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All right, let's talk about these 48 volt modules that are sealed. Okay, these are a pain in the rear to take apart they're a lot of work, the module is glued to the top and to the bottom right with epoxy. So it's really hard to get to the inside right um. The other thing is that these then have a bms that is proprietary.

We don't know how to use it and there's not enough of these ones that it make it worth it uh to figure it out. Right, if we you know, if we, if we thought that we were going to get more in the future, and it was going to be a constant thing, then we probably would figure it out. But this is a small load that came in, and so the best thing to do is because, since they're so hard to take apart, it's just to try to use them. As is inside of this module right.

They stack real nice and so what we? What we have to do in order to make that happen is we need to bypass the proprietary, uh bms right, the stock dms that's inside, and what i figure the easiest way to do that is well to we have to get access to the balance leads. These are these little flexible, uh, pcbs that are in there and so in order to do that, you'd have to cut a hole on top like this, i used a little dremel tool and not just cut it, and then after that, then you have access, and then You can pull both of these. What this allows you to do is then now connect an external bms in here. You'll need these student fixtures no bms.

The other thing is now that you have to bypass the the bms right, the main leads, and in order to do that, well, you might have you have to short out these mosfets that are in here. This is uh this. This is a board that is not populated, it's one of these on one of these boxes, so it makes it easy for you to check on here right. So what i did to do, that is cut a hole in the front, and then you have access to the mosfets there right.

You see that and then what i ended up doing was just soldering a piece of copper, solid, copper from the top um mosfet to the bottom mosfet, and what that does is well it shorts out the input all right. This is the terminal input terminal of the battery to the output, and so therefore, now this is eliminated. This is now in there, but it's doing nothing, and so once you do that, then these terminals, right here, are connected to the internal cell terminals right and so this bms here now is not doing anything. So then, what that allows you to do is to use this battery as is, but still have access to uh well still have access to the internals to the everything that you need to put an external bms and then use this battery safely um.

Now. What are we gon na do with the with the holes? Well, i can make some pcbs that are the exact size here and then we can just glue them in there right i'll make another pcb here and then we'll make a connector that connects to here and then connects it out here and you'll have a nice little Connector that you can just plug in there and you can daisy chain to all the other ones that you're gon na parallel. If you want, if you want to parallel right, uh, let's charge this battery and then see uh how much current this will handle, because now this will become the well become a bottleneck here right because uh, it's just a little connector there, that's soldered there. Let's use yeah we'll see how hot it gets.
Maybe it does 20 amps, maybe those 40 amps, maybe 60 amps. I don't know the cells could do 80 amps uh. Maybe this will handle adms. I don't know well, let's test it all right right here.

I am charging it and this is uh how it would work, see how it's got these connectors and we're able to see every single one of the cell modules or cell groups right. So we're charging to here right at 14, amps right now and then we're seeing that. So this is how you essentially would plug these batteries. And you would, you know you can parallel a bunch of them and then you connect your bms externally with the connector sort of like this, and the bms will be able to check on your battery cell groups and and then decide whether it's everything's good or if Any of those are bad and then you know stop the the charge or discharge cycle.

So right now, let's bump this up to as much as i can on this power supply. So there we go it's 21 amps, 20 amps uh and then let's put a thermal cameras here to see how that connector is doing at 20. Amps on the discharge cycle, then we'll be able to add to do a higher rates, but for right now, let's just check the 20 amps in there. Okay, so here are the two uh little meters right.

This is my hand. Uh my hand is at 34c celsius right and then there is that hole. You see that little square there that's the terminal and then there's the there's like zero uh there's like zero heat in there. That's so weird like nothing that connection there.

With that, the way i soldered it in there it's it's able to handle 20 amps, no problem, which means that 40 amps, maybe it'll, get warm uh, maybe 60 amps. I think it'll be able to do full power there. Just by doing that, i think that's a good thing, so we're that's encouraging right there right so we'll test it once it's fully charged we'll discharge it at 80 amps and then see how hot that gets and then yeah and then we'll go from there all right Here is the uh discharge test. I have two 2k uh grid tie inverters right, so i have them connected to the grid.

Now they're pushing they're taking 34 only the one right. I have one. It's only doing 1600 watts right now, uh and so that's equals about 34 amps out of the battery. I have these connected here so that we can see yeah.

They don't sag very much at 34, amps right so 34 amps. Let's let it run just for a little bit and then we'll put the thermal camera on there and see if uh, if we see any heat and if we don't then we'll double it up, we'll do 60 um and when maybe i can get more off of These, let me see if i can get more of a single one, all right, so i just connected the second one and now we're doing 70 amps that for sure that's got ta, be put some heat. Now, let's put the thermal camera there. We go.
You see that you can see the uh, you can see the uh the little window there right. So, let's see if we can put this camera there. So this is just on the one side and it's got the one okay, but that's not getting super hot. That's only 38c; now it's only been you know about a minute, or so we're gon na run this continuously to see how hot that gets and uh you know.

