Is this possible to do?

[ebike11]

With a Q6 pro charger?
I have an 18 cell pack divided into (3) 6 cell packs.
All of the cells are in fairly good shape. However all of the cells are wrapped and sealed up except for the 3 sets of JST plugs for balancing sticking out and of course the main leads which come to about 74V fully charged. Some of the cells are off a bit though so id like to balance them.
After plugging the JST plug into the Q6 pro could i then use NEG. and opposite end POS. to connect to the power side of the Q6 pro? The JST wires are thin so could balancing be done at 1A or so?
Thanks!

 

[Alan B]

I have a similar pack. I balance it using a charger that charges only through the balance leads. I use 3 amps or less through the thin Lipo type balance connectors and leads. I balance the CroBorg pack once a year or so. I just did it again yesterday. It doesn't take long if the pack is near full charge.

Very few chargers are designed to work this way. The two I have don't even have the high current leads. They are settable in voltage and current for up to 6S packs (note that only one charger can be used, and it must be applied to each 6S bank in turn):

BC168
RadioLink CB86 Plus

I have heard these also work but have not tried:
UN A6
UN A9

 

[ebike11]

I have a similar pack. I balance it using a charger that charges only through the balance leads. I use 3 amps or less through the thin Lipo type balance connectors and leads. I balance the CroBorg pack once a year or so. I just did it again yesterday. It doesn't take long if the pack is near full charge.

Very few chargers are designed to work this way. The two I have don't even have the high current leads. They are settable in voltage and current for up to 6S packs (note that only one charger can be used, and it must be applied to each 6S bank in turn):

BC168
RadioLink CB86 Plus

I have heard these also work but have not tried:
UN A6
UN A9

Thanks
Would u know its possible with the Q6 pro? Its a 1-6 cell charger. I think it cant balance..so i thought to charge fully then discharge all cells to the lowest cell BUT through the jst plug only

 

[john61ct]

I've been looking for BC168
https://www.rcgroups.com/forums/showthread.php?3357589-BC168-chargers-wanted

Don't even show up used on eBay

 

[Alan B]

The Radiolink is probably a better unit. I've heard that the BC168's have some failure issues, though mine still works. The Radiolink has a better display and user interface.

 

[Alan B]

Charging through the balance leads is generally accomplished with a different architecture of charger - they have individual DC-DC converters for each cell, and that means they don't have the high current separate charge conductors. The high current conductors indicate a single DC converter.

Having a single DC converter is cheaper but doesn't lend itself to independent cell charging through the balance leads.

 

[john61ct]

The Radiolink is probably a better unit. I've heard that the BC168's have some failure issues, though mine still works. The Radiolink has a better display and user interface.

OK, also the CP620 "hybrid" looks good.

But if anyone comes across a stash of the BC168s NOS or singleton used ones, please let me know.

Or contact information to get a factory run going, maybe just a few hundred units would be enough?

 

[Alan B]

Hybrid mode looks great if you have high current connections at the end of each parallel group. But if you only have the end connections of a series string of battery group it doesn't work unless you can bypass the hybrid mode.

 

[Alan B]

...
Very few chargers are designed to work this way. The two I have don't even have the high current leads. They are settable in voltage and current for up to 6S packs (note that only one charger can be used, and it must be applied to each 6S bank in turn):
...

Thanks
Would u know its possible with the Q6 pro? Its a 1-6 cell charger. I think it cant balance..so i thought to charge fully then discharge all cells to the lowest cell BUT through the jst plug only

I don't think the Q6 pro will work here.

 

[john61ct]

Hybrid mode looks great if you have high current connections at the end of each parallel group. But if you only have the end connections of a series string of battery group it doesn't work unless you can bypass the hybrid mode.

So far no parallel "groups", each node is a single cell, in this case 15-60Ah.

For 80-700Ah cell, different chargers required.

Never messed around with the little cylindricals, but on my list, but when I do, I'll design the packs to suit the charger.

 

[Alan B]

If you bring out the ends of each series group as well as the balance leads it gives you more choices for charging. So each 6S block (whether parallel or not, that doesn't matter) has two high current leads, one from each end, plus 7 small conductors for balancing which have the inter-cell voltages plus duplicates of the ends. Keep the paths separate as far in as you can to minimize interactions. That's what I did in the Borg pack. I then charge each 6S block with a 25V 12A voltage and current limited LED supply, so I have three of them for 18S. The balance leads I use for checking balance or for the annual balancing. The rest of the time I bulk charge with three LED supplies. They are adjustable for voltage and current limiting. Together the three are drawing about 1kW input power, so pretty much all you can legally draw from a 120V standard outlet, and it charges pretty fast on this 2200 watt hour ebike pack. Lots of variations are possible of course.

 

[dogman dan]

Any type of charger that can run a 1s charge, can balance your pack. Don't worry about .02v, just balance when it gets close to having a cell that is .1v low, or high. Then using the correct pair of balance leads, fill up that low cell with a 1s charge. You can also do similarly, with a discharge. Using the charger, or a simple light bulb, connect to that one cell that is higher than the others. If you have low, or high cells in a row, you can do two at a time. just depends where you connect on the jst plug, which cell, or cells, you are charging.

All you need is bare wires, with the male prong from a male jst plug, to make your 1s, jst charger adapter. just pull the red and black wires from any male jst pigtail. I used to buy 2s extensions to get the prongs. I have one set for the charger, and another soldered to a turn signal bulb.

 

[john61ct]

If you bring out the ends of each series group as well as the balance leads it gives you more choices for charging. So each 6S block (whether parallel or not, that doesn't matter) has two high current leads, one from each end, plus 7 small conductors for balancing which have the inter-cell voltages plus duplicates of the ends.

Interesting.

In my context, I don't parallel strings unless I want to split the bank for easier redundancy, main vs reserve and then usually only once.

So if my target is say 700-800Ah, I either have a single string of cells at that capacity, or two strings at ~400Ah each.

Paralleling say 180Ah's is a bit fiddly and makes troubleshooting and/or balancing harder.

I can see with using the small cylinder type cells to fit in eBike size packs, there aren't so many Ah-capacity per cell choice, so more complex.

I really like the idea of 6S sub-packs. Easier charging, if there are problems need fixing can be swapped out of the main pack, allows for incremental transitioning to replacement with new, rather than having to replace the whole at once.

One idea I'm playing with, is bringing out the balance-type wires only, per-cell pairs in a 12-way plug. That plugs into a little external "xPyS wiring" box that set how the cells are parallel/serially connected. Like electrical Lego, flexibility, allow for easy multi-purposing, put them all into 1P for balancing, able to use a variety of different-voltage charge sources as available, go from say 54V up to 60 or 72V and back down again without touching the physical blocks themselves.

Obviously the wire gauge needs to be sized right, and quality connectors like Deutsch add some cost overhead. . .

 

[john61ct]

Any type of charger that can run a 1s charge, can balance your pack.

Which does not require ones labeled as such, tapping the bulk charge leads adapting to a 1S balance connector. Not just "chargers" but any PSU, or DCDC converter. . .

Just needs the ability to adjust output to the right V&A.