2nd Gen Non-Engine/Transmission Battery power draw question

[CumminsPower98]

Twice now my truck has run down while sitting for about 2-3 weeks at a time. First time around I figured that my Cobra radio with weather contributed because it draws on account of the weather radio feature even when turned off. I have it hard wired to battery so I have been unplugging it. Well recently I drained the batteries clear dead so that not even a light would glow. I had a 35W solar panel sitting inside on the center console since I knew things would drain over time now that I'm not driving it every day. Problem is I think the plug wasn't fully seated this time in the power outlet and I forgot to unplug the radio. I also found a couple other drains. One being my iPod power cord that I have hardwired. It has a couple small lights. One light lights the 3 way power outlet and the other is the plug from the iPod cord. The third draw is the Prodigy brake controller.

Today I finally took the time to start testing and isolating things to make sure the OE part of the truck wasn't the problem and it would appear that I'm okay but I wanted to ask those more knowledgeable. Below are my tests and the results.

Meter set on the 300ma scale

-Cobra radio plugged in and turned off 34. 9ma (radio only)
-3-way lighted power outlet with lighted iPod cord plugged in 46. 0ma (cord only)
-Prodigy brake controller in standby mode 11. 1ma (18. 3ma powered up)
-OE part of truck with no aftermarket stuff drawing 5. 0ma after the 30 minute seat belt power down or unplugged.

Meter set on the 10A scale I got . 47A while the seat belt solenoids were active. It did drop off some though during the 30 minutes they were on. I have checked the seat belts several times and they always power off so I don't think I have a problem there.

So my question is, is all that enough to drain the batteries in 2-3 weeks of sitting and does the 5. 0ma sound about right for the stock truck. Well I should say it does have an aftermarket head unit but I doubt that makes much if any difference.

I'm pretty uneducated in the electrical department and testing...

Thanks for any thoughts on this.

Mark

 

[bmoeller]

How old are the batteries?I would fully charge the batts and have them load tested. 3 weeks shouldn't drain the batts, with the radio unplugged.

Unless they are maintenance-free batts, is the water level up to par on all cells?

 

[CumminsPower98]

All 3 power using devices were plugged this last time so it would appear that I had a total draw of about 97ma during this time. The Optima red top batteries were placed in service 11/15/05. I did a slow charge all night last Monday or Tuesday and then it sat until this morning with all nothing but the brake controller connected and it started strong as ever. I think it probably just the devices I had connected that did it. I just wanted to see if anyone could tell me for sure if that amount of load could drain them in 2-3 weeks (sorry I can't remember exact time).

 

[WTBurke]

Power consumption during stand-by can be calculated as P=EI or power equals e(voltage) times i(current). Looking at your current draw of all your devices appears to be less than 100 milliamps hence; if your two batteries are equal and the static DC voltage is 12. 6 x . 94 = 11. 84 watts of power being dissipated. Thats running a 12 watt light bulb for 3 weeks. Indeed this would pull the head charge off your Optimas. Now the figures you provide with a ten amp scale showing . 49 amps (nearly 500 mills or a half amp) at 12. 6 volts x . 49 = 6. 174 watts is half of the first figures.



I have removed all power drawing devices except the ECU and factory radio (stock factory set-up) and I see 15 milliamps total or 12. 6 (nominal DC voltage) x . 15 = 1. 89 watts of power and this too can pull the head charge off my Optimas in 4 to 5 weeks. I have found using a small wall-wart type 12. 8 volt charger at 18 mills will float the batteries with no harm done for extended periods of time.



Remember that a weak battery will pull the head off the strong one until is equalizes. You might want to check the static DC level of each individual battery by removing the parallel connections.



William

 

[RCook]

Hi Mark,

I have a 98 24-valve, with Optima red-tops from 2002. I have the Prodigy controller, but no Cobra or iPod. I thought the only draw I had was the clock (and ECU?) - does the Prodigy really use power when the truck's off? Do the lights on yours stay on?

Even after sitting untouched for 3 months (long boat trip) the Cummins will start right up (turning over slower, but turning over). Are your connections all clean and tight?

 

[EKlem]

The batteries that you have are probably around 50Ah apiece so 100Ah total. If you are drawing 500mA, that is 200 hours which is 8. 3 days of charge. If it is only around 100mA, that is 42 days of charge.

I would recommend cleaning all of the connections and then trying to minimize all of your loads. I have a 12V disconnect switch on all of my accessories to keep from discharging my batteries. If you are still having problems after minimizing your loads, then you could get your batteries load tested. The other potential problem is that you are not fully charging your batteries if there is something wrong with your alternator and regulator but this is unlikely, they tend to work or not.

