Ezee Charging problem

Nealh

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2a charge input is kinder to the cells then 4a, all my chargers are 2a and I have a few.
 

Benjahmin

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So long as the voltage and pin configuration are the same the a 2A would be fine.
I got one for another battery that seems good quality and has a cooling fan. It's a YZPOWER-42 2Amp.
Haven't been able to find it again otherwise I'd link it for you.
Any charger for 36v li ion with an XLR connector will do it.

Can't think of any other way to check the bms, so I guess it's suck it and see.
 

Pink Nigel Dean

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Thanks Benjahmin - I also had a look to see if i could modify my cable run as you suggest, but it isn't long enough, and only just reaches the battery as it is.




So long as the voltage and pin configuration are the same the a 2A would be fine.
I got one for another battery that seems good quality and has a cooling fan. It's a YZPOWER-42 2Amp.
Haven't been able to find it again otherwise I'd link it for you.
Any charger for 36v li ion with an XLR connector will do it.

Can't think of any other way to check the bms, so I guess it's suck it and see.
 

Pink Nigel Dean

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My 2A charger arrived today, and I was hoping to be posting to say that all was well and the bike was charging again, but alas no. I checked the polarity and output of the new charger, plugged it in, and it sat there shining its annoying green light at me just like my original charger.

Is there anything else it could be, other than the BMS, since the cells appear well-balanced? The fact that I measured a voltage at both the battery output lead and the battery charging port with the charger disconnected clearly shows that the cells are in contact with the charging port, so it can only be the BMS itself refusing to accept the charge can't it, or is there some other possibility?
 

Pink Nigel Dean

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Ah bummer! I don't know how or if you can test a bms or how to replace. Let's hope Neal comes along.
I know, I'd convinced myself that the cheap charger was going to save the day, but I need some idea of where the problem actually lies before I start investing in battery resurrection. Let's hope Nealh can help...

I believe a BMS can be replaced, but with an 8 year old battery it might not be easy to find one.
 

Nealh

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Testing a BMS afaics is impossible.
If it works it works, all I can think is something is a miss then on the input side of the BMS or there is an issue with charge port or charge wiring to the BMS.

For your battery you can use any BMS 10s /36v BMS currently available it doesn't have to be the same model.
 

Benjahmin

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Well, let's review.
You have battery voltage (or nearly) appearing on the charge socket pins. So no broken connection there.
The cells are well balanced, no low group to stop charge, also no apparent broken connection.
The charge fuse was OK.
From Neal's last post the only other thing I can suggest is a really close examination of charge side wiring and soldered joints. Do continuity tests, say from charge pin to soldered connection on bms. Do any appear resistive?
What happens if you wiggle said wires and connections?
Examine the tracks on the circuit board, do any look lifted?
It's clutching at straws but worth a go.
Otherwise probably good to get a good close up picture of the bms and perhaps Neal will be able to steer you to a replacement.
 

Nealh

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As Ben has mentioned go over the BMS with a mag glass or takes clear pics and use your pc to blow them up to look for any damage how ever minor.

The charger has been ruled out so only the battery/BMS & wiring can be the issue.
Not very technical I'm afraid but usually faults stand out to see.
Start with the battery charge port and try continuation from charge pins to BMS solder joint on the Negative and to the battery + on the positive (though unlikely as early in the thread you registered 36.8v on the charge pins).
All BMS wiring is negative except the sense wires which are all positive bar one.

My thoughts are BMS, sense wire connections to battery groups there isn't much else to go wrong (we know sense wires are ok as you have got ten good cell voltage readings).
Continuity check either side of the charge fuse to rule out a break down on that line.

Once every thing has been exhausted check wise then we can only assume the BMS has a fault.
 
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Pink Nigel Dean

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Curioser and curioser..

I rechecked the output voltage of the battery, which was 37.2V last week, to find it has now dropped to 29.9V. I then rechecked the voltages of the original cells, which were previously all 3.70 or 3.71V, to find that they are now all between 2.97 and 3.01V. These seem quite significant decreases, but the battery has not been connected to anything in the interim.

I then placed the black probe on B- and the red probe consecutively on B1 to B10, which I understand should produce increments of 4.2V in a healthy battery, and obtained the following voltages;

B1 2.97V
B2 6.97V
B3 10.91V
B4 13.95V
B5 17.87V
B6 19.60V
B7 19.60V
B8 29.60V
B9 29.60V
B10 33.30V

These results suggest some very significant imbalances between cells, unless there is some reason why this is not a valid method of measurement?

I then rechecked all the cells using the method Nealh recommended and found that they were still all between 2.97 and 3.01V, which suggests good balance.

They can't both be right, so why are they producing different results, which I've now checked and confirmed several times?
 

Nealh

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Ok, we might be getting somewhere now as we were basing issues around all previous voltage readings. There are some big differences from one week to another either you messed up somewhere or the meter is giving you incorrect readings, replace the meter PP3 battery with a new one and take the readings again. A meter battery that is low can give erroneous readings.
Now we have at this time new lower voltages to go by then they now make more sense as to why the charger isn't charging, because the BMS isn't switching on due to all cell groups being way too low voltage wise. The BMS won't switch on unless the voltages are above 3.2 -3.3v on each cell group.
 

Nealh

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Curioser and curioser..

