Ham Radio Battery Pack DIY LiFePO4

Build your own 10 amp hour ham radio battery pack using LiFePO4 cells.
Hello Operators
For the ham radio operator in the field, portable battery power needs to be light enough, small enough, modular, have enough capacity, and above all it should be possible to replenish it off-grid, and in the field. So today, we are buiding our own diy LiFePO4 battery pack for QRP to 50 watt portable ham radios. There is no other ham radio battery box which comes close in performance.
On September 28 2016, I published a prototype 4S lithium ion battery called QRP battery pack. I've field tested that pack for a year, before deciding to take what I've learned, applying it all to two new portable power systems. This project takes the original concept a little bit further by introducing lithium iron phosphate cells of various capacities, as a power supply for the off-grid field operator. IMHO, this is less of a battery pack, then it is a portable power system.
This build can power a QRP Radio or rig pulling up to 10A current draw.
Plan for this project are two different builds
- 4S1P/4S2P 10Ah/20Ah LiFePO4 based on Headway 38120 cells with battery management board and dell balancing. This Pat can be upgraded for a 100w radio, or extended for maximum capacity and runtime.
- 4S1P/4S2P 2.5Ah/5Ah LiFePO4 pack based on A123 cells, with battery management board and cell balancing.
Each pack can be customized by the builder for increased capacity/output rating by adding addition cells in parallel, and upgrading the BMS. The ability to charge in the field with a solar panel or other DC source, means you stay in the field longer, while carrying less gear.
The next video of the series, we will take the entire system out to the field, along with a PowerFilm F15 1200 thin film flexible solar panel.
In the third video in this series, we will build a 5 amp power lithium iron phosphate battery pack based on A123 cells. That fact will be especially interesting for the Sota operators or qrp campers & hikers, looking for a lightweight renewable power source for the summit or the trail.
- Episode notes can be read at oh8stn.org/blog/2017/09/07/por...
- The Portable Solar Powered GoKit can be found here: • Video
- The Man portable off-grid power for amateur radio articles can be foubd here: oh8stn.org/blog/2017/07/05/man...
- If you found this episode useful, consider dropping a buck in the tip-jar here: paypal.me/oh8stn/1USD
73
Julian oh8stn Disclosure: Some of the links above are affiliate links. This means that, at zero cost to you, I will earn an commission if you click through the link and finalize a purchase.

[@OH8STN]

You know guys, I finally realized I have a serious Portable Power Tech Fetish. I think portable Powers going to become one of the pillars of this channel.

[@j.b.708]

your videos are so clear and calm, they make me think that building this battery pack is something i can accomplish.

[@stahpit1971]

WOW! It's hard to believe this video is 4 years old. I remember watching it when you posted. Its been a slow process but I've finally got my pc, tnc and radio. I should be on the air this winter if my work load lightens up. Thanks for all your videos they are a wealth of knowledge.

[@chrisbarrUSA]

Thanks! 73's from KF6YSV (Chris in NorCal) . I just finished my battery pack inspired by your video.

[@OH8STN]

Thank you Christopher. 73 Julian oh8stn

[@diylifepo4]

I've not seen any other KZbin channels doing lightweight portable power. Well done!

[@bonniecrystal903]

I really liked this video. The step-by-step documentary of building the battery pack shows that it can be both fun to make and an economical alternative to turnkey commercialized systems.

[@OH8STN]

+Bonnie Crystal thanks Bonnie, that means the world to me. These steps-by-steps will be the norm for tutorials on the channel. For now the tutorial forcus is portable power. 5Ah 4S2P LiFePO4 pack coming up this month. In spring 2018, a 4S3P/4S4P 120Ah version to upgrade the shack, (based on our 100Ah discussion). Portable off grid power has remained a passion since a fifth grade science project. Planning on some ALE antenna tutorials as well.

[@hobbiehobbs]

You Sir are a fine outstanding member of our society adding incredible value to the radio community. Another fine job. Have a Merry Christmas.

[@joshwilson9393]

These videos are so awesome! Definitely inspiring me to build my own portable power system for adventures.

[@AlbertZ]

Very professional and detailed battery pack production ... outdoor power the best solution👍 Thanks for explaining increase my knowledge

[@thormusique]

Brilliant project, thanks so much! It's definitely on my to-do list.

[@RESlusher]

Greaaaaat! Thanks Julian! Now you've got me wanting to rebuilding my 30Ah boxes with LiFEPO4 batteries! :) Nicely done, Julian!

[@OH8STN]

+Richard Slusher thanks Richard. Sorry it took a of research before I got it right 😃

[@ntc490]

Haha. Love the comment about discerning battery ring colors. Thanks for thinking of us colorblind guys. Luckily black and white are easy to tell apart. Thank goodness it's not red and green - often get those confused. :)

[@OH8STN]

Here's the link to the episode notes oh8stn.org/blog/2017/09/07/portable-power-for-qrp/ If you have questions, check the episode notes first and if you don't find the answer there leave your questions in the comments and I'll update the episode notes to reflect the answer. 73 Julian oh8stn

[@Iridium242]

Nice, I had never even heard of this type of battery. I will have to look into building something like this.. very handy.

[@OH8STN]

+Iridium242 it's always nice to see you stopping by. If I'm not mistaken I think this type of battery is often used in electric bikes or cars. Definitely makes an excellent storage medium

[@twigglykevin]

i would imagine you could use just about any sized cell (ie. 18650) so long as its series'd to make 12 (ish volts) and enough cells in paralell to to supply the watt/amp hours for operations

[@jazbronoh5873]

Finally, someone who DIY a LFP battery with tremendous amount of capacity in a regular lunch box size. For cost-effective long lasting battery! instead of spending 300 - 900$ on commercial unit. I've been looking for a video like this. Because I'm also building my own battery source for my devices which I preferred compact, less weight, size, yet off-grid portable that I could fit into my Gobox kit. Satisfied to watch! Thanks for sharing! Sub up.

