Battery Gauge Issues

[DrHerbertWest]

I recently purchased a 200amp alternator from http://www.highoutputalternator.com for my 99 Mercury Mountaineer 5.0L, I also picked up a yellow top optima battery.


The day it came I installed the new alternator, the pulley on it was to large and caused many problems. I switched the pulley with the stock one.

Now ever since I have installed this alternator I have had weird problems, my battery gauge is normally sitting at low and will go up when I rev the car. I checked the volt on the battery with the car off and it was at 12v on it was at 14v, so it seems it's working right. This is my setup I am using when I put the alternator in I also installed a 1800 watt true sine power inverter. This install was done by a professional.

The blue wires are all 0 gauge, also the other day it started to have more problems, if this is related to this I doubt it, but the car started to idle rough then the check engine light came on, error code was P0303 cylinder 3 misfire, plan to look into this today.

Thanks for your time.

 

[IZwack]

Pull the 300 amp fuse you have in that last pic and see if that changes anything.

If not, then perhaps the voltage regulator in the alternator isnt doing its job properly. Voltage readings typically are in the high 13's closer to the 14 mark taken from the battery.

 

[TerryS1980]

I had that problem before too. Except the P0303 code. Three things I did to help with the idle was MSD coil packs, TPS mod and throttle cable mod. The alternator may not put out enough amps at idle that is why the voltage is dropping. Did you fully charge the yellow top before installing it?

Also usually the P0303 code is followed by the P0402 which is a bad DPFE sensor.

 

[CDW6212R]

Unrelated, is there a fuse from that new battery wire to the alternator? The factory wire goes to the distribution box, through a fused bar at the box.

 

[DrHerbertWest]

Unrelated, is there a fuse from that new battery wire to the alternator? The factory wire goes to the distribution box, through a fused bar at the box.

Nope

 

[DrHerbertWest]

Today ill try and check my battery's charge to make sure that's not the issue, check the spark plugs and hopefully it won't be the coil packs I wanted to wait todo the ignition. Thanks for all the input, ill let you know what happens.

 

[RickOTR]

With a 200 AMP alternator you need to install a 4 gauge wire between the B+ terminal of the alternator and fuse box. I had to do this with my high output alternator. The stock gauge is 8... this will cause some issues with you electrical system.

 

[TerryS1980]

With a 200 AMP alternator you need to install a 4 gauge wire between the B+ terminal of the alternator and fuse box. I had to do this with my high output alternator. The stock gauge is 8... this will cause some issues with you electrical system.

Yes you could run the wire to your fuse box, but it should be ran to the battery. Make sure to install an inline fuse that matches the 175 amp factory fuse that is on the fuse box.

 

[Opera House]

I usually click off posts that have pictures with pictures that have that many pixels. A monitor can't display them, it just takes forever to download them.

The voltmeter problem is because the meter measures voltage to the car body and the regulator references voltage to the engine block. You should run an additional ground wire to the inverter. The standard ground cables are not sufficient for your application. Running the alternator output directly to the battery side posts would also help with the + reference to the alternator regulator.