Isnt the balancing wires suppose to be the last thing you connect to the bms? Correct me if im wrong, something ive read somewhere?
this is charge only bms, so It doesnât âseeâ if there is charging port installed or not. so yeah, balance wires were installed last.
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If your p groups all at one voltage than the bms shouldn´t balance anything.
I might be wrong at this, but I thought the D140 even don´t balance at such a low voltage.
Anyway, I would check the p-groups voltage with a multimeter.
If the bms in the time you plugged it in till now drained one or more p-groups than definitly something is wrong. shouldn´t be.
@DanielMedstortD that´s right, but looks like @tinp123 did that anyway.
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@Andy87 I have checked voltage on balance connectors before connecting it in bms, every group was on 3.44V. after one hour connected in bms, two groups were lower, on 3.40V. there was no need for bms to balance anything, and only thing it did was draining voltage from two groups.
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that´s what i mean. that shouldn´t be. if it did drain already now two groups for 0.04V it will very likey continue. You could monitor it a bit more to be be sure, but looks like the bms is done.
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I guess I will leave it for 10 hours or so. just to see how will bms behave
make sure the bms doesn´t drift your cells too much.
If it does you will need to manual charge the individual p-group to match the other p-groups again.
Would not exeed 0.1V from other groups.
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yep I am well aware of that. and battery is already isolated on all sides. but I will do it for science!
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Better now than later. Not getting more easy 
I am for 90% sure the bms is faulty
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A guy asked me to make him a 10s4p 30q for a carbon GT and wanted to do his own balance cables. Welded tabs for balance and left little bits of braided copper sticking out for power cables. It came out well I think!
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where do you buy your braided copper in au?
@CLK Im gonna get some from Ali, but to tide me over, I got some from here https://jaydeeautocables.com.au/products/earth-braid
I used the 12.7mm 66a, perfect for 4p 30q.
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If everything youâve said is true, then I would not use that BMS.
Check and make sure your multimeter battery is not dead, sometimes that causes bad readings.
Anyone here have any experience with the Sony VTC6? Spec wise they seem very similar to the 30q.
EV West has these cells for sale at $3 ea, which seems like a pretty good deal, if they are a quality cell. Any feedback or personal experience would be appreciated.
Thanks!
VTC6 are good. $3 is a good price. Thereâs some question about its cycle life and capacity at high loads vs the competition, but it seems relatively minor. Itâs probably still better than 30Q overall.
Are you talking about this?
https://www.evwest.com/catalog/product_info.php?products_id=484&osCsid=3c4nm854g9cnjj82kuqs49lg35
$3.15/cell, 200qty, looks unwrapped.
Hi everybody,
I am getting a trampa complete (with a monsterbox) and a 12s7p battery built locally.
I need to figure out something for the charge port and I would ideally like to be able to take the battery out without having to remove any soldered wires so that I could swap out for lighter batteries to make it a jump board.
I was thinking what would be ideal would be something along the lines of a XT60 port that has a male plug on each side so I can just get the board, mount the port and then plug in the battery.
Does this sound like a workable solution? If so, would any of you have a link to buy such a port (or something similar)?
You could buy a 4usd xt90 parallel conector and use the wires and connectors of the monsterbox for charging when neededâŚJust unplug and change for lighter lipo battsâŚ
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I think the monster box has wiring for 2x6s, so maybe get your battery made as 2x6s 7p instead of 12s7p and than just use the wiring which comes with the box.
You can also easy charge through the xt90 and take the packs out.
I donât use the monster box, but similar princip.
Just 2x6s made a xt90 serial plug and I charge the packs with an external bms.
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Ah, someone with the elusive 2x6s pack my battery builder talked about but confused the hell out of me and was beyond my google-fu to research properly (I now realise I was off on how the two packs were split).
The builder mentioned that a previous customer had done this and (I may have misheard) that this (2x6s) could be charged without a BMS as long as you have a balance charger. Does this sound right?
And would it be possible to charge like they do with the monsterbox and zippys in this video?
Also, what are your thoughts on just getting a Graupner Ultramat Charger? Charge time for now is not a major concern, better charging systems can just be purchased down the road when I have more hands on experience with it all (it also looks like it could fit in a backpack nicely).
If I get a yes to the above three questions I think I am ready to pull the trigger so your help is much appreciated.
[Side question: If you happen to have a photo of your batteries, BMS and charger all connected so I could see the layout that would be awesome]