Ham Radio Battery Pack DIY LiFePO4 | Vruzend kit

Hello Operators
Portable power is always a popular topic on the channel. So today we are building a 12v, 4S4P, Lithium LiFePO4 battery pack using 18650 cells and the Vruzend battery kit.
The DIY 18650 battery pack is very popular. We can choose lithium Ion, or Lithium Iron phosphate 18650 cells for our build. Most 18650 project use li-ion cells, but we will be using LiFePO4 cells for this build.. Repurposed or purchased new, these lithium and lithium iron phosphate cells are a popular choice for diy power banks, solar generators, or other battery projects. One of the biggest problems with diy building 18650, battery packs is damage caused by overheating cells with a soldering iron. An often overlooked fact of 18650 building, is they were designed to be spotwelded, not soldered. The Vruzend kit solves this problem by using polymer end caps on the 18650 cells. These end caps are removeable, replacable, and allow the builder to make custom packs in varous shapes and sizes.
This diy battery build uses LiFePO4 cells in 18650 format. if you would like to use Lithium ion cells, you might want to use a 3S4P configuration, to achieve a roughly similar 12v battery result. Lithiun Iron Phosphate cells are much safer than Lithium ion cells. For the maker wishing to build a 12v battery pack, the LiFePO4 cells offer a nearlly one to one replacement over lead acid batteries.
You can consider this build a kind of DIY Powerwall for your pocket.
73
Julian #oh8stn
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[@AndyWragg]

Excellent tutorial Julian. I've shared this with both the clubs I interact with. I've also been asked to do a talk at my primary club at some point on this subject. I wouldn't be here without your pioneering and sharing.

[@OH8STN]

Thanks Andy. It seems someone can be happy some of the time :-) I've got another build coming up, it's the 384 watt-hours solar generator. That is designed to be a field station power supply. While I'm waiting for all those parts perhaps I'll do a presentation on grid down comms and power. Anyway sorry I haven't been so engaging lately. Trying to keep my and misery to a minimum 😀

[@AndyWragg]

@@OH8STN You may have seen my Headway 38140 12Ah pack is now complete. Will be giving it a run out tomorrow night in the UKAC 2m contest 8.00 -10.30pm GMT. I'll be using my Yaesu FT-290Rii operating from the car at a local high point. I managed over 400km from the same spot yesterday.

[@nonokodog622]

I'm a big fan of the 18650 cell since they can be salvaged from many sources. I did buy the Vruzend kit and like it. However, the kit is reliably not re-usable in my experience. I took apart a pack I had created and only 2/3 of the end caps were still usable. They split along the thin straight walls. I ended up buying a $35 spot welder which works fine with .2 mm bus strips and the over all size of the pack is smaller. I use Daly BMS boards and love them. I charge from my electronics bench power supply and a 1.5 A thin film solar panel. I'm trying to recreate your work on a smaller scale and budget. Love your work, thanks for all you do.

[@OH8STN]

There's a red flag in your comment. Recharging from the Bench power supply is okay on the bench. What about charging with the thin film solar panel in the field? There needs to be a charge controller between the solar panel and the battery pack. How do you manage voltage regulation, stability overcharging without a charge controller? The vruzend csps are nice if you want to re--use the cells in some other project. I haven't had the same trouble as you mentioned. Admittedly I also use a spot welder these days. It's better to get some more reliable build long-term, than more convenient to build pack at the price of reliability.

[@hrdknox2000]

I'm very new to this stuff and I did my best to hang in there with you.

[@donaldsmith3048]

I have a set of 25 AH Lifepo4 cells and 2 sets of 60AH Lifepo4 cells. I hope that will give me the power I need. I need to work on solar panels to change and I way to get a good read out on the state of the batteries. THANK YOU FOR THE INFORMATION! 73. W4DES

[@TheSmokinApe]

I like the idea of putting the bms in a separate bag.

[@OH8STN]

It will be. Just ran out of supplies

[@-sickfast434]

Nice build

[@spldrong]

I like it. After my Rpi gets sorted out and the holiday season is over i am looking forward to doing one of these battery builds.

