I'm going to build a launch controller at some point soon (still tweaking the schematics). Its going to look like the St Josephs Industries ELC-50 (same enclosure, same voltage meter in fact), but have it banana clipped into an external 12v source in a tool box.
https://www.saintjosephindustries.com/elc50.html
Quick question: If I want to do a true measure of battery strength with the meter, I imagine the reading must be taken under load, rather than straight from the battery, true? If so, whats the best way to do so? 600k resistor? I'm not an EE so be kind.
Should that volt reading be done as a parallel circuit, meaning that it can be turned off prior to closing the launch circuit (ala continuty check switch)? I had originally envisioned the meter coming on line as the primary arming switch is activated and stay active through launch sequence.
Main concern is that I don't want to impart too much amperage draw on the ignitor to possibly trip it. I had wanted to possibly incorporate LEDs for the arming switch and pad select (3 pad switchable unit), a piezo continuity buzzer, plus the meter, but I'm afraid I'm trying to put 2 gallons of water in a 1 gallon bucket. I gather under 20mA primary circuit load is considered 'safe' for Estes style ignitors (?). Perhaps an "A-off-B" toggle switch between the battery check circuit and the continuity check circuit to prevent to much amperage draw at any one time is the safe way to go.
Any thoughts?
https://www.saintjosephindustries.com/elc50.html
Quick question: If I want to do a true measure of battery strength with the meter, I imagine the reading must be taken under load, rather than straight from the battery, true? If so, whats the best way to do so? 600k resistor? I'm not an EE so be kind.
Should that volt reading be done as a parallel circuit, meaning that it can be turned off prior to closing the launch circuit (ala continuty check switch)? I had originally envisioned the meter coming on line as the primary arming switch is activated and stay active through launch sequence.
Main concern is that I don't want to impart too much amperage draw on the ignitor to possibly trip it. I had wanted to possibly incorporate LEDs for the arming switch and pad select (3 pad switchable unit), a piezo continuity buzzer, plus the meter, but I'm afraid I'm trying to put 2 gallons of water in a 1 gallon bucket. I gather under 20mA primary circuit load is considered 'safe' for Estes style ignitors (?). Perhaps an "A-off-B" toggle switch between the battery check circuit and the continuity check circuit to prevent to much amperage draw at any one time is the safe way to go.
Any thoughts?