I have been having a bitch of time with my battery draining while it's parked. At first I thought it was because I had an old Hawker Odessey PC 980 mini battery.

Last night I had to jump-start my car so that I could get home from work. I have resorted to carrying my old full-sized car battery in my trunk! Talk about retarded. Anyway, after I drove home, about 30 mins., I checked my mini-battery's charge status and it was fully charged. I then unhooked the negative terminal(s) and let it sit over night. This morning, I reconnected the battery. It started right up. It cranked pretty stong, too.

So this leads me to beleive that there is an open circut or some sort of battery leak...

How can I trouble shoot this? Is there away to disconnect the factory alarm? I don't know if there is a specific fuse for the alarm. Does anyone have any ideas? Anyone else experience this?

 

I had an issue with a hood alarm sensor draining my battery when the hood was open at night (in the garage). If you are leaving your hood open, that could be the problem.

 

You can measure minor current draw with most multi-meters easily.

Configure your meter by plugging the + lead of the meter into the Amps/Current socket instead of the usuall Volts/Ohms socket.

Pull the positive battery cable off of the battery.

Connect the + lead to the + battery terminal and the - lead to the + battery cable, connecting the circuit.

Look at the meter. This is how many (milli)amps you're drawing with the car off.

You can now start pulling fuses of suspect curcuits and look at the meter. When it drops to zero you've found your drain.


I've got the PC-925 also and with the stock alarm it's fine. I had a keyless entry system that would kill it over time though, so I pulled it off. It's likely a glove-box light or the constant power from you stereo (is it aftermarket?)

Oh, and don't fire up something that used more amps than your meter can measure. (radio, lights, horn, starter..) it'll zap the meter.

 

First, be aware that constantly sparking the battery connection (connecting it, then disconnecting, then reconnecting in rapid succession) can damage electronics. Be deliberate when you connect and disconnect the battery when you follow the method below. One good connection, one good disconnection, wait a few seconds between when you are testing.

To find the thing, use a multimeter on mA scale (you can pick up a multimeter for under $20 at places like Radio Shack). First, turn off the interior lights (don't forget the hatch light). Disconnect the battery -ve terminal, set your multimeter on its' highest DC current scale, and connect the multimeter - +ve meter lead to the car cable and -ve meter lead to the battery -ve terminal (in series with the battery -ve lead). Just touch it quickly to see if it will pin the meter. If it does not, switch to a lower scale and try again. Once you get it reading "on scale" you can go around the car and manually depress alarm and door light switches to see if they do anything. You can also wiggle cables etc. looking for intermittant shorts. Be aware, the ECU will draw around 10mA, the radio a few mA, the alarm a few, and some aftermarket stuff will also draw a few mA. To drain a PC 980 overnight, you will have to have a 100mA or greater draw. The old battery may be going (lost capacity with age) and the normal drain of the above stuff may be enough to kill it. It doesn't take much to start a rotary engine, so what you think is a "good" battery may be toast.

 

i had the same problem as you are having. i took the battery to have it "checked" and the shop insisted it was good. after trying everything and having no luck i just said f*ck it and bought a new battery. problem was gone. this has happend to me in a few different cars. now if i ever have a battery drain problem i just go out and buy a new battery. this method has yet to fail as a solution to my battery drain problems. im not saying that this is the most efficiant solution but it has worked for me so far food for thought i guess.

heath

 

Thanks guys this is all good info. I will head to radioshack after work. I mean after I jump-strat my car again...and then drive to Radio Shack.

If all else fails, I will most likely by a drycell battery and install it in side the cabin. Although I hate to do that.

 

Fan Relay Switch will drain your battery

 

any anyone recomend a good drycell for behind the seats? also, is there any risk of battery fumes etc, or is that eliminated since it is a drycell.

ps is drycell the same as a "glass mat" battery like in the miatas trunk? the miata one has a tiny vent tube though that goes through the trunk to the ground

 

Onr thing you can do to isolate electrical drain is to hook the voltmeter between the positive terminal on the battery and the actual positive connection (just undo that nut that bolts down the fuse box that's attached to the battery). Set it up so the meter is reading current (not voltage, usually different connection points to the meter). Then check the current draw. Then begin removing fuses until the current draw stops. This isolates the draw to a given circuit. Then go hunting

 

Thanks!

 

There was a problem with the glove box light on early models. I think the light was wired direct to battery and when the glove box loosened, the light stayed on. Check it to see if there is a problem.

There was a recall on it originally.

Tim

 

I don't think mine stays on. I'll have to check that.

 

I started having the same problem after adding a few mods (probably the fan switch). When I added the front mount and did a battery relocation I had kill switches added. After proper cool down I use the kill switch if the car is going to sit for any length of time. Problem gone. Plus killing dry cell batteries would not be cool as they are not cheap. I just can't use the trip meter for fuel mileage, but this is an FD, who cares about fuel consumption.

 

I had the glove box problem. Light would stay on all the time and I would have to keep jumping my car whenever it sat for an extended amount of time.

 

I'm putting money on the fan switch if you have one. Just make sure, when you shut the car off, that u turn the switch off. My car almost didnt start after sitting for a week and I realized I'd left the switch on. Its the only possibility given everything else on my car is stock and until I had this switch, its never exibited the problem.

 

I have an IC fan but it's wired to a "switched" power source. I.E. only hot when the ignition is on.

 

This sucks! I can't seem to figure out the problem. I just broke down and spent $80 on a new Odessey PC680 battery. Maybe mine is just dead and won't hold a charge.

Another thing Wrong that I noticed is that my factory alarm no longer works. I think it stopped working right around the time I had the PFC installed along withmy new motor...

I just needed to vent!

 

another source of slow battery drain is a bad diode in the alternator. The battery will charge normally but when you shut down the battery will discharge through the charging circuit

 

the pc 680 will only hold a charge for a few days if you don't drive your car. If i let my car sit for 3 days, the pc680 will be almost dead.

 

"darkside7: the pc 680 will only hold a charge for a few days if you don't drive your car. If i let my car sit for 3 days, the pc680 will be almost dead. "

Mine used to be able to sit for almost a couple weeks. But now it won't a night in the garage. I have been driving it much shorter distances, maybe 30 min. drives here and there... Th ebattery may be old. Or I have a much bigger issue. I just want it to go away. I hate having to jumpstart my car everytime I want to drive it. It's embarrasing.




"R. Gambino: another source of slow battery drain is a bad diode in the alternator. The battery will charge normally but when you shut down the battery will discharge through the charging circuit"

How can I check if this diode is bad?

 

The easiest way is to just disconnect the alternator overnite, if the battery stays charged you may have found the problem.
Next step is to put an ohm meter between the alternator terminal where the battery was connected and ground. Resistance should be infinate, if not the battery has been draining to ground through that circuit.

 

Update: It was the battery. It was a pretty old Odessey PC-680. I ended up buying one off ebay for $80 shipped and the car works fine now.

I thought that the old one was still ok because it would recharge and be able to start the car after that. It just wouldn't be able to "hold" that charge for very long. That led me to believe that I had a current drain issue somewhere.