how install a bms 72v 20s

[velooman99]

install a bms 72v 20s

hello, here I need help, we installed is bms
my battery 72v, ( purchased one year ago, but the seller does not answer my questions ..)

http://www.aliexpress.com/item/Free-Shipping-20S-72V-lithium-battery-protection-board-E-bike-Li-ion-LiPo-battery-BMS-30A/1930212978.html

I like to know if the system seems right, and if the LED is illuminated when should the load (or no load) because the LED does not light up which seems a failure pars
On the photos :
"C" is connected to the negative charger.
"B-" the negative of the battery.
and " P- " has nothing at all ... ??
The rest I tested the meter, and it seems ok, the charger is connected or not, I have aucule LED that lights on the bms.

so I do not know if the bms balance or not done .

 

[kdog]

Hi
Is this bms already in a battery or are you attempting to put it in?
P- is usually 'power neg' meaning goes to your controller/motor/load
Google bms wiring in images for a handy reference.
The bms sits on the negative side between the battery and motor. I can't tell for sure but from your photo it looks like B- has nothing attached to it so it can't be working.
Maybe post a pic or diagram of your wiring (or how it is wired)
Don't power it up until you're sure it's right.
Be sure to connect your sensor wires correctly or you'll destroy the bms.

 

[Bluefang]

most of the ones i use the C- is for the charger, b- is to the battery negative, and the p- is for the power(controller) negative.

 

[kdog]

Ok so I think I see...
B- wire goes under the heat sink to exit LHS of photo.
Is this the existing bms or the new one?
Sometimes C- and P-are the same, on other Bms's they are seperate.
Show us the rest of the wiring.

 

[velooman99]

Hi,

the battery was purchased on a guy on endless. it was delivered without bms without balancing wire.
so I bought the bms (see aliexpress link)

so it's a bms that is not original.

 

[velooman99]

bms is not the original (purchased on aliexpress)
Please help me as I get stuck with this battery (need to finish my bikes)

I want to know if the small LED lights should be lit when the battery is charging?

because I have no idea how to check the proper functioning to bms? (If it works or not)

Thank you

 

[kdog]

Hi
The led's will turn on when the cell is full and being bled down. They won't go on early in the charge.
The easiest way to test if the bms is working is to install it in your battery then do a full discharge through a dummy load, then do a full charge with your charger. Whilst doing this, with a DMM, measure your cell voltages.
The bms should cut off load when lowest/highest cell hits the threshold voltage. Leave it on the charger and also check that the top cell is being bled down ( slow decline in V) then charger could turn on again.
for lifepo values are around 3.65 and 2.0 (high, low)
For liion values are around 4.2 and 2.9ish
But check the specs on the manufacturers site for your particular BMS.
Careful though, monitor cells closely when discharging if you think it's not working a be prepared to manually remove the load if necessary.
Check your charger output is series count x correct cell V.
Did you figure out the bms installation?

 

[kdog]

Looks like yours will be 4.25 and 3.0 +/-.05v
You did specify which chemistry when you bought it didn't you!? Cause it looks like a generic bms that gets adjusted for lifepo /li-ion as necessary.
K

 

[velooman99]

hi,
the title says:
Free Shipping 20S 72V lithium battery protection board / E-bike Li-ion / LiPo battery BMS (30A continuous discharge current)

so I think it's good?

 

[kdog]

Should be...it looks like the right boxes are ticked on the label

 

[velooman99]

hello, time passed and finally we managed everything installed, here's what I have now, in a bou minutes a blue LED is on (continuous), then a minute later, a second LED and so on up to 5 LED, then the LEDs flashed began, until the green LED on the charger is on (and finally cut the charger fan)

is that everything seems right?

 

[fechter]

Nice. Looks like what I would expect. When the first blue light comes on, looks like the shunt on that cell is coming on, followed by a few others as they try to balance the cells. Current drops as the cells charge, then shuts off at end of charge.

The blinking may indicate a cell is reaching the upper limit. After a few cycles, the cells may become better balanced and not blink before end of charge kicks in.

You could repeatedly let it go through the end of charge cycle to balance it more.

It would be good to measure all the cell voltages after charging to see how close they are.