10s Battery charging using 2x 5s balanced plug

Thread Starter

JoeCK

Joined Mar 20, 2020
24
Hello Guys,

Yesterday I was trying to start my electric scooter and found it's not charging. Then I have gone on removing the battery pack and checked each parallel cell group and found group6 was only @ 1v left. I have to remove the cell group and check each cell send through the charging and discharging cycle to isolate the culprit cell.

This problem is occurring for the 4th time and I suspect my BMS for the situation. Now I'm thinking of removing the BMS altogether and do the balance charging through a Skyrc iMax B6 charger externally.

My setup is;
Battery pack - 10s 6p Li-ion
Motor - 6384 Outrunner Brushless Motor
Charging - Skyrc iMax B6 charger
Discharge Through ESC - Maytech Brushless 4.12 VESC Controller

In this scenario, I would like to know the ideal wiring diagram to achieve, balance charging as 2 separate 5s packs, and then use it as a 10s pack (without the magic smoke pls).
Please find the attached images for more info on what I'm thinking. I got the thought by seeing the APS LiPo pack which I have attached as well.

Thanks in advance for your help.
Joe
 

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Irving

Joined Jan 30, 2016
763
You can do it like the diagram below, charging 2 halves independently... which could take double the time...

or better, buy a Revolectrix Cellpro10 10s charger.

10s.JPG
 

Thread Starter

JoeCK

Joined Mar 20, 2020
24
Hello Irving, Thanks mate :)

I was wondering how to do the wiring connections for;

1. Imax b6 5s balance port wiring. Where does the RED wire (+ve from the battery pack) of the balance cable will go into the balance port? (Picture attached)
RED = 1st pin
OR
RED = 6th pin


2. Preferred gauge (AWG) of the cable that interconnects two halves of the battery. Maybe using an on/off switch? or XC60 connector? which would you suggest? or any other better ways?

Thanks a lot for your kind reply.
JK
 

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jpanhalt

Joined Jan 18, 2008
9,646
I have been using an iMax (genuine) for LiPo and Li-ion batteries for several years now. Have never had a problem.

Those look like 18650 cells. Correct? They appear to have been obtained from various sources based on color and other details. Are they all the same chemistry? Have they had different charge cycles, as in their original equipment?

I weld my Li-ion packs with nickle strips. Smaller sizes have never been a problem. The 18650 size has given mixed results. Some seem very sensitive to even the little heat of capacitor discharge welding. Others have been fine. UltraFire have not worked at all.

I suspect the problem is with your batteries and soldering heat, not the charger.
 

Irving

Joined Jan 30, 2016
763
Hello Irving, Thanks mate :)

I was wondering how to do the wiring connections for;

1. Imax b6 5s balance port wiring. Where does the RED wire (+ve from the battery pack) of the balance cable will go into the balance port? (Picture attached)
RED = 1st pin
OR
RED = 6th pin


2. Preferred gauge (AWG) of the cable that interconnects two halves of the battery. Maybe using an on/off switch? or XC60 connector? which would you suggest? or any other better ways?

Thanks a lot for your kind reply.
JK
Updated picture. The two balance cables are identical, red & black as shown, but the charge cables and balance cables should be paired physcally or with a coloured marker (here suggested white and blue) to ensure you can't charge wth the wrong balance connector plugged in. I'd not put a switch between the packs, its a high peak current area. Put a connector if you must, but that increases cable resistance and is another point of failure.


10s.JPG
 

Thread Starter

JoeCK

Joined Mar 20, 2020
24
Thank you, Irving.

1. I have updated the drawing with the actual wiring I'm intending to do. Can you please verify if I'm doing it correctly and not conducting a firework :)

2. Also, the connection between two 5s packs can be permanent (so I can use 18awg soldered in)?
or removable while charging?

Thank you again for your help.
 

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Thread Starter

JoeCK

Joined Mar 20, 2020
24
I have been using an iMax (genuine) for LiPo and Li-ion batteries for several years now. Have never had a problem.

Those look like 18650 cells. Correct? They appear to have been obtained from various sources based on color and other details. Are they all the same chemistry? Have they had different charge cycles, as in their original equipment?

I weld my Li-ion packs with nickle strips. Smaller sizes have never been a problem. The 18650 size has given mixed results. Some seem very sensitive to even the little heat of capacitor discharge welding. Others have been fine. UltraFire have not worked at all.

I suspect the problem is with your batteries and soldering heat, not the charger.
My charger is fine mate.
I wanted to know the +ve pin on the balance port of the imax charger. (Is +ve the 1st pin or the last pin?)

And regarding the battery pack, I have made various sized packs successfully by purely soldering, and the used to give me decent number of charge cycles before any of the cells down.
What I found difficult is disassembling the spot-welded pack, in order to isolate the problematic cell.
If you have any ideas and tips to ease the procedure with de-spot-welding I would really appreciate it :)

Thank you for your inputs.
 

Irving

Joined Jan 30, 2016
763
Thank you, Irving.

1. I have updated the drawing with the actual wiring I'm intending to do. Can you please verify if I'm doing it correctly and not conducting a firework :)

2. Also, the connection between two 5s packs can be permanent (so I can use 18awg soldered in)?
or removable while charging?

Thank you again for your help.
You're welcome.

Looks OK, hurts my eyes though :)

If you are charging halves separately, and not simultaneously then should be ok to hardwire. If you're planning to use 2 chargers then be careful, as if they are both mains ground referenced you will see fireworks potentially.

I've never spotwelded so cant comment. Nickel strips solder fine with a big high thermal mass chisel not pointy, tip.

Pin 1 normally ground (black).

Whats the balance current on yr charger? VGA pins aren't very substantial, don't know what they're rated at.
 
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jpanhalt

Joined Jan 18, 2008
9,646
If you have any ideas and tips to ease the procedure with de-spot-welding I would really appreciate it :)

Thank you for your inputs.
Cut the strips between cells. Then re-assemble by solder (on the strips) or welding. I would strongly recommend against pulling the strips from a cell, unless you intend to throw the cell away. You can get cells with or without tabs. If you buy cells with tabs, soldering those tabs is fine -- it may actually be designed for soldering.
 

Irving

Joined Jan 30, 2016
763
I don't know that charger so I cant be 100% sure, but looking at the near useless manual (a battery charging manual with no wiring diagrams?) the pictures seem to suggest the +v is to the left of the connector and therefore your pic appears to be correct.
 

Thread Starter

JoeCK

Joined Mar 20, 2020
24
but looking at the near useless manual (a battery charging manual with no wiring diagrams?)
Totally agreed.

I have taken another approach like... finding the balance connector polarity of a standard LiPo battery. Could that be common for all chargers?
The top side notches of the female balance connector looks like slot correctly into the charger's male connector.

Because trying to save a charge from magic smoke

Thank you, Irvine for your help

PS. http://www.tjinguytech.com/charging-how-tos/balance-connectors
 

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