18650 10s3p battery

[cmatson]

so about a month back, my enertion space cell just sorta died. After emailing back and forth with jason, we think the bms to died, but it's still a mystery that hasn't been able to be replicated. The new space cell's all have fuses on the outside, to prevent that from happening anymore. Long story short, Thanks to the amazing customer support at enertion, I now have a new space cell, and a broken old one. I already took apart the old one when we were trying to figure out what went wrong, and we know that the cells are giving off there 42 volts, and its just somewhere with in the bms where things went wrong.

so essentially I have 30 perfectly good 18650 cells in a 10s3p setup, all linked to a dead bms. I'd like to re-use the cells to make another 10s battery, but I really don't know where to start. I've seen plenty of threads on the ebike forums about 18650 packs, and many videos on youtube aswell. I was thinking the easiest thing to do would be to set it up with a balancing plug just like a normal Lipo, but my charger maxes at 6s, and the 10s ones are pretty expensive. Would the easiest thing just be to get a new bms, and if so where is the best place to get one? I have seen plenty on ebay and other websites, but I don't know what would be best for a skateboard where you need fairly high burst discharge for acceleration. 60 amps is what I believe the enertion bms was set at... but I could be wrong on that.

Thanks all for the help, and here are some photos

 

[Nobuo]

The easiest way would be just replacing the BMS board, using same balancing and even same balancing connector to the new BMS. Could you take a photo of the BMS board?

Your BMS is a 11 balancing conections to all the cells ("+" main and "-" main included) so you could use a 10s BMS with also 11 balancing wires and the plug with probably fit pefectly, in any case you could always soldering the new BMS plug.

There is a chance to find the same BMS if you could take a photo of it's PCB

 

[dnmun]

show us a picture of your BMS so we can instruct you on how to test it and fix it. show both sides with VGA pictures. post them here and not on a hosted website.

 

[cmatson]

View attachment 1


I've looked around since taking these pics, and have found one or two here or there that look really close, but are only 30 amps instead of 60 amps, and you can tell the look a little different

 

[chaka]

Here's one on ebay http://www.ebay.com/itm/36V-37V-42V...-PCB-System-/221769582503?hash=item33a27f47a7

I would recommend you go through bestech power but they usually have a 2 unit minimum http://bestekpower.com/37v10spcmbmspcbforli-ionli-polymerbatterypack/

You could eliminate the BMS altogether and monitor the pack manually with a cell log/alarm and a balance charger. I would add a fuse/breaker to protect against overcurrent if you go this route.

 

[dnmun]

while connected to the battery measure the voltage between the source leg and the gate on the charging mosfet on the right and do the same for the other 3 mosfets to the left. they are tied in parallel at the gate if you look at the traces. so they will all be the same. use the 20C DC scale on your DVM.

 

[cmatson]

ya, I saw that one on ebay but it only has 10 signal wires, as apposed to 11 on mine. how would that be setup differently?

 

[dnmun]

you don't have a voltmeter?

 

[chaka]

The first balance wire, the negative wire from the first cell runs to b- on the pcb but I have no idea on the quality of this BMS.

 

[cmatson]

yes, I got a volt meter- I was just replying to chaka it didn't see your comment until afterwards. I'll test the voltage later today, when I get home.

 

[dnmun]

do not assume it is broken until you can test it.

why no one else recommends you verify it is dead before buying a new one is a puzzle to me.

 

[cmatson]

well we have confirmed that the voltage from the cells is correct, because I measured it with a volt meter, but nothing is coming off the BMS...

 

[dnmun]

but i have seen no evidence you tested the BMS.

 

[cmatson]

ok, I'll test the voltages and then get back to you

 

[dnmun]

if both of them are turned on you will see about 7-9V on the gate.

