Emergency Battery Backup - Utility Mode

Speaking of current-limiting, it feels like a good idea to hard-limit the current pulled from the Kona. If I use a second "house" battery as a downstream buffer for that purpose, is there such thing as a 12v DC-DC charger that can supply that house battery with upwards of 100a from the car battery? I could only find a 60a unit https://www.renogy.com/12v-60a-dc-to-dc-battery-charger/

Or combo an inverter+AC-DC charger to the car and feed the house battery that way? Plenty of those do 100a+, but bummer to need this seemingly extra power conversion in the workflow.

Or parallel a second battery with the car battery to minimize total voltage drop and thereby minimize current drawn from the Kona? I was reviewing the original power backup thread and saw this was @Fastnf idea from awhile back, if I understood it correctly.

Or just properly size an inverter (or an in-line breaker?) to trip based on load?

Ugh, wish I was in the electrical mystery and understood things more.

 

Those ideas seem the most sensible. The breaker could be on either the DC or AC side but should be fast-acting.

 

I agree with KiwiMe. A fast acting breaker is the best option. I have a 100amp DC fast acting breaker between my inverter and the Kona battery. The second battery in parallel option would only be for short surges not continuous power. It also should have a breaker on it as well.