Van battery dies if not ran for 2 weeks
- Thread starter Amom2all
- Start date
Usually, a problem like this is fixed by replacing the battery. If not...
1. Does the battery fully charge when you drive it? It could be a weak alternator failing to properly charge the battery. Test the system voltage while running, usually it should be around 14 V plus or minus.
2. It could be a parasitic load on the battery. This can be a problem with the electrical system. Or it could be a modification or device that has been added to the electrical system. If this is the problem, @Silver 's advice can help you find where it is.
1. Does the battery fully charge when you drive it? It could be a weak alternator failing to properly charge the battery. Test the system voltage while running, usually it should be around 14 V plus or minus.
2. It could be a parasitic load on the battery. This can be a problem with the electrical system. Or it could be a modification or device that has been added to the electrical system. If this is the problem, @Silver 's advice can help you find where it is.
Easier just to probe the fuses and see which one is drawing with the key off/doors shut
Not really.
All it takes is one person to forget and you've nuked another battery.
This is the way. Shouldn't take long to find the offending circuit.
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Yes and no. For sure if you dont use it you are worse off.
2 weeks is a pretty long time but still something is drawing more than spec. Have to do an Igntion off draw test with a amp meter inline on neg cable/ post as a starting diag point . Can also use a IR thermal imaging camera and see what circuit is creating heat in the fuse array
New battery doesn't mean good battery. Next time you plan on parking it for a few weeks, disconnect the battery. When you are ready to use it again, connect the battery to see if it will start it. If yes, battery is good. If not, it's bad.
Close, you put an ammeter inline
Please explain what you mean. How do you check current draw by probing fuses?
Pull a fuse, put each lead of a meter on the clips when set on DC Amps-any amperage indicated means parasitic draw. BTW, solar battery maintainers do NOT need to be disconnected when driving, just have to put something on the back to stop it from sliding around the dash, they have a diode to stop the alternator from back feeding it. I’ve had keyless entry pull a battery down in 2 weeks, and a V10 takes some power to start.
Just a guess, radio, seem to remember a couple and the display staying on after the vehicle was shut off.
Do you have a security device on it. That may be using more power..
No. That will just awaken a module and give a false reading. Leave the fuse in and touch the probes on both sides of the fuse with the meter on the mV setting. Should read 0 if no current is flowing.
How would that work? A (good) fuse is a dead short, should be no voltage drop across it at all?
Actually, fuses have a very small voltage drop across them WHEN a current is flowing through them. This is because they do have a resistance ( though it is very low ).
Most automobile fuses actually have two small spots where you can apply a millivolt meter to look at this voltage drop.
The problem can be that sometimes some systems go to sleep and awake every once in a while for only a brief time. If that is the case looking for voltage drop ( actually millivolts drop or rarely even lower such as microvolts drop ) across a fuse when a current is flowing can be hard to find because there are a lot of fuses and if you are only looking at each one for a brief time and the circuit is sleeping when you look across its fuse, then you will not see anything.
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Another good diagnostic tool is divide and conquer. Simply remove half the fuses and let the vehicle sit and see if the problem goes away. If it does then the problem is in a circuit related to the fuses removed. If it does not the problem is related to a circuit that still had fuses. Then divide the offending fuses again and again until you narrow it down to one. This is a very slow process and it requires patience. But if you can not find the problem any other way, it is a troubleshooting process that almost always works. (How to you eat an elephant? One bite at a time.)
But be aware there are some circuits that are not fused. Such as the output of the alternator, and the starter.
Sometimes one or more of the output diodes of an alternator will go electrically leaky and conduct a small amount of current in the reverse direction. Usually this happens when someone abuses the alternator by jumpstarting a dead vehicle with the good vehicle running. The alternator of the good vehicle may put out too much current and damage one or more output diodes of its alternator. Usually this does not show up until that vehicle sits for several days. If the vehicle is used every day, it may not show up for years until sometime the vehicle is allowed to sit for several days.
Before doing any of this, now-days a good first step is to go onto an internet forum dedicated specifically only to that make and model of vehicle and post the year, and model, and even the trim level, and ask if there are any common reasons others have had this same problem.
My 07 Ram 1500 was killing the battery in a couple days. I checked the amps draw with my Fluke meter and it was 258 ma. Took out all the fuses and it was still there. Rapped on the boaed a couple times with the insulated handle on my screw driver and the current dropped to 28 ma. Must have been a carbonized bug that fell our.. No more issues
My 2009 F150 has been draining the battery since new. It has the magic Ford parasitic draw that seems to be a built in feature. It kills the battery in about 2-3 weeks. If I remember correctly, the battery was dead on the lot, when new. Shades of things to come.
Of course it is driven regularly, and only sits when we are ill or using another vehicle.
Of course it is driven regularly, and only sits when we are ill or using another vehicle.