[@carlblaskowitz7817]

I was going to say outstanding myself, but you stole my phraseology. That is a exceptional tutorial, folks you can use this sort of thing for more than a qrp radio, it can drive all the low power gear in camp, run a raspberry pi in perpetuity or even a CPAP machine. Thanks for a great tutorial, subbed.

[@OH8STN]

+Carl Blaskowitz Carl you're absolutely right! You've kind of let the cat out of the bag. Ultimately the goal is to bring people to the idea of lightweight portable power for the field. We're not only powering radios, we can power laptops, raspberry Pi's, tablets, telephones, or even LED lighting. Great catch and I'm really happy someone's paying attention

[@DanielWiley]

Another great video Julian!

[@OH8STN]

+Daniel Wiley always nice to get your feedback Daniel I know I'm doing a good job when I see your comments pop up here thank you

[@MadDawg91108]

Great job, Julian!! I have watched a lot of your videos...and it looks like you are having great fun. It made me so jealous, that I have purchased a KX3 / PX3 and have been putting things together for a man portable station. Currently the gear is transported with my 4 wheeler and usually while I am out checking on the cows, I will set it up and try to make a couple QSO's. I gotta say, it's the most fun I have had in this hobby.

[@OH8STN]

+Mad Dawg yeah operating portable adds a whole nother Dimension to ham radio. In fact there are so many variables when operating portable that it brings up new challenges that we hadn't considered before and makes it feel all new again 👍

[@haitch8675]

your very professional. thanks.

[@68cristian]

great build...thanks for sharing. I will develop the courage to build something like this soon...I hope... :-)

[@DavidGillooly]

Nice build. I didn't know about the LiFePO4 38120S battery.

[@OH8STN]

+David Gillooly yeah I didn't know about these either until a few months ago. I think they're excellent storage batteries and considering there's so much lighter than AGM or lead acid batteries plus almost double the capacity with the same amp hour rating seems to be all positive at the moment. Time will tell

[@kcarmical]

Amazing work, Julian. Now I have to build one of these myself. :-)

[@harenber]

Another great video Julian! Thanks for sharing your experience and knowledge. Left you a buck on the virtual jar ;-). I just use a set of three LiFePo batteries (from Hobbyking) and re-charge them at home with a controller. Together with an IC-7000 (which draws too much current for a field rig, I know) and a Buddipole that's my portable rig and it was proven to work ok in the Cayman Islands, the Bahamas, Aruba, Curacao and Canada. I mostly used a car though or only had a short distance to walk. 73s, DL1THM.

[@OH8STN]

Thx for the tip 👍 It sounds like you've got to working setup, and after all that's the main point. Lots of operators ask about this Hobby King battery so I'm sure your comment will be appreciated. Are you vacationing, or visiting those places for some other reason? I think most of us would die to operate from such exotic locations. Thx again 73 Julian oh8stn

[@fletcher3913]

Great tutorial. Thank you.

[@Ron_C]

Julian-this is awesome. I want to build one just to have it! I've been interested in some solar options. I've got plenty of battery options through my work (mainly use UBI-2590 Rechargeable Battery), but nothing solar. I always enjoy your projects and really appreciate the notes, parts lists, etc. Thanks for sharing and educating. 73 de K4SFC

[@TheSmokinApe]

Excellent video!

[@OH8STN]

+TheSmokinApe Thanks Ape! 👍

[@rjinnh3933]

Very valuable information and very well presented. A Hat-Tip to you Sir! I will also look closely at the Flexable Solar Panel. I'll be operating Portable close to my SUV and will use its House Batteries initially but I like the idea of Camping several hundred yards up the side of a Hill/Mountain. I watch all your vids because you are an Inspiration. Thank You......

[@CharlesMartel676]

You, sir, are a battery MAN-GOD!!!!

[@timdavis5937]

Thank you for the video. I like the project...

[@OH8STN]

+Timothy Davis thank you for commenting Timothy. I'm just catching up on the comments and I very much appreciate the kindness.

[@TheMountainRN]

So niceeee i have that same bag that i keep not having any use for... have one now lol

[@aldo1808]

Great video Julian, many thanks for sharing :-) 73

[@OH8STN]

Thank you Alan, and thanks for the comment. It's a very much appreciated. 73 Julian oh8stn

[@GreekPreparedness]

Julian, since you said you had problem designing the box, I will assume that you do not want to go into learning a CAD program (obviously). There are some very easy programs o design simple shapes like a battery case/box. I used TinkerCAD to make me an elaborate 18650 cradle. It follows the method of combining additive and "negative" basic shapes yuo define their size and alignment. For a basic tray you need to make 5 rectangle blocks, then you combine them. now if you want to have a hole on one side, you make a "negative" cylinder the diameter you wish and the length of the box side thickness. then you drag it where you want it.

[@graplingurty]

Very nice power pack. My UBC was a noisy affair I'll have to spend a few more bucks, it was salvaged from some old RC Quad Copter FPV gear. Even with toroids front and rear end it still produced 3 S units of hash to the noise floor......

[@OH8STN]

+graplingurty that's a crazy amount of noise. Absolutely zero noise with this pack, and no toroids were used. I use the UBEC on the first battery build last year, that required a couple of toroids, but those cleared up the noise quite well. Yeah the component choices mean the world in regards to noise.

