Pack build from LG automotive cells

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larsb

1 MW
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Dec 10, 2014
Messages
2,833
Location
Gothenburg, Sweden
I crashed my old 18650 pack so i bought some LG 30Ah/10s lithium pouch modules from a forum member to build a new pack. They are said to be good for 300A discharge and comes from a Volvo s60 hybrid car pack.image.jpg
I will use 2 modules in series for a total of 20s governed by a bluetooth 300A smart BMS.

The batteries have the usual automotive hardware, super solid and could probably be used without protection in good conditions but i'll build some covers for all the salted road driving in wintertime here.
 
BMS: https://m.aliexpress.com/item/32826820690.html

There's a huge thread on this bms on ES. The number one thing why i bought it is that the charging and balancing voltage can be set freely, all the other features like display and fancy phone app are just bells and whistles to me. 8)
 
larsb said:
BMS: https://m.aliexpress.com/item/32826820690.html

There's a huge thread on this bms on ES. The number one thing why i bought it is that the charging and balancing voltage can be set freely, all the other features like display and fancy phone app are just bells and whistles to me. 8)
Click to expand...
Sounds good

I don't see that specific vendor's product discussed in the main thread on the topic, and am not too trusting of Ali sources.

Could you link to where that specific one is discussed? https://www.google.com/search?q=site%3Aendless-sphere.com%2Fforums%2F+bms+bluetooth


Or tell me what more-specific google search string I should use here?

site:endless-sphere.com/forums/ bms bluetooth

 
Vacuum forming carbon cloth and epoxy in the mold.
image.jpegimage.jpeg

It's always a bit of a stressed feeling when you open the mold 8)
- Will the part release from the mold?
- Has the carbon fibre moved during the vacuum bagging?
- Is the finish ok?
 
It's that time of the build when you do a mockup and realise you won't be totally happy with the result..

The batteries are huge, my idea was to fit it on my moped like a tank substitute but they will stick out a lot on each side and are too long to slide forward
I will have to spread my legs a lot. To make things a little better i decided to put the BMS outside the battery covers and link it to each module with a balancing cable (and power cable off course)

View attachment 1
Since i have a display i decided to make a window for it and some switches for the bms "ON", display screen toggle and other functions
 
Extended also the display "ON" connections to switches. BMS box looks like a little robot guy with funky ears :D

The waterproof weipu sp21 connectors i got to connect batteries and bms are too long to look good.. I got 12pin overmolded connector and cable assemblies from China that was smaller, however a bit too late.

I'll run the setup i have now until i get energy to improve it 8)
 
I was wondering when you were gonna update your thread but it looks like you made a new one.

I was thinking in covering my Moped fairings in real carbon fiber (currently using carbon fiber Vinyl), you think it could be done?

Does the Motor use up that much space? I was able to put two of those batteries on top of each other where the original engine used to be with a bit of space left on my CPI SM :?:
 
A carbon overlay is certainly possible - but a lot of work. It will not want to stick well to the original fairing plastic. I've seen different ways of priming plastic for overlays but it was a looong time ago.. Flaming surface with a torch, acid etching, criss-crossing with sand paper, stuff like that.

It's a little easier to get a clean result if the base plastic of the fairings is black, then small pinholes in the carbon don't show as easily.
..

I have the old style of Rieju/derbi frame from 1998, it's got a strut from the headtube that gets in the way of two batteries. And i got the huge APT controller.. One reason to go with a moped build was to get more room for everything but now i am already back to the bike (crammed) situation :D

What bugs me is that i'm sure it would be quite easy to modify the frame so that it can fit the batteries inside. Don't know why i don't do it :D
 
larsb said:
It's in the "bluetooth bms" thread, first hit, you need to read all the 1000 pages 8)
Click to expand...
I see nothing in common between the two landing pages, definitely different suppliers, looks to me like different products.
 
Working on the finish, realised that one of the covers was just too thin so i had to put another two layers of carbon on it. Didn't want to vacuum bag it again so i tried with 20 or so clamps on insulating foam to get some pressure. Not sure how it will turn out though..
 
I have glued the top "lid" on the covers with laminating epoxy. There's a 3mm gap to be filled since i used the inner scrap metal from the flange milling to do the lids so a lot of epoxy was needed.
It's not the correct epoxy for the job, buuut i think it holds :wink:
image.jpeg
The finish of the covers is not good but i'm tired of using my car so it'll have to do :D
 
Made custom o-rings from rubber cord for sealing the covers. The ends of the cord were glued with CA glue, turned out well :D
Also got the cable glands in place, it's a really tight fit to the battery so i hope that all the cables can be routed.
image.jpegimage.jpeg
 
First of all, kudos on that casing, it is really insane! Great work, super clean.
Love the way you made the mold.

eee291 said:
I was thinking in covering my Moped fairings in real carbon fiber (currently using carbon fiber Vinyl), you think it could be done?
Click to expand...

Yes, it's not very difficult but it's very time consuming, there's a lot of sanding involved.

larsb said:
It's a little easier to get a clean result if the base plastic of the fairings is black, then small pinholes in the carbon don't show as easily.
Click to expand...

Actually, I tried using some black epoxy basecoat and it works very well for that. First sand the surfaces of the part you want to cover with very rough sandpaper (60 grit for instance), then put a coat of black epoxy, wait until it gets tacky and then lay up your carbon, transparent epoxy, etc.
It leaves a perfect finish, no matter what the base color of the part was :)
 
Got everything working!
Pack build finished :D
image.jpeg
Tried the BMS app i got from ICGOGOGO but it was 50% in chinese.. Downloaded the VBMS app to my phone, it's not free but completely in english and a bit smarter looking and it's got short explanations for each parameter. I think it's probably worth the 7$ cost.

Some screenshots from display, i can switch between them with the toggle button:
image.jpeg
image.jpegimage.png
Some pics from the app:
image.pngimage.pngimage.jpeg

This BMS has more settings than you'll ever need :D

I also tried some short racing runs and the cells seem good. They coped well with close to 300A output without excessive voltage drop.
 
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