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Top Balancing - Not Needed?

NLS444

New Member
Joined
Dec 19, 2023
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31
Location
San Diego
Hi! I ordered these cells and was following this video to top balance. I'm attaching two photos of what I see when I turn the charger on and off. Am I correct to read this as these cells are fully charged? or are they completely dead? Thank you for your help!

IMG_1987.jpegIMG_1986.jpeg
 
alligators work fine for lower amperage. 10 amp is nothing. OP you have a volt meter right? just check the voltage.
 
86 the alligator clips for starters. Crimp on some 1/4" eyes or forked ends that you can tighten well onto the terminals. Before you connect the power supply set the voltage you want, then connect the wires.
On top of this, I would get rid of the banana plugs and small-gauge wire too. You should be able to use crimp fittings on the power supply end as well; usually those black things thread off revealing a terminal.
 
are they completely dead?

You may have a short circuit on the power supply output. Disconnect and sort things out.

Have you determined the positive and negative of the cells?

Did you measure the cell volts when you received the cells?

My personal thoughts on 'traditional top balancing' is there is a strong posibility that things will go wrong and the cells will be damaged.

As an alternative, connect the cells as a 12v battery, adding restraint or compression. Connect the BMS, idealy a BMS with Bluetooth, and charge with a 12v charger to 14 volts. This will give give you an idea as how well the cells are balanced.
If the cells are reasonably matched the BMS will sort the balance over time or with active balancer within a short period.

You can always manually balance by discharging the high cell or charging the low cell.
 
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If there is any question use your separate voltmeter direct on the cell terminals.
Could be an open connection. Best to use #10 wire and ring terminals.
 
Following up on this, voltage is 3.24 when measured from both the bus bars and battery terminals.

I followed the directions of the machine (set voltage to 3.6, set amperage to 5, connected black then red and instantly torched the charger.

I am now realizing these are advertised as 3.2v cells, not 3.6, so it it safe to assume they are fully charged and the error was the over voltage?
 
Following up on this, voltage is 3.24 when measured from both the bus bars and battery terminals.

I followed the directions of the machine (set voltage to 3.6, set amperage to 5, connected black then red and instantly torched the charger.

I am now realizing these are advertised as 3.2v cells, not 3.6, so it it safe to assume they are fully charged and the error was the over voltage?
3.2 is not full charge.

turn the amperage to 0 voltage to 3.6 and connect, and see if the psu works. then slow increase the amperage.
 
Here is what I set it to

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And here is what it shows the moment I connect it. It shows this regardless of how I turn the dials up or down, and the wiring is instantly hot.

IMG_1994.jpeg
 
have you tested this psu before? does it work with another battery? the dials should change the amounts both for voltage and amperage.
 
This is the only battery I have - when its not connected to the battery, the dials change just fine. Once connected, the voltage immediately drops to zero, but I am able to adjust the amperage up and down
 
This is the only battery I have - when its not connected to the battery, the dials change just fine. Once connected, the voltage immediately drops to zero, but I am able to adjust the amperage up and down
triple check the polarity
 
Triple checked, looks good. Checked again with the voltmeter, it shows 3.25 when red to red and negative when red to black. I attempted with a second battery charger and am having the same problem (although this one just shows all ones when I connected it, and is the one I torched earlier, so it wouldn't surprise me if that was a separate issue.
 
i don't own the psu that you show. mine doesn't work like that it should show the voltage, and you should be able to control the amperage in cc mode.

you can set it to 12.4 and try it with your car battery if you literally have nothing else. 2 psu's doing the same thing is unlikely.
 
advertised as 3.2v cells, not 3.6
3.2 volts in the nominal 'average' voltage over the working range.

As I stated in an earlier post, you have a short circuit on the power supply.

Check again that you have the cell polarity correct. Check your voltmeter against an AA dry cell to confirm its OK.

The wires are hot because of the short, that seems to be your cells. The power supply has hit the 10 amp limit.

I suspect the cells are incorrect connected, verify which is the positive and negative.

As I suggested, the parallel top balancing to often a way to damage the cells. There are many examples of disasters reported. I have outlined alternatives. Read post #5.

When things are not working out in any electrical system, take a step back, disconnect the everything. Then test each part independently. A 12v car bulb is a great test device.
Can the cells light the bulb? Can the power supply light the bulb? Test the polarity of the cells.

Many low cost off the shelf' batteries don't seem to have balanced cells as supplied, and after a period of use the BMS sorts out the issue.
 
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Thank you Mikefitz

Have you determined the positive and negative of the cells?

Yes, they have been red to red and black to black the entire time. Photo below (bus bars removed)

Did you measure the cell volts when you received the cells?

Each cell is at 3.26v when disconnected. When connected with bus bars in parallel, along all points the bars also read 3.26v.

As an alternative, connect the cells as a 12v battery, adding restraint or compression. Connect the BMS, ideally a BMS with Bluetooth, and charge with a 12v charger to 14 volts. This will give give you an idea as how well the cells are balanced. If the cells are reasonably matched the BMS will sort the balance over time or with an active balancer within a short period.

I do not have a BMS, ordered and should be here in a week or two. The consensus I thought I had seen was to top balance using a charger, then connect a BMS.

I suspect the cells are incorrectly connected, verify which is the positive and negative.

Here's a series of photos showing the batteries as organized, then how I put on the bus bars.

Unfortunately, I don't have anything that turns on with 3v
 

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Looks like the power supply is going into self protect mode (C.C led on, and current reads the max the power supply can deliver 10.09A).

Disconnect power supply red lead from cells. Set the power supply to 3.24 volts. re-connect power supply red lead to cells.

Then slowly increase power supply voltage while monitoring ampere reading. Do not let the ampere reading exceed 10A. Stop increasing power supply voltage when it reads 9A.
 
tinyt
So for both chargers, even when starting from 0, I am getting the same result as described. I your voltage and lower, same result.
 

OK, thanks for that.

I think we have a measuring issue here.

Put the BLACK meter wire in the COM hole and the RED meter wire in the V ohm mA hole (i.e. not the 10A hole).

And let's try again :)

You also cannot guarantee that the red(ish) terminal on the battery is really +ve. My 280Ah cells have a black terminal as +ve and white as -ve.
 
I just tried my similarly el-cheapo meter hooked up as out OP shows and it reads BACKWARDS!

Which means his charger is backwards on the cells, explaining everything!
if you look 4 posts up i said check polarity. I am a bit shocked it read anything, also curious if the fuses are blown due to this.
 

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