Discharging Battery Options

[mrholland2]

So, my second new battery since October is dead as a doornail and my little charger says "Check". I didn't drive my car for about 5-6 weeks. The last several times I drove it, it started fine, charged fine, no idiot light.

What have I done? or what has it done? to the battery? I'm not sure NAPA will be thrilled to give me another one, but I will try in the morning.

(IMG:style_emoticons/default/WTF.gif)

[bulitt]

If you are not driving the car frequently then you have answered your own question as to why the battery is dead. Pick up a trickle charger or battery tender and hook it up to the battery when it is sitting. They sell for as little as 10$ at Harbor Freight and most auto parts stores sell them.

If you are driving frequently and for a long enough time then your alternator should be keeping the battery charged. If you are driving and the battery is dying you could have a bad alternator, bad diode in the alternator or some other issue draining the battery that you will have to isolate.

[mrbubblehead]

sounds like you might have an amperage draw somewhere....have you checked?

[6freak]

If you are not driving the car frequently then you have answered your own question as to why the battery is dead. Pick up a trickle charger or battery tender and hook it up to the battery when it is sitting. They sell for as little as 10$ at Harbor Freight and most auto parts stores sell them.

If you are driving frequently and for a long enough time then your alternator should be keeping the battery charged. If you are driving and the battery is dying you could have a bad alternator, bad diode in the alternator or some other issue draining the battery that you will have to isolate.

my car sits for 3 months and starts right up! well it turns over anyway for a second then fires, pops and spits coughs ,smokes (IMG:style_emoticons/default/lol-2.gif) .sounds like you have something drawing down the battery...jmo ..good luck
MikeC (IMG:style_emoticons/default/smile.gif)

[mrholland2]

sounds like you might have an amperage draw somewhere....have you checked?

How do I test for this?

My bigger concern is that my battery charger says the battery is "bad" and did it with the previous battery too

[underthetire]

New batteries suck. I had one short out in six months. I have since switched to exide and have no problems. Napa won't be suprised, trust me.

[mrbubblehead]

sounds like you might have an amperage draw somewhere....have you checked?

How do I test for this?

My bigger concern is that my battery charger says the battery is "bad" and did it with the previous battery too

you wil need a multi meter for this job. they are pretty cheap now a days. or borrow one....

disconnect the clock.

now with the car dead quiet/ everything off, like you are going to let it hibernate. loosen and lift the negative battery terminal. set you multi meter to read amps, the black probe goes to the negative batt cable that is disconnected and the red probe goes to the negative post on the batt. if the multi meter reads any current at all, you have a draw some where....

[mrholland2]

sounds like you might have an amperage draw somewhere....have you checked?

How do I test for this?

My bigger concern is that my battery charger says the battery is "bad" and did it with the previous battery too

you wil need a multi meter for this job. they are pretty cheap now a days. or borrow one....

disconnect the clock.

now with the car dead quiet/ everything off, like you are going to let it hibernate. loosen and lift the negative battery terminal. set you multi meter to read amps, the black probe goes to the negative batt cable that is disconnected and the red probe goes to the negative post on the batt. if the multi meter reads any current at all, you have a draw some where....

Cool, I do have a multimeter somewhere around here. . but I need to get the battery charged/replaced first. . . thanks

[Tom]

If you don't have a multimeter, look for a spark when you hook the negative terminal back up. If you have a spark, you have a draw on the battery. Is yours L-jet? One member had that problem and it lead to the dual relay.
Tom

[mrholland2]

If you don't have a multimeter, look for a spark when you hook the negative terminal back up. If you have a spark, you have a draw on the battery. Is yours L-jet? One member had that problem and it lead to the dual relay.
Tom

Carbs. I found a test light. When I use it, I get a a glimmer for one second, and it fades out and stays out.

Wouldn't a "real" drain keep the light on? For now, I'm disconnecting the neg cable when I leave the car parked. I'm betting it has to do with the aftermarket stereo the PO "installed".

