24 volt system charging batteries at different rate

Joined
Apr 3, 2011
Messages
101
Location
Toronto, Ontario, Canada
I've only had my 87 HJ60 for a few months and am still working out the kinks from PO's and 24 years of abuse. The PO had put in some cheap reconditioned batteries with different sizes and the battery on the grounded side kept dieing after a few days. I bought 2 brand new batteries that properly fit the 12" trays and have 1000 CA each which seem to working fine after one month.
My issue is that one battery is charging more than the other grounded one. With the truck not running one battery tests at 12.75v while the grounded one is 12.25v. When running the non grounded battery is at like 14.25v while the other is about 13.25+/-v. My battery guy was worried the one battery was going to get cooked. The alternator seems to put out a steady 27.9v. Is this normal as I've read on here that some folks rotate batteries when doing an oil change?
thanks
 
Joined
Jun 6, 2003
Messages
3,588
Location
Maple Ridge, BC, Canada
The PO probably wired 12v accessories on your 'grounded' battery. There should only be one feed for your headlights of of the 'grounded' battery's positive post. If you have more than one, like stereo or ??? then this is likely your draw.
 
Joined
Mar 28, 2002
Messages
4,802
As Kim says, good chance you have a 12V tap on one of the batteries (other then the factory center tap that feeds the headlight dimmer switch).

However, if there are no other 12V taps, make sure all your battery wiring is in top shape. This includes the neutral wires from the lowside battery to the frame, engine to frame, and lowside battery positive post to highside battery negative post. Once the batteries have a slight internal resistance difference, they will accept the charge differently. That difference will become more pronounced with time (as one overcharges and one undercharges.

Check out this for some good trouble shooting info, and for some charging basics in the link in post #9 https://forum.ih8mud.com/diesel-tech-24-volts-systems/413194-battery-eating-hj60.html#post5873554

You could try switching the batteries, and see if the charge difference follows the batteries. You could also (if you have available) pull both batteries and put them on a pulse charger to see if you can get the sitting voltages closer to one another. This is after confirming there are no 12V taps, and all grounds and battery wiring are in top shape.

hth's

gb
 
Joined
Apr 3, 2011
Messages
101
Location
Toronto, Ontario, Canada
Thanks for the advice. I did check for a draw with a 12v test light on both batteries but no light. I will proceed with checking all ground wires are proper. The wire connecting the 2 batteries looks good to me. Just to clear something up for me: My passenger side battery is connected to the driver side battery which is then grounded. Is this HIGH to LOW side? Also where is this 'center tap' I hear so much about? How do you identify? A photo would be awesome!!
Thanks
 

BreckenridgeCruiser

I break things.
SILVER Star
Joined
Aug 14, 2006
Messages
4,052
Location
Oceanside and Encinitas, CA
Website
www.doublehelixcreative.com
You may have a switched draw so a 12v light when the truck is off won't help. To clarify, you are not looking for a 12v drain while not running, any 12v tap when running or not will unbalance your batteries, which your alternator will not be able to fix.. it will just exacerbate the issue.

Low side is the 12 volt side (ground) as it has the low voltage and the high side is the 24v side which connects to the starter. The center tap is the wire from the low side terminal to the headlight and then on the high side to the other headlight.

This may sounds stupid, but are both of your headlights the same and in the same condition? If one is out or has been upgraded, the higher draw of one will unbalance the batteries.

Yes, they seem to be that sensitive.

HTH
 
Joined
Apr 3, 2011
Messages
101
Location
Toronto, Ontario, Canada
Okay so I removed both batteries and double checked all connections. The connection from the negative on high side battery to positive on low side felt loose to me so I replaced with an HD battery connection and made sure it was tight and clean. Then, on the low side battery the negative went to an engine mount 17mm nut. There was another ground wire from this nut to the body. I eliminated the extra ground wire and now there is one negative wire from the battery to the body only. I will look around to see if there are other ground wires disconnected elsewhere on the vehicle.
There is a tap on each battery that goes to the horn and headlight on each side. Both look the same to me. To my knowledge there is no other tap but not sure how to check a draw while the engine is running. I do not have a stereo hooked up as the PO botched it and I'm waiting till I solve this unbalancing act.
I switched batteries around now and am charging the one that was the low side battery as it is not matched to other and will try to get it as close as possible and we'll see if the charging issue's persist.

One thing I noticed after I switched batteries around: With the headlights on the high side battery read 13v while the low side went down to 14v. Switch the headlights off and the high side battery went down to 12.5v and the now low side battery went back up to being overcharged as previously stated.
Thanks for reading.:popcorn:
 
Joined
Dec 29, 2006
Messages
9,165
Location
Abby
Given the centre tap seems to have probloems, I don't know why people just don't wire in a 24V power and change the bulbs to 24V??? The same goes for the horn.

