Parasitic Drain Issue?

[Rearanger]

Trying to understand my low voltage reading on my battery after sitting - 12.32v. Bad battery or parasitic drain - not sure. Always starts strong but it's North Carolina weather.

I did some research here on past threads but want to clear up some points.

Does this truck have a battery saver mode? If so how long before it goes into battery saver mode?

Initial testing with my DMM (negative battery cable) shows 200 milliamps draw - is this normal before battery saver mode? After battery saver mode kicks in what should I see for amp draw?

Plain Jane truck, roll down windows, manual trans, installed electric fan. I pulled the fan fuse - no change, also pulled my added back up lights fuse. No other added lights. Also pulled fuses under the hood. Removed the dome light.

There was a comment about leaving the doors open so I'll know when battery saver mode starts??

Thanks

 

[Curious Hound]

200ma is way too much. I'm not sure if you have a battery saver circuit. But just guessing, I would think 2003 would have that. If you pulled all the under hood fuses, that should have killed anything in the cab since the cab fuse panel is fed from a fuse under the hood. Try disconnecting the smaller at the alternator. Sometimes when the voltage regulator starts failing, that causes a drain through the alternator.

 

[Rearanger]

I'll check the voltage regulator tomorrow. The fuses I pulled from under the hood were just the smaller ones, not the bigger square ones (non-relay).

What's also strange is I can charge the battery to 12.85v with my manual charger on 2amp, then switch to my auto electronic charger overnight for maintain mode and check in the morning and get 12.3V.

I've been checking voltage since 3:30PM when the battery tested 12.32v, several checks later at 5:15PM and 8:00PM all have been 12.32V.

The battery is not appearing to discharge any further. I'll check in the morning. Hoping it's the battery.

 

[Dirtman]

200ma is normal before the computer starts shutting things down. Yes you have battery saver mode, in 2003 it may be a battery saver relay or if it has a SJB instead of a GEM the timers are integrated into the SJB. (They switched from GEM to SJB somewhere in that year so could be either).

My truck draws around 200ma for about 10 minutes, then drops to 70ma for 2-3 minutes more, then finally drops to around 5ma after all the systems have gone to sleep.

You either need to leave the dmm attached and on for the full 15-20 minutes or use a jumper wire. Connecting and disconnecting the dmm will wake up the relay and you will never see it "sleep". Test also needs to be done with the doors shut or the latches closed the entire time and never touch ANYTHING! Touching the brake pedal, opening the door, etc will all wake the system back up. Like I said, even the minor fluctuation from attaching the multimeter is enough that the computer will sense it and wake up and leave you with a 200ma reading.

12.3 is normal but on the low side meaning the battery is just old. The reason you get a higher reading after charging and then a drop, to put it in less than scientific terms is because the battery slightly overcharges and then spills that extra juice off.

 

[Rearanger]

12.3 is normal but on the low side meaning the battery is just old.

Thanks for all the info. I'm going to have to be more patient with DMM hooked up. I'm going to fashion a jumper wire with a switch so I can then use the DMM with no break in the current flow.

The battery is less than a year old so I think once I understand my parasitic I'll get a new one under warranty. Under covid I use a solar trickle charger. I also checked the electrolyte level and it's up to the top.

 

[Dirtman]

You don't need a switch, just disconnect the negative cable and attach a jumper wire from the negative post to the cable. Wait about 30 minutes and then hook the meter up from the negative post to the cable, make sure its on and reading amps, and then remove the jumper wire so all the current is running through the meter. This way you never break the circuit.

 

[Rearanger]

Last night the battery voltage was 12.3v and this morning was 12.27v. I did a long parasitic draw test and could only get down to 27mA. Much better but not to 5mA.

I'll get the wife's help later to look at the meter while I unplug fuses at the inside fuse panel. Removing the small wires at the alternator did not change the amps.

I'm off to try and get a new battery under warranty and then start from there.

Thanks Dirtman, your info made it a lot easier.

 

[Dirtman]

27ma is an acceptable parasitic draw and wouldn't cause any issues. Acceptable range is basically anything less than 50ma. There are things that never turn off, computer memory, the radio's clock etc.

 

[Rearanger]

27ma is an acceptable parasitic draw and wouldn't cause any issues. Acceptable range is basically anything less than 50ma. There are things that never turn off, computer memory, the radio's clock etc.

Ok, good to know. I'm still going to pull some fuses tomorrow and see where the drain is just to make sure it's nothing I did.

Went to Advance Auto and got a new battery under warranty. Initial charge is 12.79v I'll see what it is in the morning.

 

[Curious Hound]

I'd be happy with 27ma.



Or even 0.027amps

 

[Dirtman]

Ok, good to know. I'm still going to pull some fuses tomorrow and see where the drain is just to make sure it's nothing I did.

Went to Advance Auto and got a new battery under warranty. Initial charge is 12.79v I'll see what it is in the morning.

Start with the ones under the hood. You will see a drop when you disconnect the main fuses to the GEM/SJB, ignore that because that just disconnects the ENTIRE set of fuses in the cab. Ill bet you find your draw mixed between the logic power, kam, and radio on the interior fuse panel.

Let us know if the battery holds its charge now. It's not uncommon to get a crap battery from the auto parts store. I've had several from advance and autozone die in less than a year.