If, if it gets too hot, then you start having problems like uh like the solder starting to melt right, and so that's that's not a good thing. You don't want to get to that point. There um - and i think that happens around 200 degrees celsius, or something like that, so we got quite a ways right. It's like this is 34..

This is not even 40 here uh. This is not even a hot day in the summer right in australia, for example, right so it's uh yeah. This is it's not hot. It's just it's just getting warm uh all right! So we're still doing continuous here now we're uh a few minutes now still pulling 71 amps and look at this um.

This is very interesting. There cell number one and cell number 14, like those - are the the lowest see how see how they're seeing the brunt of that uh that load there so yeah even pros man, professional battery designers. They get this problem too, when they're designing their their batteries, where, like the the cells at the edges, right right at the terminals uh, they they get to see a little bit more stress. So it's not an easy problem to fix.

I know there are ways to fix them uh by having some symmetry on the things, but it's yeah. So that's something to keep in mind there around this right. We're almost at the max continuous uh about nine amps more con continuous, is the max right on the continuous on these cells. So now, let's look at the uh, the temperature of that uh hack there that we do so there we go.

There is about 49.48 degrees celsius after a few minutes. Oh 50., there we go 50c, all right, a few more minutes, five minutes after and it's still doing, continuous 71 amps and now this seems a bit more saturated but still 50 c. Htc is not a lot, and i think that is well. That's like the pcb board in there right, uh, not so much.

The copper like the copper jumper that we put there now that's fairly, that's fairly uh cool at 42 degrees or you know, 40 degrees celsius. Uh, it's just the surrounding area there, but here's the other thing: let's take a look at the whole module and uh you'll get to see other stuff. So there we go. Look the standard, uh! There's another thing over here! Well, hell! That's that! Well, that's where the the board meets with the terminal, yeah, there's a bolt there and that's creating a hot spot, and then this is creating a hot spot.
Uh. These are the cells right, there's a hole there, but if you back out, then you can quite see the battery that the battery is well. It's it's warm right. It's not super warm! It's 33 degrees, but you know compared to the ambient so yeah i'd say that could do the max.

If you do that hack, if you do it right, if you clean the terminals, if you put enough heat and solder a jumper like that similar to what i did there uh yeah, i should be able to do 80. Amps no problems continues there not much heat. Maybe around 60 degrees celsius uh, which is about no. These cables are good.

I have a 6 gauge or 8 6 gauge cables in there, and these are are warm but yeah. Nothing, not they're, not hot. You know, they're doing good. All right, i'm gon na stop.

This test here this uh - this is four kilowatt uh worth of inverters, and this can put out right about four kilowatt um. The cells are rated at 2c, so this test would run for about. You know half hour, um we're pulling three right now right at 71. Amps, and so it would run probably more like 40 minutes or something like that, so so there you go.

These are two kilowatt hour modules capable of 2c. You would have to do this hack to be able to use them like this. These are the rest of them that we have right uh, and so imagine i'm going to make these little boards that have this breakout, uh idc plug in here, so that you can stack them. Let me stack up, so you can see what that would look like there.

We go so i'm going to build these little boards here, uh the breakout board, so that you can just stick them in there and then you can daisy chain them. Um a board in here to cover the hole for the hack right, uh i'll, probably make this uh yellow instead of this black right and then like the top one. That goes up here i'll. Do that one black, but these are pretty cool um! You imagine you you have five of these.

That's a 10 kilowatt hour, uh battery pack right a little powerwall! You do ten of these and stack them up and daisy chained them right, connect them on parallel, and you got 20 kilowatt hours, uh very easily. Uh of some of the most you know a premium cells right, 2170s uh, and these are brand look at look at the dates on these guys right, so they were putting this pack together in may 25th. 2021 um, i saw i even saw january 2022, which is a couple months ago, so these are fairly new cells. These are not cells that have been there forever.

These are not rejects, as it turns out. What we're finding out is that these are not rejects. The reason why they send it up is because this is the the like the test run. This is probably like a brand new product, and so before they figure all the stuff in dial in order machines, then they have to do a bunch of these tests and that's what these are right, because that would explain why some of the boards, some of the Modules inside are not even spot welded together, uh some are spot welded together, but they're not actually connected to the bms board, but they're sealed in the box right.
So they needed to have the real modules inside of this machine and then so that when they they were running and the sealing the the box right and also when they were laser uh spot welding. The the the modules to the actual bms thing right - some of them were just used with the screw and some are like lasered, there's a bunch of different versions of these boards of these modules, and they you can see that they were trying a bunch of different Things right, and so as a result of that some of these cells - i've never been cycled because they've never been connected, they put in a module and that's it and some of them are were connected together, but then they were never used. Maybe they were tested. A couple times or something to test, maybe like the bms or something so this is kind of an opportunity that comes around not very often to get batteries that are kind of new, so clearly, some of them clearly brand new unused uh or some of these are Like test units or whatever and then they're kind of easy to hack there now this is a diy project.