 

[cmatson]

So I am pretty much a newb to all of this with the BMS and everything, so I am sorta confused on what you mean by the source leg and the gate on the charging mosfet... I'm just not familiar with how all of this is labeled. Now that I have the battery in front of me, I am realizing that I'm just kinda lost...
Here is what I know so far though: there is 40.2 volts coming from the cells- thats been tested before, and I just verified it again. But, there is nothing coming off the BMS even when turned on. I've also tried just bypassing the on switch to see if thats the culprit, but still got the same results.

Sorry for probably being a huge pain, but I really haven't done anything with a BMS, or even used 18650 cells before now. Thanks for the help!

 

[cmatson]

Thanks all for the help, but I have actually found a replacement BMS through also talking with enertion!

 

[dnmun]

but there is nothing wrong with that one.

 

[riba2233]

but there is nothing wrong with that one.

Yeah, he's just decided to stop using his battery with no reason at all

 

[onloop]

do not assume it is broken until you can test it.

why no one else recommends you verify it is dead before buying a new one is a puzzle to me.

You are right.. it should be tested and the exact fault should be isolated then repaired.... but as this is a new product from enertion, actually its the first of its kind for the DIY eboard industry and as we are a small business trying to grow and build a loyal customer base i simply could not afford to have early adopters who have spent good money being asked to do advanced trouble shooting.

My theory is if you pay good money for product you should get good results and even better service.

So in this case we accepted responsibility for the fault (even if we could not physically test it, due to being in different countries, to determine exactly what happened) ultimately it was our oversight for not including a fuse with our product to guarantee it is not being discharged at higher amps then what the BMS is designed to deliver.

We have also communicated with the ESC supplier and helped caden modified the settings to make sure the system is not pulling huge amps.

So in this case caden got a brand new battery shipped to his door under warranty And we will also arrange to send him the replacement parts (at his expense this time ) so he can repair his original battery.

Caden I think considering your young age (not that it should matter). 15ish? I think you are doing a great job so far, even with some hurdles along the way, you have stayed positive an kept an open mind on this project.

 

[dnmun]

no mr onloop, you missed the point of why we try to show people how to repair stuff.

by openly walking people through procedures of how the user can diagnose and determine what has happened to cause their battery or BMS to not work, it educates others who read and follow the thread on how they can proceed in fixing their own equipment.

some people just do not fix stuff themselves, they get others to do it for them.

some people can learn how to examine and fix their stuff by following the analytical procedures we try to show them.

this thread just went nowhere so no one learned anything except how to buy replacment BMSs off of ebay for no reason.

just one or two measurements would have isolated the problem and many others would then have an idea of how to fix their own equipment. that is what we try to engender in the readers here. or what some of us try to do, anyway.

usually it is a loose sense wire, but it would have been interesting if it were more complicated but i can see from the pictures that there was no failures of the mosfets that caused them to overheat so i am fairly certain that the BMS is functioning properly, but is getting an input that tells it one of the cells is out of spec because a sense wire is disconnected. or the thermal breaker has opened and shut off the circuit current.

 

[onloop]

Don't get me wrong... if my products breaks....I would love to tell my customers to fix it/diagnose it themselves... if they complain I'd love to say hey its better if you just learn how to fix it yourself.... but how long do you think I would last as a respected vendor with that attitude?

- there is a difference between building something yourself from scratch using parts sourced from wholesalers and then trying to troubleshoot/problem solve issues that happen to arise after you self-built-it

VS

- buying a prebuilt product/solution from a retailer and expecting to get some after sales service.

Wether you are, or the rest of the ES members you feel that you represent with your comments are, electronics engineers or wanna be EE's it doesn't mean that there are not countless more people out there who don't have your expertise and who ask for help and want solutions.

YES people should learn about stuff... but a person's level of knowledge shouldn't be considered when it comes time for customer service to be provided....

Consumer Knowledge and after sales customer service are not related variables that should influence one another.

Both should be as good as they can be.. but often in this game they are both not as good as they could be..

My mission is to elevate both to higher levels.

Peace.

 

[dnmun]

people do not have to be an EE in order to examine their BMS.

