From RobotinoWiki

Gallery illustrating the installation of two NiMH battery packs

Gallery illustrating the installation of an optinal third NiMH battery pack


By replacing the Pb accumulators shipping with Robotino with the NiMH accumulators the time of autonomous operation can be doubled. While the Pb accumulators have a capacity of 9.5Ah and an average voltage of about 23V the NiMH accumulators have a capacity of 18Ah at an average voltage of about 22.5V. The available energy of the Pb accumulators is therefor 218Wh and the energy of the NiMH 414Wh. Furthermore the NiMH cells show a much better performance over time, i.e. the amount of energy that can be stored by the NiMH remains almost unchanged after hundreds of charging cycles.

Robotino v3 is designed to load up to three NiMH accumulator packs. We recommend to install two NiMH accumulator packs because the installation of the third pack is quiet complicated. Also we think that the autonomous operation time of 8 hours and more with two NiMH packs is a reasonable value.

Tools needed

You need a big screw driver to unfasten the screws holding the control unit. You need a 2,5mm and a 2mm hex-wrench for the rest of the screws.

Step 1

Remove the fuses from the two batteries. Now you are safe to disassemble Robotino.

  • Remove the control unit.
  • Remove the caps covering the wheels.
  • Remove the handle bars.

Step 2 and 3

  • Unfasten the hook-and-loop tape holding the Pb batteries.
  • Remove the batteries.
  • Remove the battery holder.

Step 4

Prepare the additional charger for side B. Install the screws with the spacer. Install all the cables to the charger before mounting it on Robotino.

Step 5

Mount the prepared charger on side B. Fasten the screws with the 2mm hex-wrench.

Step 6

Remove all cables from the charger at side A. Attach the new cables to the charger on side A.

Step 7

In the gallery you find a picture showing a detailed view of the mounting position for the battery holder. For the NiMH batteries the holder needs to be mounted closely to the chargers, because of the different dimensions of the NiMH compared to the Pb batteries. Also have a look to the pictures showing the usage of the rubber band shipping with the NiMH batteries. The idea is to isolated the batteries from the metallic battery holder. We found out that over the years the isolation of the batteries can be destroyed by small vibrations of the batteries. The rubber band will ensure that the isolation of the batteries is not affected.

Now you can install the battery holder on side B. Fasten the four screws fixating the battery holder.

Step 8

Install the NiMH battery to side B and attach all cables. Connect the cables from the top of the charger to the left battery. Connect the cables from the bottom of the charger to the right battery.

Step 9

Repeat the actions from Step 8 on side A.