BMS Questions / Installation

[nukezero]

Hi

I'm building 52 cells 18650 cells. I am using signal labs 13s 30amp BMS. It has row of LEDS. I connected the balance connector and each time I do so, I get a momentary blink of all 13 LEDS...then it goes away. Is this right? All cells are at 3.64V approx. and total is 47.2V pack.
So as of right now, with BMS connected, no more LEDs stay on.


I also connected a charger. But it doesn't seem to be charging. I think charger problem... it just blinks red. With charger connected, it still shows 47.2V. Charger output is oscillating voltage like crazy. Not steady. It's a brand new charger I bought off eBay victorstudioz.

Yes, I soldered the 13 pin cable sense wires. Yes I went down each row and measured 3.64 between each sense wires. Yes I'm positive they are connected properly. I can also probe the little boxes(whether they call)

and they seem to go up in increments like: 3.6, 7.2, 10, 14v, 17.6v, etc.etc. and they go up in increments across the board ... so is that mean its working?

 

[dnmun]

you should not have the sense wire cable connected to the BMS when you solder the sense wires to the battery.

solder the sense wires up first and then double check that the sense wires are in the proper order with the voltmeter before connecting to the BMS.

that BMS will not function without the other 3 channels being populated with cells and the circuit parts. the reason your battery does not charge is because that BMS is dead the way the guy sold it to you. he obviously doesn't know either. it needs a jumper from the top of #16 to the top of #13 on the LVC opto chain.

 

[nukezero]

you should not have the sense wire cable connected to the BMS when you solder the sense wires to the battery.

solder the sense wires up first and then double check that the sense wires are in the proper order with the voltmeter before connecting to the BMS.

that BMS will not function without the other 3 channels being populated with cells and the circuit parts. the reason your battery does not charge is because that BMS is dead the way the guy sold it to you. he obviously doesn't know either. it needs a jumper from the top of #16 to the top of #13 on the LVC opto chain.

Hi there, the sense wires were NOT connected to the batteries when I was soldering them. After I finished soldering them, that's when I connected it up and got the blink/flash.

What do you mean the BMS is dead now?

I think I just read that the LEDs will only LIGHT up when there is a FULL charge and it lights up when each cell is at 4.2V max??? right now, each row of cells is 3.63V

 

[dnmun]

there has to be a jumper from the top of #16 to the top of #13 since there are no optotransistors there or cells to power them. i did blow up your little picture, and it seems like he might have put some solder between the through holes, but that is not a picture of yours but is from their website i assume?

you can check the gate voltage on the charging mosfet to see if it is turned on. measure the gate to source voltage.

 

[nukezero]

there has to be a jumper from the top of #16 to the top of #13 since there are no optotransistors there or cells to power them. i did blow up your little picture, and it seems like he might have put some solder between the through holes, but that is not a picture of yours but is from their website i assume?

you can check the gate voltage on the charging mosfet to see if it is turned on. measure the gate to source voltage.

I would appreciate it big time if you can edit my picture and draw exactly where to measure the gate/source votlages? then upload this picture?

Anyhow, here is the picture of my BMS. Don't mind the plastic tape on the sides, jjust using that to hold up a piece of foam temporarily in the back. I am doing a battery build write-up for the triangle mount pack, but this is hindering me. Plus, I think I've got a busted charger, which I'll post in another thread or maybe this thread.

 

[nukezero]

there has to be a jumper from the top of #16 to the top of #13 since there are no optotransistors there or cells to power them. i did blow up your little picture, and it seems like he might have put some solder between the through holes, but that is not a picture of yours but is from their website i assume?

you can check the gate voltage on the charging mosfet to see if it is turned on. measure the gate to source voltage.

Ahh yes, i do see that he has SHORTED, JUMPED all lines from 14, 15, 16, across the top. it's underneath my tape. it is there... what does that mean?

when I put my pos+ meter led on these shorted lines and negative lead to the battery (-) or to the voltage regulator's negative pad (P-), I see 14.13V. Is that good?

