Preparing the Controller Connectors

September 23, 2010



  • A soldering iron and solder wire is desirable but not essential
  • A pair of wire snippers
  • A pair of crimpers
  • A multimeter

The next thing to do is prepare the connectors on the new controller so that they can connect securely to the bike’s system. Your controller should be something like the one below. For the upgrade we only need concern ourselves with connectors A-F. You can forget about connectors H, J, K, though if you want cruise-control, you could wire G into one of your horn buttons (the one you don’t use).

Generic 72V Controller

  • A – Main Motor Power Feed (R +72V, Bk Gnd): To main battery bank +/- terminals
  • B – Phase Wires (Bl, Gr, Y): To corresponding wires on connector block.
  • C – Hall Sensor: To corresponding connector on loom
  • D – Throttle Connector (Bk, Gr, Red). Warning! – Wires in connector may be reversed.
  • E – Brake Cut-off: To brake/sidestand 12V line (meets 2-pin Gr, R/Bk connector on loom with F)
  • F – Controller Power Feed: To R/Bk in 2-pin Gr, R/Bk connector on loom with E. (N.B: This spade fitting comes as part of the A connector)
  • G – Cruise Control Switch: Short to ground briefly to set cruise level (for use with button)
  • H – 60°/120° Option Switch: Open for 120° (Ego Motor  is 120°)
  • J – ‘Alarm’ (details unknown)
  • K – ‘Alarm Setting’ (details unknown)

The Power Cable & Anderson Connector

This is really the most important connection of the whole bike. However the wires from the controller are quite a bit thinner than the crimps for the Anderson connector, so – like others in the Electric Motoring Forum – I elected to ‘double-crimp’ these by using the existing connectors on the wires as ‘fodder’ for the larger crimps.

Here’s the main motor power cable as it came on my controller. It came as one of three spade connectors housed in a triangular-style three-pin plug with the ground and the low-current feed-wire for the controller. Since this connector isn’t in use on our bike, it needed dismantling into its component wires. This and the black (ground) wire need to be crimped into an Anderson Connector to connect with the one served by the main power cables on the bike. The low-current wire (the other red wire, F) will be connected up to the two-pin mini connector that also takes the the brake wire.

If you have different connectors on your power leads you can still use this method – or a variation – to good effect. If you have bare wires, you could crimp/solder them onto bullet connectors first, as with the instructions for the phase wires.

First I just folded over the spade  so it fits inside the Anderson crimp.

To pad out the crimp for a tight fit, I’ve used 10mm lengths of thick copper wire I took from an old cooker cable.

I pack the spade connector in with this ‘filler’ then crimp it for a good solid connection.

Next a bit of heat-shrink for insulation before it is clipped into its Anderson connector along with the black ground-wire.

The Anderson connector for the controller (left) is now ready to be joined with its counterpoint on the loom.

The Anderson Connector (left) for the controller power cables, connected to its counterpart (right) which takes power from the main battery bank via the breaker switch.

The Brake/Power Feed 2-way Connector

On the Ego Scoota, the white brake cut-off wire (E) and the red power feed (F) to the controller both need to hook up to the R/Gr female 2-pin that served the R/Vi wires on the old 48V controller. You therefore need to wire these in to the male two-pin mini-connector listed in the parts.

If you’re desperate, you can just take the one off the old controller, but it’s nicer to just use a fresh one, as whoever inherits your old controller won’t be too happy.

The final arrangement for the brake/power feed wires: A two-pin connector replaces the red/violet two-way that ran from the old 48V controller, and which now holds the equivalent red/white connections from the 72V controller.

The Phase Wire Ring Connectors

If you’re lucky, the phase wires on the controller you have will already have ring connectors. And if you are even luckier, the holes will be big enough that you won’t have to drill them out (beware!) or just replace them.

However if you are left with just some bare wires, you might be wondering how to give these a solid connection to the large-bored ring connectors you’ll need for the connecting block on the Scoota. The smallish guage phase wires are way too small to suit the large bore of a standard 6mm ring connector. However they are just the right size, for one of the many bullet connectors I got in my handy megapack of connectors.

To get rid of the plastic, two or three seconds under a lighter softens it enough to slide off with very little persuasion, and with no gooey mess…

which is great if you want to add a smidgeon of solder to the resulting crimp, like I did, to make sure the connection is as solid as possible.

With the phase wire bullet connection duly crimped and soldered, I then shoved it into the bore of the 6mm ring connector (not forgetting to slide a length of heat-shrink down the wire first).

Next I used the honking great crimper to crush it into a nice, solidly fused mass, then packed the heatshrink around the resulting join.

The Throttle Connector

The throttle connector on the controller should be a 3-way mini-connector just like the one on the loom. However you need to check this as the wires are frequently reversed, as below on my controller.

Watch out for that hinky throttle connection!

The Green(/White) – Black(/White) – Red(/White) throttle connector on the loom (bottom), corresponded to the Black-Green-Red on the controller’s own connector (top). This should be Green-Black-Red, NOT Black-Green-Red, so that they match their counterparts on the loom. On both of the controllers I have used, the black and green wires on the controller’s three-way connector needed ‘picking’ so that these wires could be reversed.

The problem, of course, may not take this form on every machine, or even exist at all, but whatever your configuration you need to make sure that the colours match up either side of the connectors.

Once you’ve got these four sets of connectors checked or fixed, the controller will be ready to attach to bike in the next section Installing the 72V Controller.

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