Prismatic LiFePO4 cell prices have once again come down. Even with the wide-spread popularity of cheaper-than-ever, commercially-build lithium packs, you can still build your own for a lot less. I mean like 35% less and with all of the high-end features such as low-temperature cutoff and Bluetooth app connectivity. In this video, I will show you how I built a 280A pack for less than $700 and where I sourced all of the parts. Buy 280Ah LiFePO4 Cells from Shenzhen Qishou Tech www.alibaba.com/product-detail/Grade-a-lifepo4-3-2v-280ah_1600551390417.html?spm=a2747.manage.0.0.73e871d2RVwOMi Buy RadioB Tech 120A BMS: amzn.to/39OYgYA My Preferred LiFePO4-Compatible Smart Charger: amzn.to/3A2eeJq

@johnnyb3726

Жыл бұрын

I am a very novice LiFeP04 guy looking for the best, most cost effective solution for my needs...This video was excellent...How many cells can you actually add to that BMS and it still work? I have a truck bed camper and want to max out the AH for the space I have available. So can you build a 400 AH battery this way, using the same parts, just more cells? and do you have any other forums you are a host/member of that i might be able to sign up for?

@freelyroaming

Жыл бұрын

Johnny, I offer coaching sessions here freelyroaming.com/coaching

@menglei6301

Жыл бұрын

This guy is awesome, thank you so much for sharing. I used to buy a lot of ADCBATT 100ah lifepo4 batteries and although they are not expensive and still work, I plan to make one myself.

@robertboyer5498

7 ай бұрын

I thought that the cells from Ali express were b grade junk? I’ve heard several people never even got their batteries. Now, these were complete batteries, not cells, so maybe it’s different?

@freelyroaming

7 ай бұрын

@@robertboyer5498 AliExpress is a platform with thousands of independent sellers. So the quality varies from each one. You can not blanketly assume anything across all of them.

I am a professional electrician for over 40 years. I immediately teach my students to take off the wedding ring. If you somehow short circuit with your ring on. Suddenly an arc flash! Safety first. I have known people who have been hospitalized for weeks!

@markgerloff7928

11 ай бұрын

I've seen this happen to a co worker working on a Harley 🤣 goodbye skin! Gnarly

@billcollins7009

10 ай бұрын

That happened to my brother. It was a nasty injury!

@Bozemanjustin

9 ай бұрын

Yes, I'm sure that's what you tell the wife when she finds your ring off.....lol

@RaafatALBadran

8 ай бұрын

Staying in hospital rather upset the wife is more effective 🤪

@dogfood61188

3 ай бұрын

Place I used to work a guys wristwatch shorted between a vehicle chassis and the positive of the battery. It got very hot very quickly He got 3rd degree burns all round his wrist.

Thank you, very impressive! I'm picking up off-grid trailer soon and this build will be the perfect addition!

Simple video, easy to understand. Glad you suggested to beginners to watch other more detailed assembly and test steps.

This is a fantastic video! Thank you for making this. Gives me the confidence to try it.

WOW, nice and simple build one of the best to be honest and straight to the point, and yes LifePo4 batteries are the best I am glad you went with the Eve brand as I have heard a lot of good positive feedback from other folks too, thanks for sharing man, cheers.

Thanks for the tutorial. Was debating whether or not to get off the shelf stuff. But this seems pretty straight forward and has more potential.

@steinanderson9849

Жыл бұрын

nice pun!

Best thing I ever did! Going to build out a second one this fall I think so I can run my AC on an inverter.

Excellent video! Exactly what I was looking for. Thanks for taking the time to make it.

Nice job! Thanks for making this video.

Nicely done, straight forward, simple to follow by design. Thanks for sharing the education. I’ve got 16 cells 100ah that need a Bms to construct either a 12, 24, or 48v battery. This has been very helpful in understanding what needs be done to continue. 👍🏼

thank you very much for this it has helped a great deal and very concise ,direct,well explained , and easy to follow .