[@OH8STN]

Don't be too much in a hurry. 👍 I've also got the solar generator build coming up in the next weeks.

[@spldrong]

@@OH8STN im in more of a hurry for the DRAWs videos... i want the radio and computer to be at 90% solution before I move to batteries

[@rossbassette7518]

For ease of construction, its winner winner chicken dinner!!!!!!!!

[@OH8STN]

Yeah it reminded me of building Legos

[@ekoms108]

I have a question... Most pack builds I have seen make the series connections between as many parallel cells as possible. In this build you arranged the cells so that you only made one series connection between parallel cells. Does it matter?

[@OH8STN]

Do you mean the physical connections (busbars) between them? If so, we can always use more busbars. If I were experiencing some voltage drop, or couldn't reach the packs current potential, I would certainly add more busbars.

[@USNERDOC]

Awesome tutorial Julian. I really enjoy and look forward to these videos. 🙏73

[@OH8STN]

Awesome coming from you. I don't usually give two cents about opinions but yours matters to me. I was afraid this one was "too much".👍👍👍 73 Julian oh8stn

[@hardlife3844]

Awesome video as always Julian. Gonna have to save some funds for a new pack to power my fridge as I gave my last one to a couple in need and am now killing my jeeps battery.

[@OH8STN]

Thanks hard life, it's very much appreciated. Make sure to measure that refrigerator before you design your pack. 👍👍👍

[@atrujillo7836]

I bought this kit for a unrelated product a 10s 3p battery pack for a scooter that was defective one of the tabs broke off and it ruined the whole pack. Instead of buying a pulse spot welder I decided to rebuild it with the kit will update if I succeed or fail.

[@djryder2002]

Shared to a Ham radio groupd on facebook. Great Job.

[@OH8STN]

Very much appreciated 👍

[@AlGritzmacher]

I have been unable to find the Headway cells at any kind of reasonable price. Where do you get them? Also, what's your source for the very large clear heat shrink you use on your packs?

[@julianwhite1077]

I love the idea. I just wish they were available in multiples of 6 or so.

[@Taketheride23]

Very awesome, thank you for the great walkthrough!

[@OH8STN]

Thank you for taking the time to watch and letting me know. It's very much appreciated.👍👍👍

[@2kMario]

Can you pleas give us exact size of this 4s4p package ,I can see that using Vruzend kit there is a gap 3-4mm between in my ebike frame size does matter I am trying to figure out how many cells fit in my frame.

[@OH8STN]

sure, later when i get home

[@W4TRI]

Hi Julian. Can I use 40 cells and the kit parts and use the same BMS with appropriate fuses to go say 4x10 cells or is that pushing things? Thanks!

[@OH8STN]

Hi Ronny I don't think that's pushing it. The Vruzend FAQ says the v2 kit can output 3A per cell. From experience I know you need to do some meticulous work making sure each connection is perfect. You also have to double or triple up on the bus bars on each connection. I haven't built such a big pack yet so I really can't say. If you try please come back and share your experience with the rest of us. Here's the Vruzend FAQ. vruzend.com/faq/#how-much-current

[@williamwitt911]

Great video. One small question. Where did you get shrink wrap that large?

[@michaelstarling4553]

Julian, Is there a BMS for a pack built with 2 groups of 4 serial wired 18650s with the groups wired in parallel yielding 16.4v with twice the capacity of a single group of 4 serial wired batteries? Would such a configuration be called an 8S4P?

[@OH8STN]

Hi Michael. You left out some critical information but let's assume we're talking about lithium ion battery chemistry. With eight cells for in series, and another identical set in parallel. This is called 4S4P. It will output ~16.4-.8 volts when fully charged. If we're talking about lithium iron phosphate as we normally work with them this channel, that same configuration would also be 4S4P, but output ~14.4-.6 volts fully charged.

[@michaelstarling4553]

@@OH8STN Will be using Li ion batteries as they are in the box. So how what do I use for a BMS for such an experiment? Am in the US so Amazon is a decent supplier. Thank you for your reply!!!