My other recommendation is you discharge them both - maybe by leaving your lights on for 30-40 minutes. Pull both batteries and put them on a battery charger to bring them both up to the same charge level. Then re-install them. This should take care of one battery continuing to be overcharged.
 
Joined
Apr 3, 2011
Messages
101
Location
Toronto, Ontario, Canada
Given the centre tap seems to have probloems, I don't know why people just don't wire in a 24V power and change the bulbs to 24V??? The same goes for the horn.

My other recommendation is you discharge them both - maybe by leaving your lights on for 30-40 minutes. Pull both batteries and put them on a battery charger to bring them both up to the same charge level. Then re-install them. This should take care of one battery continuing to be overcharged.
Hmm never thought of that. I guess it's an option if I don't resolve the issue.
I'm also considering a Redarc equalizer from Aussieland unless there is a Canadian equivalent. I would like to figure out the problem though.
I switched batteries around and put the one that wasn't getting enough of a charge on the charger and seemed to balance them out as best as possible with a voltmeter. This morning before starting I checked voltage and both were around 12.8v. After driving to work I put my tester on both with engine running and one was 15.1v (high) and 12.5v (low).
 

BreckenridgeCruiser

I break things.
SILVER Star
Joined
Aug 14, 2006
Messages
4,052
Location
Oceanside and Encinitas, CA
Website
www.doublehelixcreative.com
Equalizers may not work... for the same reason that your alternator will have issues charging the batteries properly.

When you set up a 24V in series, the systems does not know there are two seperate 12V batts making it 24. The lat throws 24v at it so if you have a low battery, it will undercharge and the high will overcharge. There are no systems that will recognize the voltage of each battery and hit it with the needed charge.

Best way to fix this is to remove the center tap and get 24V lights (I use 24v Heavy Duty Hella H4s) and horns, and then buy two identical batteries from the same date and batch codes.

Sometimes polishing a turd (or in this case turdy batteries) just gets you shiny poop.

K
 
Joined
Apr 3, 2011
Messages
101
Location
Toronto, Ontario, Canada
BreckenridgeCruiser said:
Equalizers may not work... for the same reason that your alternator will have issues charging the batteries properly.

When you set up a 24V in series, the systems does not know there are two seperate 12V batts making it 24. The lat throws 24v at it so if you have a low battery, it will undercharge and the high will overcharge. There are no systems that will recognize the voltage of each battery and hit it with the needed charge.

Best way to fix this is to remove the center tap and get 24V lights (I use 24v Heavy Duty Hella H4s) and horns, and then buy two identical batteries from the same date and batch codes.

Sometimes polishing a turd (or in this case turdy batteries) just gets you shiny poop.

K

Thanks for your reply. I didn't know this about equalizers.

Update: I inspected and replaced the wire connecting the two batteries as the old one was actually corroding and part of it was fusing onto the battery connector. I am also missing a frame to engine ground (broken). Maybe with these fixed it will balance out better. I will run for a few days and see how they charge up.
 
Joined
Mar 28, 2002
Messages
4,802
Equalizers may not work... for the same reason that your alternator will have issues charging the batteries properly.

They are designed to do exactly that: allow you to take 12V off one battery, and it maintains the correct charge to each. CE Series Charge Equaliser | Redarc Electronics


Sometimes polishing a turd (or in this case turdy batteries) just gets you shiny poop.

This is true! And if this system has been mucked with like I think it has, an equalizer would be doing just that.

There is a tap on each battery that goes to the horn and headlight on each side. Both look the same to me.

I really need to find an unmolested Cdn spec HJ60 and check this out, as this problem keeps cropping up. It sounds to me like someone has been into the wiring harness for the headlights and dimmer switch and mucked things up. I thought there should be one tap only, from the negative pole of the highside battery. The main harness coming off the 24V pole looks after the other side of the headlight system...unless the HJ60 is totally different then the Cdn spec BJ42 or Cdn spec 24V BJ70. What someone with a clean Cdn spec HJ60 needs to do is check the voltage at each headlight pin (lights off, then lights on) and record the voltage for each colored wire. Oh, and check out "evil center tap" for some color coding and drawings of how the BJ42 setup runs 12V lights in the 24V system. While not your truck, it may help point direction and leads.

Sorry I can't be of more help. Do you know someone close by who has an clean HJ60?

If you decide to make the system simple and go 24V headlights, I would suggest you still figure out what each wire should be carrying for voltages, so you either trace back and totally remove the wires, or dead head them with protection, and some tape with comments on each wire for future owners.

You do have two round headlights, right?

