The Associated SC28 battery takes an hour to charge the battery using the charger in the transmitter. I wanted to be able to charge the battery using my lipo charger and I didn’t want to have to wait and hour for the battery to charge using the OEM method.

The SC28 come with a small 150mAh battery mounted inside the chassis. It will be replaced with a small 3.7v 180mAh UMX battery normally used in small quads. I started by removing the body then the 10 screws that hold the chassis together. To make it easier I popped the top of the shock off on each side. The lets you remove the chassis top completely. I then drilled a hole large enough through the top of the chassis for the wires to pass through. I drilled mine just in front of the channel where the power LED is located. I then pried the battery loose which was held in place with double sided tape. Cut the battery leads about 1/2 in from the esc/rx. This leaves enough wire on the batter that an end can be soldered on and the OEM battery still used. Equipped with Ultra Micro plugs so all that was needed was to solder the female end to the 2 wires attached to the control board, paying attention to the polarity. The female UM plugs I have come with leads. I used shrink tubing to protect the solder joint.

It’s now time to start reassembling the SC28. The easiest way to do this get the rear end back in place then put the chassis top back on making sure you don’t pinch any wires. Hold the chassis top in place using the 2 rear screws. Now put the front end back in place making sure it connected to the servo. With the front end in place install the 2 center screws. Flip it over and reinstall the bumper and install the 2 screws that hold the bumper and the front end together. Now install the remaining screws. I ran the lead for the battery through the front body tower to take up the slack and still leave enough to plu and unplug the battery.

Put a small piece of velcro on the battery and between the shock tower. This spot is raised a little so I also put a small piece of hard foam just in front of the power LED to support the front of the battery.

With the new battery installed I wanted to see how the SC28 ran and handled. The battery that I used was rated at 45c and I think it showed a little more punch that the stock battery. As far as run time on the stock battery I was getting about 27 minutes of continuous run time on my patio track. With the new UMX 180mAh the SC28 ran 34 minutes on the same track. The extra run time wasn’t my goal, I did the battery mod for the convenience of being able to charge the batteries using my UltraPower charger. Typically these types of batteries are charged on a parallel board charging up to 6 at one time.

The nice thing about this mod is that the TX charger or the Hpi USB charger will still work using the charging port on the side of the SC28.

Remove the 7 screws on the top and 2 bottom front

Ultra Micro plug leads soldered to the leads from the esc/tx

Ran wires for the Ultra Micro plug through the body tower.
Small hard foam block to help support the front of the battery

Battery mounted in the rear with velcro

Top view of the battery mounted

Batteries that are being used. I got these at Amazon 4 of them for $19.95

The UMX battery being charged via the TX

Charging the battery using the Hpi USB charger plugged into the UltraPower charger.
It takes about 1.5 hrs to charge this way when the battery was run to Lipo shutoff.