[@JOHNMORIN100]

Very good, like your work thanks for taking time to share John Morin in Milo, Maine 10 27 2018

[@mattcero1]

Freakin' bad ass project. I'd love to get a Bill of Materials and costs to decide if I want to delve into this project. I had to laugh when he said "I did a crap job of....." later in the video as his dialogue and demeanor was void of any slang or otherwise until then. Awesome video and will consider after my recent purchase of an X5105, which I LOVE! My Bad! I just read the notes and other appendages to you post and you my friend have one squared away video sir! Thank you.

[@OH8STN]

For those of you interested in the QRO version of this pack, I'm just putting together to build video and episode notes. The new build Easley power any 100 watt radio like our new Yaesu ft-891. The episode notes for this new built a work in progress but I'm adding information constantly. oh8stn.org/blog/2018/02/19/diy-lifepo4-yaesu-ft891-intro/

[@OH8STN]

Portable Off-Grid Power for Amateur Field Communications: the entire series up-to-date. kzbin.info/aero/PLKMrdrsNkFA43q0POuXM-5-49yOd3t4CP

[@OH8STN]

Updated the episode notes. It's always work in progress so there's more to come. oh8stn.org/blog/2017/09/07/portable-power-for-qrp/ 73 Julian oh8stn

[@Seeker43]

Totally awesome Julian, I would sure love to get a parts list and schematic for that whole setup to build a field pwr supply for my x108g. Luv your videos, you should be a teacher.

[@OH8STN]

+Walter Perry thanks for the kindness Walter. I don't know if I would make a good teacher, I have little patience when people don't apply themselves. But with a class full of eager learners I would take on that challenge. Give me a day or two and I'll post the schematic on the episode notes on oh8stn.org

[@Seeker43]

Thanks so much. I really appreciate your patience and clear explanations of your process, what , where, why, results. Good DX de N5EQY

[@guidelineuk]

Well my brother your videos are amazing with so much info and effort it would be rude not to try this..😎👍🏽...73

[@mikerosenberg7726]

Excellent work as always. Best 73s de N9YB

[@OH8STN]

+Mike Rosenberg thanks for the kindness Mike it means the world to me

[@rkaag99]

What a superb video, project, and tutorial!!! P.S.: I wonder if a section of motorcycle inner tube (tire tube) would slip snug over the pack?!? It would insulate & provide some shock absorption... and it would be removable/reusable as opposed to large shrink wrap. Again, great job! -Rob

[@OH8STN]

+rkaag99 hi Rob the motorcycle tube idea is a magnificent one. I get so many questions about these projects that I thought to use a clear vinyl sleeve, so people could see what's inside, and I can answer questions about it without taking it apart again 😀 I'm going to add your idea to the episode notes because for almost anyone else that would be an excellent way to seal the battery pack.

[@jamesventura5106]

Hello, MY Names is James and I got MY First Radio not as a Child (As a Child I did have a Transistor Radio I carried with ME all the time) but when I was in the Marines from a Fellow Marine in 1976 in Norfolk Virginia... Since then I got hooked on CB Radios, but not until 2000 did I get MY First Ham Radio because some Fellow Truck Drivers I met told ME to get a better Radio to talk on. I have not gotten a Ham License and not to Hot on HAM Operators because how Arrogant they are and think they are better than even a Neural Surgeon which after MY Divorce I began MY Education to become a Forensic Lab Tech, I did work with the best Cytopathology Doctor in the World, in San Francisco CA..... I am now 63 and still do not have a Ham License but still interested in Radios. I have talked all around the world as a Truck-driver and never was one of those CB Hacks who like to cause problems for others. I like the Hobby very much and now that I am Retired I can devote more time to the Hobby. I tell YOU all this so YOU understand ME better and MY Interest. When in College I learned from The Very Best Math and Science Professor there to give Detail, Detail, and more Detail and not assume YOUR Students understood what was going on. In the Marines I was Nicknamed Inventory ________ because I asked Sooooo many questions..... I have seen many KZbin Videos and I have to say YOU have one of the Best Presentations I have seen so far, some are Good but I have to say I have yet to see any Presentation like YOU gave, VERY GOOD!!!!!!!!!!!!!!!!!!!!!!!!!! Like to see more of what YOU have done and once again VERY GOOD!!!!!!!!!!!!!!!!!!!!! Outstanding and I do not give this kind of Accolade to just anyone!!!!! YOU have to earn it!!!!!! JAMES LOVELAND COLORADO PS; I have no Friends who are CB'rs or Ham Operators either.

[@OH8STN]

+JAMES VENTURA I know what you're saying James and I appreciate it. If you stick around the channel for a while, you'll notice that I don't do things the way I'm told they should be done. Like you I learned in the Marine Corps o keep moving forward. That is simply the best way to learn, so I leave all the talking and clubs and groups to others who are more suited for it. Get out there in the field, get the experience with it, then share what we learn. I know there's a lot of Knuckleheads in every community, I just don't let myself get bothered by them, since most of them don't have a library of material to back up the arrogance. Just do what you do James and don't let others stop you from enjoying radcomms. Thanks for taking the time to tell your story and share it with us.

[@anthonymarino4260]

now i understand thanks

[@debohannan4315]

You have great videos love watching what you are doing with ham radio and lithium battery . I want to get all I can out of my solar .and when I hooked up my mppt controller my vhf radio went nuts so wondering if that charge controller does the same ? I need to get all I can on my 4 , 50 watts portable panels I am setting this up for my van for road side deployment .

[@lir5048]

Love ur videos!!! Subbed. Got me thinking I need to build one it would be used to charge 18650z and ennaloop rechargeable batteries and baofang radios. A nudge in the right direction if you read this would be greatly appreciated. I’m sitting here wondering how I measure the draw to get the right controller... Thanks!!! Awesome content!!!!

