48V500W Rear Driving BikeConversion Kit

[billi]

Hi all

I am struggling to get the LCD and the controller working

Its a Bafang BPM2 48V500W Rear Driving BikeConversion Kit
The LCD screen lights up for 1 second and goes dimm, i connected a multi meter to the 48 volt battery poles and i can see a very fast decline in Voltage down to 20 Volt . Sounds worrying to me
As well , i have my problems what cable i should connect to the PAS sensor
The display is a S-LCD3
The controller a S12S 500Watts Torque Simulation Sine Wave Controller

The motor is not doing anything when i turn the trottle

Can someone advice ?

Thanks Billi

 

[markz]

My advice is to not use the LCD display, but I dont think you can use the controller without it. Which would mean buying a new controller, which maybe an option for you. The voltage drop after you connect things up, is not promising.

 

[billi]

Ok thanks , yes that voltage drop worries me , hopefully there is no damage in the battery , as the red on of button does not work :?

 

[docw009]

The action of the LCD3 and confirmation from your voltmeter says the battery is not turning on. Your description suggests it charges the controller capacitors briefly, and when you turn on the controller. they discharge.

I think you need to figure out why the battery isn't working. It's got a red on/off switch?

 

[AHicks]

I believe your LCD 3 is working normally. It's working the same as any LCD3 I've used anyway. The full bright display comes on for a second, then it goes to the brightness level YOU set in the parameters and stays there.

 

[amberwolf]

Ok thanks , yes that voltage drop worries me , hopefully there is no damage in the battery , as the red on of button does not work :?

the battery's bms has shutdown it's output to protect the pack from damage.

usually this means one or more of the cell groups is so low in voltage that they're "empty".

charge the battery, and leave it on the charger, at least overnight. you may have to leave it for days on the charger, if it's unbalanced.

if it still will not power on, then there's something wrong with the battery itself; you'll have to check with the place you bought it from, assuming it's still under warranty.

if it's not under warranty we can help you disassemble and diagnose it.

 

[billi]

Hello and thanks sofar
Yes the battery has a red on/off power switch .
First time i connected the powerwires to the controller i got a little spark on the battery + , but as well something sounded strange behind that powerswitch .
Is that relevant during charging to be on or off ?
Voltage reading on the batt terminals is 45V when switched off and 52 V when switched on
I guess i charge it with the powerswitch turned off ....??

 

[amberwolf]

the powerswitch should only affect the output. shouldn't affect charging, unless it uses the same connector for both.

 

[Hwy89]

It sounds like the BMS is shut down in the battery. Charge it and leave it on the charger for 24 hours to let the BMS try to balance. The manual that came with the last set of batteries I bought said to charge with the red switch in the on position.

 

[billi]

Charger shines with a green light , so seems to have stopped charging , after anothe 2 hours of charging , power of switch voltage is 45 volt , power switch on on is 54.6 V

 

[amberwolf]

if it's unbalanced, it could take hours or days for it to fix. you have to leave the charger on it.

or you can talk to the seller about sending it back for repair.

optionally if there's no warranty you can take it apart and find out what's wrong and fix it.

that is assuming it's the battery...

 

[billi]

But , if the charger indicates a green light , i assume then he is not charging , or ?

Anyway , i read here that one can try jumpstarting a battery ? https://lunacycle.com/jumping-your-luna-shark-battery-pack/

 

[amberwolf]

the charger stops because the bms turns the charge port off when the first cell gets full.

if all the cells are not equal (they rarely are on common ebike packs, especially cheap ones), then some cells are much less full than others.

in your case, i would guess that some are very very low, while others are much higher. this usually means something is seriously wrong inside, so that some of the cells in the high groups simply don't work right or aren't even connected. but even in this case, eventually the pack can be balanced enough to see if the bike works at all.

anyway, after a while, a few minutes or much longer, the bms will have drained that full cell down enough to let the charger restart without overfilling it, and it will turn the charge port back on. then the charger will detect this and restart charging.

this cycling will go on until the low cells and the high cells are equal. it can take hours, days, or even weeks.

but you should be able to at least test if this is the problem with just a day or so's worth of leaving the charger on the pack.


note that if osmething is really seriously wrong inside the battery, it is just remotely possible that something disastrously catastrophic can happen, like a fire. so i would recommend doing this charging in a fireproof area (inside an oven, etc), or outside away from buildings, and so on. it is a very very tiny risk...but the consequences are very very extreme, so it is worth taking precautions about.