 

[CumminsPower98]

Hi Mark,



I have a 98 24-valve, with Optima red-tops from 2002. I have the Prodigy controller, but no Cobra or iPod. I thought the only draw I had was the clock (and ECU?) - does the Prodigy really use power when the truck's off? Do the lights on yours stay on?



Even after sitting untouched for 3 months (long boat trip) the Cummins will start right up (turning over slower, but turning over). Are your connections all clean and tight?

I don't know if this is normal or not but like I said in the first post mine was registering 11. 1ma when testing on the 300ma scale. Yes the lights are off at this point. Fully powered up it was drawing 18. 3ma. I think its odd that it would use any power at all when powered down but maybe its the nature of it. Since I don't tow much now or even drive the truck much I will just leave the controler in the glove box.





All connections are clean and tight (gotta love the sealed Optimas). I probably should go ahead and test the batteries to make sure there isn't something going on there, which reminds me when I first started testing I forgot to unhook the passenger side battery. This was making for strange readings that on the surface seemed normal except that they kept changing. My current draw would start out higher and slowly keep dropping. This would seem to indicate some flow from one battery to the other if I'm thinking right. I tossed my records of all those readings though. Maybe it was so small it was normal but it gives something to think about as an added draw if one battery is weak.



This truck has been my daily driver since I got it in '01 and also saw a lot of road miles transporting RVs but last fall I started driving a car to save on fuel so this sitting for long periods is new to the truck. I have been keeping a solar panel in there to hold the batteries but like I said I think the plug wasn't fully seated in the power outlet this last time.



WTBurke. The . 49 amp figure really didn't even need to be included. I just tested that to get an idea how much the seat belt solenoids used because I have heard of them being a problem and not timing off. Mine do however. I think I had all my other stuff disconnect for that test.



The calculation you did with the 12. 6x . 94 isn't right I'm thinking as that's figuring the . 94 in the 10a scale. All my accessory device measurements were on the 300ma scale not the 10a scale. The seat belt solenoids were drawing far more power than my accessories. So the way I'm seeing this is when I add all my stuff up for the total draw ( not counting the seats) I get 97ma. so if I went 12. 6x. 097=1. 22 watts? Maybe I'm confused, which wouldn't be surprising. I have been making most of my living twisting wrenches for the last 12 years or so but I don't have much formal training and I'm very poor in the electrical area as you can see.



In the end I will leave all this stuff unplugged of course and hope the truck itself is okay and I think it probably is. I do need to check the batteries for sure.

 

[CumminsPower98]

The batteries that you have are probably around 50Ah apiece so 100Ah total. If you are drawing 500mA, that is 200 hours which is 8. 3 days of charge. If it is only around 100mA, that is 42 days of charge.



I would recommend cleaning all of the connections and then trying to minimize all of your loads. I have a 12V disconnect switch on all of my accessories to keep from discharging my batteries. If you are still having problems after minimizing your loads, then you could get your batteries load tested. The other potential problem is that you are not fully charging your batteries if there is something wrong with your alternator and regulator but this is unlikely, they tend to work or not.

I have had it drain twice now in less then 42 days so either I have an intermittent drain problem or maybe something wrong with a battery. I do have a rebuilt alt. (couldn't afford to do it right at the time) but it always shows a strong charge according to the dash.

 

[WestTN]

I don't know if the 12V trucks have a IOD (ignition off draw)fuse but the 24V's do. This fuse supplies the radio station memory, the computer system and probably a few other items. Those draws need to be considered as well as the accessories you have added.

 

[WTBurke]

Mark

At 18 milliamps it's in the correct range of trickle discharge to support the ECU and radio with clock/memory program. As I mentioned I believe mine was around 15 mills and this is in the ballpark. No problem on the test for a half amp draw on the ten amp scale. I too use the 300 milliamp scale as I wanted to see the most sensitive measurement for the small devices drawing current.



I would encourage you to disconnect the parallel connection between the two batteries and examine the static state of each battery by itself. You may find one or the other has a soft-cell and this will tax the healthy battery.



I also have found during non-operation that the ol'Cummins will really put a load on the discharged state of the batteries. Twice in the past I have had to slow charge overnight in order to start my truck after hibernating without trickle charge for over 6 weeks time. Your photovolactic panel maybe just the ticket to keep the charge level at a correct float and compensate for the trickle-draw of the electronic devices.



All of your measurements and calculations are darn good for a guy who claims to be challenged in this aspect of maintenance and research



Cheers,

William

 

[CumminsPower98]

Yes my truck does have the IOD fuse. With all my additions unhooked the truck was showing only 5. 0ma after sitting long enough for the seat belts to power off (30 min) so it would appear that the truck is fine as long as there isn't an intermittent problem. Next I will test the batteries.



