Batteries

[GTRealest911]

Im a nubie to site and I'm looking at M1085 LWD bu it needs batteries, i have access yo Group 34 AGM but doesn't know if they will work. And help out there on this. Thanks all.

 

[Mullaney]

Im a nubie to site and I'm looking at M1085 LWD bu it needs batteries, i have access yo Group 34 AGM but doesn't know if they will work. And help out there on this. Thanks all.

You can have 2 or 4 batteries in that truck. There are three pictures attached from three different trucks. Assorted sizes and shapes...




Shop around a little and pick whatever. Really cold weather might need four, but there are an awful lot of the guys with two batteries - and they are happy.

 

[GTRealest911]

I appreciate that thanks. I'm in NJ ill use the XS Power 3400AGM

Sent from my SM-N950U using Tapatalk

 

[Ronmar]

You only really need 2. The milspec for the LMTV battery bank was gross overkill.

Caterpillar specs a pair of group 31’s for equipment using the 3116/3126 engine (100AH, 1000CCA). The 4pack of 6TL’s originally specced(240AH) is way oversized for the alternator installed and is probably why these rigs have so many alt and battery problems. A pair of group 31’s is a much better match for the alternator. I run a pair of group 31’s...

The group 34‘s are smaller at only 65AH but being AGM’s can still deliver 1050CCA. AGM’s put a greater charging demand on the alt(draw nearly double the charging current for a given AH rating), but at that size, a pair would probably perform comparably to a pair of group 31’s

 

[Third From Texas]

I've run dual batteries on all three trucks I've owned.

*not my drawing, I don't know whom to credit, though

 

[GTRealest911]

Hi Ronmar. You recently gave some good advice on Youtube comments about the turn signal issues.
The back story. Today i finished plumbing of fuel line and installing FASS Fuel pump and wiring. i went to start truck but nothing,the fuel solenoid doesn't click. i checked voltage at Alternator and RT wire 12v and LF wire is 3v. same at battery and voltage regulator. NOTE.. I converted to 2 battery system per your recommendation,and truck was running before i eliminated primer bulb setup.
I saw an old thread in forum where u said oil level could have disabled start. i noticed mine is above 14 so i will investigate.
Also is there a parts lookup for the relays mine have pt numbers but no labeling of if its 24v or 12v.
i know i threw alot at you but in stuck but don't want to get dismayed with my purchase. Thanks.

 

[GeneralDisorder]

What was the reasoning behind deleting the primer?!?

The CAT engine already has a lift pump. Not understanding the point of installing an electric lift pump when the engine has a (very reliable) mechanical lift pump built in......

What do you mean when you say "RT wire 12v and LF wire is 3v"?? Are you trying to say right and left? Who's right - who's left?? Which alternator do you have? Are you talking about the voltage regulator connections or the alternator output lugs?

You're going to need to be much more specific - pictures might help us - take pics and mark them up with your phone's image editor?

If it ran before you touched it - it's very likely that whatever you touched has something to do with the problem.

 

[Ronmar]

Yea need more info… i don’t understand the other pump either, how is it plumbed, how is it controlled. The fuel system moves a lot of fuel and must run at specific pressures. Modifications done incorrectly can restrict fuel and KILL the MUI injectors…

 

[GTRealest911]

What was the reasoning behind deleting the primer?!?

The CAT engine already has a lift pump. Not understanding the point of installing an electric lift pump when the engine has a (very reliable) mechanical lift pump built in......

What do you mean when you say "RT wire 12v and LF wire is 3v"?? Are you trying to say right and left? Who's right - who's left?? Which alternator do you have? Are you talking about the voltage regulator connections or the alternator output lugs?

You're going to need to be much more specific - pictures might help us - take pics and mark them up with your phone's image editor?

If it ran before you touched it - it's very likely that whatever you touched has something to do with the problem.

 

[GTRealest911]

i checked voltage at the alternator leads, the lead atop the alternator the right one 12v and the other lead was 3v, its the same volts at the the battery isolator.
all the way to the battery. my Alternator is 100A

 

[hike]

Your description is all so confusing, no idea where to start. Photos of primer delete; which FASS pump did you install and why; photos of the alternator tag and which terminal is 12v and 3v; what did you notice above 14?

 

[GeneralDisorder]

If you have 3v at one terminal and 12v at the other AND it's the same story at the batteries then you have a connection problem at the batteries, bad/discharged batteries, etc. Fix your batteries and connections - even with the truck off you should have 12.6v and 25.2v at the batteries and about 0.5v less at the alternator terminals considering the voltage drop through the LBCD.

