Battery charging question.

[coachgeo]

I'm starting to think it's not the batterys. I drove it about two weeks ago. And I've let that thing sit for months at a time before and it fired right up. I did notice that when the issue started yesterday, the "boot up" was different. I'm not 100%, but I swear normally, when I hit the power switch everything would come on almost instantly. But now there is a delay and sometimes the lights come, on...go off, then come on again.

sounds plausible. while you check the other voltages..... guess its back to cleaning all your grounds and wires between battery bank and the solenoids etc. beside them (disconnect switch area) and the LBCD connections.

PS- "cold" intensifies connection issues.

 

[Chickenbone]

Charge each battery individually with a 12V charger if you have any doubts that they're all good.

Or charge them all together with a 24V charger through the slave port if you're sure you don't have a bad one.

Where did you get that setup at?

 

[98G]

Where did you get that setup at?

I make them. I'll send you a PM.

Thanks

 

[Chickenbone]

If you have the 260amp alt.... no "need" to go go 2 batts. Not too many A1 C7's in civilian hands. You got a sweeet rig once you get her figured out.

on the regulator pretty sure your era truck would have the two LED's on the alternator voltage regulator. Red and Green I believe they are. They light up based on what the regulator is doing/not doing.

Looks like I have the 100amp.

And the LEDs are both flashing red (orange?)

And it turns out the batteries were down. I pulled them and checked. They were all at 11.5.

 

[Chickenbone]

sounds plausible. while you check the other voltages..... guess its back to cleaning all your grounds and wires between battery bank and the solenoids etc. beside them (disconnect switch area) and the LBCD connections.

PS- "cold" intensifies connection issues.

Turns out I'm a dumbass. They were low. Charging them now

 

[Ronmar]

Ok, lets try and figure out which flavor of A1 you have… do you have a remote and manual battery disconnect? They are in a box just to the rear of the battery box. Do you have a red guarded switch(remote battery disconnect sw) under the dash below the steering wheel?

flashing red means over-voltage. If the batteries were flat I would expect it to flash yellow for undervoltage. Green flash is normal voltage.

i highly reccomend you only put two batteries back in. At 120AH each(Cat only specs 100AH batts), that is still way more than enough power to meet the trucks needs and will charge faster and be far kinder to the alternator.

if you have the extra box to the rear of the battery box, you need to clean and inspect the connections in there. The 12 and 24 leads then go to either a polarity box or a LBCD between the air filter and spare tire. Those connections are out in the weather and are prone to corrosion. Easiest way to reach them is to lower the spare tire and crawl in that way.

 

[Chickenbone]

Ok, lets try and figure out which flavor of A1 you have… do you have a remote and manual battery disconnect? They are in a box just to the rear of the battery box. Do you have a red guarded switch(remote battery disconnect sw) under the dash below the steering wheel?

flashing red means over-voltage. If the batteries were flat I would expect it to flash yellow for undervoltage. Green flash is normal voltage.

i highly reccomend you only put two batteries back in. At 120AH each(Cat only specs 100AH batts), that is still way more than enough power to meet the trucks needs and will charge faster and be far kinder to the alternator.

if you have the extra box to the rear of the battery box, you need to clean and inspect the connections in there. The 12 and 24 leads then go to either a polarity box or a LBCD between the air filter and spare tire. Those connections are out in the weather and are prone to corrosion. Easiest way to reach them is to lower the spare tire and crawl in that way.

I have both switches. One outside under the slave connector and one inside in the cab.

They may have been flashing yellow. I thought it looked orange, so I just assumed red.

I am considering just putting two back in. I'm charging them now. Looks like at least one of them is not holding a charge.

 

[coachgeo]

with that combo of switches you have an LBCD. Not that it matters which when it comes to just clean the terminals. Look for any hints of a burned up solenoid in the area of the switches by the battery box while cleaning all those terminals.

Somewhere in here is an image of wiring when of dropping down to two batteries when you also have nato and the switches/solenoids to deal with.

PS- mark all your starter battery cables as you pull them, in particular the ones relative to where they go to things outside the battery box. Example starter lead It's often NOT in the battery wire diagrams...

 

[Ronmar]

Ok looks like you have a full A1 electrical system. I woukd take the ones that appear to hold a charge to an autoparts store and load test them, and re-install the best pair.

A 120AH wet cell bank(a pair of 6t batts in series) is just within the alt output limits. A pair of the 6T in AGM is still too large for that alt.

The problem is the dual volt alt. It is 100A total, and has a fair 12v load. The alt can only deliver ~60A@12v, and nearly half that goes to feed the lights. A 120AH wet battery wants 30A to charge(an AGM wants 55A). So flat batts put a terrible load on the alt. The 4 batt bank also wants 60A(4AGM wants 110A)...

Two 6ts will work better, group31 or 27 @~100AH is closer to ideal for this alt...

 

[Third From Texas]

I drive my 2008 A1R daily. But it occasionally sits for days and has sat for weeks on occasion. I run the 4 battery system - my 6TL's are in good condition and I have the 260A alternator - If everything is working properly the batteries hold a charge no trouble at all for me. Something is not right if you are having dead batteries after a short time. I guess the most important question is - how long did it sit before you tried to start it?

Same truck and year. Mine bleeds 12v like a stuck pig. I've chased it for three years. Stumped. Costs me a 6TL if I don't drive the truck for a few days and forget to flip the disco switch (I've flattened two batteries because of it). I just leave the charger pulsing when it's parked now.

 

[GeneralDisorder]

Same truck and year. Mine bleeds 12v like a stuck pig. I've chased it for three years. Stumped. Costs me a 6TL if I don't drive the truck for a few days and forget to flip the disco switch (I've flattened two batteries because of it). I just leave the charger pulsing when it's parked now.

Watch this on testing voltage drop across your fuses to find the draw. I have some really nice schematics that have some of the circuits color coded if you need them.

 

[Chickenbone]

Ok looks like you have a full A1 electrical system. I woukd take the ones that appear to hold a charge to an autoparts store and load test them, and re-install the best pair.

A 120AH wet cell bank(a pair of 6t batts in series) is just within the alt output limits. A pair of the 6T in AGM is still too large for that alt.

The problem is the dual volt alt. It is 100A total, and has a fair 12v load. The alt can only deliver ~60A@12v, and nearly half that goes to feed the lights. A 120AH wet battery wants 30A to charge(an AGM wants 55A). So flat batts put a terrible load on the alt. The 4 batt bank also wants 60A(4AGM wants 110A)...

Two 6ts will work better, group31 or 27 @~100AH is closer to ideal for this alt...

Got the 4 batteries tested. Looks like one of them has a bad cell.

I think I'm gonna just do as you and a couple other guys suggest and just go with 2 batteries for now. Gonna clean up and check the connections as well.