batteries issue

[dmoumane]

It seems the batteries on my Toyota landcruiser 78 model, 2.5 litres, are dead but not sure yet. When I jump start the car it continues runing for long periods of time until I turn off the engine. But one not running for a few hours the batteries seem to be dead again and I need to to jum start. I am considering changing the batteries, putting new ones, but don't know if the batteries on the car are 12 volts each or less. The dash board says 16 volts and that's confusing. Don't know if they are in series or prallel installation? Why two batteries on this car and how do they work?

That's all for now. Thank you.

Driss

 

[Jan-78FJ40]

It seems the batteries on my Toyota landcruiser 78 model, 2.5 litres, are dead but not sure yet. When I jump start the car it continues runing for long periods of time until I turn off the engine. But one not running for a few hours the batteries seem to be dead again and I need to to jum start. I am considering changing the batteries, putting new ones, but don't know if the batteries on the car are 12 volts each or less. The dash board says 16 volts and that's confusing. Don't know if they are in series or prallel installation? Why two batteries on this car and how do they work?

That's all for now. Thank you.

Driss

That is not enough information to work with.
I guess you have 2 batteries. Both will be 12V batteries, that is clear.
Measure the output at one of them, you'll see right away how they are connnected, 12V (parallel) or 24V (serieal).
what year is the truck, and what engine is it exactly? A gasser, I guess.

If you can keep the truck running, but it does not start, then the alternator is probably working, but the batteries are dead, or you have an enormous draw somewhere.
j

 

[Greg_B]

It seems the batteries on my Toyota landcruiser 78 model, 2.5 litres, are dead but not sure yet. When I jump start the car it continues runing for long periods of time until I turn off the engine. But one not running for a few hours the batteries seem to be dead again and I need to to jum start. I am considering changing the batteries, putting new ones, but don't know if the batteries on the car are 12 volts each or less. The dash board says 16 volts and that's confusing. Don't know if they are in series or prallel installation? Why two batteries on this car and how do they work?

That's all for now. Thank you.

Driss

Load test...

Then you will know.

hth's

gb

 

[dmoumane]

More on the batteries issue

The car was built in 1992. It's a diesel engine.

I don't have access to any reasonable measurement methods or tools to be able to measure the output of the batteries. All what I was able to do is measure the voltage of the two batteries separately. One was 8.5 volts and the second one was 6 volts. With this level of voltage I was unable to start the engine. It's was not enough to turn on any of the indicators in the dash board.

I agree on the major draw option and this is the reason I am reluctant to buy new batteries before I make sure that the problem is not caused by something. I want to continue to explore this option.

I appreciate the support.

 

[Ron R]

The car was built in 1992. It's a diesel engine.

I don't have access to any reasonable measurement methods or tools to be able to measure the output of the batteries. All what I was able to do is measure the voltage of the two batteries separately. One was 8.5 volts and the second one was 6 volts.

Well Driss, that's a good one to start with. This indicates that at least one of them is in a poor condition, otherwise their voltage should be more or less the same.

With this level of voltage I was unable to start the engine. It's was not enough to turn on any of the indicators in the dash board.

That's what you can expect with this kind of voltages

I agree on the major draw option and this is the reason I am reluctant to buy new batteries before I make sure that the problem is not caused by something. I want to continue to explore this option.
I appreciate the support.

From what you indicated in one of the previous posts I think your system is a 24V system. (somewhere you say something about 16 V or so)
In that case the two batteries are set-up in series.
You can find out by looking at how the batteries are connected.
Look at one of the batteries.
Can you find a thick(!) cable that runs from the + (plus = red) terminal from the one to the - (minus = blue) terminal of the other one.
Than it defenitely is a 24 V set-up and you will find that the batterie that has the + connected to the other one has it's - (minus) connected to the body and or chassis by an other thick cable.

Now how to check for the possible major draw?
Make sure the ingnition key is removed.
Disconnect the - minus (!) terminal of the batterie that is connected to the body.
Now measure or there is a current between body and the minusterminal you just disconnected.
You can check that in two ways.
Easiest and safest is with a bulb (lamp).
Take a bulb (12 or 24 V-type that is not that important in this setup but 12 v is more convienient )that has only one filament. In that case it has a leaden centre-point at the very bottom of the housing.
Press this part against the minus pole of the batterie where you disconnected the terminal. Then press the terminal (which still is connected to the body) against the metallic housing of the bulb.
Is it shining bright? --> you have a major draw.
Is it not shining at all. ---> no draw, replace batteries I would say.
Is it shining dim or very dim? Check or there is some equipment left on. If not there is a draw somewhere but this should not be able to drain your batteries in just a few hours when they are in a good condition.

Second way is to check with the help of an Am-meter. Yoy have to be carefull there, because, if there is a real major draw this could ruin your ammeter.
If you do so, make shure the meter is set to it max capacity. (10 Amps at least I would say.)
Connect one lead to the minus pole of the batterie and the other one to the terminal.
If you find a current of just a few milliamps there is nothing to worry about. Any larger current asks for an investigation.

Last of all: go to a shop they sell batteries. Good chance they have batterie-testing equipment. Normally they do these tests for free.

Regards

 

[dmoumane]

When I look at the way the two batteries are installed, there is no visible and obvious connection to suggest that the two batteries are in series. However, the (+) poles on the two batteries are connected to each other, which seems to suggest that the two batteries are in parallel. To complicate matters there are two cables on each side of the (+) sides of the two batteries that don't seem to be connected to each other, and all what is visible is the sides connected to the batteries, but the rest of the two cables in question goes to join the electrical wiring system. From what is visible to the eye, the system could be either a parallel system or a hybrid one. Never thought of this option. I also never heard of 24 V system for this type of cars.

More when I get a chance to investigate further as I need to jump start the car, run the engine for a couple of hours for the batteries to charge and then turn off the engine and try to either confirm or eliminate the draw option.

Regards and thanks.

 

[Ron R]

Driss,
There is a 12-24 V system possible. During starting the two batteries are switched to series instead of parallel.
The way you describe it now this can be your system.

As far as draw, you still can check the way I described it, but you then have to check each batterie individually. And indeed, charge them before you do the check.

One word about safety.
I did not state this very well in my previous posting I think and maybe I'm a bit to paternalistic here, but be carefull handling batteries, especially when connecting/disconnecting. Always start with disconnecting the batterie-pole that is connected to the body/chassis (generally the minus). After that disconnect the other pole. When connecting, first the pole that goes to the 'cabling' then the pole connected to the body/chassis.
Try to avoid shorts in any case. Batteries (even when 'empty') can produce enormeous currents and set fire to your system. So when you are 'fiddling' with the electrical system it's a good idea to disconnect the batterie(s) as long as they are not essential to what you are doing( e.g. testing a light or a cd-player)

 

[Joe70]

My 12V BJ70 showed 16V on the gauge. My 24V BJ74 shows 32V. I am almost positive your truck is 12V. Disconnect them both, then Charge them up. A trickle charger is ideal. This will take several hours per battery. After charging make sure to give the batteries about an hour or so for the volatge to level out. Then check the voltage. If the voltage is still low (less then 12V) you will need new batteries regardless if you have a draw or not. After new batteriers are in monitor them closely, checking the voltage every day. If it starts to drop, then you know you have a draw. Then the fun begins.