Brian your explanation makes sense. The problem I have with an ANL is based on an experience I had about 8 months ago. I fly an all steam airplane with no low voltage warning. This was a newly purchased RV-6. One of the problems it had initially was it was really hard to start cold. The previous owner/builder just accepted it. One evening I decided to go fly and ran the battery down trying to get it started. So I decided the keyswitch wiring was the culprit, got under the panel, pulled the keyswitch, removed the jumper, and voila, it started just fine. The mag leads were reversed, so the impulse-coupled mag was being grounded. Put it back together and got it going again, the battery was strong enough to get it started. After it started I checked the ammeter and it was showing about 40A charge. I thought hmmm, ok, that should drop off soon. Do my runup and about that time it showed a little bit above zero. Well that was quick. Take off for the local flight and after about 15 minutes I start noticing all the instrument lights are low. Voltmeter showing about 10V. Hmmm, not good so I come back in and land without landing lights, flashlight is in my mouth with it pointing to the airspeed indicator. Shut down put everything away I notice the alternator B-lead breaker popped. Never had that happen. The low battery and strong charge current caused the breaker to pop (40A breaker, which is too small IMO). ANL's are simply slow-blow fuses and in a situation like this would have left me stranded somewhere because they're not commonly available. That and having them mounted on the firewall means rooting around inside the cowling. The ammeter sort of fooled me due to the way it is wired.