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fixed that for ya 
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When using a battery indicator on a bms that has a common charge and discharge wire you get a 100% reading whenever you charge as it will read full voltage from the charger that’s on the same wire so you would have to unplug the charger to get a accurate reading. With lights having a extra wire may be helpful so you don’t need to make a harness to tap in to the main discharge leads.(less wire clutter)
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Put 30mg of Heroin in each box and you’ll look like the new premium dealer in town.
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Where do you get them from
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This batch is from liion warehouse, shipping was only 30 bucks for all these cells!
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someone has to make a gb for battery clearing house in eu
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good stuff goes too quick to organize anything
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Hot diggity damn. I love these cells. Mind if I ask what your cost per cell was including shipping?
Do you mean Liion Wholesale?
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Yes that place, cost was under 5 per cell cant remmeber exactly how much tho. I got the 400 cell discount
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Hey folks,
Need some input on a BMS.
Taking a look at a local friends new board that won’t charge. Charger stays green. Reading 0%. Got it today and opened it up. No fuse on charge port so can’t be that, total pack voltage is 39.6 V (12S).
Everything unplugged, time to open up. I’m not here to flame on the battery builder, just get this pack fixed for the owner. Let’s keep any criticism about the pack construction and it’s components professional.
This is a 12S5P with Sanyo 20700B cells. P groups 11 and 12 (from B-) are on the side with a narrow staggered arrangement. The remainder are flat laid.
Voltages at the BMS connector
B0 is jumper underneath to B- on the back of the BMS.
B1 4.1
B2 8.3
B3 12.4
B4 16.6
B5 20.8
B6 25.0
B7 29.2
B8 33.4
B9 33.4
B10 37.6
B11 38.5
B12 39.3
Okay so we’ve got some dead P groups and a BMS or connection issue. Got the okay to keep going from the owner. Lots of fiberglass reinforced tape on this battery.
Voltages at the cells
P12 0.87 V
P11 1.04
P10 4.14
P9 0.0
P8 4.18
…
Obviously those three P groups need replaced. This battery has only been through a few charge cycles.
What interests me is that the P10 group was fine. That makes me less suspicious of a series connection at P8 that would’ve hurt all following P groups if it had separated temporarily. (That’s what happened to my battery a few months ago)
A good look at the BMS. This appears to be a bestech d140 12S BMS. What’s interesting to me are the following areas:
The mosfets ? Black squares along the edge, half of the banks are empty. Only 3 in place and the stock photos show 6.
There’s an area I identified that looks to have gotten hot. Looks like there’s a solder bridge underneath though. Any ideas?
Here’s the pics and the third is the stock photo from bestech website.
As of this moment, I believe it needs 3 P groups replaced and the BMS. Any thoughts?
Appreciate the help
Bill
Regarding the BMS, the D140 comes in a few variants, 15A charge only populates 3 mosfets and 15A charge and discharge populates all 6 mosfets. You have the 15A charge only version, most people don’t use the discharge side anyway. The rest of the smaller resistor/transistor array is for balancing. Only fully populated at 15S. 12S will only have 12 rows. The solder bridge there is only for a thermo sensor. The discoloration looks like flux not cleaned up. Check the corresponding pins to see if the transistors on the BMS failed closed and drained the pack. If that is not the cause, may be another cause somewhere.
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Ah very nice thank you
@BluPenguin can you point me to any info about testing the transistors? If I test for voltage on the adjacent side of the “101” blocks from the connector I get the same voltages as testing the connector pins. Make sense?
Tell him my 30q order got cancelled so I call dibs if there’s a next batch 
yours got cancelled too?
anybody other than me manage to actually get?
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I got one order my second got cancelled
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Mine should be arriving monday
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What are ports are people using for 8a+ charging
XT-30
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