[@stevefrank353]

Thanks for your videos. I enjoy them both for the content and their style. I've been considering using self made Lithium base battery packs for portable communications but have two concerns. First, is it necessary to match the cells for charge and discharge compatibility so the pack functions safely? If so, do you know if matched cells can be purchased? Second, when using Lithium based batteries in parallel should I use a fuse or fuse wire between each cell and the bus wire connecting each of the parallel cells? Doing so would prevent the other paralleled cells from discharging through a shorted cell creating a catastrophic failure. The blown fuse would also remove the shorted cell from the circuit allowing continued use of the complete battery pack. (Although at a lower capacity) 73, KB9SF

[@OH8STN]

He thanks for the comments. I find it is usually close enough to use quality cells, all from the same manufacturer, from the same lot, all having a very similar internal resistance, and manufactured at the same time. Matching the cells is something that was usually necessary when using recovered cells. If one buys a box of brand new cells from a good manufacturer, all of this cells are usually within spec. Cell level fusing is not a bad idea but it is a personal choice. If I were using lithium-ion cells to construct a larger pack, I would definitely go for it. Since I'm using lithium iron phosphate cells and not pushing them anywhere near there discharge capacity, I'm not too worried.

[@ekbanjosworld4926]

Everytime I checked with Vruzen they are out of stock!?!?

[@philipchandler330]

Great information as always Merry Christmas

[@AZZapper11]

Nice clean install. One stupid question. I want to buy a mobile radio for my Mobil Home. What can you recommend for a "no idea" user like me. Thanks.

[@OH8STN]

Awesome question but it's impossible to answer without a bit more context. BHF/UHF? HF? I have used Kenwood and Yaesu radios for mobile. Unfortunately you'll have to decide if you're going to be using repeaters, if you want to operate Simplex, or if you want to do some aprs. There's also the questions of a DMR radio, a system Fusion radio, where D star radio just to name a couple. If we are talking about a mobile HF radio, the question is a little easier. You need to decide if it's going to be a radio you use while driving, or a radio in a fixed location inside your RV. Icom makes excellent radios for fixed and mobile portable like boats and RV. Yaesu is good with traditional mobile HF rigs. If it's your only rig in the RV, and you will only use it while parked, I would go with a Icom 7300 for HF

[@AZZapper11]

@@OH8STN Great. At least now I know how much I don't know. I will research. It will be used while on the road and while parked at camp sites. Much like truckers use it, I suppose.

[@OH8STN]

We all start someplace 👍👍👍

[@hamtechoutdoor]

Hi Julian, just a quick questison, does the BMS prevent automatically batteries' over-discharge below 3.0 or 2.7 V for LifePO4 cells ? If yes, Can you set a custom value (i.e. 3.0 or 2.7V)?

[@OH8STN]

Excellent question Fabio. You can't do it with the BMS without changing out some resistors. However you can do it with your BMS for example the Victron BMS. It's programmable allows you to set high and low voltage values. I'll have one here for the channel pretty soon

[@timk7749]

Great video as always. As a total noob to this, I would like to ask how you charge these cells at home. What kind of special charger?

[@OH8STN]

Thanks Tim. Standard hobby charger set to ~14.6v 0.5A, or through a solar charge controller for LiFePO4 4S batteries. It's very standard stuff these days.

[@timk7749]

@@OH8STN RR thanks!

[@in3rpe]

Thanks, 73 from the alps

[@OH8STN]

You're very welcome 👍👍👍

[@guiterman6263]

Where can I find laptop batteries I live in lenoir hard to find here

[@OH8STN]

Here you go. ebay.to/2so1tbj

[@kevinmaxson7304]

Nice work!

[@OH8STN]

Thanks Kevin

[@jamesr.9239]

Hi, noob here and was wondering why you chose LiFeP04 cells as opposed to 18650 Lion cells. Was it due to the voltage output being closer to 12 volt than the 3.7 volt Lion cells would produce or was it something else?

[@OH8STN]

Excellent observation. Yeah the lithium-ion cells will Top out around 16.8 volts. That voltage makes it difficult to charge with a portable solar panel in the field, and require some voltage regulation if you use them in 4S. You can use them in 3S, but then you have to run parallel cells to maintain the capacity. Great question, and excellent observations

[@touchthesun2448]

very nice job....I like it!

