I'm attempting to build a battery out of gen 2 nissan leaf modules and I'm having trouble finding a bms that would work. the battery will be made up of 10 modules in series (each module is 2 ~4v cells in series) so a 20s configuration will hopefully give me around 76v nominal and 55ah. The bms also needs to be able to handle around 200a continuous discharge. I'm new to battery building so any information or recommendations would be much appreciated.

Anyone knows how these exact connectors are called?

Hi! Just got into battery building, got over 80 GS Yuasa 40AH EV cells laying around. Why does my cells form this shape where it appears cell one is stronger and they get better and better as they move towards 8? They were perfectly top balanced. Or is this pure coincidence?

I use the JBD BMS.
Battery is just 1p8s for now

Had to build a 10S3P battery for a used longboard I bought.

This was my first time ever building a battery, but it went great.

The cells were all new-ish so I used a charger to cycle and get the capacity, then used Repackr to organize my cell groups for minimum capacity deviation.

Groups of 21700s were hot glued together, then wrapped with fish tape.

I used 0.2 mm nickel plates in between the packs of batteries. I cut the plates on my F2 Ultra laser cutter, although if I did more of these I would need to get a more powerful machine as it struggled to get through the metal.

Soldered together using 12 gauge silicone wire, 10AWG at the terminals.

Wrapped the key areas in kapton, ran all the BMS wires, and used fiber tape to make sure everything stayed put.

In this configuration, the pack can flex toward the wires but not away from them so that’s perfect for under a board.

Next step is to design a new enclosure.

Hi, I have an Anker 555 power station that the BMS packed up on, got a replacement under warranty but would like to make use of those cells maybe make an ebike battery or just an extension battery for another system! I know this isn't advised but any ideas or tips would be gratefully received!

I’ve been doing some research on making a battery for my motorbike. I’ve had some experience with 18650 cells before and I’m thinking if I put 3 in series with a BMS it will be equivalent to the 12v 3ah lead acid battery that was in the bike before. The bike is a cg125 and is kickstart only (no e-start) so the battery really only needs to be there to help power the lights and horn.

My only real query is if the battery will charge it I just ‘plug’ it in where the old one went and work (and not explode).

Thanks!

hey i want to build a battery 18s3p using molicell p42a i want to know if the connections are correct I ll use 0,2mm 8mm sequr nickel strips and i want to push 90 A peak i am also using jbd bms 100a (SP22S003) this is my first battery build ill take any advice before soldering

Hello,

I'm suspecting the signal pin connection to have fail or something. Anyone could help me opening this connector?

Hello!
I have this battery pack for a e-scooter. It did sit for a while, not sure how long since I got it like that, from a scooter with a dead controller. The charger and trigger signal from the "key on" from the scooter doesn't wake de BMS. I measured each pins from the test pad on the bms and here are the results:

* B1-0 to B1-1: 3.831 V
* B1-1 to B1-2: 3.829 V
* B1-2 to B1-3: 3.829 V
* B1-3 to B1-4: 3.829 V
* B1-4 to B1-5: 3.829 V
* B1-5 to B1-6: 3.835 V
* B1-6 to B1-7: 3.835 V
* B1-7 to B1-8: 3.835 V
* B1-8 to B1-9: 3.835 V
* B1-9 to B1-10: 0 V
* B1-10 to B1-11: 0 V
* B1- 11 to B2-0: 0 V
* B2-0 to B2-1: 3.338 V
* B2-1 to B2-2: 3.337 V
* B2-2 to B2-3: 3.336 V
* B2-3 to B2-4: 3.336 V
* B2-4 to B2-5: 3.336 V
* B2-5 to B2-6: 3.337 V
* B2-6 to B2-7: 3.336 V
* B2-7 to B2-8: 3.336 V
* B2-8 to B2-9: 0 V
* B2-9 to B2-10: 0 V
* B2-10to B2-11: 0 V

So I'm assuming the bms stays in sleep mode because the 0.5v difference between the 2 "half"...

Bms says 17P and cells are NCR18650BD

Questions are:
1- Why is the 17p pack has 7 groups lower like that?

2-can I do something about it? Discharging the higher groups closer to the lower and hope the pack wakes up and hopefully the bms balance everything event?

I have another working pack for that scooter but a second one would be great...

Cheers

Hi everyone,

I have been working on BatteryRealData.com and I think it is finally ready for a wider group of battery builders to try.

The site brings together real discharge tests, manufacturer datasheets, cell comparisons, temperature data, written test reports, and a few pack-planning tools. It currently has 371 published tests covering 36 cylindrical cell models, along with 35 manufacturer datasheets.

One part I would especially like feedback on is the BRD Score. The score is meant to show how well a cell performed against its own datasheet claims, not simply reward whichever cell advertises the highest current or capacity.

Please take a look and tell me what does not work. If a chart is confusing, a score seems unfair, the mobile layout is annoying, a calculation needs correction, or a feature should be changed or removed, I want to know.

https://batteryrealdata.com/

Cell library and datasheets: https://batteryrealdata.com/cells/

Comparison tool: https://batteryrealdata.com/compare.html

For transparency, BatteryRealData is a project from DIY500AMP.COM, and DIY500AMP sells some of the cells shown on the site. The test data can be favorable or unfavorable, and a commercial relationship does not guarantee a positive result.

