I know some are going to ask why so I will answer that as well. But, in theory would it be possible and has it ever been done?
The thing I want to accomplish is to use the second one to charge an independent battery separate from the main system. I’m aware there are a multitude of ways to charge another battery. This would all be run through a circuit to charge a high cap battery, IE, a large lithium battery for an inverter.
Yes I know I always ask the weird questions and the why ones. That’s just the way I am. I appreciate any input any of you could give. Even if it’s not what I want to hear. Thanks

Not really a terrible question, but.......charge rates and cycles for lithium are a fair bit different than a lead/acid battery normally found in auto applications.
While it's entirely do-able to hang another alternator on your engine, you'd have to isolate it from the rest of the car's electrical system. And keep in mind that Chrysler alternators don't have an internal regulator.
My suggestion might be a small Nippon Denso, internally regulated alternator. That way, you could keep the wiring relatively simple and isolated. None of this helps you with the charge rate issue of lithium batteries, though.

Just an after-thought......there are such things as 12vdc-to-12vdc battery chargers. There might be one for charging lithium batteries, and if so, you might be able to hook that up with a manual switch arrangement.
I don't really know if that exists, as I haven't done any searching for one.

Roger

I would do it that system with one alternator big enough. The additional battery could be also lead battery but separated with a power relay. The extra battery will be connected when engine is running and disconnected when engine is shut down. So the extra battery usage to dead will not cause "no start" at the next time.

Adding any power alternator to an old Mopar has to be made carefully. The wiring harness including firewall connections and the charging gauge in the dashboard are old pieces and in the limit with the original alternator with no extra amperes. Been there seen that....

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1966 Dart. 170 cu.in. 200 rwhp.

Thanks for the replies. As stated by another person it would be separate from the trucks existing wiring and be solely on it’s on. The charging would be controlled by a boost inverter board to get a high enough output to charge the li battery, although it would have loss due to heat etc.

If there's no electrical connection besides ground to the rest of the system, this is just a matter of fabrication.

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Matt Cramer
1966 Dodge Dart turbo / EFI project