Balancing connector with wires

This review is barely even a micro-review; it's more of a nano-review, it's so short. Still, I thought it might be useful to someone.

A friend asked me to buy him some connectors with wires. They're marketed as balancing connectors for an iMax charger. The price was pretty low, so I ordered them, paid, and received them.
As you can imagine, this is the kind of product that's very hard to damage; there's not much to break here anyway.
Everything arrived without any problems: two lots of 10 pieces each.


Each one consists of a connector and several wires in different colors.


The connectors come with the part that gets soldered onto the circuit board. I've seen similar sets cost more here. Of course, you can crimp them yourself, but that's not always convenient, even though it can be noticeably cheaper.


The wire is 15 cm long, as specified.


The connector latches securely and doesn't wobble. The pin spacing is 2.54 mm, not 2.5 mm. For just four pins, it doesn't really matter whether it's 2.5 or 2.54 mm, but with a lot of pins, it's worth paying attention so you don't have to bend them later.
By the way, connectors like these can also work well for all sorts of Arduino projects.
The wires have a small cross-section, but they'll handle 0.5–1 A without any problems—and that's more than enough for a balancing connector, where the currents are low.


Just in case, here's a quick explanation for anyone who doesn't yet know what balancing is.
Because batteries in a series pack aren't perfectly matched, they can become unbalanced: one battery's voltage is higher, another's lower. Balancing is used to address this by bringing the battery voltages to the same level. This is most often done during charging: the most charged battery is deliberately held back by drawing off some of its “extra” energy, until the voltages across all the batteries gradually become equal.
At low currents, this isn't so critical. But in cordless drills, radio-controlled models, and similar devices, it matters because the currents are high and problems can arise. And that's not to mention that an unbalanced battery pack will have a lower overall capacity, since the protection circuit will cut off discharge when the most discharged (or least charged) cell reaches its minimum voltage. In other words, if all the cells in a pack except one finish charging first (because they discharged less last time), the pack's capacity in mAh will be determined by the capacity of the most discharged cell.


Packs are usually configured as 2S, 3S, or 4S, and sometimes 5S. But in some cases, packs with 15S are made too. The battery shown in the photo is 15S2P + 15S2P—that is, two separate batteries, each made up of 15 cells in series and two in parallel. A battery like this is quite difficult to balance—or, more precisely, it just takes a very long time.



That's it for this nano-review. I'll just say that I paid $4.72 in total (2 lots + shipping), which worked out cheaper.

I hope this information was useful.