@freelyroaming

Жыл бұрын

You're welcome! Thanks for your comment and thanks for watching the video.

Great tutorial, can’t be more explicit. You got me. Cheers

Thanks for the tutorial and recommendations. Good to know.

i bought 4 cells back in i wanna say 2020.. and just got that same exact bms recently. works well. very nice build dude!

@freelyroaming

Жыл бұрын

Thanks man. Love this BMS!

Been waiting for a video like this for a long time. Awesome job on the video!

@freelyroaming

Жыл бұрын

Thanks. Sorry it took so long!

I am going to get this ordered up so that I can build out my own battery system for our camper.

@freelyroaming

Жыл бұрын

That's exactly what I use it for. It has been great so far.

@sbabcock71

Жыл бұрын

@@freelyroaming Outstanding!!!

Thanks , very educational for beginners. Very good video compared to others out there. You stressed safety which is very important but safety glasses and at least sunglasses should be worn at all time working on battery like you did. No metal when welding or electrical work period.

Excellent. I like your posts.

nice point on the length of the wires thanks!

Great info.Thanks

Thank you, I am now convinced that I am going to do this, very much appreciated 👍👍👍

Just found this video and this channel. GREAT JOB, thank you !!!! Liked and subbed

@freelyroaming

Жыл бұрын

Thanks!

These batts will probably be lower in price over time. The other facet not mentioned in this video is the ability to add more cells either in series or parallel. Either changing the bms or adding another depends on how you wire. But these are a great starter with budget in mind which can be increased over time without tossing any you've already purchased. 16 in series give you a 48 nominal volt setup which requires smaller wiring for the same watts used. The versatility is just wonderful.

Congratulations my friend the best battery for lifepo4, it's a big Peck.

people should not be afraid to try this, I really appreciate those who will encourage diy crafting. Some of the direct replacement options are total crap and unless you are willing to cut them open and see what is inside you have no idea what you have bought.

@freelyroaming

Жыл бұрын

If you are not afraid you should try. If you are, you should not. I've seen too many poorly constructed electrical project built into moving vehicle and enough fiery inferno as a result to think everyone should do it. There are more than enough budget yet high quality batteries out there. Just buy a name you recognize and you will be fine.

Life is easy with those big cells

Very nice 👍 Helped me allot

Thank you, I liked your video.

@freelyroaming

Жыл бұрын

Thanks for watching!

Very informative video. You mentioned at the begin about showing a 3rd temp sensor, was it mentioned or did I miss it?

Nice video. One item that you should consider doing is to connect the main negative load leads directly to the battery terminal, then attach the balance lead on top of the load leads. That way the load leads have better contact with the battery terminal and the lug for the balance lead is not carrying load current.

@leonhardtkristensen4093

Жыл бұрын

But then it is not turning off if the voltage goes too low which is one of the main functions of the BMS. I would suggest not to do that.

@freelyroaming

Жыл бұрын

He's talking about the stacking order of the ring terminals on the lug. It's not really that critical for off grid power use but for high current draw applications like EVs it might help. But even then it's not really gonna make any noticeable difference. Just best practices kinda thing.

@leonhardtkristensen4093

Жыл бұрын

@@freelyroaming Ok that makes sense. I understood that he didn't want the load to through the BMS. Sorry.

Very good! Iuse strapping tape with glasfibers in it. In case of the cells getting hot, it wont fall apart.

@freelyroaming

Жыл бұрын

That's why I used. Although it's really not likely to reach any temperature hot enough to cause the adhesive to fail when this is used in an low c rate environment.

I have been using similar batteries to these as almost my only source of power for nearly 4 years now, all done from youtube videos like this and zero experience. The price to performance has improved so quickly in that time, roughly 40% more capacity for the same size and weight for less money is incredible.

thanks bro!!

