A simple and fool proof discharger/tester
- Thread starter auraslip
- Start date
I don't know; it depends on your keyswitch. If it's not rated for that, it's going to get more complicated. 
Hmm. First thought was to use a FET that's turned on by the keyswitch, but that means the FET would need a gate voltage spec max of >pack voltage.
Second thought was that you could use a resistor and a zener, switched on by the keyswitch to pack voltage, to power the gate to the FET. Then the FET would provide power to the DC-DC.
Just need a FET that will handle the power load, including any power-on surge, and proper heatsinking to handle the continuous power thru it.
Then I had another thought: Are your lights actually running off the DC-DC itself? Or off the pack? If off the DC-DC, then the problem applies. If off the pack, then it doesn't, because the DC-DC would only be supplying the power to the relay coils.
Anyway, the FET is probably the "simplest" way I can think of, beyond a resistor for a coil on a relay, where the coil is switched by the keyswitch, and the contacts provide power to the DC-DC.
Another way to prevent the problem of max power at turn on is to use a latching relay for the lights, so that your lightswitch is a momentary type, and all you do to turn them on is to press the switch, whcih latches the relay. Then when you cut power with the keyswitch, even if you forgot to turn the lights off, they wont' be on when powered up again next time. Catch with this is taht you have the keyswitch break-contact still doing so for your full load. Might work better than *making* contact with the load, but I wouldnt' guarantee that.
Hmm. First thought was to use a FET that's turned on by the keyswitch, but that means the FET would need a gate voltage spec max of >pack voltage.
Second thought was that you could use a resistor and a zener, switched on by the keyswitch to pack voltage, to power the gate to the FET. Then the FET would provide power to the DC-DC.
Just need a FET that will handle the power load, including any power-on surge, and proper heatsinking to handle the continuous power thru it.
Then I had another thought: Are your lights actually running off the DC-DC itself? Or off the pack? If off the DC-DC, then the problem applies. If off the pack, then it doesn't, because the DC-DC would only be supplying the power to the relay coils.
Anyway, the FET is probably the "simplest" way I can think of, beyond a resistor for a coil on a relay, where the coil is switched by the keyswitch, and the contacts provide power to the DC-DC.
Another way to prevent the problem of max power at turn on is to use a latching relay for the lights, so that your lightswitch is a momentary type, and all you do to turn them on is to press the switch, whcih latches the relay. Then when you cut power with the keyswitch, even if you forgot to turn the lights off, they wont' be on when powered up again next time. Catch with this is taht you have the keyswitch break-contact still doing so for your full load. Might work better than *making* contact with the load, but I wouldnt' guarantee that.
John in CR
100 TW
Use a decent keyswitch for a car. You could even run the accessories supply to the DC/DC converter off of the separate lead from the switch especially for that. I've got thousands of on/off cycles on mine and no issues, not many with the lights on, but a few.
izeman
1 GW
neptronix said:
this is no suprise. this is how those bulbs are ment to work. they where constructed to illuminate goods in shops w/o heating those too much. those bulbs beam MOST of there heat to the BACK of the bulb (the side with the connectors) and NOT in the direction you normally would think of.
so letting them shine DOWN to the floor is the correct way. of course you should always keep some distance.
