Battery won't charge

marcoredit · Jan 2, 2021

Hi,
I connected the bms to the 14s battery and in output it shows 54 V. The cells charge is 3.89 on average. I connected the battery to the bike and the motor works, but when I try to charge the battery, it doesn't charge. The same battery charger works on other batteries.

What could it be?
Thanks and happy new year.

goatman · Jan 2, 2021

wheres the P-

marcoredit · Jan 2, 2021

My BMS has only B-, C-.

attach the schema I followed

Jonno · Jan 2, 2021

Probably the wrong bms
Does your charger show fully charged when plugged in?
If it does then the bms is not for18650 cells that charge to 4.2v
Check which bms you purchased

Jonno

E-HP · Jan 2, 2021

marcoredit said:
Hi,
I connected the bms to the 14s battery and in output it shows 54 V. The cells charge is 3.89 on average. I connected the battery to the bike and the motor works, but when I try to charge the battery, it doesn't charge. The same battery charger works on other batteries.

What could it be?
Thanks and happy new year.

Are you sure it's not a 13S charger? 54V and change would be for a fully charged 13S battery.

marcoredit · Jan 2, 2021

this is the bms https://it.aliexpress.com/item/32823750783.html?spm=a2g0s.9042311.0.0.27424c4dV3d7nC.

It has 15 wires.

E-HP · Jan 2, 2021

Do you have a link to the charger, or a pic of the label?

Jonno · Jan 2, 2021

.......or test the output voltage of the charger.

BMS looks correct

Jonno

marcoredit · Jan 2, 2021

The charger I use

kcuf · Jan 2, 2021

what is the voltage of the charger

label isn't marked

use volt meter and measure

charger output not connected to battery

if 54v and change?

wrong charger

if 58v and change

something else wrong

marcoredit · Jan 2, 2021

The charger output is 58.8V.
So something else is wrong. Maybe the 15 wires are wrong connected?

fechter · Jan 2, 2021

I have the same single port model BMS on one of my packs and have had no issues with it.

You could try completely disconnecting it and reconnecting it. It looks like you have it wired correctly. If any of the balance wires were misconnected, you should not have output to run the motor.

It may be a defective BMS board.

marcoredit · Jan 3, 2021

So I'll try to check alla the wires again and then change the BMS.

Thank you

kcuf · Jan 4, 2021

many bms die easily

high power gets expensive

consider low power charge bms only

discharge directly off tabs

outdoor battery discharge

no bms usually safe enuf

controller lvc should match 14s

cheap ebay solution

10-20A 14s bms wired charge only

Voltron · Jan 4, 2021

Have you actually pulled the balance wire plug out, and checked the voltages at the terminals there, starting from one end of the plug? If you do, you really really want to have steady hands as they are pretty close together and easy to touch the meter probes together, which I find doesn't make a big spark at that voltage, but is just enough to deform the plastic plug body around the terminals from the heat.
If it's the really tiny style plug, I usually just stay on one end terminal, and go down the line writing down the totals, then calculating the individual group voltages after, so the probes aren't as near each other.

If it is even voltages at the plug, and totals the same as the voltage straight off the pack, then it's almost for sure a bad BMS

Battery won't charge

marcoredit

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goatman

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Voltron

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