new battery 12ah only 5m range !!!

motornews

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serres greece
hi everyone
i just purchased a 12ah 48v batt from vpower(16s 4p)... andi have very short range (5-6 miles)
i tried to balance it and i got it to a point (resting after charge cells are from 3,4 to 3,5)
but as soon as i ride the bike in full throtle i see from 54 volts the voltmeter to drope to 44 volts.
and as i said the range is very short
can you figure what is wrong?
 
Did you do any research on Vpower before you purchased? There are many threads on here that talk about Vpower and their shortcommings.

Let me guess.. ebay right?
 
If it's the type with small cylindrical LiFePO4 cells have a look at the corners to make sure none have been squished. Even a tiny squish causes them to short or self-discharge.

You can find out which cells are giving trouble by measuring the cell voltages on the multipin connector on the BMS.
 
motornews said:
hi everyone
i just purchased a 12ah 48v batt from vpower(16s 4p)... andi have very short range (5-6 miles)
i tried to balance it and i got it to a point (resting after charge cells are from 3,4 to 3,5)
but as soon as i ride the bike in full throtle i see from 54 volts the voltmeter to drope to 44 volts.
and as i said the range is very short
can you figure what is wrong?

first off have you got a amp meter ? if so what is your no load current of your bike with a fully charged battery ?
if you have not got a amp meter then get one..

edit: it could be that you bike is pulling way to much current.. is this a replacement battery for a existing running bike or a new build ?
 
put the battery on the charger and when it reaches the point where it turns green then measure the cell voltages with the 20C DC scale and measure to .01 volts on each cell.

measure while it is still charging. do not remove the pack from the charger while you are measuring.

do not remove from charger while measuring.

you can measure the voltages at the spot on the BMS where the sense wire plug is soldered to the pcb.

the first cell is measured between the B- spot and the first wire and the top cell is measured between the top wire and the B+ red wire that is soldered to the pcb.

you should have 16 meassurements.
 
ευχαριστω for the replies
so when the charger goes to greene while is conected to the battery my mesuments are(naked pack straight from cells)
1 3.80
2 3.38
3 3.38
4 3.38
5 3.38
6 3.39
7 3.38
8 3.38
9 3.38
10 3.38
11 3.39
12 3.38
13 3.39
14 3.38
15 3.38
16 3.43
total 54,9 on the bms
sims that the first row has something BUT WHAT
thanks again
 
you can use a 10-30 ohm 5-10W power resistor to drain charge off of channel #1 to get the charger to turn on again. you may need to pull the duck tape off but if you can get to the BMS then you could unplug the sense wire plug and put one end of the resistor lead in the first hole (for the top of #1) and connect the other end of the resistor to the B- spot and that will drain charge off of the cell.

or you can use a little light bulb such as used in a two cell alkaline type battery flashlight. same trick, connect one end of the light to the top of cell 1 and the other end to the B- spot on the BMS.

you wanna drain that #1 cell down to 3.38V before restarting the charging.
 
dnmun said:
you can use a 10-30 ohm 5-10W power resistor to drain charge off of channel #1 to get the charger to turn on again. you may need to pull the duck tape off but if you can get to the BMS then you could unplug the sense wire plug and put one end of the resistor lead in the first hole (for the top of #1) and connect the other end of the resistor to the B- spot and that will drain charge off of the cell.

or you can use a little light bulb such as used in a two cell alkaline type battery flashlight. same trick, connect one end of the light to the top of cell 1 and the other end to the B- spot on the BMS.

you wanna drain that #1 cell down to 3.38V before restarting the charging.
did that with a bulb previously and nothing
is it posible that 2 cells from the 4 parallel somewhere in the 16s are dead and when i mesure them with my voltmeter are showing ok?
 
gwhy! said:
motornews said:
hi everyone
i just purchased a 12ah 48v batt from vpower(16s 4p)... andi have very short range (5-6 miles)
i tried to balance it and i got it to a point (resting after charge cells are from 3,4 to 3,5)
but as soon as i ride the bike in full throtle i see from 54 volts the voltmeter to drope to 44 volts.
and as i said the range is very short
can you figure what is wrong?

first off have you got a amp meter ? if so what is your no load current of your bike with a fully charged battery ?
if you have not got a amp meter then get one..

edit: it could be that you bike is pulling way to much current.. is this a replacement battery for a existing running bike or a new build ?
its a new project new motor controller but where the power is been consumed
(i have volt meter do i have to buy an amp meter?)
 
motornews said:
gwhy! said:
motornews said:
hi everyone
i just purchased a 12ah 48v batt from vpower(16s 4p)... andi have very short range (5-6 miles)
i tried to balance it and i got it to a point (resting after charge cells are from 3,4 to 3,5)
but as soon as i ride the bike in full throtle i see from 54 volts the voltmeter to drope to 44 volts.
and as i said the range is very short
can you figure what is wrong?

first off have you got a amp meter ? if so what is your no load current of your bike with a fully charged battery ?
if you have not got a amp meter then get one..

edit: it could be that you bike is pulling way to much current.. is this a replacement battery for a existing running bike or a new build ?
its a new project new motor controller but where the power is been consumed
(i have volt meter do i have to buy an amp meter?)

