I'm looking for a true battery isolator that mantains battery isolation even when charging the auxiliary battery. Anybody know of one? NOCO made one but it is the old school diode version that burns up a few amps to operate and it appears that they stopped making it; but it is still available on Amazon. Seems like current technology are voltage sensing relays (VSR) or automatic charging relays (ACR) but both of those parallel the batteries during charging. I want to maintain isolation during charging. Only two options I've found are the old school diode isolators or this expensive "charger" from Stealth 1. The Stealth 1 looks nice but it is expensive and overkill for what I'm wanting.