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Electrical help: Draw on a truck

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Jay G.
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Posts: 374
Joined: Fri Sep 21, 2001 4:00 pm

Electrical help: Draw on a truck

Postby Jay G. » Sun Dec 27, 2009 4:53 pm

Hello all!
My own personal truck is a 99 ford explorer xlt. I have 3 CDM1550's and a bunch of lights installed, NONE of which stays on when the car shuts off.
I have been experiencing a dead battery too often lately, and want to make sure its not something aftermarket or just simply a bad battery. I just went fuse by fuse on all the aftermarket stuff to find NOTHING drawing over .04amps when the truck is off. Im pretty happy that this is normal.
I then disconnected the battery and put my meter across, to find that the whole truck is drawing .38 amps with the truck off. Is this normal or is there something else like from the factory which is drawing too much.

Any thoughts??

Thanks & Happy Holidays to all!
Jay Goldmark, EMT
Ex-Captain, Woodmere Vol. Fire Dept.
Fire District Communications Supv.
KC2ZHI Amateur Radio Operator
Licensed Master Electrician
Owner, Top Class Electric, LLC.
Woodmere, Long Island, NY


"Enjoy Life, it's not a dress rehearsal !!!"

************************************************************

tvsjr
Posts: 4113
Joined: Fri Nov 28, 2003 9:46 am

Re: Electrical help: Draw on a truck

Postby tvsjr » Sun Dec 27, 2009 5:10 pm

You're on the right track... no, 380ma isn't acceptable. Think about it - a car battery is about 50Ah... 50Ah / 380mAh = 131 hours to battery exhaustion. Considering vehicle starting demands, you'll have a no-start condition long before the battery is totally exhausted.

So now you need to figure out where the load is coming from. Disconnect everything aftermarket and confirm the high parasitic load, then start pulling fuses and see when the load drops. Have a friend watch the meter, and pull each fuse then replace it. Sooner or later, you'll figure out which circuit is affected. Once you've isolated the problem, start tracking it down. A service manual may come in handy at this point.

You never know what weird things may cause problems. A friend of mine purchased my old Expedition... after enough years, he developed a water leak condition at the driver side of the windshield. The water will leak in and get into some of the vehicle electronics and create a similar condition... once it dries out, it goes away.

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jackhackett
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Re: Electrical help: Draw on a truck

Postby jackhackett » Mon Dec 28, 2009 6:50 am

When you measure the battery drain on an Explorer (and other Fords) you need to put your meter in line and let the vehicle sit undisturbed for about 45 minutes to an hour. There are some things in the electical system that don't shut off right away. If you disconnect the meter or open the car door it'll reset and you'll have to start again. If everything is working right you'll get an initial high current drain, 380 mA sounds about right, then it will drop off as the vehicles computers shut down.

fineshot1
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Joined: Wed Oct 12, 2005 5:13 am

Re: Electrical help: Draw on a truck

Postby fineshot1 » Mon Dec 28, 2009 7:31 am

Jay - how do you have the CDM1550's hooked up to power?

I have two of these in my van and experienced the same thing until I discovered I had them
hooked up improperly. I had the main power wire on each hooked up to +12V hot all the time
and was not using the ignition sense (pin 10) on the accessory connector. This caused both
radios to draw current all the time and on the weekends I would have a dead battery after
not using the vehicle for several days.

I had to change the main power wire hookups to +12V ignition switched to kill power to them
when the vehicle was not in use and that solved my problem. I also had to short the accessory
conn pins 7 & 9 to get the radios to power up function once +12V ignition on the main power
cable was present.
fineshot1
NJ USA

Jay G.
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Re: Electrical help: Draw on a truck

Postby Jay G. » Mon Dec 28, 2009 7:35 am

I think jack hit it on the head. I'm pretty sure it is the computers. I pulled all the fuses one at a time and lost over 210ma of draw from 2 of the computers.

Thanks to all!
Last edited by Jay G. on Mon Dec 28, 2009 4:46 pm, edited 1 time in total.
Jay Goldmark, EMT
Ex-Captain, Woodmere Vol. Fire Dept.
Fire District Communications Supv.
KC2ZHI Amateur Radio Operator
Licensed Master Electrician
Owner, Top Class Electric, LLC.
Woodmere, Long Island, NY


"Enjoy Life, it's not a dress rehearsal !!!"

************************************************************

tvsjr
Posts: 4113
Joined: Fri Nov 28, 2003 9:46 am

Re: Electrical help: Draw on a truck

Postby tvsjr » Mon Dec 28, 2009 4:29 pm

jackhackett wrote:When you measure the battery drain on an Explorer (and other Fords) you need to put your meter in line and let the vehicle sit undisturbed for about 45 minutes to an hour. There are some things in the electical system that don't shut off right away. If you disconnect the meter or open the car door it'll reset and you'll have to start again. If everything is working right you'll get an initial high current drain, 380 mA sounds about right, then it will drop off as the vehicles computers shut down.


Yep, very true... plus there's also delayed accessory where things like radios and lights stay on for up to 10 minutes.

thebigphish
Posts: 1477
Joined: Sat Nov 29, 2003 10:10 pm
What radios do you own?: AM/FM

Re: Electrical help: Draw on a truck

Postby thebigphish » Tue Jan 19, 2010 3:30 pm

Jay,

I'm on my fourth Explorer so I'm right there with ya on the parasitic loads issue... How old is the battery, and which alternator do you have in it? With 3 radios, plus stock equipment, plus lights...you're probably over the stock generation overhead figured into the system.
"How do you plan to outwit Death?"
"With a knight and bishop combination; I will destroy his flank.
" --Antonious Block


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