Hi Dan, BTW The 280K is the 6,000 cycle battery from EVE as the 280 normal is 3 - 4,000 cycles. Best charging the batteries in parallel to connect the positive at one end and the negative at the other end of the battery bank. This will avoid the first cell in the line taking the most current and last one the least. If you get a chance to try the JK BMS it is the best on the market according to me and Off-Grid Garage on KZread. André

@freelyroaming

Жыл бұрын

What do you like about JK BMS? Active balancing? And you actually believe what Andy says over there from his broken shack down under?!?! Just kidding 😂 He's making some good content over there.

@SoundzAlive1

Жыл бұрын

@@freelyroaming Yes the active balancing is the main difference. It is fully featured and seams to be very reliable. I was commited to package deal with a DeliGreencs BMS new parallel version so I could not change. André

bought 2000wh ac200p for $650. cant beat that on DIY.

Nice vid !

Great information will help me greatly deal I'm goin to make battery pack to charge on off peak electric @ night to use during day giving me 24hr off peak lectricity shud save a great deal with big rise in energy prices, think l need to aim for sbout 10kw to run bungalow in day! Don't think l should have any problem putting that together, I'm a retired electronics tech! Just hope l can get all stuff you got shipped here to U.K. very good presentation lot good information thanks so much saves me time on researching all this myself!🤗🤩😎🌹

Hi: Thanks for this video. Can this cell pack and BMS times 3 power my golf cart, or is there to much inrush current for this BMS. No doubt the batteries can do the job, but how about the BMS.? Thanks. Bob

i just bought a 304ah with heating for 1700 euro, it just has a JBD bms and eve cells - i know this costs only about 5-600 euro so its was hard to swallow, but it helps a local guy out and i dont have to think about it, i think next time in 10 years or so I will build my own.

@daleval2182

Жыл бұрын

If all goes normal world, a battery will be already built for 10c a watt

Nice video, Im thinking about building one myself and took contact with the reseller you linked, so did you have any problem with them and Cassie Wang there said it would cost 560$ with shipping and all to Europe. So you think that this is a good price or should I wait?

Can you do a video on the Bluetooth connection. I am concern there are complication or it gets tricky to connect to it.

Hi, since Im taking a deep dive into renewable energy, I understand there is a cost saving in a DIY version of a battery vs buying a LiFePo4 battery. My question is the following, how big or small is the safety concern of a daily use of a system built DIY vs just buy a portable solar generator system with a battery bank integrated in the same compartment like the Bluetties and Jacakrys? I do like to tinker with stuff, and you made it look fairly easy to build that 280AH battery. That motivated me to think in building a system.

I'd like to build a 36 volt 100 amp hour battery for my 36 volt ezgo golf cart. Any suggestions on components would be appreciated. Thank you, great videos !

Very well.i have one question :i have 4 cells of this kind batery :12v/320A .the BMS must be 320A or less?i do not understand.can i use bms 150A?thank you

Nice👍👍

Thanks for sharing the knowledge. As right now, you can buy Chins 300AH around $970. I don't see much of the saving because the cost of 4 cells 3.2v is $750 + $130 BMS + bluetooth.

@freelyroaming

Жыл бұрын

If not a lot of savings you will have more features like low temp protection, Bluetooth connectivity, smaller footprint and most of all, ease of maintenance. This for me was less than 700 bucks all in. I don't know about you but that's more than 300 bucks cheaper than Chins using my math especially when factoring in tax.

@dnlmachine4287

3 ай бұрын

@@freelyroaming Espcially if youre going 48/51 Volts, savings add up. Stay gold.

i got an aliexpress 150Amp clone of that bms and a BT module for i think under $80 USD shipped, if not around $75, that was a year or two ago

nice

Thanks for the concise video... One comment: The cell sense wires of the bms CAN be cut, there is no way 20ga wire, at .01 ohms per foot at 3,2 volts, with virtually zero current draw, is going to have any voltage drop. I notice nearly all the DIY builders think the same way, which tells me they all watch each others channels. The instrument doesn't have close to the resolution to read any difference. Simple ohms law for voltage drop. It would be microvolts

@freelyroaming

Жыл бұрын

Of course it can be cut practically speaking. But when you make a video showing people how to do things, you need to teach best practices. The best practice is to not shorten them. There might not be a measurable difference but there is a difference at least in microvolts.