I was just thinking along the lines that you may have the wrong phase wire combination .. even though the wheel turns don't mean to say that its the correct wire combo and this can pull huge amounts of current if not correct and a good way of testing is by measuring the no load current of the motor at WOT. if you have a voltmeter then it may have a current function that you can use inline with the + of the battery but your meter may only be able to read upto 10A so if you use this to test then open the throttle very slowly and watch the current meter if the current start to go above 2-3A before WOT then you have the wrong wire combo
 
The only 12ah 48V Vpower battery I found has a 15A MAX discharge current. What's the max amp of your controller? If it's more than 15A, which I'm guessing it is, the battery is not suitable for your system, and that's why it's sagging so much, At 44V you're likely only 2V from LVC of the controller. You didn't provide any info on your setup, thus makes it hard to guess.
 
"did that with a bulb previously and nothing
is it posible that 2 cells from the 4 parallel somewhere in the 16s are dead and when i mesure them with my voltmeter are showing ok?"

if the voltage did not change then you did not drain any charge off of the cell. i tried to explain what you need to do but i cannot make you but this is what the problem is with your battery and prevents it from charging.
 
It's a LiFePO4 battety, so it looks fully charged to me. LiFePO4 voltage climbs rapidly when charged, so the difference between 3.38v and 3.8v is not a lot of charge. The acceleration upwards starts when they've got past 3.34v, which is probably about 95% capacity.

I think you need to measure the cell voltages again when it cuts out to see whether any cells have reduced capacity. I'm still betting that group 1 has one or more squished cells.
 
dnmun said:
3.8v is enuff to keep his battery from charging. too bad he cannot drain it off.
i drain it allready and i must did it ..a lot?
now after 24 hours of charging every row its 3,70 to 3,71 except the 1st witch is 3,63
 
Well how does it work now?
 
hi guys
so i did some work
i replace the battery-controller-bms in the bike with an 10ah and i am getting a disent 25 km of range
so i thing the bike is ok
then i connected a 4 brake bulb in series (12v 5w=20w load?) to the sick battery and left it for 15 minutes(bad thinking?)
and now they are all 3,30-3,31 and the first is 3,28
so i connect the charger againand when it turns green
everybody is 3,49-3,51 and our guy is 3,88
and the charger is starting and stoping all the time(the fun)
if i knew what to do now i would be happy....
 
It's normal for the charger to start and stop while balancing the pack.
 
Like I said before, 3.3v is still nearly fully charged. In a LiFePO4 battery, everything happens between about 3.0 and 3.3v. As soon as you apply a load, the cells will drop from 3.6v to 3.3v, then they stay there for ages, gradually going down to about 3v, then they drop like a stone.

Your cell group 1 is showing a lack of capacity because it goes down faster than the others and it goes up faster than the others. Something is wrong with it. Peel off the covering and have a look. The possibilities I can think of are a damaged cell (high probability), broken weld joining the cells (medium probability) and leaking cell/s (medium probability). Leaking in a new battery would probably be caused by damage.
 
You may have one or more bad cells in group one with high I.R. and less capacity ah and fills up faster shutting off the bms. You could cut up group one and find bad cell or some have tried and put one extra cell in line for more capacity. Never tried that.
 
this is my last chance to it 999zip999
did that and tomorrow i will test it and feel you up
thanks all of you
greatings from a 'changing' GREECE
 
no, do not cut the battery apart.

there is nothing wrong with it except you have one cell that is so high it is cutting off the charge.

i asked you to drain charge off of that cell but you said you could not as i recall so i wondered why you could not drain the charge off of the high cell and you never replied.
 
sorry my friend
i riped it apart any way and i mesured the row of 4 and intividually they where all at the same hi voltage but one
then i drain the charge of as you said (i follow the ideas because i am pist off with this pack)
and they were almost identically low cell by cell exept one
so now iadded a 5th cell in the row and charged it again and discharge it againand balanced it to come to the voltage of the rest 15 rows
so now i charged it finally and came to 59,9 the pack and equally 3,7 to 3,75 all groups while hooked in charger
now of the charger 2 hours and i getting from all groups 3,58 and from the nasty group 3,49,i thing its not a big deal ...or is it???
tomorrow the test.
 
dnmun said:
no, do not cut the battery apart.

there is nothing wrong with it except you have one cell that is so high it is cutting off the charge.

i asked you to drain charge off of that cell but you said you could not as i recall so i wondered why you could not drain the charge off of the high cell and you never replied.
i did it and after charging it again i have the same hi mesurement on this group
so i added an extra cell to this group and i thing iam in the wright road now
ikeep you posted after the test tomorrow
thanks a lot
 
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