Hi from hilly Sheffield

[Deleted member 4366]

Please give a photo of the battery itself or a link to the listing, so that we can see what it is instead of cryptic pictures.

there's still only nine results. You need to measure between the positive and negative, so that we can calculate the 10th one.

 

[sheffieldmike]

There are 10 the 6th is ZERO. I will take try and take some different pis in the morning. I will have a look for a listing. Have I done the readings right this time please? I tried to show the end of the battery with the negative terminal I used, shown with probe. Bottom left

20.6.
16.61.
12.44.
8.30.
4.13.
0. ZERO
3.87.
7.65.
11.37.
15.06

Thanks yet again Mike

 

[Deleted member 4366]

I think you'll find that that zero is a common ground. the last cell is between where you measured 15.06 and the battery positive.

 

[pdarnett]

0. ZERO
3.87.
4.13.
7.65.
8.30.
11.37.
12.44.
15.06
16.61.
20.6.

looking at these in order there's some worries here,there should be at least 3v difference between each cell, not less than 1v in some cases.

Over in West Yorkshire any time?

 

[Deleted member 4366]

No. If he's measured like instructed, the ground is in the middle and there's 5 cells either side. I've had a BMS like that before.

 

[sheffieldmike]

I have just had another look and wonder if I didnt get the negative , as instructed. (will send pics and links next)
Do these figures make more sense?

10 From the red-

39.4
35.2
31.1
26.22
22.8
18.78
14.87
11.11
7.37
3.67

I feel sorry for your trouble in trying to help someone who doesnt know anything
mike

 

[sheffieldmike]

Conhismotor- The listing cant be found, in fact they do not seem to sell on Ebay. There is a website but can only guess that this battery is the same. Mine came with no documentaion . It was made 2011.
http://www.conhismotor.com/ProductShow.asp?id=42

 

[Deleted member 4366]

I think the 26.22 is wrong because that would make cell eight 4.88v, which is too high. Can you re-check it.

I still need photos that show what the battery is.i can't make out how many cells or how they're wired, no what the BMS looks like. Can't you take some photos that show what you've got?

In the meantime, have a look at the cells themselves. Are any of them a little expanded?

The results that you've given indicate why the battery isn't working properly. the cells should be all within about 0.1v. We need to find out whether the BMS isn't working properly, or whether cells are knackered.

 

[Deleted member 4366]

Some progress. We now have a photo which shows 30 cells. Can you show a photo of the other side of the BMS?

 

[sheffieldmike]

Checked again, twice, figure below,

39.40
35.30
31.10
27.00
22.80
18.82
14.90
11.11
7.39
3.68

The cells look ok to me, its only the wrapping that is kinked.
The other side of the BMS has a blank plate glued? I can try and prize off?

 

[trex]

the black tape covers the metal plate of the BMS, there may be some screws holding the thing together. Peel of the black tape on the BMS if you like and take a look.
You'd need some tools to locate the fault. It's not clear cut.
4 of your cells seem to have lost much of their capacity but that could be because the BMS stops balancing them.
Try this any way:
find a 4.5V torch light bulb.
Connect the bulb to two adjacent balance wires to discharge one cell at a time
Discharge the top 4 cells until they reach 3.7V

Now you have manually balanced your pack, try recharging the pack.

 

[sheffieldmike]

Hi all - taken back off bms, had to cut thruogh silicone? I dont think it looks good but the wires are not burned through. Its burned the plastic cover. Should those two rail type things be together - negative terminal? Thanks
Shall I still try to discharge?

 

[Deleted member 4366]

The BMS looks fine. I just wanted to see if it had bleed resistors, which it does. The one interesting thing is that it doesn't have a B+, which means it gets its power from the balance leads. One of the middle ones has an extra connection, so it's possible that the cells between it and ground are powering the BMS, which could account for why one bank is low and the other high. The only other logical explanation is that some water got in and drained some charge from the cells at the bottom. It's still not clear to me which are the lower voltage ones. Are they at the bottom of the battery or the top?

