The V-I curbe of a trickle charger is shown below. I'm not real sure what is going to catch on fire. A GFCI will only protect you if you break the cover off the wall wart transformer and poke around in there.
Quote:
Originally Posted by rick-l
harborfreight.com Itemnumber=42292
I went into harbor freight and they had these for $3.93 with the coupon that was by the front door. They easily had 500 of them sitting there.
It looks like the 7805 and R1, R2 and R_VR1 sets the output voltage to 13.75.
The charge current is set by R5 D1, D2( a generic LED not the one listed in the spice model) and the beta of Q1 which is a TIP41C.
Q2 (an S9013), R3 and R4 shut down the output isf the battery is below about 9 volts.
The plot is the current into the battery versus battery voltage.
It looks like if you have it attached to the battery and not plugged in it will draw about 50 mAmps, however you could change that by adding a diode and adjusting the resistors around the 7805.
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