Grounds are a good thing. Engine to battery, engine to frame, frame to body, battery to body. The wiring harness carries it's own ground as well, and stops off at different body points all over the place. If it was me, I would reconnect the one you disconnected.

hth's

gb
 
Last edited:
Joined
Jun 6, 2003
Messages
3,588
Location
Maple Ridge, BC, Canada
I really need to find an unmolested Cdn spec HJ60 and check this out, as this problem keeps cropping up. It sounds to me like someone has been into the wiring harness for the headlights and dimmer switch and mucked things up. I thought there should be one tap only, from the negative pole of the highside battery. The main harness coming off the 24V pole looks after the other side of the headlight system...unless the HJ60 is totally different then the Cdn spec BJ42 or Cdn spec 24V BJ70. What someone with a clean Cdn spec HJ60 needs to do is check the voltage at each headlight pin (lights off, then lights on) and record the voltage for each colored wire. Oh, and check out "evil center tap" for some color coding and drawings of how the BJ42 setup runs 12V lights in the 24V system. While not your truck, it may help point direction and leads.

Sorry I can't be of more help. Do you know someone close by who has an clean HJ60?

If you decide to make the system simple and go 24V headlights, I would suggest you still figure out what each wire should be carrying for voltages, so you either trace back and totally remove the wires, or dead head them with protection, and some tape with comments on each wire for future owners.

You do have two round headlights, right?

Grounds are a good thing. Engine to battery, engine to frame, frame to body, battery to body. The wiring harness carries it's own ground as well, and stops off at different body points all over the place. If it was me, I would reconnect the one you disconnected.

hth's

gb

I have a stock HJ60 cdn model. I just checked the wiring harness to the headlights and no pin on either drivers or passenger had power when the headlights were off. When headlights on, Pass R/W had 0v, R/G had 24v, R/Blue had 12v. Drivers headlight R/Y had 0v, R/Black had 12v and W/Blue had 0v.
 
Joined
Mar 28, 2002
Messages
4,802
I have a stock HJ60 cdn model. I just checked the wiring harness to the headlights and no pin on either drivers or passenger had power when the headlights were off. When headlights on, Pass R/W had 0v, R/G had 24v, R/Blue had 12v. Drivers headlight R/Y had 0v, R/Black had 12v and W/Blue had 0v.

Awesome, thanks Kim. One more request. These are for headlights off, then on low beam. What about on high beam?

gb
 
Joined
Mar 28, 2002
Messages
4,802
Cdn Spec 24V HJ60, with one single round 12V headlight on each side:

Headlights off: ..............Right side- R/W 0V, R/G 0V, R/Blue 0V. Left side - ...R/Y 0V, R/B 0V, W/Blue 0V.
Headlights on Low Beam: Right side- R/W 0V, R/G 24V, R/Blue 12V. Left side - R/Y 0V, R/B 12V, W/Blue 0V.
Headlights on High Beam: Right side- R/W 24V, R/G 0V, R/Blue 12V. Left side -R/Y 12V, R/B 0V, W/Blue 0V.

Hopefully this keeps form. Did I transpose correct?

The 24V and 12V signals are controlled in one spot in the BJ42. It has a 24V, and 12V feed coming in, and directs the voltage where needed. On the BJ42 its called the dimmer relay iirc. Find the one on your HJ60, and all those colored wires should be exiting it, in addition to the 12V and 24V leads coming in.

(Ignore this) Kim, one final request when you are back out there in the next couple days. Do your batteries have leads off each battery to the headlights and horn? Shouldn't, but to eliminate this for the OP and make sure I'm not steering wrong.

hth's

gb
 
Last edited:

BreckenridgeCruiser

I break things.
SILVER Star
Joined
Aug 14, 2006
Messages
4,052
Location
Oceanside and Encinitas, CA
Website
www.doublehelixcreative.com
To confirm, I wasn't saying equalizers don't work, I was more talking about adding an equalizer without first finding all of the causes of the unbalanced batteries is a bad idea. An equalizer in my mind is better suited to maintain a healthy system than to try to keep up with one with drains and other issues. It.may work, but if it fails or cannot keep up, you get stranded because you never fixed the disease, just the symptoms.
 
Joined
Mar 28, 2002
Messages
4,802
To confirm, I wasn't saying equalizers don't work, I was more talking about adding an equalizer without first finding all of the causes of the unbalanced batteries is a bad idea. An equalizer in my mind is better suited to maintain a healthy system than to try to keep up with one with drains and other issues. It.may work, but if it fails or cannot keep up, you get stranded because you never fixed the disease, just the symptoms.

We're on the same page. I miss-read it then, sorry. Should have seen a text conversation I was having the other day on picking up a cheque and dropping off keys with a fellow from work. Even though we were both speaking English I don't think there was much clear communication going on.

gb
 
Joined
Apr 3, 2011
Messages
101
Location
Toronto, Ontario, Canada
Awesome info here! I will check the voltage at these terminals when I have some time. I should say that the only tap I found was on low side battery. The wires from high side headlight and battery come from harness it seems.
 

Users who are viewing this thread

Top Bottom