One more question and that concerns the solar panel. This one is pretty big for the job but I think I'm still okay. Its rated at 19 volts and 35 watts at full power. So if I go 35/19 I get 1. 84 amps, which I'm guessing is higher than a normal float charger would put in. The thing to consider though is that the panel is not in full sun or at the perfect angle where it sits on the center console. The other thing is that its not putting any power in at night. I haven't tested its output where it sits. This would be changing all day anyway as the light changes. So do you guys thinks this would be okay to keep doing?



Thanks for all the replies!!

Mark

 

[Shelby Griggs]

Does your solar panel have an integrated charge controller? If not, you probably want to add one for long term life of the batteries. I have a solar setup on my Wells Cargo trailer for running equipment and battery charging, I have two deep cell Optima batteries (1500 CCA) that I keep charged, BUT I have twin 80W panels on the trailer roof.



On my truck, I have noticed I have a drain too, more than about two weeks of setting and it cranks real slow, you better hope it isn't too cold! My Optima's in the truck are coming up on 5 years, so maybe they are just getting weak?



SHG

 

[CumminsPower98]

No built in charge controller on my panel. I have wondered if I needed one but since it puts out so little I figured I would probably be okay considering the stuff mentioned in the last post (not full sun and proper angle) and the fact that its feeding two batteries.

I think I got about 4 years out of my last set of Optimas but I have seen others go up to 7 or 8 years. I did take the top off of mine many times while running my laptop when I was out driving and ran them dead at least twice so I figured maybe that shortened their life. I didn't want to treat my current ones this way so I bought a couple Interstate deep cycles and put those in the back of the truck to run the computer off of. This way I could go all weekend or more while sitting at truck stops (log book restart) without starting up and idling for power. During the day I would plug the batteries in and let them charge while driving and this worked very well.

 

[lukeduke96diesel]

power drain

I have a 1996 12 valve diesel 1 ton. I have a power drain problem so i measured the draw with my multimeter and it is about . 175 so i started pulling fuses and when i pulled the I. O. D. fuse out the drain went down to spec. I don't understand fully but I know the i. o. d. pulls some amps but not that many. Any help I would appreciate it a lot.

 

[Technoheck]

Funny how these problems seem to crop up in groups... .
@lukeduke- Do you have a stock radio in that truck?
I have been having the problem mentioned with my 96 2500 4x4. It has the infinity system in it. Since I replaced the stock radio with a Kenwood with Bluetooth for the handsfree, the truck will drain out in a couple of weeks max. Bought the radio from Crutchfield, their tech had me pull what I now know to be the IOD fuse and the problem went away. Still testing but I think that narrows it down considerably. Will post when I resolve it- for now have a battery tender jr hooked up when it sits. With diesel at $3. 89 a gallon in Kalifornistan, the truck has been sitting a lot lately.

 

[lukeduke96diesel]

Thank you for your support. I do have a aftermarket radio and a amplifier and a sub in the rear seat. My cd player is a sony xplode. I too just pulled out the I. O. D. fuse but do you leave it out wile u drive your truck? Plus I if u do that then your radio won,t remember the time or stations will it cause the power to keep it going is through the i. o. d. right. I don't know what to do with it right know but I know I already have a battery tender on it. I just don't like that drain. It is draining at . 175 and I really don't know how much that could be but when I turn on a small light it goes to . 825 so the . 175 is not that much but it is still bugging me to know that something is not right. If you hear any more please let me know and I will do the same. Thank you.

 

[Technoheck]

I was told by the radio representative that some low power draws are higher than they are supposed to be and require the radio be returned for service. I have not gone that route yet, because I have not isolated the radio to be the problem. Evidence that the radio is the issue is still circumstantial at best, however the problems started pretty much together, so connecting the dots was easy. No I do not drive with the IOD unplugged, though in the 96 truck you could I guess but would not have some functionality of internal devices. An earlier poster said that it also feeds the computer, so there might be issues there. The battery tender is a stop gap until I get time to work out the problem- unfortunately a battery tender and extension cord carried in the truck has lowered the priority a little... . I do need to get busy on this. Yes, please keep in touch with your findings. Thanks

Heck

 

[DODGEDADDIE]

So if this IOD fuse is making the batterys draw down... .

So do we just put in a NEW one or are there OTHER ISSUES going on. .

Sorry I'm coming in late on this.



But I'm having same issues on 2 new 1000 amps batterys



Mike In Maine

 

[cgoder]

Me too. . Same promblem#@$%!

 

[Road Dog]

IOD = Ignition Off Draw. Basically its for all the things that require power all the time (like the clock in the radio or the seat belt controller). I think its pulled after the truck leaves the factory so the battery stays charged as it gets transported and stored. It will always have a small draw (milliAmps) and if the draw is larger then you have to start unplugging other fuses to isolate the problem.