Funny most on this forum told me to take it off the battery and put it on the alternator to save the bulkhead connector ....
Yes, you should hook it to the "alternator side" of the amp gauge, but this is very simplistic answer.
First, for the alternator: Your current alternator is externally regulated. One wire vs. 3 wire control how the alternator understands how much power to make. 1 vs. 3 wire alternators
do not solve wiring upgrades needed if you are providing greater power to your system.
VERY BASICALLY, power goes from your battery and through the bulkhead connector to the amp gauge. The other side of your amp gauge feeds your car's power needs and also exits through a different bulkhead connector to your alternator. If your battery provides more of the power, your amp gauge will read discharging, if the alternator is powering your cars needs plus changing the battery the amp gauge will read charging.
A couple examples:
#1: Your car is drawing 45 amps and the alternator is feeding 45 amps. In this case, 45 amps are going through the bulkhead and feeding power to the car. The battery needs to do nothing so your amp gauge needle will sit dead center.
#2: Your car is drawing 45 amps and the alternator is feeding 25 amps. In this case, 25 amps are going through the bulkhead and feeding power to the car, but the other 20 amps are being supplied by the battery. The amp gauge reads discharging.
#3: Your car is drawing 45 amps and the alternator is feeding 50 amps. In this case, 50 amps are going through the bulkhead connector feeding 45 amps to your car, plus 5 amps to charge the battery. The amp gauge reads charging.
Option A: So if you connect the fans to the battery side, you will force the alternator to drive that power through your system, through your amp gauge and power your fans. You might feel good that your battery will always look like it's charging, but this is wired incorrectly. Bottom line - not a good idea.
Option B: So you connect the fans to the alternator side, outside the bulkhead connector on the firewall. While you are driving around and if the alternator can provide the power, it will provide 26 amps to the fans and the rest through the bulkhead connector to the remainder of the car's needs. That scenario is OK on the bulkhead connectors. However, at times where the alternator cannot adequately power the fans, the needed power will come from the battery. In this case you will send extra power from the battery to the amp gauge and back out to the fans. In this case, the weak link could be the bulkhead connector between the battery and the amp gauge. This is a better scenario than option A (and the more proper way to wire it), but you still should consider better (thicker) wires to handle the extra load, at least between the Battery and the connection point under the dash where other power is fed.
I know this is wordy, but I hope it helps. The bottom line is you need to understand the way current will travel in your system in all cases. My rule of thumb is if any part of the system will see power greater than 35 amps, upgrade the wiring and connectors in those areas.
Hawk
