A few battery questions

[rloaderro]

These past 2 weeks I've noticed the battery level dropping. And the cruiser has been slower to turn over when I start. Then yesterday stopped at the supermarket on the way home and couldn't get it going again. Someone gave me a jump and I made it back - but I have a couple questions now:

- If the battery is losing power while the car is running is it possible to "die" on the road?

- If the battery is dead can I roll the truck and get it going by popping it into gear?

I'm going to check the battery, than the cables and the alternator over the weekend. But it's my only ride so I don't want to take it out again if i'm not sure I can get it back. Any advice would be appreciated!

 

[Coolerman]

Yes,
Yes, and good luck. You are on the right track to fix it. Search around on here, this was just covered recently.

 

[rloaderro]

Yes

Hm... I've wondered about this but haven't tried it. I have a kill switch in the truck. If the switch is active (no current) then it's still possible to start the truck by popping it into gear?

 

[Coolerman]

If the battery is too dead to start the truck it probably still has enough juice to run the ignition for a few miles after being bump started.

Your kidding about the kill switch right? If kill switch on it no start regardless of method...

 

[bsmith123]

something's gotta give

if You have a bad alternator or its not charging you can drive quite a while on the battery as long as you keep it running--so at night you would notice lights going dimmer and dimmer and eventually the motor would die

If your battery is bad but the alternator is charging you should keep bright lights and keep running for a long time but eventually the alt is gonna give up the ghost from constantly charging at a high rate


Battery should read approx 14 volts with it running and the alt charging


whats the ammeter look like while its running---to the left or to the right of zero?

 

[bsevans]

You may have a bad VR. If you are going to have the alternator tested, then make sure the VR is also tested. If the mechanical contacts in the VR stay shut it will kill the battery and when running can damage the diodes in the alternator by running the alternator at too high a voltage- ask me how I know this.

 

[rloaderro]

I guess I'm going to take the truck in this week. I cleaned up the battery and the posts. I am a little concerned cause the positive cable is pretty corroded. I cut away about 2 inches to make a new contact and even then, deep inside the copper braids, it's all green dust. The cable itself doesn't feel "crinkly" though. Either way the charging system appears to be damaged as there is no return current going to the battery.

The battery was tested at 12v - which is OK - but not enough to turn over the motor. Could it be that this is a 24v system? 12v is also what it says on the voltmeter in the dash - so I know that's more-or-less accurate. But then previously the battery was charging to around 20v.

What's the VR - the regulator? Could it be that previously the regulator was adjusted too high? I have the suspicion that when I bought the truck it was adjusted to give a good first impression - all show and no stamina. So I guess I'll find things out as time goes on

 

[Coolerman]

Your regulator is bad if your charging voltage was 20 volts. That would also destroy the battery and very likely the alternator if it ran that way for a while.

I doubt the previous owner would have adjusted the regulator just to make it 'look good'...

 

[reddogfj45]

20 volts is way to high!!! suspect regulator
i do not know of any 24v landcruisers all 12v
if battery voltage drops too low coil cant fire = wont run even if roll starting it, if diesel it will run as long as the fuel pump fuel solinod has enough power to open
check voltage at back of alternator as well as battery if you have corrosion in the end of the cable it may have made its way further up the cable but it is not visible, readings should be the same
get battery and alternator checked along with the regulator if one part of the charging system is faulty it puts extra strain on the others possibly damanging them
one last thing, once had a faulty amp meter in the dash caused heeps of problems and was a pain to find, but i would start with the reg

 

[rloaderro]

Thanks, nevermind about the 20. I completely misread that without a flashlight. Before it was functioning correctly at about 15v. It must take about 13 to turn over, and right now it has 12. Will be curious to find out whats wrong. The regulator looks new. But hope it's not the alternator.

 

[bsmith123]

alt

I am a little concerned cause the positive cable is pretty corroded. I cut away about 2 inches to make a new contact and even then, deep inside the copper braids, it's all green dust.


Get a new cable---this one is toast ---once it is up into the wires it will only get worse

You should be reading approx 14 volts at idle, rev it up a little and it should not go up above 1 or 2 more volts, if it does not rise above 12 there is a good chance it is the alt

what's your ammeter reading with it running? to the left or right of zero and by how much?

There's another recent post on alternators that talks about how to test the VR but assuming it is fairly new also check it is hooked up correctly

 

[rloaderro]

I'm trying to find an ammeter to get a reading. What would left or right of zero indicate? What should the reading be?

I do have the Toyota repair manual that goes through the steps of checking the VR - whether or not I'm technically capable of following them though is another thing

 

[destin]

I just went through this same thing.

I rebuilt the generator and the voltage regulator.

Check the voltage regulator first

 

[bsmith123]

ammeter

I meant the gage--is yours not working?


at zero it means it is balanced and fully charged battery

to the left of zeo the battery is draining to the right the altenator is charging to provide the current

 

[rloaderro]

Haha - yeah, nothing in the console works. I have a separate voltmeter but that's it.

Anyway I brought it into the shop and the mechanic said it was a combination of things - a badly corroded cable that wasn't getting the current to the alternator, a blown fuse (!) and a loose connection in the VR. Does that make sense? I was surprised about the fuse - I never imagines that fitting into the whole cycle.