24V battery drain/leakage/monitoring

[CanuckMariner]

My '91 PZJ-T77 is 24V and using the Solar Converter from G&S. I have a relay hooked to my ignition position of the power block so both batteries don't equalize to zero when I leave the rig sit for weeks. All 12V apps work fine. Both batteries have been tested (Interstate) and are fine.

Couple of things with my blue top Optimas batteries:

Red light on Solar converter always on when truck is stopped, start her up and it flickers like it is about to go out, touch the throttle and it goes out, once driving for a bit red light come son again, once driving for hours it goes out completely. I suspect the red light comes on because of a battery difference of ~ x Volts. Problem is why the difference?

Secondly, and possibly related to above, is that the battery closest to the front (rad) is always significantly lower (up to 3V less) than the one closest to the firewall. I have only ground wires connected to the front battery and only positive wires to the plus on the firewall battery. I rotate the batteries every 6 months and have recently rotated them. When I first noticed the difference, I charge the lower batter to be within 0.25V of each other, yet the difference creeps back. Only connection between the batteries is the Solar Converter.

My thoughts are that I must have a parasitic leak with one of my 12V apps. But all are turned off except the stereo memory. Clock memory is 24V. I keep as many apps as possible at 24V (GPS, Fridge, Aux driving lights, etc.) unless I have no choice.

Anyone have any ideas? Had similar problem and found the solution?

Currently have the truck on a 24V smart charger from Soneil but the difference remains, but truck starts OK.

Lastly, I would like to get a LCD voltage gauge/meter (where to get a small cheap gauge?) so I can monitor both batteries while driving and stationary. How can I wire it up so I can simply press a switch/toggle to turn it on and see the voltage of one battery and toggle/switch to see the other one?

Thanks in advance for any assistance or comments.

 

[Stone]

Secondly, and possibly related to above, is that the battery closest to the front (rad) is always significantly lower (up to 3V less) than the one closest to the firewall. I have only ground wires connected to the front battery and only positive wires to the plus on the firewall battery. I rotate the batteries every 6 months and have recently rotated them. When I first noticed the difference, I charge the lower batter to be within 0.25V of each other, yet the difference creeps back. Only connection between the batteries is the Solar Converter.

I'm trying to understand what this setup would look like, and I can't picture it. WOuld you be able to clarify this with either a photo or a diagram of how it is setup?

 

[Greg_B]

AGM batteries do not like 24V (twin 12V series) setups. They may test fine, and will work ok in 12V parallel systems. But, put them in a series configuration and something about the way they take a charge mucks things up. Something about the internal resistance charge rate, and when they get to this unequal charge state...all spell trouble. Even with load balancers in the system.

You can try and change the balance (adjust the POT inside the Solar Converter) so the charge rate is the same for both. You can switch the battery position to try and manage this. You can take each out of the truck and charge to full independently..but it does not seem to make a difference with AGM batteries in 24V configuration.

Do a search on AGM batteries in this section. Here is one thread: https://forum.ih8mud.com/diesel-tech-24-volts-systems/354570-new-battery-advice-2.html

Also here is a data sheet on the different types of batteries. Note the "sensitivity to charge" column for the AGM: http://www.eastpenn-deka.com/assets/base/1081.pdf

I've got some dual purpose lead/acid batteries in the BJ74 now, with the converter set up to load balance when running only...and it's been fine. It was not with two yellow tops, or two red tops. I gave up on Optimas in a 24V truck when I walked by Petra's truck with two yellow tops and heard one hissing: No load balance, no taps, all connections and leads in excellent shape.

hth's

gb

 

[CanuckMariner]

I'm trying to understand what this setup would look like, and I can't picture it. WOuld you be able to clarify this with either a photo or a diagram of how it is setup?

Greg knows how it is setup as it is the same as his. And his comments below maybe just the problem I am experiencing.

AGM batteries do not like 24V (twin 12V series) setups. They may test fine, and will work ok in 12V parallel systems. But, put them in a series configuration and something about the way they take a charge mucks things up. Something about the internal resistance charge rate, and when they get to this unequal charge state...all spell trouble. Even with load balancers in the system.

You can try and change the balance (adjust the POT inside the Solar Converter) so the charge rate is the same for both. You can switch the battery position to try and manage this. You can take each out of the truck and charge to full independently..but it does not seem to make a difference with AGM batteries in 24V configuration.

Do a search on AGM batteries in this section. Here is one thread: https://forum.ih8mud.com/diesel-tech-24-volts-systems/354570-new-battery-advice-2.html

Also here is a data sheet on the different types of batteries. Note the "sensitivity to charge" column for the AGM: http://www.eastpenn-deka.com/assets/base/1081.pdf

I've got some dual purpose lead/acid batteries in the BJ74 now, with the converter set up to load balance when running only...and it's been fine. It was not with two yellow tops, or two red tops. I gave up on Optimas in a 24V truck when I walked by Petra's truck with two yellow tops and heard one hissing: No load balance, no taps, all connections and leads in excellent shape.

hth's

gb

Thanks Greg, will look into this.

 

[Stone]

Oh, I see...I know Greg's setup in his BJ74. Good luck.