battery help please faulty

[billym1967]

so guy came to pic his trice up today and there was no power. after a quick bit of missing i found with the charger in everything worked, unplug the charger and dead. now the charger say fully charge, the little lights say only on light so needs charging.

so its 37v 9a sony cells 40 x 3,7v 2250ma. so as it seems nacked i took it to bits.

so first thing i did was check some cells, all the ones i could check are reading 2.75v. the + and - out on the battery case is dead reads 0. so i measured the + on the cells (1) and the - (2) i get 27.75v. so those 2 go to the bms board (3) (4) again i got 27.7v now the final to that go out of the BMS board to the battery connectors (5) (6) i get nothing. if i plug a charger in i get 42v

is it the bms board or the cells. what do you think. tried wiring another chager and it also says fully chaged

 

[Deleted member 4366]

The 27.5v is too low, so the BMS has switched off the output and the charging. You need to connect your charger to the main wires from the cell-pack to the BMS (should be marked B- on the BMS and B+ if the red one is connected, though they're more often not connected to it. When the pack has got up to about 31v, you should be able to charge normally.

 

[billym1967]

thank you will try that now, bypass the bms board - straigh to + and - on the cell pack. cheers

 

[billym1967]

so ive connected that up. only thing is the charger still has a green light on saying its charged. is that normal

 

[Deleted member 4366]

Unplug the charger from the mains. Wait a few minutes, then try again. Some latch off once the green light has shown.

 

[billym1967]

yes got a red light now on the direct charge. its up 34v with the charger unplugged. but the normal charger still wont click in.

 

[billym1967]

ive ordered another battery, as i didnt want the buyer to take it with a dodgy battery. bit of a swine as i was already letting it go at a slight loss. but such is life

 

[billym1967]

so i'm at 36v, if i conect the charger direct i get the red light. if i then connect it to the proper charging points green light. also the battery has the little leds. if i press the battery one i get just the one red light no greens. i i use another one i have and connect directly bypassing the BMS board i get a green light now. it may need more time but i'm starting to think its a knacked bms board.

 

[Deleted member 4366]

Most likely the fuse ha blown. Follow the wire from the charge connector to the BMS to see where it is.

 

[billym1967]

hi d8veh. so no fuse. but what i did try is the charger im using i connected into the two charging wire bypassing the plug. and still that charger doesn't kick in. what is strange is 3 and 4 in the picture are from the cells to the BMS 5 and 6 are the power outs and the charging points. 3 and 4 give me over 36v now but 5 and 6 only 3v so it looks like the power gets from the cells to the board but doesn't get back out again.

 

[billym1967]

i'm guessing as 5 and 6 are the main wires that go to the battery houseing plug and then to the controler, then they should be a lot more vaults

 

[Deleted member 4366]

It's a bit unusual that it switches the positive. Normally, they switch on the negative. The charging wire seems to go to P+, so no separate charging mosfet or control.

You should try connecting your charger positive to P+ and the negative to P-. If it charges there, there's a fault in the connection between P+ and the charge socket. If it doesn't, something is wrong with the BMS. It seems to have more connections than most. Is there a switch on the battery somewhere that needs to be on to allow charging?

 

[billym1967]

so excuse the mess in the picture. i was getting quite sure it may be something to do with the BMS. so as i had a BMS board ready for my battery project i though give it a go. wired it all up just by cutting and solding the board plug. plug the charger in. not only does the red light come on but its also kicking out 36v through the out plug. so looks like it has been the BMS board. so i will get another. also one final question the little red and green light display. what are they called and where will i get one.

thanks for your help d8veh

 

[Deleted member 4366]

Do you mean the charge indicator LEDs? They're pretty useless. I wouldn't bother. Don't you have a battery level indicator on your handlebars somewhere?

 

[billym1967]

yes theirs one on the lcd screen. also the gtood new is it fully charged last night. so just have to decide now weather to put it back together, or make it a soft battery

 

[billym1967]

well if the BMS board wasn't blown it is now lol