOTECH thread. It's not a bad panel for charging phones or charging usb battery packs and things like that. I actually ripped mine apart to see what made it tick.  it's actually 3x 5-6.5 watt panels in parallel for 7.48vdc feed a usb DC/DC converter. I'm going to order a second and perhaps the third one of those getting rid of the USB converter and putting 3x3 in series parallel for a ~30-40watt porta panel.

I now beleive the key point about these rigs and portable power is the ability to charge/discharge simultaneously. If we have to carry external Chargers for 18650 then we start to be overloaded with gear again. In this way the Ultra Pack with your Genesun wrapped in heatshrink, with cables coming out,  seems smallest and most efficient.

Julian
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gil

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Re: UltraPack DIY External Battery Pack for Field Comms
« Reply #7 on: August 12, 2016, 05:28:13 AM »
Looks good! Elecraft also opted for 18650s for the KX2 with a non-balanced charger, but they use protected cells, which solves the problem..

As to the Choetech, my GoalZero Nomad 7 was enough to charge 4 AA cells, so if the Choetech produces 14W I'll be happy.. I plan on getting a 20W 18V panel later. I also need to find a way to charge PRC-320 24V batteries via solar.. Maybe I'll use two 12V batteries instead and charge them one after the other.. Good point about charging while in use though. For this upcoming trip I would expect to charge my AA cells on the go with maybe a late afternoon top-off and operate in the evening. I also have a phone to charge, Delorme inReach and a tablet. It better be sunny!

Gil