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Ammeter Overcharging
My ammeter shows +25 or higher when I start it up...I don't drive it very often so it kind of spikes when I first start it; after a while it's still +15-+25 though - worried that that is too high.
I added Holley Sniper fuel injection; when I did that the 40 amp alternator wasn't keeping up, i.e. was running at 11-12.5 volts, so I added a 100 amp; seems OK now as voltmeter shows a range of 13.4 to 14.2 volts ... But wondering how I troubleshoot a high reading for the ammeter? Any suggestions? Is that range OK? Thanks all. |
I think as long as your voltage is within normal limits, it's fine.
The ammeter measures the direction and flow rate of electricity. After starting your car, the battery is being recharged after being drained, and as the car runs, the battery recharges, the value should decrease. If you normally have a battery charger on your car, then your battery should recover more quickly, if not, it will take longer to recharge, and the ammeter will still be at a higher level for a longer period of time. Also, the value of the ammeter may be affected by how the ammeter is connected to the electrical system of the car. Again, as long as your voltage is OK, then I think you are fine. |
I think 13.5 volts is normal, but 14.2 volts is too high. I suspect your voltage regulator is not working properly. High amps and high voltage is two meters telling you that your battery is getting cooked.
If the regulator is in the alternator, you would need to replace it or take it to a shop that will repair it. If the regulator is located separately somewhere, I would first verify it has a good ground. I unmounted my ECU and a bolt was mounting both the voltage regulator and the ECU. It turned out the voltage regulator was grounding to the ECU. My voltage went to about 14.5. I ran a new ground wire to the voltage regulator and voltage returned to normal. PS If the regulator is in the alternator, I suppose there could be a ground issue at the alternator, if it is relying on the mounting bolts. |
Really the volts don’t get in the 14s. Stays pretty close to 13.4. Do you agree with Anthony (thanks Anthony btw)
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Remember, your ammeter is measuring current. If your battery is fully charged, and you fire her up, it's perfectly normal to see 25 amps going through the meter for a couple of minutes as the battery recharges to full capacity. If you are still seeing greater than a few amps going through the meter after the car has been running a while, and your system voltage is a normal value of under 14ish volts, then you have to ask "where is the load on that side of the gauge?" Is there a high amp load (like a fancy audio system), or maybe an ignition system, maybe the fans, that are wired directly to the positive terminal of the battery? Or to a lug that is between the ammeter and the battery? Or maybe it's a poor connection that is creating heat -- just like a space heater. Or maybe it's the battery itself. Remember, you only have amps measuring on your gauge when you have current, and you only have current when you have a load of some sort. 99.9% of the time, there is less than a couple of amps running through your ammeter, and that's just to keep the battery trickle charging after it has been fully charged up.
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patrickt,
Thanks; that's very helpful. I need to check to see what is directly wired to the battery; the only thing that really changed is the holley efi and distributor - I didn't install it so I'll need to check it out. but... why/how does it matter if something is wired directly to the battery. In your example, i.e. a fancy audio system (in my case the electronic efi), if it's wired through the fuse box or wired directly through the battery (with an inline fuse), wouldn't the ammeter read out the same way regardless of the way it's wired? Also, would you agree, assuming there are no poor connections, that as long as the system is producing the proper amount of volts, that a high ammeter reading is OK? Thanks again. |
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Conversely, let's wire a 1,000 watt bulb (80 amps) right off the alternator of my car. I start the car up, turn the light bulb on, my alternator serves up the 60 amps that is all it's got, and my battery supplements the needed extra 20 amps, so my ammeter shows I'm discharging by 20 amps. My battery will soon be dead. If I wired that light bulb right to the battery, my ammeter would show that I was charging to the tune of 60 amps but my battery would still be dead pretty soon.
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Check the water level of your battery, if you are cooking it, the level should be going down, if it's down add and then see if it goes down or remains the same. BE VERY CAREFUL around the battery, if you are cooking it, it will be putting out a lot of explosive gas and a spark will set it off. Saw one blow the top of the battery off sending acid all over, be care full.
BillK |
Put a charger on your battery and bring it to full charge. Then check your ammeter reading. Should be just to the right of the zero mark after a few miles. Sounds like your battery has run down due to inactivity.
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voltage
Modern alternators are set at 14.1 to 14.4 volts charging.
Perry:cool: |
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My Holley efi wiring schematic shows that power should come directly from the battery so that’s probably where my funkiness is coming from. |
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http://www.clubcobra.com/photopost/d...teramps001.jpg |
Yes. Need to get one of those.
Will call Holley tomorrow to see what they say it draws and ask about wiring alternatives. Thanks again. |
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Maybe , if you turn your ignition on without starting the car, and take an ammeter reading. Then, pull the fuse on your FI system, including the fuel pump, and again turn your ignition on without starting the engine, and take a reading, the difference may be the current draw from the fuel injection system.
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With that much current draw, I would take the Ammeter out of the circuit entirely. At this rate its going to overheat and be a fire hazard.
Don't forget , all that current runs through the Ammeter and those thin wires. Also. If it came with a 40 amp fuse, I hope you have a relay in that circuit too. |
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