 

[GTRealest911]

If you have 3v at one terminal and 12v at the other AND it's the same story at the batteries then you have a connection problem at the batteries, bad/discharged batteries, etc. Fix your batteries and connections - even with the truck off you should have 12.6v and 25.2v at the batteries and about 0.5v less at the alternator terminals considering the voltage drop through the LBCD.

If you have 3v at one terminal and 12v at the other AND it's the same story at the batteries then you have a connection problem at the batteries, bad/discharged b

If you have 3v at one terminal and 12v at the other AND it's the same story at the batteries then you have a connection problem at the batteries, bad/discharged batteries, etc. Fix your batteries and connections - even with the truck off you should have 12.6v and 25.2v at the batteries and about 0.5v less at the alternator terminals considering the voltage drop through the LBCD.

Your description is all so confusing, no idea where to start. Photos of primer delete; which FASS pump did you install and why; photos of the alternator tag and which terminal is 12v and 3v; what did you notice above 14?

The FASS 165 with Preset 1-20 PSI

 

[GeneralDisorder]

Huh? Not feeling like we can help this one.

 

[GTRealest911]

Both batteries voltage 12v when disconnected, i checked with FLUKE meter,when all wires are connected the side that's suppose to be 24v reading 3v.
I don' think i hooked battery cables up wrong, i only Have 2 battery setup also no NATO plug or cables. it's the way i purchase vehicle

 

[GTRealest911]

Both batteries voltage 12v when disconnected, i checked with FLUKE meter,when all wires are connected the side that's suppose to be 24v reading 3v.
I don' think i hooked battery cables up wrong, i only Have 2 battery setup also no NATO plug or cables. it's the way i purchase vehicle

i'm not trying to confuse anyone in the forum,i know i threw a lot of info out on original post to ronmar.
if i did screw up wire install does anyone have the setup. wires that go from battery to starter to isolator .

 

[GTRealest911]

Your description is all so confusing, no idea where to start. Photos of primer delete; which FASS pump did you install and why; photos of the alternator tag and which terminal is 12v and 3v; what did you notice above 14?

Tomorrow i will recheck wires and take some photo. My apologies for the initial info dump on my initial post.

 

[Ronmar]

Well if you hooked the batteries up wrong, either nothing will happen because the polarity box will prevent flow, or things will get really hot. If a good battery was dropping to 3V because of load, something would be getting really hot. Sounds like a bad battery. Are they charged and do they pass a load test?

battery 1 -/ground runs to the starter motor housing, and on to the drivers frame.
battery 1 + connects to battery 2 - and 12V lead to the 12v batt stud on the polarity box/LBCD where the 12v alt lead Also connects
battery 2+ connects to the starter solenoid, to the 24v batt stud on the polarity box/LBCD and the 24v alt lead also connects there…

 

[GTRealest911]

Battery was defective,i got issue corrected.

The start issue i found is related to the oil pressure,with the start switch off the ol pressure is 14PSI and when switched off it climbs to 40PSI similarly to a fuel gauge.

 

[Ronmar]

Battery was defective,i got issue corrected.

The start issue i found is related to the oil pressure,with the start switch off the ol pressure is 14PSI and when switched off it climbs to 40PSI similarly to a fuel gauge.

The oil pressure gauge and gauge sensor is not related to the start circuit in any way… the only thing they have in common is they both sample engine oil pressure…

There is a separate oil pressure switch that is plumbed into the oil system on the lower drivers side of the engine block near that gauge pressure sensor. It is closed/completes a circuit until the engine reaches 15PSI, then it breaks the circuit. It controls the oil warning light in the dash, the starter lockout circuit(K24 keeps someone from engaging the starter on a running engine) and the alternator excite control(K11 keeps alt offline until the engine is running). When you turn on the ign switch, K24 and K11 must energize, no K24, no starter pushbutton circuit

the oil pressure gauge reading 14PSI could be a bad gauge or a sender. The sender is a variable resistor that changes resistance with pressure. The gauge measures current thru the variable resistor. The gauge moving to some other reading when shut down is not that unusual as it may misenterpret current flow thru the circuit as the circuit collapses, then it display sticks where it last read a signal… i forget the resistance spec but they are setup to read between 2 resistances from 0psi to their max PSI spec. You test them by applying a known pressure and measuring for the corresponding resisitance. You test the gauge by attaching resistors to the sense circuit lead to ground corresponding to minimum midrange and maximum displayed pressure…