Balance charge 13s potted pack?

[Ham]

OK so my last pack build has been a clusterf***k and I am currently exploring options and would appreciate any advice.

The pack (as with my others) has been built to a custom spec, potted and bms managed. 21700 cells, 13s5p 0.2 nickel strip. Cool so far.

The builder has built it to the wrong size so no longer fits in the built space. Not cool.

Ideas are pinging around from selling the pack and going lipo to running it sans bms like a lipo and just using a balance charger. Now my question becomes:

How can I use the current 13s balance connector on the potted pack to split down to a 6s and 7s connectors for a standard balance charger to work?

Or perhaps there is a 13s balance charger I don't know about knocking around out there somewhere?

Merry Christmas All!

 

[Ham]

Or perhaps it is possible to simply use the BMS as an external balance charger and plug it in for each charge session?

 

[goatman]

you dont need to balance every time
if your cells are good you could go months without needing to balance

 

[john61ct]

Top notch, world class balance charger: Pulsar 3+, highly reco. Very fast balancing.

https://www.pp-rc.de/CHARGING-TECHNIC/ACCU-CHARGER/Profi-accucharger-Pulsar-3-.htm

https://www.rcgroups.com/forums/showthread.php?p=47719775

 

[john61ct]

Dedicated balancing unit, "non-protective BMS"

Can balance at any voltage

decent Active ones keep the balancing rate regardless of imbalance delta, much faster then cheap "resistance burning" ones

examples

https://tinyurl.com/yx4fn379

 

[john61ct]

Or perhaps it is possible to simply use the BMS as an external balance charger and plug it in for each charge session?

Sure but actually watch the balance process so you don't hold the top voltage too long, reduce longevity.

Ideally the BMS is adjustable for both StartV and StopDelta, with a high balancing current.

Cheap ones are none of the above

 

[Ham]

Wow that is a pricey unit!

 

[Ham]

you dont need to balance every time
if your cells are good you could go months without needing to balance

Yup agreed...just need to know how to balance them at all

 

[goatman]

you can use one of those bluetooth active balancers
i think the Ant bms with bluetooth can start balancing at any voltage you choose.

it wouldnt be hard to connect one to the pack, once a month and see whats happening with the pack on your phone

 

[Ham]

I currently have an ant bms and yes the balance parameters can be set to choosing.

So if I want to run this bms as basically a balance charger that i plug in for charging only it is just a case of adding the appropriate connectors to the battery negative line and plumbing it in for charging?

 

[goatman]

yes.

 

[Ham]

Well that makes life a little simpler, many thanks for the confirmation!

 

[TrotterBob]

13S charging? Well theres expensive:

https://www.buddyrc.com/products/isdt-x16-dual-channel-2200w-20a-16s-uav-ac-dc-battery-charger

And then theres a cheaper way if you're careful:

https://heltec-bms.com/project/5a-capacitive-active-equalization-active-balancer/

Those 5A active balancers are also available from the usual suspects, feebay, scamazon, aliexpress, GoodLuckBuy etc.

High cell count balance chargers are becoming more popular thanks to big size Agriculture and cinema drones. Shame you're using 13s and not 12s, that would open up a lot more options for balance charging with a single JST-XH connector and the main charge/discharge connector.

 

[Ham]

Thanks, if I can source a 14 pin jst extension for the battery to bms connection then I will just use the bms as an external balance charger as I have it here to hand.

Any ideas on those connectors...first searches come up with nothing much above 7/8s connectors

 

[TrotterBob]

These are the housings:

https://www.ebay.com/itm/232392291015

And found a pigtail (with wires) from Aliexpress:

https://www.aliexpress.com/item/32483151149.html

If you start with just a housing its not too difficult to pry up the little plastic retainer clips and slide out each individual wire. Just dont touch 2 of them together if they're still connected to a battery at the other end. What I do is buy the empty housing then a handful of 2 pin jst-xh pigtails and remove the wires from those, but that involves some soldering and shrink wrapping to do the job correctly.

Found them from a supplier in India too, but I've never ordered from this outfit.

https://www.sunrom.com/p/14-pin-jst-xh-25mm-one-side-female-with-30cm-wires

 

[Ham]

Thank you for doing that, very kind of you.

I may just cut and solder in extra lengths of wire one by one and shrink wrap them.

Merry Christmas All