Do I install this before or after a 100 amp bus prewired in my vehicle?

It depends which battery you want to power the bus, and how the bus is wired. If the bus is connected in between both batteries, I would put the isolator before the bus to only drain the accessory battery when the vehicle is off. Once again, depends on how the bus is wired though.

Is it better to leave the 2 battery connected all the time or its better to disconnect the auxiliary battery if i choose to use a switch

The purpose of the Stinger SGP32 200 AMP Relay is to provide an electronic "switch" that can connect two batteries (or battery systems) at the control of a 1A, 12V signal. In typical use, the relay's signal input is attached to your vehicle's Accessory On, Ignition On or Engine Run signal. In this way, your two batteries are automatically connected by the relay when your vehicle is on and disconnected when your vehicle is off. You could add 1 or more additional manual switches to provide a manual override to the automatic relay.

What gauge wire is recommended?

You can search google for "Wire Gauge Amps Chart" and that will provide more detailed information on what size wire gauge is required for your specific installation. But I would definitely recommend using 1/0awg Oxygen-Free Copper (OFC) power wire if your components will be drawing anywhere near 200 amps.

I have a 210amp alternator will this size work for me or would in need to go bigger? Am i also capable of also using this as a relay without 2 batterys

1. Your relay capacity should match your alternator, not your load. So you theoretically need a minimum of 210 amp relay. 2. Yes. It is basically just a solenoid that isolates one terminal from the other until it is activated.

ASIN	B001HBYXVS
Best Sellers Rank	#23,445 in Automotive ( See Top 100 in Automotive ) #15 in Automotive Replacement Accessory Power Relays
Brand	STINGER
Brand Name	STINGER
Coil Voltage	12 Volts
Connector Type	Quick Connect
Contact Current Rating	200 Amps
Contact Material	Copper
Contact Type	Normally Open
Current Rating	200 Amps
Customer Reviews	4.6 out of 5 stars 1,537 Reviews
Global Trade Identification Number	00609098796019, 00609098797788
Included Components	Stinger
Item Type Name	SGP32
Item Weight	1.4 Pounds
Manufacturer	Stinger
Maximum Switching Current	1 Amps
Maximum Switching Voltage	12 Volts
Minimum Switching Voltage	12 Volts
Mounting Type	Chassis Mount
Operation Mode	Automatic
UPC	609098797788 609098796019
Unit Count	1.0 Count
Warranty Description	1 year
Wattage	12 watts

SGP32 200 AMP Battery Relay Isolator and Relay

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