 

[billi]

Ok thanks for the note , i will move outside the house to charge safe

I would like to do a load test , i have a 250 watt 230 Volt AC infrared bulb , that could work ?

 

[billi]

Ok charger is not charging always green light on , battery is at 48 volt , connected a small LED lightbulp to the discharge poles for an hour , connected a phone to the USB of the battery ( that worked for 1 minute , opened charger and battery , to just to have a look if i spot something obvious .... , but cant see anything obvious

Cab i do some thing with the BMS ? i suppose its under the cells ?

 

[amberwolf]

Ok charger is not charging always green light on

does it matter whether you turn the red switch on or not?

what voltage does the voltmeter show on the charger output, with the charger not connected to the battery, just plugged into the wall and turned on?

 

[billi]

The charger output not connected to bat , shows 54.6 volt

 

[amberwolf]

well, that sounds normal for a 13s (48v) battery charger. so the charger itself is probably working ok all the way to it's connector pins.

so the battery may have a problem inside it, of one of several possible problems.

--broken wire between charger port and bms charge input

--blown fuse between charger port and bms charge input

--a cell group has dropped so far below lvc (overdischarged) so that the bms has disabled charging to prevent cell damage that can result in a fire (the cell discharge itself could be caused by several things, including bad cell(s) or broken bms balancer that's stuck on and draining a group all the time).

--a cell group's sense wire has disconnected from the bms, so it can't tell if the cell is ok or not, so it disables charge and discharge (most cheap bms don't care, so this is probably not it)

--a cell group has overcharged and it's balancer is broken stuck off, or the bms doesn't actually even have balancers, so it's turned off the charge port to prevent cell damage that could lead to a fire.


at this point, if there's no warranty on the battery, your best bet is to measure the voltages between all the wires on the bms, and list them here, naming each wire as you go.

 

[billi]

as i expected sounds like i go trough that .... what on earth does warranty means ? to ship a 300 euro product bvetween europe and china ? i would not think about that

 

[markz]

as i expected sounds like i go trough that .... what on earth does warranty means ? to ship a 300 euro product bvetween europe and china ? i would not think about that

Cost of shipping product back to China is not cheap.

 

[docw009]

Charger shines with a green light , so seems to have stopped charging , after anothe 2 hours of charging , power of switch voltage is 45 volt , power switch on on is 54.6 V

Step back. Is this still true? Your power switch sounds like it's working.

While this is OK, if the 45 volts is just residual charge that would be bled to zero with a load, I still don't like that result. A good BMS, in my opinion, drops output to zero volts.

Anyway, what happened again when you put that LED bulb on the battery? Did it glow dimly and the voltage stayed at 54.6V? How about a hair dryer for a load test? Mine will run on 48V DC very slowly.

 

[billi]

for sure that is not an option, to sent it back , markz

two events i should mention , behind red power switch on battery pack did sound not right after connecting power wires to batt , recently , charger had a similar "small short meltdown" (but fuse is fine)

 

[billi]

Charger shines with a green light , so seems to have stopped charging , after anothe 2 hours of charging , power of switch voltage is 45 volt , power switch on on is 54.6 V

Step back. Is this still true? Your power switch sounds like it's working.

While this is OK, if the 45 volts is just residual charge that would be bled to zero with a load, I still don't like that result. A good BMS, in my opinion, drops output to zero volts.

Anyway, what happened again when you put that LED bulb on the battery? Did it glow dimly and the voltage stayed at 54.6V? How about a hair dryer for a load test? Mine will run on 48V DC very slowly.

well , to be honnest , i expected that that 12 volt LED light will blow , but it didnot , so was connected to battery all night long , well i guess it draws close to 0 watts , but still ....

the USB connection worked for a while , but for some reason , it seems to destroy attached equipment , so my external powerbank that i connected for a try is now dead too

 

[billi]

....I guess BMS is gone , if not worse :x

Any helping suggestions ?

 

[billi]

Ok pretty obious