Guru
Joined: 31/12/2012
Location: New ZealandPosts: 2552
| Posted: 12:23pm 08 May 2019 |
hi,
can you post some more details of the solenoids - what are their rated voltage, coil resistance, perhaps even a photo may help.
if a solenoid is only activated occasionally, say every couple of seconds, you can have a current-limited supply feeding a reservoir capacitor. the capacitor will ensure plenty of current to initially pull in the solenoid, with the backing supply providing enough volts/current (less than the initial requirement) to hold the solenoid in.
quite seperately, you'll then have a switching trasistor to turn on the solenoid itself:
in the above, pick C1 to provide enough 'oomph' to pull the solenoid in, R1 high enough to not exceed the peak current output from your boost converter yet low enough to not drop too many volts when Q1 is on, and make R2 around 680 ohms or so so that Q1 is fully saturated when activated.
btw: use a boost converter based on the LM2577 or similar in a TO-220 sized package; those little grain-of-wheat devices like the MT-3608 are a bit of a joke.
cheers,
rob :-)