Amp gauge reading

[vtboy51]

I’m back to chasing weird electric “problems” on my bronco. I first noticed my dash amp gauge was reading about 30 with no lights or heater running, then I noticed my battery voltage at 13.50 volts when idling and 14.50 when revving the engine. All I can think of is my inline fuel pump is drawing the load, does this sound right?? Or another bad voltage regulator, this caused me headaches last year but can’t believe i’d Have another go bad this quick...

 

[Broncobowsher]

Doubt it is the load of the fuel pump.

A lot of it can be depending on how you have added electrical loads. To understand you need to realize how the amp meter works. It reads the flow of current (nothing to do with voltage) into and out of the battery. Idealy when you turn on some lights or the radio without the engine running, the amp meter will read a negative number. Start the engine (the starter is a huge load and bypasses the meter) and the alternator starts charging. The amp meter goes positive to recharge the battery. Once the battery has recharged the meter drops off to zero. The alternator is feeding the electrical loads with no amps flowing into or out of the battery.

If you attach electrical loads directly to the battery the amp meter will never zero out when the battery is fully charged. It will read what the battery is taking to charge plus the electrical loads you attached to the battery. Reading a positive charge number might be an overcharge situation, or it might just be feeding the loads that were added. Really hard to know.

Amp meters are a great gauge. You can tell what is happening if you know how to read it. Too many people don't know how to read them these days. Too many people don't know how to wire them correctly either. And that makes them read incorrect and they are pretty much useless. When you see an amp meter reading positive too much, it is overcharging (or accessories were added to the battery). If it reads negative, the battery is powering the vehicle because the charging system doesn't have enough output.

 

[vtboy51]

Doubt it is the load of the fuel pump.

A lot of it can be depending on how you have added electrical loads. To understand you need to realize how the amp meter works. It reads the flow of current (nothing to do with voltage) into and out of the battery. Idealy when you turn on some lights or the radio without the engine running, the amp meter will read a negative number. Start the engine (the starter is a huge load and bypasses the meter) and the alternator starts charging. The amp meter goes positive to recharge the battery. Once the battery has recharged the meter drops off to zero. The alternator is feeding the electrical loads with no amps flowing into or out of the battery.

If you attach electrical loads directly to the battery the amp meter will never zero out when the battery is fully charged. It will read what the battery is taking to charge plus the electrical loads you attached to the battery. Reading a positive charge number might be an overcharge situation, or it might just be feeding the loads that were added. Really hard to know.

Amp meters are a great gauge. You can tell what is happening if you know how to read it. Too many people don't know how to read them these days. Too many people don't know how to wire them correctly either. And that makes them read incorrect and they are pretty much useless. When you see an amp meter reading positive too much, it is overcharging (or accessories were added to the battery). If it reads negative, the battery is powering the vehicle because the charging system doesn't have enough output.

If I understand you correctly, because my fuel pump is powered from the FItech unit, which is directly connected to the battery, my amp gauge will not zero out?? Everything else regarding the electrical is stock, no added goodies.

 

[Broncobowsher]

That sounds right. EFI pulling about 30A total sounds a little high, but with a little battery charge and error could very well be correct.

 

[DirtDonk]

Does your meter ever go all the way to zero when the key is off? If not then the gauge is likely tired.
If it reads zero when off, but goes negative when you turn the key on, that's expected and the level of discharge will indicate how many, or how big a load is being pulled through.

If it goes to 30amps positive all the time though, and only reads the usual 13.5-14.5 volts, that is a bit strange, unless the reading on the gauge does slowly but consistently come down back towards zero as time goes by?
The lower voltage reading though, tells me that your alternator is a little weak. Or it's just an old stock style alternator maybe? That lower reading at idle would not be out of the ordinary for that type of alternator.

 

[Broncobowsher]

Paul,

Did you see that he attached the EFI directly to the battery? Doing so the amp meter will never drop below the EFI draw even when the battery is fully charged.

 

[DirtDonk]

Yep, got that. But I was more thinking along the lines that the unit was not active until the key was on.
Was following along on your statement about the mis-reading when directly connected to the battery. I forget to take that into account a lot on other people's Broncos, because I never had to worry much about it on mine. Very little (if anything now that I think about it) was connected to the battery itself.

Thanks

Paul

 

[DirtDonk]

But like you said too, it should not be reading 30a just from the EFI either.
That could just come back to the meter not being quite right anymore too. They do get old, just like anything else.

Paul

 

[vtboy51]

Hard to know for sure, but the gauge seems to be good. It stays pretty steady at 30 when running and zeroes when off. When I turn on the heater it does wiggle a bit. The fact that I have a decrease in battery voltage when idling and my amp gauge is running at 30, it lead me to the conclusion I had a problem with something.

I'm about to order up a new 3g 1 wire alternator from WH, but have read running a larger alternator on a v-belt can cause belt squeal, especially at startup.

I do have a dual pulley setup (not sure if PO did this or it is stock), and I think I read somewhere people are using 2 belts to the alternator to help with squeal. Would I just order a dual pulley for my 3g alternator?

 

[bronconut73]

Your dual pulley will likely bolt up to the 3G. Gotta try. May be a washer under the pulley if it rubs the case.

Double pulley would be a great idea.

I run a single on my 3g.

But its a new pulley so good friction still exists on it. I still have to replace or tighten that belt every year or so or it will squeal on start up occasionally.
It has not been bad enough to encourage me to go to the double pulley but I should have.

Going Explorer serp soon myself.

 

[Broncobowsher]

3G will be higher output. More than the stock wiring can handle. Easy fix, run a lead straight from the alternator to the battery and bypass the stock wiring. This will also bypass the amp meter.

 

[vtboy51]

3G will be higher output. More than the stock wiring can handle. Easy fix, run a lead straight from the alternator to the battery and bypass the stock wiring. This will also bypass the amp meter.

I just ordered the upgraded wiring kit from WH with fuse, thanks for the heads up though.