XRAY - Model racing cars

I've been back to the store in the meanwhile and got two fresh new packs. These new packs seem to work reasonably well on the standard 180 size motor. When I use a graupner 300 size motor I get the usual problems.
The packs seem to charge fine and when discharging them the capacity seems OK too. They just won't supply enough power under load.

For the 300 size engine I've now ordered some 6 cell GP 1100 packs, and I'm going to make my own 5 cell packs using some of those same cells. I hope these work better.

Does anyone know the brand of the xray cells? 1200 cells are hard to get, 1000, 1050 and 1100 are most common here...

Not sure what xray uses for cells but i highly recommend using GP1100 cells.

These things sell for 2$ a cell and rock!! We run 7min qualifiers and 10min mains with stock motors, and the cars are rockets

Here is a typical pack cycled on a REEDY QUASAR at 2amp charge and 5 amp discharge:

1160mah charge
1055mah discharge
12:48 run time @5amps
7.573v Peak voltage
5.948v Average voltage