RepRap Pro Mendel
Does anybody know what temperature the bed should be able to reach.
I can only just make 100degrees, which seems barely hot enough to stick ABS.
The power is delivered through the thick, probably around 2.5mm cable supplied with the Mendel pro kit
with a board terminal block voltage of 11.9v which should be high enough - I will check on the bed terminal end.
The ambient temperature is around 23 degrees
Is this normal?

I recommend insulating the under-side of your heated bed, also any fans blowing across it will dramatically affect the temperature possible.

What's the total resistance at the board of the bed and it's wiring?

Hi, The resistance as measured at the pcb terminals is 1.6 ohms cold rising to 2 ohms at 70 deg. Voltage is not 11.9 I got that wrong, it's 11.4V on the pcb and 11.2 on the bed terminals. It falls another 0.2V with the hot end on. It draws 8.8 amps, so that's around 100 Watts which seems a bit low to me, for heating that sort of area.
The heater plate doesn't have any ratings written on it. And the PSU is rated at 12 Amps.
Any suggestions welcome, thanks.

The power supply is totally inadequate at 12A

If you insulate the bed bottom, you should be able to reach 105-110 degrees with 100 watts. That should be pretty optimal for ABS. I used self-adhesive high temp pipe insulation, commonly available from hardware stores...

Thanks Ttsalo and Konwiddak
That worked a treat, I couldn't find the self adhesive stuff you spoke of, so I used double sided carpet sticky tape, bubble wrap and silver foil. Now I can get it up to 215 and the abs sticks very well.
I had wanted to get it hotter than 100 because when printing multiple small objects the print head would often clip previously printed items whilst passing across the bed , making some come unstuck.
Thanks.

215? Are we talking Celsius or Fahrenheit here?

doh !! Sorry 115 celsius