There is no need to open the case. You measure the output voltage at the battery output port, where it makes contact with the controller. Post a picture if you are not sure.
Battery only charging partially
- Thread starter Chris Maluszynski
- Start date
We don't know the status of the ten cell groups so knowing the ten singular voltages may help.
We know to a degree the battery will charge to a point so all cellgroups are above LVC, though we don't know if one is weak or one is high.
We know to a degree the battery will charge to a point so all cellgroups are above LVC, though we don't know if one is weak or one is high.
A step by step process will soon determine the fault.
What surprised me is he thought he needed to open the battery case to measure the battery's voltage.
It does look like you said, we don't know if one block or more is bad, The battery is more than 5 years old and should be retired in any case.
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I suggested opening th battery to read the ten cell groups to see if their is a fault but mostly agree that due to the battery age recycling is most likely better.
In the short term though Chris can learn some new skills by opening and learning how to check cell group measurements .
In the short term though Chris can learn some new skills by opening and learning how to check cell group measurements .
When you say recycling it means i I need a new battery? That would be the end of the bike pretty much as those are crazy expensive.
the battery was fine (and still sort of is though it needs to be charged much more frequently than before) so I don’t see why it should be scrapped due to age? Couldn’t bad cells be replaced?
I’ll report once I’ve opened the case. I guess it’s just a matter of removing the screws?
the battery was fine (and still sort of is though it needs to be charged much more frequently than before) so I don’t see why it should be scrapped due to age? Couldn’t bad cells be replaced?
I’ll report once I’ve opened the case. I guess it’s just a matter of removing the screws?
yes, to open the case, it's just a matter of removing the screws.
Batteries are generally safe but they have limited life expectancy. As they age, the risk of fracturing the electrodes increases. Fractures can create a shortcircuit between the electrodes and the cell will overheat to the point of setting fire to the battery. Batteries should be preventively recycled after 5 years to minimise the fire risks. Same for EV cars, their batteries should be replaced after 8 years, making their green credentials looking a bit dubious until now but in the long run, we'll get solid state batteries that should last 20 years.
Batteries are generally safe but they have limited life expectancy. As they age, the risk of fracturing the electrodes increases. Fractures can create a shortcircuit between the electrodes and the cell will overheat to the point of setting fire to the battery. Batteries should be preventively recycled after 5 years to minimise the fire risks. Same for EV cars, their batteries should be replaced after 8 years, making their green credentials looking a bit dubious until now but in the long run, we'll get solid state batteries that should last 20 years.
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The cheapest way to repair your battery is to remove the cell-pack and buy a replacement of a similar size and put in in the case. That normally involves cutting 4 wires and soldering the 4 new ones, and adding a bit of packing to stop it rattling .
the white connector at the top of the BMS has 11 balance wires. They are connected to the cell blocks. One end is ground or Bat-, the other is the Bat +. The voltage at the wire next to the Bat- should be about 3.6V, the next wire 7.2V etc until the 11th wire 36V.
Let us know what you find.
Let us know what you find.
You may have to carefully cut that wrapping to access it, it looks like you have 11 wire inputs .
The first should be B0/B- then the other ten are all B+ so B1 thru to B10, set the meter dc dial to 20v.
A pair of sewing needles or hem pins come in handy to poke in the pins outs on the wire connecotor, then one can place the meter probes on to them.
Starting with B0 & B1 take a reading don't allow the probes or needles to touch (place a bit of thin card between them to prevent accidental shorting), one should get 1/10th of the battery voltage so 3.6v if the battery is reading 36v or 3.47 if reading 34.7v as an example. For reading # two move both needles along one position ( so B1 into B2 & B0 in to B1 ), do this ten times until you have ten individual voltage readings. Write them down and post the results.
The first should be B0/B- then the other ten are all B+ so B1 thru to B10, set the meter dc dial to 20v.
A pair of sewing needles or hem pins come in handy to poke in the pins outs on the wire connecotor, then one can place the meter probes on to them.
Starting with B0 & B1 take a reading don't allow the probes or needles to touch (place a bit of thin card between them to prevent accidental shorting), one should get 1/10th of the battery voltage so 3.6v if the battery is reading 36v or 3.47 if reading 34.7v as an example. For reading # two move both needles along one position ( so B1 into B2 & B0 in to B1 ), do this ten times until you have ten individual voltage readings. Write them down and post the results.
Ok. Here goes.
(Battery was not “fully” charged as a short bike trip was made after last nights charging)
3.6
7.6
11.3
11.3
15.4
19.5
23.5
27.6
31.7
35.8
(Battery was not “fully” charged as a short bike trip was made after last nights charging)
3.6
7.6
11.3
11.3
15.4
19.5
23.5
27.6
31.7
35.8
If the pack was built as is recommended, with all cells from the same batch, then if one or more has failed, its liklely there are others very close to failure too.
So the voltages of the cell banks are
3.6
4.0
3.7
0
4.1
4.1
4.0
4.1
4.1
4.1
Repair is not worth the risk. You would have mismatched cells in your battery.
Isn’t there a way of charging the bank with 0 voltage separately? Or is there nothing more to do at this point?
You found the fault and it is a shorted block. Take it to the recycling centre.
What size battery? Is it the "traditional" battery type
There are places that will re-cell them or winstanley bikes have the batteries slightly cheaper or if you are more adventurous just buy a 36 v battery and connect it to the controller
Interesting that one cell bank is down to 0V but the BMS seems to assume nothing is wrong.