Thanks Great Video Why was cell #1 red and a B flashing in the bluetooth display?

@freelyroaming

Жыл бұрын

It is showing the balancing of the cells. Red signifies which cell has the highest voltage and is being resistively drained to a lower level.

I live in Canada. Any chance you could recommend a BMS with same features but also able to accommodate heat pads. Appreciate the tiem and effort you put into your videos.

@GoGadgetsLife

Жыл бұрын

Lyndsay,Whats you battery details ,Maybe i can offer help

@lyndsaybeck2249

Жыл бұрын

@@GoGadgetsLife SOK 100Ah 12V LiFePO4. I bought them 3-months before the same battery with the option of heater pads became available.

@svendittmann3105

Жыл бұрын

@@lyndsaybeck2249 use an active balancer (aB) for your 100Ah cells. They have much more precisious performance then such types. You configure only the cutoff voltages (2,5Vmin / 3,65Vmax per cell) in your inverter. The balancer manage the cells until 0,001V difference. An aB produce no heat and your system has no powerl loss! negative: aB have no BT and Apps if you want present your cells your neighbour ....

Have you tested cold temp disconnect is working on this bms?

So for an application such as car audio that has high current draw what BMS should I use?

I hooked my daly sensing wires to the positive terminals is this a different set up or does it not matter ?

I did this set up with just the 120 amp bms. I have a 40 amp. Rich charge controller and two 200 watt. Panels. Also 3000 watt pure sine inverter. I have been all over the app and can't get my cells to charge past 13.4. I put my Noco genius 10 on it with the bms hooked up and I only get 13.4 and only 3 out of 4 red bars on the charger no matter how long I wait. When I charge the cells without the bms hooked up, I get 14.4. Then, as soon as I hook the bms up it takes it down to 13.4. I have calculated about 50% capacity. Maybe less. The only thing I can think of is the bms needs to be a 250amp? Advice would be perfect. Maybe parameters I need to change? Thanks

That was great. I'm just starting to think about building a battery system. So the two temperature wire r for low & high temperature, right? Do u hv a video about discharging & charging the battery b4 u build the battery pack? I need to know what type of equipment is used to do that?

@bobforte9343

Жыл бұрын

The most common charger is often a 30V 10A bench power supply that goes for $75 on Amazon. You could probably get a higher amperage charger for ONE specific voltage but that gives you no flexibility so I would really recommend getting a bench power supply. If you can afford something that can do 20A then I would recommend it just to save yourself some time. Discharging…first ask yourself, do you want to capacity test? For $50 you can get a DL24 load tester but it’s limited to discharging at a max of 150W or 20A. If you don’t want to capacity test then you could hook up a super basic DC load (bulb) or get some bigger power resistors and use ohms law to calculate a load small enough that won’t melt some 100W resistors but big enough that it won’t take centuries to drain it. You need a low voltage disconnect module

@GHE2005

Жыл бұрын

@@bobforte9343Wow thank u for all that info. I'll do some more research about all that u noted. I'm a visual person so reading the info I don't get yet. But I truly hope ur explanations. 👍🏾😊

Hi Dan, you spoke about balancing on the video at about 13m 53secs did you do a video on this after thanks in advance.

I don't know if it was ask can you use these for car audio

Can i solar trickle charge a LI battery,the type used on a power tool.

I know a lot of these bms have Bluetooth, I’m thinking wifi connection for remote monitoring and data logging is highly desirable. Are there other bms with wifi connection or a Bluetooth - wifi bridge to log the data??

Does this bus do active or passive balancing?

Correct me if I'm wrong but last time I checked, red was positive and black was negative. You appeared to have connected the blue bms negative leads to the positive terminal on the battery pack. Just an observation

Could all the tape cause the batteries (cells) to not dissipate heat well enough? This was very enjoyable to watch and makes me want to make one (or more).

