Thank you! All Right Video Time! Uh, this is probably the my favorite battery that I've designed so far. This is a 52 volt, 10 amp hour E-bike battery. Um, as you know, I've been getting into designing batteries. Here are some other ones that I've designed that are from different cells and different things on this one I Started with the small one here 24 volt just to see how I can get the dimensions and then I went into that I made a couple mistakes here and then a couple mistakes there.

those are the different iterations but then finally we're here. This one has everything on the right place. Um yeah, all the dimensions are correctly and when perfectly So now this, this is probably the final one here. I'm gonna order all these parts and then oh, the only thing that there's left is to test it.

So what I'm doing here is I'm charging it. Here's a three amp charger 58.8 volts right? and that's what a 14s battery would need and it's going through the BMS here. I want to see if it will, uh, balance the cells, but these are brand new cells so they're perfectly balanced to begin with. Uh, but I'm just testing it right and then eventually I'm going to load it up here.

The BMS that I chose for this one is a 45 amp. BMS continues. It'll do up to a 90 AMP Max bursts right? So this battery is perfect for an E-bike Uh, what's uh, 45 amps times? 52. Is it like that's like two kilowatt? and then 90 is like four kilowatts.

So this might be able to be used for a very high performance E-bike I mean I don't know. high performance? maybe mid performance? I don't know I don't know where the levels are on E-bikes I think high performance goes into like five kilowatt or something like that. some crazy amount that's ridiculous power when it comes to a bike level, right? But another thing that I'm doing here is that it fits in a bag like this. In fact, this bag is a bit too big which allows you to then also put the controller here.

Everything in the one single thing and then just cables would come out and then go into your thing. but this, uh, I've ordered smaller ones in here that I might fit in here. adjust the battery in case you're just adding it to a new bike that already has the controller and those other electronics somewhere else, right? But these are, you know, just the experiments that I'm doing. Um, stay tuned for the final video where I'm showing you how to put this all together.

This will be an open source project. Like all my projects, you'll be able to download the files to print your own boards and then put this battery together yourself using any Uh 21 700 cells, right? These are very, very popular. These are the latest that are on all the new cars on all the the Teslas. The model 3s have these uh, and the Rivians.

those ones cars that I'm uh driving around and getting these have the 2170s and so these are gonna be pretty cool. This is, uh, very small and very light for being a one kilowatt hour battery pack. I think this is uh, good for like 25 miles, 30 miles or something. something like that.

um depending on the E-bike of scores right, but stay tuned for that. It's coming up once. I Finally do the testing. Oh yeah, it even has a thermistor here for temperature.

All I'm missing is the little white uh glue that will allow me to glue this little guy in here so that it transfers the heat from the south into this uh sensor. So then the BMS knows to either to cut off if it's the cells are too hot. uh and probably yeah, probably this is probably heat I Don't know if it's for cold, but we'll test it. We'll see how that goes.

now. time to test this battery. Here it is. It's connected in there and it's going to do this.

This is just a meter so that uh, it's got the capacity and it tells you the voltage and then tells you how much current is going through there. Then that connects into two grid type inverters. I'm gonna try one first, but I think the total that this does is like 20 amps. So I think both of these will load this battery for with about 40 45 43 amps I think at the beginning and then it's gonna gradually get into like higher closer to 50 amps right? So it's a 45 amp.

Uh, 45 amp BMS Will see how it does under this load, will measure everything including the capacity, and then the thermal camera will check to see if there are any problems with the design of the battery. You know, if anything is getting hot and stuff, these are all welded with a single weld. I Want to see if maybe we need to do a second weld on there to be able to carry more uh, current, right? Or maybe just increase the power on the welder? Uh, we'll see this is around 30 I Think it, no, it's 25. I think whatever the setting on the thing is.

So if we'll do another test, we'll test this one. If it gets too hot or it's got hot spots or whatever, then we'll do another one and we'll increase the power. We'll test that one and then, uh, then we'll take it from there. Let's test it.

We have just started the test. We connected the inverter there it is 900 watts, 21 amps batteries being loaded with 21 amps. All right there we go. 98 So we've taken two percent of the battery.

Uh, there's a hot spot here. Oh, but it's just that connector this connector might turn out to be. Uh I Might have to make a better cable if that's the case. but let's move that out of the way there.

Yeah, this is my hand so this is still all very cold. It's just you know, 25c is. uh, all right. So now we've connected second one.

now. it's 1800 watts. Oh, 2.2 kilowatt according to this. But then this one doesn't match that.

Anyways, 43 amps, 44 amps. Uh, let's see how this camera see what this thing is gonna do. It's still pretty, uh, cold. It's not warming up.

Okay, now we're starting to see some warming up there on the sides. That's the BMS The BMS is really hot. A hundred? oh my. God Okay, it can't be good for that.

BMS and I'm only pulling 43 amps. so I'm within spec of uh, that. BMS it's a 45 amp BMS and I'm pulling 43 amps. It was pulling a little bit more for a little bit for a few for a minute or two here and then I had to reset my things to higher but it is still Rising As the voltage lowers diminishes, then the amperage keeps going up, but it's still pulling 1.9 kilowatts.

So this is continuous though. So continuous it's gonna get that hot in there. And that's the mosfets. Yeah, if we point out here, oh I mean that's really hot too.

That's okay. So my bus bars are what? Yeah, that's in the 70s. that's kind of hot. but But man, that BMS is that's hot.

It's really hot. So this is what will happen when you run this battery at a hundred percent. Maybe I need to rate this at 40 amps instead of uh, 45 amps. So we're trusting that BMS right now that it's gonna cut power when the voltage of the cells goes down 127.

Okay, that's way too hot. Okay, Okay, so I'm gonna disconnect this. Okay I just terminated this test because that's a 130 degrees and I can see a little bit of smoke that BMS is um, well, it's not gonna survive this test. We were at 5.4 amp hours left, 26 left.

uh, 48 volts right? It was around 43 volts when I terminated this test, but that was already starting to smoke and in fact this thing might still go off I might just have to throw this battery outside just to make sure. Yeah, so this BMS does not impress unfortunately. So I think my batteries my bus bars are okay I might have to just beef up a little bit. Um, the uh, the nickel strip here so that it doesn't heat up as much.

but I didn't see any hot spots in the actual cells. You see? That's all pretty even. All right. So final result: I Don't know what do you guys say? Did this survive? Is this good design? That's probably not a good? BMS but uh, they're kind of.

It's hard to find good BMS that are that size and stuff so maybe we just have to do rate this battery. Thank you.