[@WA8QFE]

The BMS I received is slightly different and has a temperature sensor for over temp at 70c.and a small connector for the balance leads...real ham radio project ! ! hi...hi.. Lee, WA8QFE

[@OH8STN]

+Francis Thompson outstanding! Please send us a pic when you have it all put together with love to see it

[@blackpepperprepper2025]

Very cool! 73, KB4ROR.

[@OH8STN]

Thx Bobby👍

[@A-_-_A]

Julian, you said you were looking large shrink tubing - Might I recommend using a two liter bottle, if you cut the end off and heat it like shrink tubing it will contract and provide a strong tight seal.

[@OH8STN]

+A A this was a magnificent idea. I found that heat shrink I was looking for the clear PVC kind but I also tested shrinking the two liter bottle around my pack. That is an excellent hack! I think I'm going to have to make a video about this hack just because it's so cool. Thanks for sharing the knowledge

[@Pieh0]

You win the internets, congrats!

[@OH8STN]

Internets?

[@DavidSmith-li9je]

Classic .

[@donaldsmith3048]

Thank you for the information and ideas! The only thing I am not sure about shrink raping as much. It looks like you are stopping the air moving around needed to cool things. The BMS drops the cells that are hi through resistor, this makes heat. The power you use goes thought a solid state device to be able to switch the power on and off, this makes heat. I understand making it bulleit proof or where it can take what ever, but I am not sure about the heat build up inside. I am sure you have thought about this and made sure that it will not be a problem. I just would like to know what you have done for this. Over heating of the BMS and or the batteries can shorten there life and have other problems.

[@OH8STN]

No problem David I agree with you. We've also covered that in the comments. On my latest build the solar generator, I omitted the heat shrink. Thanks for the comment. 73 Julian oh8stn

[@WA8QFE]

I guess I'll be coming back to this video again...I have the carrier and cells coming after half way through the video. I have a charger (BMS) from Budipole I want to use ..so I need the connector for the A123 packs they use. The shipping charge to Indianapolis was more than the cost of the cells ! ! Thanks for the video, and thanks for dropping by QRZCQ to comment. Try the QRP chat room some time ! Lee, WA8QFE (BushRadio on BCUSA site.)

[@OH8STN]

Francis Thompson have I forgotten something Lee?

[@WA8QFE]

Julian, Not in the least...you've just launched me on another project ! I did find the BMS you used and ordered that one also. I was thinking of using my Cellpro 10XP balance charger, but it uses a small connector for the cell balancing on the A125 systems packs, and I can't locate one that matches it. Lee, WA8QFE

[@OH8STN]

+Francis Thompson try HobbyKing for those Balance connectors

[@OH8STN]

+Francis Thompson wait a moment. You don't need a balance Charter charger when you're using that BMS. The BMS itself is doing the balancing. LiFePO4 charger.

[@WA8QFE]

I know, I just happen to have one. I'm doing this build with the same BMS as yours now. I bought the balance charger for the 2 A123 7Ah packs I have. The 9Ah Bioenno I use has it's own BMS built in. Just first time I built my own, and now following your lead ! Lee, WA8QFE

[@Indigenous_Patriot_1175]

I would love to learn More

[@D1Snobs]

Hi Julian, Your videos are a wealth of information. Thank you for sharing what you do. I do have a question. The 150A watt meter/data logger that is in some of your videos. Where can I find one of those. I've done some searching and have only found one similar out of Au. Thanks...Eric, W6ETR.

[@Ted-F-Strassburg-III]

Thank you for doing these videos, I'm very excited to try making one of these for use with a Raspberry Pi 3 based SDR rig. KE8DZW

[@SWrider77]

Do these projects come in kits or do you order the parts yourself and build? I love everything your doing! Keep up the good work! 73, KD2DPL

[@OH8STN]

I ordered all the parts and build. Have a look at the episode notes for the details

[@artadams1]

The positive side of the cell has a grove ring around the perimeter of the cell. (if you're color blind)

[@James_Bowie]

Great project. I'm going to look at doing this myself. (PS: I wish I could turn off that damn annoying repetitive electronic music from your soundtrack. I really don't know why some KZbinrs think that such music tracks are necessary.)

[@QUADBOYification]

Great video, thanks. I wanna say this about it. I am a newby and wanna build tiny home power systems for gadgets (Off-grid). I find it strange you have to scale up so much extra electronics to have a simple battery pack with 10Ah capacity. I recently bought a 30 Watt Solar panel and only wanna charge phones or tablets. So i figure i can easily use a 3A (Max) DC- DC converter that efficiently buck-converts down (adjusts) the solar voltage output to 5v constant for use with USB powered gadgets. This (6-30v) DC- (5v)DC converter is basically a charge controller and an efficient power converter in one. It's the size of a matchbox. Has all the electronics sealed-in and has a micro USB out connector ready for me to plugin to phones or tablets. By using USB 5v Power banks you can create some capacity on the go when the sun might be blocked or to use at night. All the BMS and relevant electronics is basically in the powerbank and also in the cells themselves if they are any good. The overal cost is significant less and you have more direct use of sunlight. A 30 Watt solar panel with the right specs can easily charge phones on Daylight (No direct Sunlight) only this way. Everything above 30 Watts changes the usability, weight and cost of it all. You either end up with a very bulky battery on the go or a large solar panel, not both. Simple 7 watt fold-able solar panels can do a great job if you only wanna charge a phone, even 2.5 watt is sufficient if you only need 500 mA to charge an iphone 4S. These panels are so small and lightweight under 100 grams, look great and you can put them anywhere in a backpack.