@freelyroaming

Жыл бұрын

Perhaps. But so would an enclosure. For off-grid power, the c rate is very low so batteries don't heat up that much. It would actually be a benefit in cold temps. Like I said, there are lots of ways to build a battery. this is just a good and fast way to build one in about 10 minutes for a KZread video.

I have a tight build width - whats tbe widt6of these 280ah cells in mm? - thanks

How many of those bats would be needed to run an RV 15,000 btu AC? So one said I’d need 7 or 8 400 watt panels on the roof.I think I can mount 7 on my roof but not 8.

i gone a do 2 pack of 8s in series to make 2 pack of 24v and 320ah and them connect in the 2 pack in paralel and made 24v 640ah the question is to do that whith one bms whith 16s cell. the question is can di that 2 pack of 24v in series to them connect in paralel to make 24v 640ah which one 16s bms or not

There are a few things you should take care of, apart from not assembling the battery on a steel table. Don't use an adjustable wrench to tighten the nuts - it.s too easy to accidentally creating a short circuit. Use a socket wrench instead. Don't use scissors to cut tie-raps but use short snips (with insulated handles) for the same reason. Do not tie-rap all balancing wires together, if there is any damage on the insulation of the wires you may get fire or at least smoke. Do not tie-rap the C- and B- wires in one bundle - if they short circuit you are disabling the complete BMS. Never ever use those large heavy cells wrapped in just packing tape. It's too easy to get a puncture in the wrapping or denting the cells. Also, follow the manufacturers specifications on how to mount these cells. I've seen manufacturers specifying that you must compress these cells to make sure they cannot bulge, resulting in de-lamination of the cell. How do you think these are EVE cells? EVE is a brand with a well known reputation so anyone selling EVE cells will leave the EVE label on the battery or at least have their own label with "Manufactured by EVE" on it.

@freelyroaming

Жыл бұрын

You should watch some more of my videos before making your critiques. I've got plenty of real world and technical experience building off grid electrical systems. 'Not my first rodeo' is the common expression .There is plenty of other videos showing how I've built packs that I actually use. As I stated pretty clearly in the video, this was not meant to be a 'best practices' build video. It is just to show how components go together which was something requested by subscribers. And for a non-mobile setup, there is zero risk of insulation rubbing, chafing and shorting. As a full time traveler who does a lot of DIY projects, we don't have the luxury of a workshop full of tools. Learning to do with what you have is a very useful skill. It is all about understanding and assessing the risks and make it work with what you have. I assume you just landed here from KZread recommendations without knowing other already posted contents my channel. There is one all about cell compression as it sounds like you might learn a few things from it.

With the BMS you used can you program the max charging amps? I am building one for my van and wanted to know if I can program the BMS to a max 40 AMP charge. I could use a DC/DC charger if needed but would be nice if I could do it without the DC/DC charger.

@freelyroaming

Жыл бұрын

You can't exceed the hardware limits of the BMS so usually it is not programmable

Yes akb LiFePo4 🔋⚡👍

@freelyroaming did you have any problem with the cellar supplier?

this was fascinating but i disagree about one thing, i would definitely put the BMS on top. Put it on the side and it's vulnerable to squishing or impacts, but on the top it's protected somewhat by the + and - terminals. And i would cut the sensor leads (and the ground leads) as necessary. Because the input impedance of those sensor inputs is quite high. That means that those leads are not pulling any real current and so cannot drop a measurable amount of voltage no matter how long they are. I noticed that in the menu settings the balance precision was set to 30mV. The voltage drop on those leads is much less than 1mV. Great work though, thanx for posting.

@freelyroaming

3 ай бұрын

Thanks. There are lots of pros and cons to how to build a simple pack. Doing what makes sense to you is what is important. This is just meant to show the easiest, no frills build so that more people can understand how they come together. Thanks for watching.

Why not top balance before assembling?

