Equalising NiMh Stick Packs
Stick packs are notorious for being poor quality and not good for racing. This doesn’t have to be the case. You can buy stick packs made up of matched cells, so they start off life as a decent pack.
The performance can drop off though, as the cells become out of match. Racers who use side-by-side or saddle packs usually balance dicharge each cell individually using a discharge tray.
Much More have a discharge tray designed for stick packs, it’s less obvious how it works though.
First of all, it’s not obvious where each cell connects, as stick packs are usually in heatshrink, without the ends of each cell visible.
The stick pack balancer connects to the cells via the side of each cell, which is the -ve terminal, which essentially provides a connection to the connection between any two cells.
To connect to this you have to remove some heatshrink from each cell where the screws make connection. To do this, place the stickpack in the tray, note which way round the +ve and -ve wires need to be at the top, and tighten the screws to make some marks.
Now, you need to remove a small amount of heatshrink to get down to the bare metal of the cell, this might be 2 or 3 layers thick! You can use a craft knife to cut a small circle away, or Much More even sell a special tool to do it, which turns out to be a drill bit with a handle, so you could just use a drill bit instead. But!! Careful, don’t use it in a power drill or a dremel, do it BY HAND, you only want to go down to the cell metal casing, and not drill into the cell – explosion could result if you did that!
Now you have metal available on each cell, well, actually, only on 5 cells, as the 6th cell connection is made via the black -ve wire, so you can sit the cell pack back in the tray, tight up all the screws, 4 lights will come on, then plug in the top wires, and the 5th light will come on.
The red light will also start flashing, let it dicharge, it’s quite slow, perhaps only an amp or so, so it’s best to bulk discharge the whole pack before putting it on the tray if you don’t want to wait an hour or two.
Sit and watch the lights get dimmer, until the red one stops flashing. Then remove the cell pack and charge it immediately.
Good care of NiMh cells will keep them working well, I’ve noticed my stick packs improve considerably after several balance cycles.
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