[@OH8STN]

Thanks. It was a fun kit to work with. 73 Julian oh8stn

[@TheStevenhull]

I have the kit and have been using it for months now. The connections are not that tight, I'm lucky to get a few amps thru it.

[@OH8STN]

Hi Steve. The version 2 kit is quite tight on my cells. I was actually surprised the kit could power the 891.

[@OH8STN]

By the way Steven. One of the things I figured out was adding additional busbars in parallel. I'm not sure which kick you have the version 1 or the version 2, but diversion to allows you to use I think it's 5 or 6 bus bars in parallel. I think I'll do a follow-up video sometime on this topic, showing the amp meter versus Power output with the radio.

[@tomstdenis]

Thin nickle strips aren't the best conductor either. You may want to double up the bus bar (or switch to copper).

[@TheStevenhull]

OH8STN good idea I’ll try it

[@robertfandel9442]

So what is the advantage compared to AGM as far as cost and weight a 20ah 12v AGM is around 70$

[@OH8STN]

The price at the cash register is a deception. We need to look at the cycle life of the battery. The typical AGM battery has about 500 Cycles. LifePO4 has 2000 cycles. You would have bought 4 AGM batteries before the LiFePO4 started to degrade. Another point is the AGM battery having only 50% usable capacity. So if you want 20 amp hours oh, you need 40 amp hours batteries to achieve it. If I want 20 amp hours out of my lithium iron phosphate cells I simply by 20 amp hours of lithium iron phosphate cells. Here's a comparison we put together on my website. It Compares this or generator, with a Goal Zero Yeti lithium, and a Goal Zero Yeti let acid. It also explains very well the cycle life. I hope this helps. Thanks for the question oh, it's very much appreciated. oh8stn.org/blog/2019/02/23/the-real-cost-of-a-solar-generator/

[@austinanthony4016]

But that's a difference of 20 amp-hours vs. 4.4 amp-hours....so I guess the argument youre making is this is still a better solution for low powered solutions over longer periods of time vs. High amp applications? Pricing is still a bit high for 18650 based solutions but I can definitely see the argument for weight/portability vs. AGM batteries

[@OH8STN]

My only arguments are the 500 cycles lifespan and 50% useable capacity of AGM or lead-acid batteries, versus 2000 cycles 95% usable capacity of Lithium Iron phosphate. So not only is lithium iron phosphate lighter, and has a much great cyclic lifespan, we would have bought four AGM or lead-acid batteries before the lithium iron phosphate would have reached the beginning of its end of life. If we're concerned about performance under load and capacity, we should also consider Peukerts law which states "as the rate of discharge increases, the batterys available capacity decreases". Peukert's law is much less relevant with lithium based cells. So really, certainly lithium iron phosphate packs are more expensive at the cash register. Thankfully their increased performance, longer cyclic life, and increased performance are all reasons to invest in them.

[@steveposson544]

Julian, what is the recommendation for torque on the nuts? 73 KM6OND

[@OH8STN]

Hi Steve. I don't remember it off hand you'll have to check the documentation, or one of the e-bike/ev websites.

[@steveposson544]

RRR will do.

[@tomstdenis]

Why not make it a cube? Or it is because the BMS is longer than a string of 4 cells?

[@OH8STN]

I can buy any Cube shaped battery from the shop. I needed this shape for the available space in the rucksack. It's a portable battery. I might even take it apart then make it flat. 👍

[@tomstdenis]

@@OH8STN That answers that :-) Cheers.

[@OH8STN]

Yeah I know it seems a little crazy :-)

[@Andi-Maringer]

Very nice Julian!!! Thank you! 73 de Andi OE3APM

[@OH8STN]

Thanks Andi 👍👍👍 73 Julian oh8stn

[@Hondacber]

I'm ready to purchase some batteries the Headway LiFePO4 40152S but I'm in the USA and I'm not sure who to order them from. I'm very cautious on who I'm buying from. I only order through AUTHORIZED dealers with FULL WARRANTY and I'm covered if anything goes wrong I want FAST SERVICE. I have decided to build a 4S 3P pack.

