Charging problems hopefully solved

[billstoudt]

hi guys sorry if this is lengthy i hope at some point this information will be somewhat useful to someone else.

For the past few months ive been having a problem with my batteries keeping a charge. The pig runs fine once it starts but according to my voltage meter in the car ( as well as a multimeter) the voltage would slowly decline until the point that none of the electronics would work. however the engine still ran fine. it would run down to 10 volts but then pop back up again after a day or so.

figuring it was the alternator i took it down to autozone to have them test it. according to them it was well above spec. however i was dismayed to see that spec on it was 45 Amps. but whatever.

so after talking to someone who told me that autozone tests were worthless and recommended a second opinion i took it to a alternator rebuild shop and they tested it and said that while it was underpowered for my battery application it should have been adequate to keep the system charged properly and according to their tests it was operating fine.

with all this in mind i had picked up a 2F alternator at the swap meet and installed it. this did not fix my problem so i think its safe to assume that the problem was not with the alternator.

a small bit of luck i ran into the Optima rep ( i have two red tops that are less than a year old ) at my local autozone. he was nice enough to let me swap my batteries out for a new set. just in case they were the issue. but they ran down just as the old ones had. but it was nice to be able to rule them out.

My suspicions moved to the voltage regulator i took it apart and manually actuated the connections everything looked good and practically new inside but fearing that it may still be the culprit, i ordered another one. after some research i found the ACDelco E602A or Duralast VR729 appeared to be identical in circuit structure and pin outs and plug to the toyota.

installed this and started the piggy up and still only got 8 volts out of the alternator. revved the motor and ran it at 1.5 - 2k and still only 8 volts coming out of the alternator lug. ran it for a little while and sure enough the voltage slowly dropped. so i turned the car off.

the last thing i did was to check to make sure that i was getting a solid connection and that there were no wiring issues with any of the wires from the alternator to the voltage regulator all of the wires had solid continuity and ground and battery were solid as well.

so last night i got this idea....

i have an internally regulated 90 Amp alternator. that is waiting for install on my vortec. how hard would it be to adapt to mount into the place i took a look it the wiring diagram and all of the other wires ( except the one that provides power ) go to the voltage regulator. so this morning i gave it a quick fit and swapped the pulley and by god it fit. i had to shim the pivot bolt and use a different bolt on the bracket to secure the alternator ( i had some leftover ARP bolts for that ) so i got it in and started the car and i saw 14 volts for the first time in a very long time.

so i cant think of a reason that this might be a bad idea in the long term but if anyone has any input or words of warning i would appreciate them.

Poorly taken pictures to follow.

 

[billstoudt]

 

[davegonz]

Should work fine. Did you set it up as a three wire or one wire? You will have to remove the amp meter from the circuit since the new alt can put out more than the stock meter can handle.

 

[billstoudt]

its a one wire setup. as for the amp meter i ditched my old gauges long ago.
i drove it around town today the new alternator is really hot. i checked the "fan" (that metal thing that pulls air into the alternator for cooling) i was concerned that it was somehow different from but the blades are identical to the old ones so its not a directional issue.

my thought is that because the battery was so low it was working overtime to try to keep up.
i re-used the stock Toyota pulley which is quite a bit larger than the GM one so in theory it should be running slower right??

 

[tatat]

It si à mystery for me that all elts seems to work correctly but all together are not working. Are you sure the regulator dos fit the toyota specs,?it is the only part that is fluctuating when working?

 

[billstoudt]

No i'm not positive but the wire loom matched, the wire colors matched, when i opened it up it looked the same and the schematic (dual relays) that was in the box matched the schematic in my book. but i couldn't find anything definitive. and maybe there is some other arcane difference between the one i bought and the one in the box.

there is one other detail i left out. yesterday at the cruiser swap meet i purchased a regulator from someone and tried that and it also didnt work. now it could have also been faulty ( for 4 bucks it was worth a shot ) but this just made the whole thing even more mind boggling to me.

i am almost more comfortable thinking that there is a problem with the wiring to or from the alternator to the regulator. i was just completely stumped. so i went the GM route. ive never been a big fan of the externally regulated alternators.

 

[Lilgreen77]

Sounds to me that there is a huge amp draw on the alternator, which would also affect the voltage. Part of that could be wire sizing. I say this because of your concern with the temperature of the new alternator. If it is overloaded, it will run hot until the windings eventually fail. If you have an external amp meter, start the motor and turn everything on in the vehicle. Take an amp reading and see if it is in the range of the rated alternator. The new one is probably rated for more amperage then the old stock one, thus giving you a charge to the batteries.

 

[billstoudt]

yeah i considered that might be the culprit, i was considering getting my existing alternator re wound to accommodate a higher amperage but i'm only going to have this motor for a little while longer so i decided to go with the GM as a temporary solution.

i think the initial heat from the alternator was because it was trying to charge two very low batteries. the alternator has since started running at normal temperatures. i am about to rewire the system to take advantage of an isolator (which i should have done to begin with). during that process i'm going to run new wires to the amps and inverter