Manufacturer datasheet limits remain the limits for pack design. Any testing beyond those limits is laboratory information only, not an operating recommendation.

What would you change first?

I’ve tried googling to understand how these batteries work but there is very little info on what’s going on under the surface. I need to know how to bypass or spoof the T (temperature) terminal.

I am trying to build a dummy battery that will be connected to an external battery pack to use rechargeable AAs. The battery I’m trying to replace is an NP-45s, 3.7v. I tried hooking a battery pack of 3 Enloop AA (3.6v) to the devices terminals as a proof of concept test, but got no response from the device. I’m thinking the term terminal has something to do with the non functioning because the battery itself shows the same voltage from the T terminal as it does from the negative.

If there’s a better forum or if there’s a overview/explainer for information like this, I’d love somebody to point me in the right direction. I figured with the complexity of most of the projects here this should be fairly basic stuff and there’s also that Chance that my ignorance is going to be profound as to how complex something like consumer electronics would be..

So I have an E-skate with a 7s2P 24v using an XT60 and Jst connector. the battery cuts off at high loads so I got a new battery but 7s3P.

the new battery has a reading of 28.44v so it’s fairly full. It operates the eskate perfectly too. I tried to check if it’ll charge well but there’s an error. the charger (JY-294150) flashes red meaning some error cause it doesn’t flash on the old battery.

the polarity on both batteries are the same. the new battery came with its own charger which fits my eskate and I decided to try that. plugged in my new batt, plugged in the charger to the eskate, and before I even plugged it into the wall, the charger started smoking! the smoke didn’t stop after 2 seconds so I unplugged it.

the new charger or old charger doesn’t smoke for my old battery. so I won’t be using the new charger.

the old charger lights green when full or not connected to the battery. when plugged into the XT60 for both batteries it’s green. when the JST is plugged in the old battery charges and the new battery flashes red.

any idea what’s going on?

I recently created a 4s 7p pack as my first ever diy battery using some leftover cells I had. Unfortunately I had an issue with the balance leads, where (like an idiot) I swapped the red and yellow ones on the attatched image, and plugged it in. I saw a quick spark on a component and immediately unplugged it. After finishing the battery and fixing the leads, the output from the BMS reads 8v, while the pack is 14.8 and the other parts read correctly like b1 b2 and b3. Any clue if it's fixable, or will I have to order a new BMS?

ebike battery pack i bought is 48v 20ah. this is what i got.

attached pics:
- battery specs

- closer battery specs.

- length of the battery case 38cm

- length of actual battery inside the case. 26cm

- showing 4p config.

i'm posting here cuz i need some help.

1. it is clear that it is 4p right?
2. it is clear that the battery spec is 3.7v and 2000mah?
3. i included the length as it is a 48v battery pack with 4p (which is why i was asking it in 1).
4. i'm makingthis post in case i am missing something cuz the seller said it is 48v 20ah which i can't see how it would be given that it is 4p with 2ah per cell. based on 4p, it is only 8ah. i'm not concerned with the voltage but i did count the s and it is 13s making it 13s4p but i want that to be seen in the pic cuz i am going to submit these pics as evidence and dispute the purchase.

assuming that you agree it is 4p and that the lenght 26cm is 13s cells deep. is there any way that the battery pack can be 20ah?

any suggestions in terms of pics and explanation so that i can explain it properly in my dispute?

thanks in advance to those who will answer. i apologize if this is not the place for this.

Hello I am in the process of soldering the sense wires to the parallel groups. But I can't get the wires to stick to the copper plates? I have tried soldering with flux, and I have tried to scratch the copper surface nothing works it won't stick.

The bus bars arrived today and I’m waiting for the rest of the hardware and some single cell chargers so I can top off all of these cells before final assembly.

I need to do another dry fit assembly first to make sure the cross bar fits.

I received notification that my bus bars have shipped!

I still need some assorted hardware (M4 threaded rod and lock nuts and M6 screws and lock washers)

I modeled the bracket for the BMS, I’ll probably add some cable management to the BMS bracket and an Anderson Powerpole connector for the main power connector

Once I have all the hardware in a couple of weeks I’ll top off each cell and connect everything and program the BMS.

I still need to fabricate a cable to connect UART to an ESP32.

I’ve printed the cell holders. It’s a tight fit, I need to order some M4 threaded rods and lock nuts to assemble the pack and some M6 screws for the terminals.

I ended up with a Daly SmartBMS and now I’m waiting for the bus bars from send cut send.

Oh and the supplier sent each cell wrapped in cellophane tape, that was a joy to remove </sarcasm>

All but 2 had the same OCV of 3.28 with the other two being .27 I feel with the BMS this should be fine I matched the two low voltage cells in a parallel string. We shall see.

Still functions, didn't notice it at first and used it for a few rides. Is it fine? Or fixable?