Editor Houlahan recently took his '66 Mustang on a road trip. Check out his solution for monitoring his recently installed replacement battery and read why he rigged this up in the blog below...
So I recently had to get my '66 Mustang jump started after stopping for gas. I've been nursing a nearly 10 year old battery for the last six months or so (start fine cold but had slow cranking when hot) and when I had to get jump started recently I knew it was time to finally get off my butt and buy a battery.
Over the course of two weeks I hit every auto parts store in town, plus a few tire stores, and the usual places like Sears, Wal Mart, and other auto centers. No one had the correct Grop 24F battery with the short side retaining lip that would secure properly in the battery tray. I finally called a friend with a '66 convertible and asked where he got his. He said he couldn't remember, but he would look and see what brand it was. I got a call back a bit later telling me it was an Exide 24F-60. A quick search of the Exide website for a local dealer showed Tire Kingdom (one store I had not tried) sold Exide batteries. My local store ordered one for me and it was there the next day. The Exide 24F-60 is perfect. It's a black case with a short side retaining lip, plus it has a completely smooth maintenance free top if you use one of the Autolite Sta-Ful dummy covers (which I do).
I get the battery home, drop it in, clean the terminals, and twist the key. My 289 roars to life for the first time in weeks. I grab my DVOM (digital volt-ohm meter) and check the charging system. Holy crap, it's charging at nearl 17 volts! I have repro mechanical voltage regulator on it, so I remove the regulator and proceed to file the points, and adjust the relay frame. I get the regulator set to about 13.8 volts at idle and I'm happy.
The next weekend I took the car to Ocala for the Silver Springs NPD show and I figure I better watch the voltage on the adjusted regulator and my new battery. Unfortunatley, for those '65-'66 owners out there with the five-dial cluster, we only have a ammeter in the dash. While the ammeter moves a little to show charging it doesn't show voltage, so I needed to be able to see the system's charging voltage at a quick glance. Did I mention I was leaving in less than an hour for said show? '67 and up owners and '65 Falcon cluster owner with the red ALT light don't have it any better either!
The low-buck DVOM you see here in the photo I picked up for my roadside tool kit that I leave in the trunk of the '66 (my main meter at home is a Fluke). I clipped the positive lead to the fusebox, grounded the negative lead and rested the meter on the Rally Pac as shown. It obscured the speedo a bit, but I was able to still see between 20 and 90 mph on the speedo, more than enough for my ride to the show and back. The meter worked great for what I needed to do and I knew exactly what the voltage reading was at a quick glance. I still need to tweak the regulator a little (idle voltage was only 12.8-volts with the headlights on), but I'll sneak up on it. Or I might just bolt in an electronic regulator and not worry about it either!