Parasitic Draw
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Laughing Gas
Joined: Jan 2006
Posts: 1,098
Likes: 11
From: Minnesota
Parasitic Draw
With the hood open and the hood light bulb pulled out, has anyone measured the parasitic draw on their truck? I checked mine because it appears my battery is slowly discharging if the truck sits 3 or 4 days. I got 0.24 amps which seems in line with running the clock memory and the computer. I have a feeling the battery is shot even though it is only 3 years old. When I bought the truck it had a ton of yellow fuzz on the terminals. That is cleaned up and with it running I get about 14.35 volts at idle so it is charging. Just curious what you guys think about the 0.24 draw??
Hotshot
Joined: Jul 2005
Posts: 11,932
Likes: 181
Two 60 watt head lights would draw 120 watts or 10 amps. Thats about 50x what your parasitic draw is. I would guess the head lights would draw a battery down pretty good in 8 hour day. 50 x 8 would be 400 hours or 3 weeks ? I would think you could set a couple months without charging the battery so your draw might be a little high.... that being said, we have a 2002 EXP that will kill the battery in 14 days if i dont run it once a week to recharge. I have found some corrosion on the starter terminal (when i changed starter this week) and im hoping that is some of the small current loss.
Lead Driver
Joined: Sep 2006
Posts: 7,907
Likes: 143
Set up to measure current flow.
Then remove the alternator power lead.
If the current draw goes down the alternator rectifier stack has a shorted diode/s and will drain the battery over time when setting but still allow battery charging after starting the motor..
Good luck.
Then remove the alternator power lead.
If the current draw goes down the alternator rectifier stack has a shorted diode/s and will drain the battery over time when setting but still allow battery charging after starting the motor..
Good luck.
Fleet Owner
Joined: Mar 2012
Posts: 26,228
Likes: 4,152
From: Near Cal. Avenue
XX have UR battery tested. A good battery will easily restart UR motor 10 times in say 5 minutes. If it runs down fairly quickly that is probably UR answer but an alternator test will also be good.
Cargo Master
Joined: Apr 2003
Posts: 3,476
Likes: 224
From: Frequently frozen MN
I used to read stuff that said 0.1 was about the limit, but things have changed.
One thing that you might try though is to leave it set up for around an hour -- some stuff 'goes to sleep' after a while.
I checked some specs and F150s have something like a 72 amp hour batt -- that's around 12 days. (72/.24 =300).
But, you won't get all of that out of the battery because the voltage will get too low.
So, if it doesn't drop in an hour, it might be worth doing that alternator trick mentioned above. Also, you could pull fuses one at a time to see if there's an issue with any particular circuit.
Good Luck,
hj
One thing that you might try though is to leave it set up for around an hour -- some stuff 'goes to sleep' after a while.
I checked some specs and F150s have something like a 72 amp hour batt -- that's around 12 days. (72/.24 =300).
But, you won't get all of that out of the battery because the voltage will get too low.
So, if it doesn't drop in an hour, it might be worth doing that alternator trick mentioned above. Also, you could pull fuses one at a time to see if there's an issue with any particular circuit.
Good Luck,
hj
Hotshot
Joined: Jan 2004
Posts: 19,768
Likes: 1,082
From: St Louis
Just curious what you guys think about the 0.24 draw??
Do NOT perform any other current draw tests except, perhaps the alternator disconnect test above, until after the timeout interval as they will be erroneous.
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Laughing Gas
Joined: Jan 2006
Posts: 1,098
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From: Minnesota
Thanks guys for all the input. I was wondering about that battery saver thing and testing....thanks for that. Maybe I am expressing my number wrong. 0.24 was the reading between the negative cable and the post with my meter set to mA on the 20mA scale. Is that .24 of one milliamp or .24 of one amp? There are 1000 milliamps in an amp...so I would assume that is very low?
Anyhow....I took the battery back. They put it some machine to test it and the first test showed it was bad. It had a 3 year 100% warranty so they grabbed one off the shelf and I was on my way...great no hassle service. I had 2 weeks left on that warranty...I am NEVER that lucky...LOL.
When I did take the battery out the bottom of the tray was solid white with fuzz. I assume there was some event maybe with the PO where maybe they over charged it or whatever... All is cleaned up and the new battery in. Hopefully that is the end of this...I'll post up if the problem comes back
Thanks again for all the help
Spotty.
Anyhow....I took the battery back. They put it some machine to test it and the first test showed it was bad. It had a 3 year 100% warranty so they grabbed one off the shelf and I was on my way...great no hassle service. I had 2 weeks left on that warranty...I am NEVER that lucky...LOL.
When I did take the battery out the bottom of the tray was solid white with fuzz. I assume there was some event maybe with the PO where maybe they over charged it or whatever... All is cleaned up and the new battery in. Hopefully that is the end of this...I'll post up if the problem comes back
Thanks again for all the help
Spotty.
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Laughing Gas
Joined: Jan 2006
Posts: 1,098
Likes: 11
From: Minnesota
Not really related but the the time out interval must be what sets off the aftermarket remote-start alarm exactly 40 minutes after it is set. I just don't lock it with that FOB and then all is OK.....but I bet that is it ( It is a Viper 550-ESP).
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Threadjack complete...
Fleet Owner
Joined: Mar 2012
Posts: 26,228
Likes: 4,152
From: Near Cal. Avenue
Vipers can be a real PITA with all kinds of weird stuff happens. Doors unlock, windows turn down that sort of thing. Even start in the garage all by themselves. Just saying any more problems unhook it or shut it off at the toggle switch.
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