[@OH8STN]

Try batteryspace

[@OH8STN]

www.batteryspace.com/lifepo438120pmsizecell32v10ah100asurgerate32whwith6mscrewterminal-unapproved.aspx

[@Hondacber]

@@OH8STN They already have a prebuilt pack I don't have to assemble anything. Here is the pack I got www.batteryspace.com/LiFePO4-40152SE-Battery-12.8V-45Ah-576Wh-100A-rate-with-PCM.aspx

[@OH8STN]

@@Hondacber that's a monster 👍👍👍 Publishing a very similar build on the channel in a few weeks.

[@809castro]

Do you need a bms if you using a solar controller?

[@OH8STN]

Sure. The bms offers cell balancing, short circuit protection, high and low voltage protection, ...

[@809castro]

@@OH8STN thanks God bless..

[@JoseA-Divergent]

Good work! :- )

[@SirSmartyPants]

Thanks very much Julian. VK3DEK.

[@OH8STN]

No problem. It was a fun experience. 73 Julian oh8stn

[@pNoid2k1]

What is the total cost of the 4S4P battery build?

[@OH8STN]

Built the 4S4P & 4S2P packs for ~78$ total cost including 20A BMS for each.

[@pNoid2k1]

OH8STN awesome.. Been wanting to build a 15aH pack for a yaesu ftm400 that I just picked up. I don’t really have a reason to build a 15aH battery.. just kind of want one for when I go camping on weekends. Are all the required parts linked in the description ? Sorry I did not check all of them.

[@OH8STN]

I didn't include the cells in the description, but everything else is there.

[@pNoid2k1]

OH8STN all right cool thanks for getting back at me!. subd

[@brianogram5194]

Thank you Julian! //K6OGR

[@OH8STN]

No problem 73 Julian oh8stn

[@davidm1635]

Nice but about 2 min of TX without ID

[@mrgcav]

Only an armature would put use fuses in a battery pack. then put in two of them to double the resistance. Use on and only one circuit breaker.

[@rustyb78]

Great videos but DAMN, do you have to include ads in the middle of the video? PIA!

[@OH8STN]

Unless I'm mistaken ads are also added multiple times in the middle of football and baseball games. I know it sucks but it's the only way to recoup what I invest in the channel in time and equipment. Just another point. If you had a KZbin premium subscription, you would never have to see ads on KZbin ever again. It's only 9 bucks in a month. On the flip side thanks for the kindness

[@Hondacber]

Those are 4S batteries that means your running that radio at 14.8 VOLTS at full charge your giving that radio 16.8 VOLTS BAD IDEA your going to burn that radio up. You need a 3S pack.

[@OH8STN]

Sorry Roger you're wrong! The build uses LiFePO4 cells, not Lithium ion. A 4S LiFePO4 pack is 12.8 volts nominal, 14.6v max. These cells are identical to the cells used inside Bioenno batteries.

[@Hondacber]

@@OH8STN O OK sorry. I didn't know there was a difference. THANK YOU for telling me. I have put together a lot of 18650 packs and all of my 3S packs at full charge was 12.6. I have a lot of 18650's but none of them are LifePO4. Where do I get those ? Also are they better ?

[@OH8STN]

No problem. I expected this question a little sooner to be honest. No harm done. Lithium ion have a greater cell density than lithium iron phosphate. So you can get the greater amp hours with fewer li-iin cells lithium iron phosphate have lower cell density, are much safer to work with, and have a good return on investment with 1500-2000 charge discharge cycles. There isn't a big variety of lithium iron phosphate 18650 cells, but they are becoming more popular. Check out your e bike shops.

[@Hondacber]

I found some of the LiFePo4 18650's but there not as common as the LI ON ones. I'm wondering why that is ? That is why I have never came across them yet.

[@Hondacber]

@@OH8STN I have The BOSE Acoustic Wave Music System II Radio and I build a TWO 3S 5P packs for that. I'm thinking of taking the 2 pack's apart and making a 3S 10P one instead. I like long run times. I'm using the Samsung INR18650-30Q ones.