http://www.autozone.com/autozone/accessories/1Sunpro-2-in-black-face-mechanical-oil-pressure-electrical-voltmeter-and-mechanical-oil-water-temperature-chrome-panel-triple-gauge-kit/_/N-26b9?itemIdentifier=84181_0_0_ http://www.harborfreight.com/mini-triple-gauge-set-65210.html
There is a difference. The Sunpro set has a voltmeter. The HF one has an ammeter. Go with a voltmeter to know better hoe you charging system is doing and how charged it is.
The sunpro ones are not even that good, mine started rusting in 3 months. And the car never saw rain in any of that time. My first tach from them crapped out after 30 days, but the second one has lasted 5 years. If you can afford autometers go that route, or stewart warner makes some beautiful ones as well.
I have some experience with the HF gauges... They are hit and miss, like everything else at Harbor Freight. The ammeter is a good thing to have. I bought one just for doing diagnostics, and hooked up correctly an ammeter is useful in your dash too. One thing an ammeter can do that a voltmeter can't is tell you when your alternator is starting to die before your battery is drained, and I think that's kinda nice... Both the ammeter and the oil pressure gauges in the Harbor Freight kits are consistently good. I think I've bought at least four sets and those have all worked and read accurately. The temp gauge has not always been consistent. I bought one that was defective and couldn't even be installed. Another one was DOA. The worst though, was the one that did work, but read too high. That gauge caused me to spend a good amount of time, energy and money trying to solve a cooling problem I didn't have. Finally I bought an infrared thermometer to see what the temp really was, and discovered the gauge was off. I replaced it with a Sunpro gauge and it's been consistently accurate when compared to the IR thermometer.
Problem with an ammeter is you have to size it and the wires to your electrical system. For instance, I have a 150 amp 3G alternator, I'd have to run 4 AWG wires to the gauge if I could even find a 150 amp ammeter. Maybe nowadays they have models with a shunt but I haven't seen them. A voltmeter will tell you if your regulator is treating the battery right by not over- or under-charging.
Sunpro has been around for a long time, i would trust them over the harbor freight junk. My sunpro tach is over 20years old
If I had those two for my only choices, I wud go w/ the Sunpro. I don't think vry much abt anything HF sells.
i have 4 sunpro gauges all work fine except the coolant temp gauge is slightly off (reading high) As for voltage vs. amp gauges if the voltage gauge is accurate you can tell if the alternator is charging or discharging, if voltage is below 12.6 its discharging however 99% of the time if the alternator is working it will be above 13.5 volts. so why bother with running high amp wire though your car just for an amp meter. imo
I only use the finest Canadian Oil in mine... I've been happy with sunpro. What I want though are Glow Shift gauges. They look so pretty. www.glowshiftdirect.com
Been using the sunpro gauges in my car for about 7 years/171,000 miles, now. Just had to replace the temp gauge, but other then that no problems with them. Original volt and oil pressure gauge still going strong.
Back "in the day", you had to have SW guages. Anything else was junk at that time. A lot of it today depends on what look you want. I've got the SW "standard" series in my car and will probably add the Sunpro retro tach to the steering column. http://stewartwarnerinstruments.com/Site/Home-1.html Sunpro has some "retro" guages that look like SW for a lot less money. http://www.sunpro.com/product_detail.php?pid=16384 JR
Although generally correct, this is a common misnomer. Lets clear up a few misconceptions. At first glance most people think that if you have a 150A alternator you need an ammeter that can read up to 150A. In practice however, the entire current of the alternator never flows through the ammeter when wired properly. The purpose of the ammeter is only to measure the current used by the battery. Now think about the bulky battery charger they use at the local auto repair shop... the high current setting is what? 50-60A at most. This is why you don't see ammeters rated over 60A most of the time. This is what you might see in a hypothetical charging situation. **NOTE** ALL loads are attached with the alternator to one side of the ammeter. The only thing on the battery side of the ammeter is the starter motor. Under these conditions the alternator wire sees the full 110A from the output of the alternator. The load wires in the vehicle see the 100A divided between existing wiring. (This is why you run big power wire to the amp in your trunk) The ammeter wiring only sees the 10A being used to charge the battery. There is one situation you need to plan for though. If your car is not running all loads draw power from the battery which DOES go through the ammeter. Moral of the story is... rate the ammeter wiring for the load the ammeter will see with the car off. Or... Don't park with your high-beams on and your big-ass stereo kickin' while the car is not running. So, if you have a large load that requires 150A and you'll be running that load with the car off, ammeters are not for you. This is not due to the size of the alternator, but the size of the load you're running.