Nice weather, I got to drive it today. Was a blast.

[mrbubblehead]

If you don't have a multimeter, look for a spark when you hook the negative terminal back up. If you have a spark, you have a draw on the battery. Is yours L-jet? One member had that problem and it lead to the dual relay.
Tom

Carbs. I found a test light. When I use it, I get a a glimmer for one second, and it fades out and stays out.

Wouldn't a "real" drain keep the light on? For now, I'm disconnecting the neg cable when I leave the car parked. I'm betting it has to do with the aftermarket stereo the PO "installed".

Nice weather, I got to drive it today. Was a blast.

pull the fuse for the stereo and see if your still getting a draw....

[Mike Bellis]

Remove the negative battery terminal. Connect a test light between the battery cable terminal and the negative battery post. If the light "lights up", you have a drain. remove and replace one fuse at a time until the test light "goes out". That fuse will be causing the draw. Check to see what works and does not from that fuse. You will find your draw.

Happy Hunting! (IMG:style_emoticons/default/smile.gif)

[Spoke]

Buy a multimeter. You can get one for as little as $20 and an excellent one for $100. You will use it many times on your 914 and be thankful you have it.

Do you really think this will be your last electrical problem on your 914?

[mrholland2]

Buy a multimeter. You can get one for as little as $20 and an excellent one for $100. You will use it many times on your 914 and be thankful you have it.

Do you really think this will be your last electrical problem on your 914?

I have one. It is just hiding amongst a home improvement project right now.

[Spoke]

Put it on Amps. Connect in series with the negative lead. Reason for using the negative lead is if the negative lead touches chassis it will not spark and kill your meter like the positive can.

If you have high current like greater than 100ma or so, something is wrong. Try disconnecting things one by one until you find the leak. Remove fuses one by one.

[rgalla9146]

Put it on Amps. Connect in series with the negative lead. Reason for using the negative lead is if the negative lead touches chassis it will not spark and kill your meter like the positive can.

If you have high current like greater than 100ma or so, something is wrong. Try disconnecting things one by one until you find the leak. Remove fuses one by one.

The test light and the " spark " method are effective tests. A multimeter is not necessary and can be misleading. Better used for other issues. As described remove fuses one at a time until the lamp goes out or the spark stops when you connect/disconnect the NEG batt. terminal. Clock and after market systems are likely suspects. Double relay draw is new to me. Was it bypassed ?

[mrholland2]

Put it on Amps. Connect in series with the negative lead. Reason for using the negative lead is if the negative lead touches chassis it will not spark and kill your meter like the positive can.

If you have high current like greater than 100ma or so, something is wrong. Try disconnecting things one by one until you find the leak. Remove fuses one by one.

The test light and the " spark " method are effective tests. A multimeter is not necessary and can be misleading. Better used for other issues. As described remove fuses one at a time until the lamp goes out or the spark stops when you connect/disconnect the NEG batt. terminal. Clock and after market systems are likely suspects. Double relay draw is new to me. Was it bypassed ?

Clock is currently non-functional. The weird thing with the test light is that it doesn't stay on. It goes off almost instantly.

[Spoke]

The test light and spark method have inherent drawbacks that limit the accuracy of the test.

In this test, you want to open one of the leads to the battery and measure the current with a low resistive element. The test light is used to measure voltage and will not give a quantitative result on how much current is flowing.

The spark method is not accurate either because the amount of spark observed depends on how the 2 conductors are placed in contact. Also, there will always be a spark even on a properly functioning auto as the wires and parasitic capacitance of the wire harness and electronic components are charged from 0v to 12v when the terminals are touched together. My 71 914 always sparks when I reconnect the battery and it does not discharge the battery even with the clock always running.

The multimeter in the current setting will provide a very low resistive connection which will not disturb the system while you test it. The total current could be a combination of several items like the stereo, clock (if installed), and other leakages like a bad voltage regulator or alternator.