I rechecked the output voltage of the battery, which was 37.2V last week, to find it has now dropped to 29.9V. I then rechecked the voltages of the original cells, which were previously all 3.70 or 3.71V, to find that they are now all between 2.97 and 3.01V. These seem quite significant decreases, but the battery has not been connected to anything in the interim.

I then placed the black probe on B- and the red probe consecutively on B1 to B10, which I understand should produce increments of 4.2V in a healthy battery, and obtained the following voltages;

B1 2.97V
B2 6.97V
B3 10.91V
B4 13.95V
B5 17.87V
B6 19.60V
B7 19.60V
B8 29.60V
B9 29.60V
B10 33.30V
Elaine going by those new readings your battery is dead/a goner.
These are extrapolated to individual cell readings from the above something isn't correct esp B8 10v isn't possible.
Recheck all again with a new PP3 battery in the meter please.
B1 2.97v
B2 4.0v
B3 3.94v
B4 3.04v
B5 3.92v
B6 1.73v
B7 0v
B8 10v ?
B9 0v
B10 3.7v
 

Pink Nigel Dean

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Elaine going by those new readings your battery is dead/a goner.
These are extrapolated to individual cell readings from the above something isn't correct esp B8 10v isn't possible.
Recheck all again with a new PP3 battery in the meter please.
B1 2.97v
B2 4.0v
B3 3.94v
B4 3.04v
B5 3.92v
B6 1.73v
B7 0v
B8 10v ?
B9 0v
B10 3.7v

OK, I'll replace the meter battery and report back. Could a fault with the meter explain why the two methods of measurement gave such different results, which were consistent as I measured them several times?
 

Nealh

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Certainly yes if the meter battery is tired, voltage readings can be all over the place.

Following the second batch of voltages I certainly now believe your ebike battery has a low cell issue and why the BMS won't allow both chargers to work.

If the meter battery is old or failing and hasn't been used for a while, on the first use energy may have been stored up and then on the second use it wained and why you have got widely different results. I can't believe the BMS has somehow failed over such a short period of time.
See what results occur with a new battery installed.
 

Pink Nigel Dean

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These are the readings with new batteries in the meter. They were taken from the pins in the plug after first disconnecting the plug from the BMS. For each reading I held the probes in place until the meter gave a steady reading, and where the values differed from those I had obtained previously I took extra care to make sure I had a good contact.

Using the method you first suggested, i.e. measuring across B-/B1, B1/B2, B2/B3 etc. all ten cells gave readings of 2.97 or 2.98.

Measuring from B1 to B10 using B- as the neutral gave the following five sets of readings;
B1 2.98 2.98 2.98 2.98 2.97
B2 7.00 7.00 6.98 6.99 6.69
B3 10.70 10.99 10.69 10.96 10.40
B4 14.42 13.98 14.41 14.67 14.11
B5 18.13 17.94 17.90 18.38 17.82
B6 19.90 19.90 19.90 19.90 19.90
B7 19.90 19.90 19.90 19.90 19.90 B8 19.90 19.90 19.90 19.90 19.90 B9 29.90 29.90 30.00 27.30 29.90 B10 29.90 33.50 33.60 30.0 29.90 I appreciate that the 10V jump from B8 to B9 is impossible, but that's what I got, which is why I took multiple readings. Looks like I need a new battery, but I still don't understand why the method of measuring across the pins in pairs gives near identical readings for all ten cells?
 

Nealh

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Due to the lack of use all of the cell groups have equally drained so whilst connected on the bike a residual small current has done this. Now we have got to the bottom of things and we have 10 pretty well balanced low voltage readings they are recoverable at above 2.8v each.

All your battery needs is for all 10 cell groups to be manually raised to above 3.3v each then the BMS will allow charging.

You need an old phone charger it will be 5v rated but that doesn't matter, chop off the charge plug :eek:.
Bare the two wires and solder on a pin to each wire using one from a computer pin strip, insulate each end with a bit of Red and Black heat shrink or tape leaving 5mm of pin showing make sure polarity is checked and correct.

This my one.
DSCF1099.JPG
 
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Nealh

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Using the modified 5v charger you can now charge each cell group up a little one at time, you will need your meter to check on process and must not leave the battery unattended. Each cell group if viable will take 40 - 60 mins approx. to raise above 3.3 v or more to be sure 3.4/3.5v will be better. Time the first cell group and then use that as a basis for each cell group to 3.5v.
Insert the pins with correct polarity in to the sense wire connector as you did earlier B-/B1, B1/B2, B2/B3 etc,etc until all are about 3.5v, don't rush the process and if it takes a day or two doesn't matter then reconnect BMS and try the charger. It should click and start the charge with the Red light showing and turn Green when finished, if all looks quite good put the battery back together and use. Balance might be a bit out so may take a few discharge/charge cycles to get right, for the first one or two charges try leaving the charger connected for a 3 - 4 hrs as the BMS should bleed down any higher cells then raise lower cells to balance all out. The balance process is slow and typically only about 50 ma current is sued hence the 3 - 4hrs balancing needed.
 
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Nealh

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I have gone over the last few posts and something is a miss with the measurements, the B1- to B1 , B2 , B3 etc,etc, measurements should go up fairly equally by 2.97 - 3v all the way to 29.9v or so, as indicated by the B-/B1, B/B2, B2/B3 etc, etc measurements. Both sets of results should correlate and back each other up.

Do the B-/B1, B1/B2, B2/B3 etc,etc measurements again and write each one down as you see it and post the ten measurements /readings.
 
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