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Alt. not charging battery... help!!!

2397 Views 9 Replies 5 Participants Last post by  docvette
I have a problem. This is what I have. I am running a Powermaster 100 amp alternator, 65 amps @ idle, 1 wire alt. I have been using this alt for 6 months, of which the last 3 the car has not been running or such short distance not noticed....

My battery is in the trunk - 4 gauge wire to the starter. 8 gauge wire from alt to batt. All seemed to work fine. I am changing to larger wires just to make sure.

I recently put in a TKO-600 and drove it around over 20 miles and I noticed my voltmeter gauge was at approx 10 volts!!! I drove it home and when I got to the house it died on me, and gauge read 9 volts!!! Needless to cay I had to charge the new Optima Battery up to get the car into the garage. I double checked that the power wire to the batt from the alt. was not cut, and it was not. I check batt and alt with voltmeter and read same level after charge 12.0 when I started the car. Had my buddy kick the RPM's up to 2500 and the alt did not kick it 100 amps. It used to, but not anymore. I replaced the alternator today after talking to Powermaster and they swapped it out for me. The new one is doing the same thing. Any suggestions on what to check next?

FYI - The wires are all solid 1 peice wires, not several wires soldered together,and are multistrand Monster Cable wire..... The ground runs from the battery to the frame, then I piggybacked another ground terminal from that ground to the motor - starter bolt, underside of motor......

Please help
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WEll just make sure the battery is fully charged before you use this new alternator. I know i put in a new one and forgot to charge the battery and put too much strain on the alt and blew it. Just make sure all the conections are on right and try using a regular volt meter instead of the one in the car sometimes they can go and you are getting a false reading.
good luck
I checked the volts at the battery with a volt meter as well as at the alternator while the car was running, and both are exactly the same reading.

I ran a new wire from the alt to the battery post on the starter solenoid and did not change anything... This sucks!!!

Any other suggestions?
Sounds like your regulator is not kicking in. Since it is a built in regulator, you will need to take it to an alternator shop to get it checked. Or, just replace the regulator, if you are so inclined.........
Charge

Doc here::pimp:

Sounds like you are not getting a charge back to the battery.

Get a DMM and measure on R x 1 scale from the Alternator case to the Engine block...It should read 0.00 ohms , If not run an 10 gauge Wire from the mount bolt to the block...

Next , with your meter, unhook the Alternator wire from the battery and the alternator, measure it on the R x 1 scale...It should read 0.00 If not, Check ring terminal clamps or replace the wire.

Are you running any fusible links? you should be...and one might be open.

Don't rule out he possibility that the new alternator isn't bad also...happens all the time.

Doc :pimp:
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Doc - what does DMM mean?

and measure on R x 1 - whats is R x 1 stand for?

How can a Fusable link be open?

I am not running a fusable link at this time, this was another question I have, how big should the fuse be?
Go to madelectrical.com and you will get a lot of good info. Basically disregard their dislike for 1 wire alternators. With your battery in the trunk, you need a minimum of #1 wire ground and positive. The ground needs to go all the way to one of the starter bolts and you need to run a ground from there to the body and frame and it needs to be a # 10 or 12. Now you need to run a minimum of a # 2 wire from the alternator to the big terminal on the starter. This will insure enough charging current reaches the battery after the auto electrics drains off voltage to run fans, lights, etc. Now for over kill install a ground from the alternator case to the block. If you call up SEARCH and type in "one wire alternator" you will find a bunch of good info and web sites to really educate you on charging systems.

Trees
Answers

whytry said:
Doc - what does DMM mean?

and measure on R x 1 - whats is R x 1 stand for?

How can a Fusable link be open?

I am not running a fusable link at this time, this was another question I have, how big should the fuse be?
Doc here:

DMM stands for Digital Multimeter...If you don't have one , you can get one at Rat Shack for like $39 Bucks...cheaper elsewhere, If you want to mail order...A Good addition to your tool box if you plan to work on your own cars.

R x 1 stands for Resistance Times 1 ohm..or the lowest resistance setting on your DMM...

Fusible links ARE not fuses...and they burn out all the time (the wire junction melts under Short Conditions..See photo)

If you Don't have one, you should install one from your Starter main terminal to the wire going off the the Fuse box...and a link should be used on all wires (except the big main cable) going back to the battery...This will keep your harnesses from melting in case of a short and prevent FIRES...

NEVER install a fusible link INSIDE the car...always under the hood...they work by burning out (melting when over~current occurs) so one could start a fire from the interior inside the car.

As far as how large a link, it depends on the draw it's expected to handle...You need to know how much total current is being drawn, (Normally, at full load) and add 25% more to size it...check at your local auto parts/electric shop...for details...

Fusible links CAN save you Hundreds of dollars in re~wire Cost (and at your own labor) In the Event you have a high current short...Not to mention, Electrical caused Vehicle Fires, The battery Blowing up under a long term dead short load, and/or personal injury from any of the above.

The #1 and #2 Gauge wire Trees suggested is a Very good Idea, considering the distance you are running the wire Positive and Ground main cables...on the frame grounds I'd suggest #8 or #10 Gauge minimum.

Doc :pimp:


PHOTO: Fusible links

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Thanks guys!!

Doc - I can't believe I did not figure that out... I have a digital meter..

I will check the resistance tonight. Do you what the resistance should be?

Now that I see the fusable link pic, I know what that is. I have blown the main fusable link in the past. The one that hook to the horn relay. I will check it tonight when I get home too. Are there any other fusable links I should check out while I am there? I have a 68 Camaro wire diagram but it does not show fusable links in it.

Also in your opinion should I get a junction block from the battery and relocate it to the engine compartment? The Madelectrical site seems to really like them...

Trees - Thanks for the direction. I printed some of the tech articles for my reading pleasure on lunch today. From what I gather, it sounds to me like I should be running a junction block and then run a wire from there to something else that will distribute power to the rest of the car, right?

Once again Thanks for the help
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more..

Doc here::pimp:

The resistance if right, should be 0.00 ohms 0.03 or 4 at the most...Actually there is a formula for that, under AWG charts...so many ohms per 100 feet , but a 20 foot run, it won't apply.

Usually, links are at the starter, Horn relay, and / or junction blocks to battery.. or all of the above (see photo for link location on 68 GM)

Junction blocks are fine, especially if you plan future additions, but some pitfalls are , loose bolt over time and resistance build up from corrosion...On long runs I like straight connections but blocks are handy.

Doc :pimp:

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