[@Sylvan_dB]

Nice battery pack. I'm definitely considering replacing my lead acid (2x 7ah) with LiFePO4. Did you consider adding one or more fuses? E.g. on the battery connector and perhaps the load output of the charge controller.

[@OH8STN]

+Sylvan Butler definitely a good idea with one 10 amp hour lithium iron phosphate you can replace the two lead acid batteries without losing any capacity. I have fuses on the output side of the charge controller via the distribution box. Heres a link: oh8stn.org/blog/2017/07/06/man-portable-off-grid-power-for-amateur-radio-part-4/ It is also possible to add fuses on the Importer battery terminal side of the pack but the BMS has Short Circuit protection built-in ( which I have tested) additional fuses although nice would be kind of a double redundancy.

[@survivalcomms]

Excellent video. I'm going to have to put one of these together. What is the overall weight of the battery and charge controller? Thanks for sharing !

[@OH8STN]

+SurvivalComms thanks Bret. I'll weight it all out tomorrow in its "ready for field" mode. I've got another build coming in a couple of weeks which is an update of our builds from last year. It's practically the same as this one but using 26650 sells instead.

[@OH8STN]

+SurvivalComms answer to your question instagram.com/p/BZT940TjTHe/

[@survivalcomms]

That is great ! That is almost a full pound less than a 7AH AGM alone.

[@OH8STN]

+SurvivalComms and remember the 7 amp hour AGM will give you 3.5 amp hours of usable capacity while the lithium iron phosphate will give you 80 - 85%

[@survivalcomms]

So true. I have been really pleased with the 4S 18650 packs and look forward to building one of these myself.

[@mezamichael]

Awesome video, thank you. I have seen these batteries around but never a well done video showing the building of a pack. For this, thank you. Do you think these cells can be used to make a 40ah pack? I'm wanting to power a DC, ARB refrigerator. I currently do on a 55ah SLA battery but yearn for a lithium battery.

[@OH8STN]

+Michael Meza sorry it took me so long to come back to your comment. I wanted to be certain that I gave you the right answer. I don't know what an ARB refrigerator is but it might be the same type of refrigerator that keeps my Red Bull cool. So I've never done parallel packs of more than two deep. But I've seen these parallel batteries done on youtube. It's no big deal making a pack which is 4S2P ir more. All the cells in parallel we'll balance themselves. More over each of those parallel cells connect to the BMS as if they were one single cell. I'm thinking I should do a video about this for the channel. I need a 40 or 50 amp hour battery for the ham Shack. I've already got the panel's up on the tower but I thought to change over to an mppt charge controller for the shack. It might take me some wants to do it but I'm certain I will. For your project all you need to do is make sure you get the right BMS rated for the amount of sales and the total amperage draw the refrigerator will pull.

[@mezamichael]

Excellent, thank you. In my research I'm finding 40 and 60ah cells. Some are Headway type others are Winston type. For the size I need I may be going with a lithium prismatic type like this: www.electricmotorsport.com/ev-parts/batteries/lithium/4-cell-12v-packs/gbs-lfmp40ah.html

[@rachmielbenberel]

First let me say that I find your videos very informative (and I should add here that I have recently purchased battery holders from your sponsor, Vruzend--I like to think of their product as DIY electronic Lego blocks). So here's my question(s). Question One: You indicate that in the shack one charges the battery pack by connecting the BMS to a power supply. So what is the rule of thumb concerning charging batteries through the BMS. For example, if I have an S5 configuration of Lithium Ion batteries with the max voltage per battery of 4.2 Volts, would I adjust the power supply to 21 (5 X 4.2) Volts; or in the case of S3, would I set the power supply to 12.6 (3 X 4.2) Volts, and so on? Should I "assume" that the BMS will control the charge, balance the cells correctly, and stop the charge when the cells have reached the proper level, and so on? What if the supply is set for less voltage? Question Two: Should I also assume that when one adds cells in parallel in order to increase the Watt Hours of the system--for example, four cells in parallel where there was only one before (so in an S3 system, there would be 12 cells, 3 clusters of four parallel cells) one would think of each cluster as merely one cell since each of the cells within it receives the same charge on account of being connected in parallel--and therefore all four are balanced) [I am assuming here the same brand/type of batteries and that each would be precharged to the same voltage before being connected together and placed into the system]? I understand that the BMS needs the proper current rating. Am I overlooking something?

[@freelancer2011]

Hi, I'm loving your videos a lot! I'm also interested to know how you ended-up in beautiful Finland. Have you thought about doing a vid about that? If you already have, I'll see if I can find it. I was just wondering: am I right in thinking that in later videos, this entire battery pack is in this clear, plastic shrink-wrapping? If so, would you be able to share how did you do that? Thanks!

[@OH8STN]

thanks. I have not done a vid about finland ye. I'm quite a private person. I can say I was recruited shortly out of the Marine Corps. The heat shrink cover is exactly that, heat shrink. You can find large diameter heatshrink on ebay.

[@freelancer2011]

@@OH8STN That's amazing, thank you!! And very interesting - I thought I picked-up a military vibe off you. -You remind me of a great friend. Hope to make QSO with you at some point. I'm still relatively new to Amateur Radio. Only got my foundation license the other month. M7LKC. 👍

[@kc5ril]

@@OH8STN You are a USMC Devil Dog? Now we have to know the back story! BTW, I plan on operating in Sweden (near Norkopping) within the next year. Christmas or summer, can't decide. Is this battery pack airline safe, or do I have to do some math on my fingers and toes to make it so?

