Inverter master switch with in-rush digital timer pre-charge.

[jerseyjeeper]

I am designing a new system for the toy hauler and wanted a master switch on the inverter so I built a timer based digital pre-charge control with an LED to indicate when it is safe to turn the inverter master switch on. Once the “main battery switch” is turned on it kicks off the pre-charge timer in the inverter switch, that passes a pre charge current to the inverter through a 20 ohm 20 watt resistor for 10 seconds (or whatever amount of time I want to program it to) and once the timer completes the timer shuts off the pre-charge current and an LED lights, indicating pre-charge is complete. All parts are very very tiny, cost under $20.00 and fit very safely (they’re non-conductive) inside a small blue sea battery switch.

Video attached.

In the video a strobe light is playing the part of an inverter (it’s what I had handy at 1 am last night..).

The timer resides inside the small battery switch (for the inverter power), the LED is flush mounted to the switch and the BIG red switch is the main battery switch, and the current limiting resistor is in plain view.

It’s going in this system ( currently being built with some changes under discussion in the new member thread)..

Best "Compromise" RV Power Plan! (that can be added to)?

The Victron shunt generally goes on the negative lead of the batteries. Probably better to run jumpers from battery to battery, and then *one* lead to the disconnect, and *one* lead to the shunt and from there to the Lynx. I'd put some sort of OC protection on the line from the...

diysolarforum.com

 

[jerseyjeeper]

I got the timer from here (link below), it’s on Amazon too.. get the program board, it makes it easy.. I used program #20
Micro Digital Timer
That is a powerful little bugger…

Here’s how to program it..

 

[jerseyjeeper]

So basically it’s a two component pre-charger, with an optional LED for under $20.00.. still under w/ the LED.

 

[Sky Noris]

Very cool idea. My pre-charge is designed to finish in 1.5 seconds so a timer and a led indicator would be a nice improvment.