New battery not charging fully

[thelateoctober]

Put a new battery in this mod, Maxamps 2250 3s, 25 watt hours. Had it on the charger all night last night, this morning battery says 66%. 2 cells show 4.2, one shows 3.9, and pack charge is 16 Wh. 

What gives? Did I get a battery with a dead cell? Are my settings messed up? Never had this problem.

[dwcraig1]

It appears to be balance charging, it's a slow process. It should get there eventually.

[dwcraig1]

In this image I used a juce bottle with wires taped to it's ends and placed in a charger. The wires run to the balance plug and connect to the low cell. While this may look a bit crude it worked very well.

If you don't want to wait till it balances via mod consider this.

[thelateoctober]

4 minutes ago, dwcraig1 said:

It appears to be balance charging, it's a slow process. It should get there eventually.

It was on the charger for 8 hours at least. Once it hits 66% the charging icon disappears. And just shows the battery. Like it thinks it's full. Photo is on the charger, with icon not showing charging. It is balance charging, yes, but that cell won't go over 3.9. 

 

How long should I expect a 2250mah pack that arrived balanced to fully charge all 3 cells to 4.2v? Thanks for the help!

[dwcraig1]

Probably a couple of days.

EScribe will show a charging rate, low but charging non the less.

[dwcraig1]

What were the 3 voltages when you first installed it?

I should have said "was it out of balance to start with?"

[thelateoctober]

3 minutes ago, dwcraig1 said:

What were the 3 voltages when you first installed it?

Whatever Maxamps ships at, around 3.5.

It's not charging, USB current bouncing from 0.000 to 0.008 and back. 

I've installed dozens of lipos and have never heard of one taking multiple days to balance charge. 

Edited February 26, 2023 by thelateoctober

[dwcraig1]

That's the balance charging doing it's slow thing. If you can implement what I posted it will get it up in like an hour. Once balanced use EScribe to see that cell #2's voltage drop when firing heavy load matches up with cell #1 &3.

If not then maybe defective.

[thelateoctober]

4 minutes ago, dwcraig1 said:

That's the balance charging doing it's slow thing. If you can implement what I posted it will get it up in like an hour. Once balanced use EScribe to see that cell #2's voltage drop when firing heavy load matches up with cell #1 &3.

If not then maybe defective.

I'm just having a hard time believing 0.008 amps is charging. That's like enough to replace the power the screen draws while on and plugged it. And 99% of the time it's at zero. The board thinks it's full and isn't charging it at all. 

[thelateoctober]

It just dropped from 67 to 66 while plugged in. That's not charging. 

[dwcraig1]

There is an option under the Tools tab / Diagnostics/ USB Recovery that will prompt balance charging.

[thelateoctober]

1 minute ago, dwcraig1 said:

There is an option under the Tools tab / Diagnostics/ USB Recovery that will prompt balance charging.

I'll give it a shot quick 

[dwcraig1]

4 minutes ago, thelateoctober said:

It just dropped from 67 to 66 while plugged in. That's not charging. 

It has to reduce the cells that are full charge in order to bring up the low one, this is done with very smal resistors.

[thelateoctober]

6 minutes ago, dwcraig1 said:

There is an option under the Tools tab / Diagnostics/ USB Recovery that will prompt balance charging.

 

4 minutes ago, dwcraig1 said:

It has to reduce the cells that are full charge in order to bring up the low one, this is done with very smal resistors.

Zero usb current, cells 1 and 3 bouncing between 4.20 and 4.21 as they have been, cell 3 just chilling at 3.91. It's been exactly 3.91 since I first connected it hours ago. Pack voltage still 12.32. 

[thelateoctober]

On 2/26/2023 at 11:37 AM, dwcraig1 said:

It has to reduce the cells that are full charge in order to bring up the low one, this is done with very smal resistors.

So after three full discharge to 3.1 and full charge cycles I'm still seeing the same thing. Cells 1 and 3 at 4.2, cell 2 at 3.92-3.93. I've tried a recovery charge after each cycle, which does nothing. Any other ideas what might be going on here? I've built tons of these with lots of different brands of batteries, to see this from a Maxamps is really weird, and for escribe to also just stop charging completely at this point is also very weird, I've never seen anything like it. Literally zero input current, whether connected to escribe and device monitor, or via the normal usb I use, having changed display while charging to show individual cell voltages. The charging icon just goes away and it sits there at 3.9.

I spoke with a guy from Maxamps this morning, he suggested the multiple charge and discharge but with no change I'll reach out again in the morning. 

The other option is forking out cash, at least as much as the battery cost, for a balance charger that will recover that individual cell. I feel like I shouldn't have to do that. Anyway, any other thoughts or ideas? I'm impressed with your ingenuity with your solution but it's not something I'm willing to try. 

[dwcraig1]

The battery in my post had been hooked up to a small hobby charger and an expensive one with no results.

So just what is your concern with my recomended method?

[Wayneo]

How did you do those 3 discharges down to 3.1volts? Did you look at cell voltages at that time, and do you remember what each voltage was?

Being wired serially, IMHO only cell 2 would have been 3.1 volts. Cell 1 and 3 should have been that ~.4volts higher.

Maybe use a multimeter and check each cells voltage manually (via the white jst connector) and report back. Is this all new wiring and connectors?

Like @dwcraig1 already said, it could take days plugged in for the mod to rebalance, if at all. I really don't understand your apprehension with his idea. By using a proper 18650 charger it would follow the proper charging protocols and cut off for that 1 cell.

[thelateoctober]

4 hours ago, Wayneo said:

How did you do those 3 discharges down to 3.1volts? Did you look at cell voltages at that time, and do you remember what each voltage was?