[@mahdichavoushi5515]

Where I can get the battery holder ? ( Tray ) . Informative video. Thank you .

[@OH8STN]

Thanks The holders usually come from the same place the cells come from. If you can't find them, a simple search of eBay for 38120 Headway holders should get some good results. They can also be 3d printed. Same search on thingiverse for the 3D printed file

[@K8BAR]

How would you charge this if you didn’t want to use a solar panel. Will any ac to dc charger work. Thanks!

[@TheHamNinja]

Thanks dude. The link to "The Portable Solar Powered GoKit can be found here:" is broken. 73

[@terrynichols3040]

Where did you get the bus bar I didn't see them on the website where I got the batteries..thiniing of another way to short battery if I can not fiond them, maybe braid with ring connectors and shrink wrap.

[@ronniepirtlejr2606]

How do you know if your BMS is working or if anything has went bad? Do you ever bottom level your cells? That's run them all low as they can go almost. Then charge the group up to their capacity at the same time. Then he group will only get charged up to the weakest ones capacity. Level. The weakest one fully charged while the rest are not fully charged.

[@raydzek]

Question about the BMS. If you were to double the capacity to 20Ah with 4 more cells would you use the same BMS in a 4s2p? Or in my case I want to build a 4s4p, would I treat the 4 cells in series as one cell and still use a 4 cell BMS?

[@SeAfasia]

thnks for share OH8STN de SV3IRG .... 73 ...

[@OH8STN]

+SeAfasia thank you for watching and for the kindness 73 Julian oh8stn

[@Charlietuna49]

I just discovered your channel. I think I've reviewed all of the videos and your blog page. What are your sources for the components, 38120 batteries, bms board etc. I would also like to read a detailed explanation on how you need only one bms board in a 4s2p setup. Thanks for all your efforts. 73's Steve, N6RUO

[@OH8STN]

All? The old videos are horrific. Each of my battery builds has detailed explanations and accompanying blog post with more detailed info. Still, I think it's important to start with this playlist, if portable power is your interest. Portable Off-Grid Battery & Solar Power for Amateur Field Communications: kzbin.info/aero/PLKMrdrsNkFA43q0POuXM-5-49yOd3t4CP Regarding the BMS, each battery build details the BMS used, how to wire it, and its specs. I use 4S BMS boards for lithium iron phosphate, and 3S BMS boards for Lithium-ion. These days I've settled on one 50A model for dual 100w rigs, and a 30A model for everything else. Thanks for watching and stopping by. Its very much appreciated. 73 Julian oh8stn

[@stevenbrewster7709]

Julian, What size wire did you use? I am currently making the 10aH battery pack. Thank you for the great videos.

[@OH8STN]

I typically use 14awg wire. 73 Julian oh8stn.

[@southernsearcher6338]

You mention elsewhere increasing the BMS to 30-40A, but the gensun can only handle a 5A load. Can you explain your thinking? (I’ve built this and a larger one, trying to understand the best power distribution). Love the videos

[@OH8STN]

+SouthernSearcher excellent question we don't have to use the load port on the charge controller. The 5 amps is only the maximum amount of amperage which can pass through the charge controller to the battery. The load Port is only used 4 low voltage cutoff of an external load. We can instead connect the load directly to the battery and still charge it with this Dodge controller. Does that make sense?

[@southernsearcher6338]

OH8STN I understand the theory, but 5h3 LiFePo needs stop delivering current, when it reaches its cut off voltage, so what will handle this, to save a rather extensive battery pack. I’m currently working on a 4S 15AH, currently 2P, hoping to make 4P or larger for home use, I’m in the South of France so sunlight is not an issue. 73 de Andy

[@OH8STN]

+SouthernSearcher i think I'm making explainer video about how to do it. Just to keep you in the loop there's two ways that I would consider. Firstly I would use an external low voltage cut off, between the battery and the load. It's not to be confused with the load port on the solar charge controller. The other way I would do it is using a relay on the load Port of the solar charge controller. This way you get power directly from the battery for your load and the load on the solar charge controller only Powers the relay. This means you're low voltage disconnect on the solar charge controller is controlling the relay and protecting your battery. Does that make sense?

[@zazouille2264]

Great video. Questions: 1/ can I make a donation somewhere else than Patreon? Like Paypal account 2/ do you have a reference for the load display? 3/ reference for the admin pouch? Thank you. Excellent content.

[@OH8STN]

+Laurent LATHIEYRE hi Laurent. You can use PayPal at www.paypal.me/oh8stn Thanks for the kindness. Everything help the channel to keep moving forward. 73 Julian oh8stn

[@OH8STN]

I almost missed the second part of your question. Here's the power meter amzn.to/2CoEnVw

[@zazouille2264]

OH8STN Done! Happy new year to you!

[@GEORGE-jf2vz]

Will the battery pack get too hot when discharging or charging with all that material around it ?

[@davidenglund]

What power distribution panel do you use? How what are the highest AMP fuses? What AMP fuse should I have for my Yaesu 991a? Thx

[@cthoadmin7458]

Hi Julian, I watched with great interest your hedway cell 10ah battery pack build. Just help me out here. The battery management system protects against shorts na d stops the cells being discharged below their minimum operating voltage. Does the bms also manage charging? If I connect a 13.8 volt power supply to the battery pack leads, the cells will be charged, but how will I know when the charge is complete? Do I need some other gadget? Cheers, Tim. Can you recommend a vendor from which to purchase a Qro bms compatible with the hedway cells?