 

[Ypedal]

yes.,, the LED's do blink momentarily when you connect the balance wires, normal.

Are your cells Lifepo4 or Li-xx ...

for Lifepo4, full charge is 3.6v ... for Li-xx it's 4.20v .. you need the right BMS for the type of Lithium you use.

 

[nukezero]

you can check the gate voltage on the charging mosfet to see if it is turned on. measure the gate to source voltage.

gate to source voltage... okay. the little boxes are 4-pins. Each seems each row gets two of these little mosfets. My mosfet is 4-pin setup. And I need to measure Source, Drain, Gate. But measure across gate to source.. ok I wonder which pin is which???

 

[nukezero]

yes.,, the LED's do blink momentarily when you connect the balance wires, normal.

Are your cells Lifepo4 or Li-xx ...

for Lifepo4, full charge is 3.6v ... for Li-xx it's 4.20v .. you need the right BMS for the type of Lithium you use.

Samsung 18650-25R 2500mah Li-Ion Cells

this is the BMS I bought, they claim it is for Li-Ion and all types: http://www.ebay.com/itm/BMS-for-48V-13-cells-Li-Ion-Battery-Pack-50A-10A-limit-With-Balance-Function-/161242799250?pt=US_Rechargeable_Batteries&hash=item258ad1dc92

it is the Signalabs one. very popular one on here it seems... but I cannot freaking tell if it's working or not. Just got new batteries from superpower111. Hoked it up all correctl. 47.2V is the power. Each row/cell parallel is 3.64V and steady.

 

[nukezero]

edit

 

[nukezero]

Anyone?

As far as I can ascertain, perhaps the BMS is working??

My charger is stlil not charging but i don't think that is a BMS problem. I connected the 48v charger to a 36V battery pack very quickly... and I did not see ANY red charging LED..

 

[nukezero]

Okay here are the REAL mosfet voltage readings... tell me if this is GOOD????

please help

 

[dnmun]

yes it is working. i can see the little trace running from the top of #16 down to #13. maybe it is a fine wire.

so you have a bad connection somewhere. it should be charging if there is 59V on the output of the charger.

 

[nukezero]

yes it is working. i can see the little trace running from the top of #16 down to #13. maybe it is a fine wire.

so you have a bad connection somewhere. it should be charging if there is 59V on the output of the charger.

dmnum

can you tell me why one of the mosfets (closest to the charger negative) is showing 11V while the rest is the same?

secondly, what are those little boxy chips for each parallel pack line? not the resistor/leds of course.

 

[dnmun]

that is the charging mosfet and it has a different current source to the gate of that mosfet than the ones on the right side. the gate voltage on them is identical because they are wired up in parallel as you can see when you look at the traces. you can even follow the traces back to where they come from.

 

[999zip999]

Did you hook up the black sense wire to the neg. end the white one next to it is on same cell pos. Then all the rest pos. In order to the last pos. On last cell .same as pos. Output.
Hope I said it right.

 

[nukezero]

Did you hook up the black sense wire to the neg. end the white one next to it is on same cell pos. Then all the rest pos. In order to the last pos. On last cell .same as pos. Output.
Hope I said it right.

actually that is not correct. this bms does not work that way. there is only 13 wires. Yes, there are 1 red, 1 black, and 11 white wires. If you look at the diagram, it starts off with the red wire being at the top of the 48v 1st cell. Then each wire after that goes to the "in-between" cells. The last wire is also the in-between cell so it will also show 3.64V nominal. There is no ground wire for the BMS sense wire for this particular BMS> In fact the BMS calls for the ground wire to be routed through to B-.

 

[nukezero]

yes it is working. i can see the little trace running from the top of #16 down to #13. maybe it is a fine wire.

so you have a bad connection somewhere. it should be charging if there is 59V on the output of the charger.

there is a strange problem with my new 48v charger I bought. I posted it in the other thread. The issue is this:

1. when i plug the 48v charger on to the wall outlet, the LED goes green after 3 seconds. But if you stare closely, the green LED is sort of "fading out.... then fades in quick..." then slowly..fades out...then fades in quick.