Being wired serially, IMHO only cell 2 would have been 3.1 volts. Cell 1 and 3 should have been that ~.4volts higher.

Maybe use a multimeter and check each cells voltage manually (via the white jst connector) and report back. Is this all new wiring and connectors?

Like @dwcraig1 already said, it could take days plugged in for the mod to rebalance, if at all. I really don't understand your apprehension with his idea. By using a proper 18650 charger it would follow the proper charging protocols and cut off for that 1 cell.

Morning.

Update - I woke up this morning with cell 2 at 3.98, 0.05v higher than I've seen it yet. So somethings happening, I guess? I'm going to reach out to Maxamps and get their opinion as well. 

I discharged by using it. I did not record exact values of cells 1 and 3 when cell 2 hit 3.1, but yes, they were ~0.4v higher. 

I'll whip out the multimeter after I've had some coffee and double check. 

As fast as that charging method, using painters tape to stick balance wires to a juice bottle and stuff it in an 18650 charger doesn't scream battery safety at me. I understand what is being done and that there is probably nothing to worry about, and if I end up with no other options I will do it... But I also feel like I should not have to do that with a brand new battery from Maxamps. 

Thank you for your reply and help!

[thelateoctober]

4 hours ago, dwcraig1 said:

The battery in my post had been hooked up to a small hobby charger and an expensive one with no results.

So just what is your concern with my recomended method?

Did you solder tabs or something to the ends of the wires going into the charger? How did you get the other end into the JST? I feel like stripping a good enough amount and tinnijg it would be good enough, but I'd be interested to hear how you did it.

Also - if I'm trying to charge cell 2, I'm going to be using (starting nearest the battery negative) the 2nd hole as my negative and 3rd hole as positive, correct?

[Wayneo]

44 minutes ago, thelateoctober said:

Update - I woke up this morning with cell 2 at 3.98, 0.05v higher than I've seen it yet. So somethings happening, I guess?

Yup, that's how balance charging works. Painfully slow. IIRC it'll raise 1&3 to like 4.21 then drop them to 4.19, raise 2 a bit. Rinse and repeat for a long time.

From the top of my head, looking at the board battery negative pad, that 1st jst pin is a ground, then cell 1, 2, 3. But I'd wait for @dwcraig1 to validate that. It should show a lower voltage.

[thelateoctober]

4 minutes ago, Wayneo said:

Yup, that's how balance charging works. Painfully slow. IIRC it'll raise 1&3 to like 4.21 then drop them to 4.19, raise 2 a bit. Rinse and repeat for a long time.

From the top of my head, looking at the board battery negative pad, that 1st jst pin is a ground, then cell 1, 2, 3. But I'd wait for @dwcraig1 to validate that. It should show a lower voltage.

Painful is right. That’s exactly what it’s doing when I watch on eScribe. 1 and 3 bounce around 4.19-4.21 with less than 1 amp input current. The only thing that’s bothering me really is that it will go ‘idle’ for long periods where it is not drawing any current at all - just flat zero on usb current.

But I did just speak to the guy from Maxamps, their customer service is top tier. He said it’s frustrating that it’s taking this long to balance out, but should eventually, with no negative effect on the overall or lifetime performance of the battery. So if I have to do this for a week or whatever I’m fine with it as long as the battery is fine in the end. And I’m confident if it doesn’t that they will replace the pack. 

Thanks again for the help. 

[dwcraig1]

1 hour ago, thelateoctober said:

Did you solder tabs or something to the ends of the wires going into the charger? How did you get the other end into the JST? I feel like stripping a good enough amount and tinnijg it would be good enough, but I'd be interested to hear how you did it.

Also - if I'm trying to charge cell 2, I'm going to be using (starting nearest the battery negative) the 2nd hole as my negative and 3rd hole as positive, correct?

I used a small gauge solid wire, no tinning. Made little circles like elecrtic stove burners for on the ends of the 5 ml juice bottle and simply taped the wire to the side of the bottle. On the battery end I just pushed the wire into the holes on the JST plug and added some tape so they would stay put. Use your meter to find them, they will be next to each other.

[dwcraig1]

If DNA250 it should be the two center ones.

#2 positive and #1 negitive for cell #2 connection

[thelateoctober]

13 minutes ago, dwcraig1 said:

If DNA250 it should be the two center ones.

#2 positive and #1 negitive for cell #2 connection

Awesome, thank you. I'm not positive I have any solid wire small enough, but if I tin some of my 24g that should work. Also might have a couple of the ground connectors that go around the 510, those would probably work too. 

I'm gonna continue with the recommendations from the Maxamps guy for now - if it gets to a point where in just over it il9ise this method. Thank you!

One other question, I'll ask Wayne too - when cell 2, the low one, is hitting the cutoff at 3.1 the other two still have 0.4v give or take,, the battery meter still shows 6% and the mod still fires, just not at full power. Should I continue using it to get those other two down to 3.1 or do I need to stop?

[thelateoctober]

1 hour ago, Wayneo said:

Yup, that's how balance charging works. Painfully slow. IIRC it'll raise 1&3 to like 4.21 then drop them to 4.19, raise 2 a bit. Rinse and repeat for a long time.

From the top of my head, looking at the board battery negative pad, that 1st jst pin is a ground, then cell 1, 2, 3. But I'd wait for @dwcraig1 to validate that. It should show a lower voltage.

One other question - when cell 2, the low one, is hitting the cutoff at 3.1 the other two still have 0.4v give or take,, the battery meter still shows 6% and the mod still fires, just not at full power. Should I continue using it to get those other two down to 3.1 or do I need to stop?