[@OH8STN]

The battery management system does not manage the charging for that you need to charge controller. That's why you always see me in my videos with the Genasun solar charge controller. you can also use a normal RC charger like the Turnigy charger for example sets for 14.4 volts, with a couple of amps maybe maximum 2.5 amps. Do not connect the power supply directly to the Headway batteries. I hope this helps and I'm really happy you asked

[@OH8STN]

I forgot the other part of your question Tim. When I publish the qro Pack video I'll try to include a parts list and some Alternatives as well

[@cthoadmin7458]

OH8STN A QRO battery pack is my goal here Julian. It seems battery technology has now advanced to the state where you don’t have to be QRP to be portable. I want to run my kx3 and a small 50w Tokyo hi-power linear. I’ll probably get a Turnegy charger to balance charge the cells. Found a cheap source of headways here in australia. Your power systems look really cool in those molle pouches. I think I’ll do the same. Well done Julian please keep up the good work (Qro power packs interesting). I don’t think I have deep pockets like you though, I looked up the price of those great portable solar cells you were using to charge the Qro power pack the 7200... ouch ouch ouch.

[@ekoms108]

@@cthoadmin7458 you need 14.4v to get a full charge on lifepo4 pack

[@johnhelt5475]

Great work. Thank you for sharing this with us. Question: Can the input to the solar charge controller be another voltage source like an automotive accessory outlet or other 12+ volt source? I am planning out a "Go Kit" which I would like to be able to simply plug into the car when driving, or plug in at the house, etc to ensure my batts stay charged and ready to go. Thanks, again. John - KB0JH

[@OH8STN]

Thanks for the question and the kindness John. I have changed the charge controller since this video. It's now the gv8 Boost from Genasun. This is a boost charge controller which will take the lower voltage from your car, boosting it to the proper voltage for our lithium iron phosphate batteries. Ideally we should limit the current, but it does work as you mentioned. The charge controllers I used in this video don't work in the same way, as they have no boost function.

[@johnhelt5475]

@@OH8STN Thank you.

[@johnhelt5475]

@@OH8STN There seem to be many different options for this. Do you have a link to the specific model you would recommend?

[@johnhelt5475]

@@OH8STN Thank you, again. I have been looking around, and I think I identified the one to which you are referring. Is this it? www.amazon.com/Genasun-GVB-8-Li-14-2V-Controller-LiFePO4-Batteries/dp/B08XPJC1JW/ Keep up the amazing work.

[@toddrogers132]

Great Video. Just ordered most of the parts from BatterySpace and hope to be building one soon. What type and size of wire are you using? Thank you. Todd W5MTN

[@OH8STN]

+Todd Rogers hi Todd thanks for the question. I think for this build I used 14 gauge wire for the load, and something much lighter for the balance leads. The power pole connectors I used are 30 amp, they generally follow the power pole wire recommendations for matching connectors and wires with amperage draw even for qrp radio.

[@toddrogers132]

Thanks so much. I've asked this in a few areas but thank you for the answer. I have really enjoyed you're videos. They are right inline with what I do for SOTA operation.

[@milesmoore5422]

What is the purpose of the inline meter ? Where do I get one ? Is it necessary for this build ? Is there a parts list posted some where ?

[@mikesexsmith7816]

Hi Julian (or others) I have completed a build of this battery, but have a question about the BMS board. Should the BMS board be pretty warm to almost hot all the time once the 5 leads (B+, B- , and B1, B2, B3) are mounted to the battery? Cells appear to be balanced, battery is charged fully, but with no charging going on, and no loads connected the board is very warm, even uncomfortable to touch. Is this normal? I am nervous about putting this battery with the BMS connected to it into the pouch like Julian shows... Thoughts? Suggestions? Do I have a bad BMS board?

[@OH8STN]

Hi Mike. The balance leads are wired wrong! If there's any heat on the BMS at all, it's wired incorrectly. We've all made that mistake, but it's easy to correct.

[@OH8STN]

Hi Mike. Did you have any luck rewiring the BMS?

[@briankeith1007]

Hello sir,with the charge controller,did the BMS come with the controller?Where did you get that component from?

[@OH8STN]

Hi Brian. The BMS is usually sourced independent of the charge controller. I noticed someone just published a comment with a link to where they got their boards. Battery space is a great place to look if you're in North America. There are also those EV shops, supplying BMS boards for projects such as hours. Feel free to add a new comment asking someone to post where they got their BMS board, 73 Julian oh8stn

[@jud-asinsmith-stansell2022]

Depending on the case and even the way you have it boxed and bagged, wouldnt there be an issue with heat durning charging and discharging? Also what about the many RC community LiPo chargers advelable for home charging?

[@OH8STN]

+Jud Stansell excellent question Jud. I don't charge my batteries at very high rates, which keeps heat down to a minimum. It's the same thing with discharge. I'll never discharge at higher than 10 amps, which generates almost no heat from these cells. The RC Chargers are certainly possible to use. Since we use the battery management system there's no need to use the balance ports on the RC charger. Since I have a solar charge controller integrated with the battery I don't need those RC Chargers when I'm charging at home. In fact I use a repurposed laptop power supply that outputs 18v/2A straight into the solar charge controller. Cheap and easy.

[@OH8STN]

+Jud Stansell I've been thinking about your comment. I think I'm going to get one of those laser temperature gauges to measure how warm the batteries get under full current draw and charging.

[@lir5048]

The BMS how I measure the draw on my devices

[@hololightful]

Hey, the link to the other video you mentioned in the beginning of this video is dead...

[@bob76451]

One of the things you mentioned was to match the BMS to the current draw on your QRP rig. How do you determine this beforehand?

[@OH8STN]

By understanding how much current you expect to pull from the pack. If you'll run a 100 watt radio at nominally 12.8 volts, or a 10 watt radio at 12.8 volts, ... The expected amps plus 10-15%.

