Dual batteries keep dying (1 Viewer)

[Crusininthe60]

Hey all,
Ive got a 84’ 60 series with dual batteries set up.. had it this way for 12 months and now none of the batteries are holding charge.
The charge light has been flickering for a few weeks but now just stays on. the car died on me completely 2 days ago and when I switched the main battery with the second one it started immediately. Then today it wouldn’t start at all. Went and got a new battery and she’s running fine.
However the charge light is still on... anyone got any advice of what it could be and if you’ve had an issue the same as this let us know how you managed to fix it.

 

[WharfRat]

I don't know much, but I added a balancer to my 24v truck and haven't had anymore dead battery issues. I did this two yeas ago.

 

[Hojack]

Have you checked to see if your alternator is putting out 14 volts?

 

[poptart]

Start simple, like @Hojack said check for 14v while the car is running or get your alternator tested. If that's fine, check for parasitic drain, that will kill batteries.

 

[Seth S]

Charge light on most likely an indication that your alternator is not charging properly. Start the truck, measure the voltage between the post on the back of the alternator and battery ground and you should be seeing between 13-14.4 volts.

You may have parasitic drains or other problems that are drawing the battery down but once the truck is running it should run just fine with a dead battery if the alternator is good.

If you need a new alternator this is the one I used when mine died this spring:

ACDELCO​

3341599 (334-1599)

Alternator / Generator

$ 43.99​

$ 5.00​

1​

$ 48.99​

1986 TOYOTA LAND CRUISER 4.2L L6 Alternator / Generator | RockAuto

RockAuto ships auto parts and body parts from over 300 manufacturers to customers' doors worldwide, all at warehouse prices. Easy to use parts catalog.

www.rockauto.com

The only thing you will have to do is swap your current alternator pulley with the replacement alternator or have a shop do it. Its pretty straight forward install and also a good excuse to install a new belt.

 

[60Works]

As mentioned, charging light indicates you have alternator problems. Check that first.

There are lots of ways to install dual batteries wrong that will wreck new batteries in a year. If you describe or post a picture of your install we can help with making sure it's built properly.

 

[Randy88FJ62]

Assuming the alternator checks out lets hear more about your dual battery setup. Do you run a blue sea 7622 ACR or a solenoid setup? Lots of different ways so let's hear what you have.

 

[Seth S]

If your batteries are wired in parallel AND you have not put in some sort of isolator then the voltage will equalize between the two batteries. So if one battery is low the second one will essentially try to charge it. Parallel circuit the voltage is the same but the current adds. Series the current is the same but the voltage adds.

 

[poptart]

If your batteries are wired in parallel AND you have not put in some sort of isolator then the voltage will equalize between the two batteries. So if one battery is low the second one will essentially try to charge it. Parallel circuit the voltage is the same but the current adds. Series the current is the same but the voltage adds.

A stuck solenoid can cause the same issue, if you're running that

 

[roalco]

Just throwing out some info....
It seems from his other posts the OP is on Australia, with an ‘84 HJ60, apparently 12v. We didn’t get the 2H engine here in Canada until ‘86, I think, when toyota was trying to put an auto transmission in the diesel 60’s. They were all 24v systems here, if I remember correctly, with two 12v batteries wired in series.
That said, the (84 and other years) BJ60’s were 12v, dual battery systems, with two IDENTICAL specification batteries wired in straight parallel, with no isolators or other devices separating them. This system is simple, and very adequate, but like any parallel battery installation, for it to function properly the batteries must be identical. Different post locations yes, but the same age, type, maker, capacity etc.
I can’t seem to get any info on the Australian 84 HJ60 vehicles from ToyoDiy.com (you can enter it, the selector fields come up, but there are no files??) so it’s hard to find the original arrangement.
The OP seems to have had other electrical issues as well, perhaps removing the previous “battery mods” and going back to the original design will help troubleshooting.
It does sound to me like a bad alternator output issue, with the light flickering and all.... easy to test.