I'd like to build a 36 Volt package for a ezgo golf cart.

so in order to buy from alibaba there are stipulations are there not?

If you don't want large Ah , lead asic is still good enough for you compare to cost and lifespans of it.

What about using coroplast corrugated plastic signs as your dividers for battery and bms that way they can get some air between them

@freelyroaming

Жыл бұрын

The only problem is if you use something too thick the bus bars will probably not reach the studs.

im building a pack myself for workdue to supply issue what does the 120amp rating on the bms stand for is that the most amps it can handle? if so how would i go about making a pack that can handle 800amps. this is for a mobile hydraulic stage

@freelyroaming

Жыл бұрын

You can connect multiple BMSs in parallel.

Where is the best source to purchase these batteries?

I found some 320a cells. I will be building a battery very soon. What amperage to you recommend for the bms? Is a 200a bms to much?

@freelyroaming

Жыл бұрын

No it's not too much. It is all based on how much max current you plan on drawing from it.

Is there a relation between the bms Amp power and battery Amp Capacity? Do these both must have the same Amp rating? Or its ok for example to make 4 series 60Ah lifep04 battery with a 20A bms?

@freelyroaming

Жыл бұрын

No they don't need to match. The output amp rating is the highest amount of power you think you might draw. Higher amp rating will need a bigger and generally more expensive BMS. You can also run multiple BMS in parallel if you choose. Just make sure it you don't draw more current from the battery than it's capable to.

Hey Dan, do you have a video that shows what parameters to use on the mppt for our diy batteries? Or did you get them from the supplier?

@freelyroaming

Жыл бұрын

If you use a victron charger then you can just use their built in lithium charging profile. In one of my older videos of the battery build I did show it. I can make a quick video to show parameters.

@melaniecollins4045

Жыл бұрын

@@freelyroaming awesome thanks! I think a quick video would help a lot of us. 🙏

I'd like to build a 36 volt for my EZGO golf cart. How many cells would I need to equal six 6 volt Trojan T-105's ? And, can it be done ? Great videos, enjoy watching......

@mikek9488

Ай бұрын

3.27 volts on the tester per cell

i just built a pack with some 310ah cells that i bought on amazon I did everything you are doing and i'm only getting 30ah capacity from the bms screen can anybody help me out.

Nice work! Why was BMS chosen for a maximum current of 120A? It's only 1.44 kW. Is this power enough? Your battery can give much more, at least 2 times. For example, 200A (power = 2.56 kW) or even 250 A (power = 3.2kW). What is the basis for choosing a BMS with a maximum current of 120A? Thanks for the answer!

@ozmanfidaar6311

8 ай бұрын

Cost and application often determine BMS selection.

car can use this battery？

I’m going thru the Freely Roaming Series. A though came up. Where are the Bodwells. Do they have a KZread Chanel.

@freelyroaming

Жыл бұрын

No they don't do KZread. We actually just spent a day with them last week. they have been living in Colorado while their son goes to high school. He was out here on California visiting college campuses.

I am using a couple of those JBD bms's from radio tech. They haven't givin me one issue in yrs but the app can be frustrating

@freelyroaming

Жыл бұрын

That's good to hear. The app is very powerful but not intuitive. I'm testing to make sure the data is accurate and reliable and the will take time

How is one of these cells 280ah?

Thanks for a nice tutorial, what is the advantage of this battery over a 12V 680Amp 110Ah lead acid battery costing $200, is the lead acid battery working out cheaper per Ah at that rate?

@bigdaadio.K2WW

Жыл бұрын

well 110ah lead acid, compared to 280 lifepo4/for one thing. So basically you need 3 so there's $600 His LifePo4 battery can be run to near EMPTY, do that to a lead acid a dozen times it will be scrap. Lead acid shouldn't be discharged more than 50%-60%... if you expect any kind of longevity. So NOW you really only have a 50ah battery. NOW you need nearly 6. Hows the math going ? 6x$200? which would you prefer?