[@bob76451]

OH8STN Ham Radio So you aren’t measuring current draw on your devices beforehand, you’re simply estimating. Gotcha.

[@locotico71]

I would love to be able to mount it like in a vietnam radio pack . All components

[@OH8STN]

There's nothing stopping you. The battery configuration is exactly the same whether it's in a backpack form or in an ammo can or something else. Give it a try then share your results.

[@locotico71]

Julian Do you have an email I can address further questions or here is fine? Also, I’m on a budget and would like to get a list if items needed to make this project. Thanks Brother

[@ac2fv]

If you wanted to charge the battery with a LifePo charger, would you plug the charger directly into the BMS? And if using a solar panel, then you'd charge through the solar charge controller, which would be hooked into the BMS. Correct? Thanks.

[@OH8STN]

That is correct. Just be sure the LiFePO4 Charger is within the c charge rating of your pack.

[@richardtwyning]

Sorry, I'm watching this video in 2020. Are the 38120s batteries still a good choice. I'm finding it difficult to locate a source in the UK.

[@gilbreathca]

Can you detail how to expand the pack to 20 or 30 amp hours for QRO work.

[@OH8STN]

+Craig Gilbreath No problem. I think you mean Peak current for a QRO radio. Please give me a day or two to add it to the episode notes in the questions section

[@gilbreathca]

Interested in seeing how you would handle expanding the amp hour rating by wiring in series-parallel to get, say, 20 or 30 amp hours. How would this be done with the BMS if you have more cells to monitor and maintain? Can the BMS modules be ganged together to handle more cells? Thanks for the quality video Julian, outstanding as usual. (Hope that clears up my original question)

[@DiyintheGhetto]

Hello 13.38v is what it is at now. But what's the max voltage it can go up to?

[@OH8STN]

+joseph chrzempiec the patch should never be allowed to go above 14.6 volts. 14.2 - 14.3 volts that's optimal

[@BillBroadley]

What parts would you change for a 8 battery/20 Amp hour version?

[@OH8STN]

I'm so happy someone is finally asked this question. I'm going to do a build video on this next month. The concept is nearly the same, however will put two cells in parallel, and four in series.

[@BillBroadley]

Excellent. I was shopping DC power supplies for my ham equipment, and realized how useful it would be to have a set of batteries between the power supply and my radio. Not only would the peak power of the power supply not be as important, but I could also still use my radios during a power outage. I was targeting 40-50 amp peak just in case 2 radios TX on full power at the same time. Of course solar is in the plan as well. Thanks for the update.

[@geraldgrogan]

If I wanted to use 8 of these powercells to double the capacity in terms of amp hours, and use it for the very same purpose you are (12 volt system), would I need two BMS boards? In short how many BMS boards would I need and how many charge controllers?

[@OH8STN]

We usually use one BMS and one charge controller. The BMS is rated for the desired current draw and the number of cells in series in the pack. So if you have for sales in Ceres you need it 4S bms. If you have 4S 2p that means four in series but two in parallel you'll still need a 4S BMS. Even if you have 4 cells in parallel you still need a 4S BMS. Does this make sense? We also use a single charge controller for the pack. The charge controller needs to be specified for the type of battery chemistry you're trying to charge, but we only use one. There's lots of confusion between a portable system and home systems which are often using much higher voltage. I hope this helps 73 Julian oh8stn

[@geraldgrogan]

Yes it makes sense. Thanks for explaining with such great detail. I also found my answer where you replied to others asking the same thing. Also your video related to the 4S2P pack was most helpful. I should have watched that video first before asking.

[@PickleballTheory]

what A/C adapter would you use for the balance charger

[@OH8STN]

Hi Tim I don't quite understand your question. Can you give me more context?

[@toddrogers132]

Julian, I ordered the parts from BatterSpace as you outlined in your episode notes. However, the BMS I recieved is much larger than the one you used in this episode. I think that I received the 30 amp BMS. Is it still ok to use this BMS with this setup? Thanks. Todd W5MTN

[@OH8STN]

+Todd Rogers yes you can definitely use a 30 amp version even with a set up he doesn't need it.

[@toddrogers132]

Thank you so much for the reply. I'm getting ready to assemble the battery pack. Suggestions on type and size of wire? Thanks so much!

[@toddrogers132]

Sorry. Missed your reply on the other post. 73

[@ceemorebuts]

What gauge wire do you use

[@cwfuselier]

Have a question. would this 30amp BMS work instead of the one used here. PCM with Equilibrium function for 12.8V LFP Battery Pack @ 30A limit. i was going to go with this one BMS 4S 40A LiFePO flat, with balancer and temperature sensor -351 but don't understand the extra P +: consumer / charger (+) D-: consumer (-) C-: charger (-) spots.

[@OH8STN]

It's hard to say. Definitely don't use one which doesn't have good documentation.

[@leemaisel7157]

I ordered everything, but could NOT find the plated copper jumpers you used!

[@OH8STN]

+Lee Maisel high Lee I'm almost certain batteryspace has them if you're in North America. In Europe there is the shop.lipopower.de I'll try to find them from Amazon or Ebay and add them to the shop

[@leemaisel7157]

Thanks!

[@aquapiranha]

Hi, and thanks! I am building this battery, but I have a couple of maybe stupid questions... how do I know if I charge it with a bench PSU, when it is fully charged? Can you charge it with a PSU using the genasun? and if so, will the genasun tell me when it is charges? Thank you, Steve MI0KXT

[@OH8STN]

Here's a video showing how I do it. kzbin.info/www/bejne/gHTEmGyKZ9mWZ6c