Whichever ones it is, i think there's good reason to believe that the battery can be repaired by re-balancing manually. This means that you have to charge up the low ones or discharge the high ones until they're equal. You can charge with a USB charger, any charger you have for single cell lithium batteries (4.2v) or a cheap lipo charger. If you use a 5v USB charger, you have to keep an eye on it to make sure it doesn't go too high. the others are automatic. To discharge you need something like three 5W 12v bulbs joined in series, and then watch carefully to make sure that they don't go too low.

 

[Deleted member 4366]

Just to confirm. Can you plug in the multi-pin connector and measure the voltage in the picture below:

 

[sheffieldmike]

Just to confirm. Can you plug in the multi-pin connector and measure the voltage in the picture below:
View attachment 8607

Hi Thanks
The lowest v cells or on top, where the bms sat.
I have measured from the terminal highted and Its 18.82 v
I have just burnt my finger and 2 of the battery indicators are back on. Is that good?
Appreciate your time
mike

 

[Deleted member 4366]

I have just burnt my finger and 2 of the battery indicators are back on. Is that good?

it depends if you're a masochist.

Nothing should be hot. What did you burn your finger on?

When you unplug the connector, the BMS should switch off the output. It'll switch off when any cell goes below about 30V, or when the current's too high. Under some conditions, it'll stay off,so it needs to be reset by unplugging and re-plugging the power to it.

You battery is a\ long way out of balance - more than what the BMS can sort out, so you have to do it manually before anything else.

 

[sheffieldmike]

Hi d8veh
I burned my finger on the main terminals. Re, getting wet, fairly sure not as I rarely went out in the rain and I always carry the battery in my pannier bag.
Having trouble discharging cells, the bulbs keep blowing, I will have to go down to Maplins and get some bulbs and holders. This is going to take a while.
I wonder if you might please confirm, which are the balance wires and which wires I am connecting across?(I know I am reducing the high ones but not below 3.7v.) I have had one wire to neutral and one to a soldered joint. (in pic) I am now in doubt.
Would it be better to charge the low ones up and if so what are the lipo chargers you mentioned? What do I ask for?
thanks again mike

 

[Deleted member 4366]

Where are you connecting the bulbs? Actually, I wasn't thinking straight earlier. To discharge a cell, you connect the load directly across it. You should chech that you have around 4v first. As each cell is about 4v, you need a single 6v bulb of about 5w, like a motorbike tail-light, but there's not so many 6v ones around these days If you have to go out and buy something, you might as well go to Maplin and buy a power resistor. 1 amp at 4v means 4 Ohms and 4W.
They have 7W and 10W ranges so either of these three. Perhaps 10w preferable:
http://www.maplin.co.uk/p/wirewound-7-watt-47-ohm-resistor-l4r7
http://www.maplin.co.uk/p/wirewound-10-watt-39-ohm-resistor-h3r9
http://www.maplin.co.uk/p/wirewound-10-watt-47-ohm-resistor-h4r7

You need a way of connecting it, like a bit of wire and a pair of crocodile clips.

 

[sheffieldmike]

Thanks d8veh. Hopefully I will get resistor tomorrow. I take it this will drain the power?
In the mean time I have wired up some lights to a high v terminal but having trouble draining the high cells, it also seems to be lowering the low ones which ever way I try. Slow process so not sure.
Between the connections on the picture, (coloured wires above in my last post) there is 4v between each, same at the other end.
I tried between the negt, terminal and a (high v) wire on the (10 wire) block (as per multi-tester method) but not sure that this works either.
Am I on the wrong track and bridgeing the wrong connections.?
Hope this all makes sense
mike

 

[sheffieldmike]

I now have a power resistor, need advice please as to how I can isolate cells. (ie which terminals to bridge). Might this entail taking them apart, balancing, then re-assembly?
Thanks, mike