@freelyroaming

Жыл бұрын

And it will be about 4x the weight. Which comes to around 200 lbs worth of lead acid. For an equivalent LiFePO4 pack comes in at closer to 50 lbs.

@agritech802

Жыл бұрын

Ok thanks for the clarification 👍

@matb5368

5 ай бұрын

Cos you can only use 55ah of it without damaging it

Cut the wires, the BMS has next to no current when measuring so therefore no voltage droop. Also when top balancing no need to wait when first connected but when charging leave at 3.65 for a few hours.

@freelyroaming

Жыл бұрын

I've explained this in several comments exactly like yours. You'd understand if you are someone who makes videos like these

Is there a hi temp sensor? Is there a problem if the pack gets to hot like if it sits in a van during a hot summer day in the desert?

@freelyroaming

Жыл бұрын

High temp cutoff is at 146F. I hope I will never have to confirm in my van that it actually works.

@professorjedi1024

Жыл бұрын

@@freelyroaming hahaha me too... just didn't want to come back to a van in flames after a day hike in the desert :)

What if a person just bought the celss and connected them without the bms. Would they work and be ok to charge?

@freelyroaming

Жыл бұрын

You could over charge or discharge cells which will permanently damage them.

Can you please provide the dimensions for this build. I am looking to build a battery for our camper and the front battery rack seems too small for some builds.

@freelyroaming

Жыл бұрын

It fits perfectly in this container and you can get the dimensions of it in the description of this video kzread.info/dash/bejne/aphllKZsiM3YptY.html

I'm considering bv this but the warranty being 3 years worries me and if I need to cash in in the warranty am I going to have to pay for shipping?

@freelyroaming

Жыл бұрын

This is one of the risk of going thr diy route. Components don't have long warranties because a lot can go wrong in the assembly process. And at these low prices, you will most likely be paying for warranty-related shipping costs from your end.

Can I use smaller BMS than cell nominal AH? For example, I got a 4x280Ah cell and use only 120Ah BMS? Is that secure? Can I use an even smaller 60Ah BMS?

@freelyroaming

Жыл бұрын

Yes. It doesn't need to match. Just don't go too much over the rated output current which is usually 1C. That would be 280A in this pack.

So should one charge up the battery one cell at a time or change all 4 once it is built? Charger type?

@freelyroaming

Жыл бұрын

All 4 at a time. If you are trying to top balance, connect them in parallel and charge to 3.65v. if you are just charging them as you normally would during regular use, build the battery with the BMS and charge to 14.4-14.6 or whenever the BMS cuts you off. You need different chargers depending on what you are doing. A typical 4S LiFePO4 charger will not work for top balancing. This is a topic for a standalone video.

What torque did you use on the terminal nuts? Perhaps I just missed it.

@freelyroaming

Жыл бұрын

Didn't specify a torque spec. I am using a lock washer instead of the serrated flange nuts. I just get it down to snug and give it another 8th turn. Usually enough to hold.

You where touching all reds in one hand at the last steps of add. bms. Is that advisable?

@freelyroaming

Жыл бұрын

Are you talking about 19:25? If so, it's not a problem. All 3 of those wires are combined into the main negative of the pack. There are just split into 3 conductors to be more flexible while still able to carry a full 120A load.

How does the battery charge on negative? You leave the negative bms wires "hanging?". Huh, interesting. I would have thought you would be connecting loads directly to the battery but i guess if the bms has protections it hzs have to have the current go through it

@freelyroaming

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That's correct. If you connect directly to battery negative, it would work of course but you would lose all of the protections of the BMS. Because this is a common port BMS, it means it charges and discharges from the same negative port. The protection schemes apply to both charging and discharging so you never want to connect anything directly to the raw negative battery post besides the BMS.

@researchandbuild1751

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@@freelyroaming That makes sense now. Thanks a lot for making this video! It looks pretty straightforward to build this. That's a huge battery ! 4Kw of energy for only $700ish, wow