Battery charger upgrade and purpose of solinoid

My Friend has a 2013 ram powerwagon with what i think is a 180 amp rated alternator.

I made a portable powerpack containing an inverter and a pd9245 inside it.

I used 2awg, about 14 feet, One way from alternator to Lifeline GPL-31XT 125AH battery. About 12 feet of 2awg from lifeline(-) to engine battery (-) and through a very large Winch connector:



http://www.amazon.com/Superwinch-2236-commercial-terminals-capacity/dp/B000C7LYYM/ref=pd_sbs_263_2?ie=UTF8&refRID=1J8H2NJ0BYB8BASQRABX



I depleted the battery to ~50% in my own rig.

I then hooked the Lifeline powerpack to the Ram powerwagon, started it, waited for the cold start high idle to mellow, then flipped the switch.

The 100 Amp Ammeter was pegged, and in the time it too me to get my Clamp on ammeter, amps had tapered to just under 100.

~5 minutes later amps had tapered to 86a. Alternator temp skyrocketed to 220F, battery voltage had risen to only 13.4v.

More RPM did not significantly add to Amperage at this point 3K rpm went back upto 92A. I believe the alternator has temperature protections as it never went over 221F on the hottest spot I could find with my IR temp gun.

I was impressed with how much current the single group 31 lifeline accepted, I was impressed how much current the alternator was able to make at idle speed.

The alternator was right on top of the engine, in full flow of the radiator fan. When the alternator first reached 220 F, the oil and coolant temps was still sub 155f.

When designing it, I was considering 1 awg. That winch connector can handle 1 awg. 2 awg maxed out the alternator so 1 awg would likely be even more overkill.

My winch connector mocks your 7 pin connector :)