55 years ago when i was 15, there was no internet or online information sources so i had to ask the high school librarian if she would help me find a treatise from bell labs on this new thing called a transistor.

this is the best way in the world for 15 year old to be learning how to do stuff and educate himself. by removing the incentive for him to learn you have neutered him and removed his only motivation to learn something new that would benefit him for the rest of his life imo.

 

[onloop]

by removing the incentive for him to learn you have neutered him and removed his only motivation to learn something new that would benefit him for the rest of his life imo.

Man.. I hear you. I really do.... but you are blurring the lines.

This thread was started by someone who wants to learn... he came here to ask questions about how to fix a fault.... maybe there is NO fault, maybe there is. But he will work it out because he has an open mind and a desire to learn.

Therefore everyone here who has knowledge about the topic should just use some simple terms and tell him specifically what he should do. Using terms that he is not familiar with is not education.... it is condescending.

Also, Just because I replaced a product with a fault under warranty doesn't mean he is being "neutered" it just means he is dealing with a reputable business. I was actually the person who originally encouraged him to use this community to not only become a student and learn, but also to eventually become a teacher and pass on knowledge.

So rest assured we are all here to learn. And hopefully teach a bit as well.

 

[cmatson]

I see both sides-

it's a $300 usd battery that died before I had a chance to use it more than twice. So, after talking with onloop, we did some tests, confirmed it was something to do with the bms, and then he sent out a replacement. The other thing that really enforces that we think the bms was killed by to high of an amp draw from the esc, is that I blew a fuse on the second battery, that was designed to protect against too high of a draw. Without the fuse, I would have just killed another bms. I've since changed my esc settings, and its working perfectly.

on the other hand, I can see where you'd want me to make sure its dead- it makes total sense. Believe me, I tried doing research, and emailed videos and photos to onloop back and forth for a couple weeks, testing different voltages. And again, I would have gone right ahead and tested the source leg, or gate voltage, except I am pretty lost in terms of where those are- I tried looking them up, but a bunch of circuit boards pointing to different outlets wasn't really helping me much...

as onloop said, I'm 15, and and started building my first board about a year ago. I'm not trying to say that I'm just a kid who doesn't know anything, and in contrast, I've learned TONS over the last year. I wasn't that guy that started off with a complete kit that had everything you need: I just figured out what components I needed (without knowing what endless sphere was at the time), and then got everything I needed separately. And before this build, I'd seen plenty of videos on how to make your own 18650 pack, but that just wasn't something I wanted to do. When the space cell came around, that's when I could get the 18650 cells without making my own.

is this me not wanting to learn my way through it?
no, this is me not having a spot welder (yes I know you can build one from a microwave), or the confidence that I could get a bunch of 18650 and successfully make a pack without screwing anything up. and yes, messing up would be learning, but I still don't want to take that risk as building a pack isn't cheap.
Is a space cell more than building a pack? yes- but it's done, and done better than I could do, making it worth it.

I understand that I could watch I bunch of youtube videos, and read a bunch threads on the bike forums on how to build an 18650 pack with a bms, voltage meter, and everything the space does; and I did some of that, but I just didn't feel confident in me being able to build one.

I see it as the same as when I was first considering building an electric skateboard- I didn't just hop on my computer, and research every esc, how they all work, all the lipos, all the motors and their kv or size... I didn't even know endless sphere existed until only a couple months ago. Just through watching videos, looking a threads, and doing research on my own, I slowly learned everything I know now about batteries, motors etc...

So in short: yes, I do think it would be good to learn about the bms, and how it all works. And, I definitely think over time I will continue to read more threads, and start fully understanding whats actually going on. But I bought the space cell to keep my first 10s, 18650 build simpler, so that I didn't also have to worry about making my own pack. So before I order another BMS, I'll go through and troubleshoot it further with the help of everyone on this thread, and then we will go from there. Just keep in mind, that I and honestly lost with where everything is located on the bms, and can't tell you the difference between a gate on the mosfet and the source leg...This again, is not trying to say I'm just some kid who knows nothing- I just don't have any experience with it yet.