84 Tercel Wagon - Battery Can't Keep A Charge

[dustinmyblood]

Hi. Great forum here. I've used it a lot as a reference for several issues with this 84 Tercel Wagon.

A few key points:

• The car has no standard ignition. The keys were stolen, so I use a little push-button start mechanism that bridges the starter / acc wires in order to start the vehicle.
  Before I had to resort to using this method of starting the vehicle, there were no charge issues that I know of.
  Now the battery, fully charged, won't last more than several starts if there's any electrical functionality used when driving the vehicle ( heater, ac, lights, even wipers ).
  It's winter, so I've been using the heater every time I drive it. If I don't use the heater or ac, there doesn't seem to be an issue with charge.
  There's a noticeable dimming when the fan kicks on with the heater or ac.
  The alternator puts out ~13.2 volts at idle, and usually maxes around ~13.7 with rpms. * Unless the heater or ac is on, then voltage significantly drops *
  The battery was replaced over the summer, and has been checked.
  The alternator was replaced a couple years ago.
  The alternator has an internal voltage regulator. ( haven't been able to locate an external voltage regulator anywhere on the fender wells. )

Only reason I figure the alternator is fine is because it was replaced 2 years ago. The battery is relatively small in comparison to other vehicles, so I figured the lower output was enough to keep the smaller battery charged.
Another possibility is the ignition mechanism uses probably 8 gauge wires ( think computer power supply size wires ). Not the thick, standard ignition wires I've seen. I'm only guessing, but could there be a resistance / strain on the electrical system because I'm using smaller gauge wiring in the ignition mechanism? I haven't replaced the ignition setup due to finances. Just trying to keep the car running on what I have.

Thanks for any help!

[marlinh]

Charge rate at higher rpm's seems a bit low. You would want at least 14 volts. Are you sure the battery is in good shape? How long does it sit before it doesn't start? Are the battery connections clean and tight and there is no oxidation on the lead terminals. It would look dull. Not sure how you have bypassed the ignition. If it is done correctly there shouldn't be any parasitic draw. Something to try is disconnecting the battery when you park it and see if it is dead afterwards. There could be something else draining the battery. Did you use 8 gauge wire to replace the ignition switch? That seems rather large unless I am misunderstanding you.

[TURTCEL]

I would also recommend charging your battery with a charger to full charge and then drive down to your local auto parts store. They will test your charging system for free but can only do it acurately if the battery is fully charged.

Check the water level in the battery before charging...add distilled water if low. Make sure all connections are cleaned of corrosion and that the alt belt is tight. These are all factors in a good system.

13.7 seems a little low for the high side of the charge. Mine gets up to 14.2 and 13.1 at idle.

If the alternator is from a parts store and was replaced a couple years ago it is possible that it could be the culprit. Aftermarket parts like these are remanufactured with low end parts to keep them affordable. They tend to not last as long as factory parts. If the alt is bad I would suggest having a local alt/starter reapir shop rebuild it for you instead of buying another from a parts store.

These Tercs don't require a huge battery so I would not think by the sounds of it that yours is too small. It could have a bad cell though.

Try the disconnecting test that marlinh suggests...you could have a draw somewhere. Have you installed an aftermarket stereo or alarm? I have also seen a bad starter cause a draw on the battery before.

Good luck.

Peace

[Petros]

Welcome to the list!

do not assume a rebuilt alternator is still good. sometimes they are bad right out of the box, I would rather buy a used factory alternator from the wrecking yard than buy a remanufactured alternator. the factory alternators last 20 to 30 years, are well worth buying new. You can get a new one from a store like NAPA, which uses the same brand as the factory, for a reasonable price.

Best bet is to have the system' tested for battery capacity and alternator charge, which also seems low to me. Many auto parts stores will load test the battery and the alternator for free. A battery in perfect condition should have 13.2 volts (2.2 volts per cell x six cells), so it needs to recharge at over 14 volts.

I would also get your ignition key, any Toyota dealer can give you a new key with the chassis serial number, or the code on the passenger side door lock (inside the door under the inner panel) according to others on this list. You can also remove the key cylinder barrel and just use a screw driver. It is easy to remove by either turning it to the run position and push the button down on the edge of the ignition key assembly, or just chisel off the button and the cylinder will side out. I once had to do this when the tumblers in the lock failed and jammed up, it would not turn even with a key. I removed the cylinder and than removed all of the tumblers and replaced the cylinder. You could put any key in it and turn it to start the car, and the ignision key was more of a "decoy" because it look normal for the outside.