When I put the multi-meter at the output DC plug, the voltage is jumping all over the place...

2. when i plug the DC connector to the battery pack, the red LED on the charger then blinks every 3 seconds and I can hear some "tick" when it does that. It looks like it is not steady and not charging. So it sounds like a problem with charger?!!????


I have a 36V li-ion charger that I put my multi-meter at the dc output. It reads 42.1V output, holds steady. No problem. So that's why I think my 48v charger is broken. what do you guys think?

 

[dnmun]

how much does the current coming out of the charger vary? does it ever produce the full charging current or just a trickle?

can you isolate the source of the click inside the charger?

 

[nukezero]

how much does the current coming out of the charger vary? does it ever produce the full charging current or just a trickle?

can you isolate the source of the click inside the charger?

at this point, I don't want to fix this charger anymore. The seller has agreed to a return. I don't want to ruin my new battery pack that I just built.

I plugged it into my girlfriend's 36V 18650 pack very quickly just to see if the red light would go steady, and it does the same thing. Then I plug my girlfriend's 36V charger onto her 36V pack and it's okay. Then I plug my girlfriend's 36V charger and to my 48v pack and it does nothing. Well no surprise, because the charger sees beyond 42V and does not charge anything.

 

[Minn-Ebike]

You might this this a horrible observation to make at this point but I had similar issues with the charger I got for my bike. I was ready to bash the thing with a hammer. Nothing I could do would get the thing to charge my battery...

And then I noticed the little 110 / 220 recessed black on black switch on the back...

Not saying that's the case...

Just saying...

Good Luck!

 

[nukezero]

You might this this a horrible observation to make at this point but I had similar issues with the charger I got for my bike. I was ready to bash the thing with a hammer. Nothing I could do would get the thing to charge my battery...

And then I noticed the little 110 / 220 recessed black on black switch on the back...

Not saying that's the case...

Just saying...

Good Luck!

There isnt any switch that i can see unfortunately...

 

[izeman]

maybe i overread it, but why don't you just plug the charger directly to the battery instead to the bms? just bypass the bms and see if it charges. if it doesn't, than maybe the voltage set is too low for the battery, or the charger is broken.
charged voltage for one of those samsung cells is 4.2v, so 13s should be 54.6v. and this is what the charger has to output.
what is the charger output? is it really 48v? if so, then it's too low. you need 54.6v. if your pack reads 47.6v at the moment, and you want to charge it with a 48v charger, how could that work?
maybe i'm mixing up some things here ...

 

[nukezero]

maybe i overread it, but why don't you just plug the charger directly to the battery instead to the bms? just bypass the bms and see if it charges. if it doesn't, than maybe the voltage set is too low for the battery, or the charger is broken.
charged voltage for one of those samsung cells is 4.2v, so 13s should be 54.6v. and this is what the charger has to output.
what is the charger output? is it really 48v? if so, then it's too low. you need 54.6v. if your pack reads 47.6v at the moment, and you want to charge it with a 48v charger, how could that work?
maybe i'm mixing up some things here ...

sorry, when the market advertises 48v charger, or 36v charger, they actually mean 54.6v or 42.0v charger. But to prevent people from getting confused they stick with advertising chargers at the batteries nominal voltage, not max voltage.

the charger i got was broken. the new charger I got works fine now.

 

[izeman]

sorry, when the market advertises 48v charger, or 36v charger, they actually mean 54.6v or 42.0v charger. But to prevent people from getting confused they stick with advertising chargers at the batteries nominal voltage, not max voltage.

the charger i got was broken. the new charger I got works fine now.

i don't know of your charger. but every charger i had (and included the ones i repaired those were 10+) each of them had the charging end voltage written on them. and this is how you order them as well. but maybe this is different for those low voltage chargers?