bought a laguna 2.2dci pre heater, looked a nice compact design with 4 heater plugs.(edit, bit of a clean revealed 300w on the plugs so I need to control 1200w )
wanted to make some measurements and calculations before i made up a control circuit.
did a test on a 6a battery charger to see what they really pulled and listed at the bottom shows current already 4a with just one plug over 6 with 2 battery, charger is probably regulated so wont supply required amps but after a few tests with all 4 plugs the charger started smokin, oops so running test came to an end.
anyway looks like i must be looking at a a voltage regulator to drop to 9v or 10v or 80a relay in the circuit which i dont want as i dont want battery draining so much.
have ordered a few bits to make a start on the control side, im thinking a 40*c n/c thermoswitch connected to the preheater body that will switch off the complete circuit once above 40*c and prevent it restarting on restarts if temp is already over 40*C.
i have a 12 v timer on the way 6 sec to 450 seconds adjustment i think, to play with time on at start ups
i also have a 12v temperature controller and probe on the way that i may also use and again i can play with temperatures that it comes on or off at.
might put a timer delay on in there also to keep the circuit off for say 10-15 seconds to make sure engine glow plugs are off so not drawing mega amps all at start up.
im not sure how long these preheater plugs are designed to be continually on for?
best location for access seems to be fitted in the egr cooler line between the cooler exit and the rail going over the exhaust manifold, might need some reducers as pipework is a bit smaller on that line.