Automatic House Power Backup

September 21, 2018, 10:03:57 pm

I made an automatic backup circuit for the house power. It acts as a:

1. UPS (Uninterruptible Power Supply)
2. Boost switch, in reverse. Boost switch is removed.
3. Surge protector. House supply is clamped at 15 Volts.

It consists of three types of >60 Amp diodes that allows power to flow out of the following sources:

1. Primary house supply: IOTA DLS-90 12V DC, powered by 115VAC powered by the inverter.
2. Backup supply: Engine battery supplies 13.2V. It's a LIFEPO4, 400 AH battery. Boost and isolator circuits are removed.

It switches from primary to backup in 2 nanoseconds, or 2 billionths of a second. It has a massive heat sink to dissipate diode heating at high currents. Since the inverter runs off a 48 V lithium pack, the 12 Volt house currents fed by the IOTA are typically less than 20 Amps.

If anyone wants to duplicate or improve upon the circuit, let me know.

Re: Automatic House Power Backup

Reply #1 – September 22, 2018, 05:36:09 pm

Nice idea.

Re: Automatic House Power Backup

Reply #2 – September 26, 2018, 10:58:39 am

This also solves the issue of when the 12VDC house power glitched, the hot water heater Dinosaur control board to stick on, tripping the TP valve and blowing scalding hot water all over the water bay.

With this diode backup circuit, the worst case voltage deviation would be 1.5VDC. I believe all of the house equipment can handle this change much better than a 13.3VDC glitch.

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