Right you'd have to hack these and do them. I can't do it for you, because if i do it i mean i'm in california, so i have to pay california wages. I don't pay my guys. You know minimum wage all if i'm going to do a few of those, maybe 10 of them or so put them up there, they're going to be done or whatever uh, so that i can show you like in the video of what looks like finally and stuff, But the likely scenarios that these are going to sell out anyways these are at the prices that we're offering these people are buying them up right and so um yeah i to be able to get these uh like this.

You have to do the work because i do the work. Then i'm gon na have to charge you a bunch of money and it would tie up all my guys and myself uh. I i'm looking at the next loads of batteries that aren't coming in right. Uh.

That's the that's kind of my daily thing: it's like uh, it's always like what came in today. Yes, all news and what's gon na come tomorrow, it's better like we have a a load of like inverters coming in and other batteries that are coming uh. So we i have to start looking into those. I can't spend too much time in these, especially since these are already half of them are sold out and uh at the posting of this video.

This second half will likely sell out right, and so, as far as i know, there's there's not going to be another one of these loads uh coming from this company, so yeah we're just gon na have to keep moving, and this is a great opportunity to get A cheap battery that is uh pretty premium and it looks cool and it's very easy to hack into a very usable thing right. So there you go uh. I will oh, so here's one other thing before: how would you manage the bms right? If you do this? Do not run without a bms, i mean you're right because you will be taking a chance. So what you do is you parallel these right? Parallel all the positives, all the negatives, and then you would run the uh, the cable here, the the idc cable and connecting all the uh balance leads of these batteries.
Now, when you do that, you would have to do these first to let all the batteries uh balance right. If any of them there's any variance in voltage, then you connect them together and you let and these can handle. You know large currents right like up to 80 amps continues right, uh and then after a while once they're there, then you can connect the the ribbon connector right and then that way, once they're all balanced, there's less chance of any of this stuff like running and Trying to run too much current through this and then once you do that the the leftover thing now could go to an external bms sort of like this look. This is a dolly bms.

14S. 48. Volts 80 amps right. So this is good to do one module.

If you need this is about four kilowatts, so if you need more than four kilowatts, you have to get a bigger one or get uh another. You know several of these and parallel them, but they make these up to 200 amps right, so they make them like really big and all you would have to do. Is you put this cable here right and then the p minus goes to your load. Goes to your inverters and then your charger you charge to here and all this other stuff right.

So this is how you would uh run one of these battery packs in parallel or a bunch of these in parallel and then run the bms externally right and you would run these and they would be safe. Because you'd have this bms managing your batteries and if anything happened, if any of the groups were to go out of balance, then this thing would let you know, and it would just disconnect itself and it wouldn't let you uh keep going charging or discharging the thing Right and so i'll make i'll make like a little board, uh that where you can connect the thing and it's labeled, so that you know how to connect this in there and stuff right um again. I can't go too much into this because these are basically sold out. I know that right, i they're not yet, but as soon as i upload this video, it's gon na be kind of thing uh.

This is great for the diy. You guys are my diy crowd right, so this is uh the thing right here right, so there you go. Thank you for watching this video, we'll see you guys on the next one. Uh yeah stay tuned.

If you're into doing battery stuff uh make sure you hit that like button, it does help the channel uh, get more views and get more subscribers and get more people to find uh this this cool world and hobby about batteries. Right i mean i don't know. I thought i was crazy, uh and a complete nerd uh. You know with this battery obsession that i had and as it turns out, there's a lot of you.
Look at my channel keeps growing every day right so hit that like button, so that other people that are interested in stuff would find this stuff interesting would find it also right there you go we'll see you guys, the next one bye.

2 thoughts on “Diy hack to use the 2kwh 48v stackable modules”
  1. Avataaar/Circle Created with python_avatars Jose Arrasola says:

    Hello sir sounds like an awesome plan but about the ones you said that might be spot welded also on the mosfets three pin outs source drain gate if you it just any one of the pins the mosfet is dead and no power ! I was thinking about getting some but when I get play money I have payments to go out and right now I’m looking into getting more land Miami prices are way under market

  2. Avataaar/Circle Created with python_avatars Shaul Jonah says:

    Explain bms I googled it and what you said isn't there.

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