Hi Barthmobilers, I've noticed in the last 4 months my 2 chassis batteries (Breakaway) have been mysteriously draining on their own while the vehicle is parked. The batteries are less than two years of age, distilled water only and I charge them up completely when I return from each trip. I always keep the cables and posts clean. I do plug into shore power next to my garage but thats a seperate circuit anyway...right? I can't think of anything I've done in the last 6 months...actually I cleaned up my trailer wiring but it functionally works fine. Only two visible items that are ON is a digital clock over the doorway and a blinking alarm system LED..One thing that is different is recently (2 weeks ago) I removed the battery cables to clean the posts, etc. When I reinstalled the cables the alarm started blaring. After finally silencing the alarm, I noticed this LED on my dash is constantly flashing now. I'm guessing this is related to the alarm that I never use. But the batteries have been draining months prior to that anyway. Any suggestions on how to start the search for my battery drain/ leak?

Chances are your batts are good, but check them anyway. Charge them fully, and let them sit overnight with nothing connected. Does the voltage stay up? Hydrometer?

Put an ammeter in series with the ground curcuit. Note the reading. Pull the big fuse. Any change? Pull the smaller fuses, one at a time. Any change?

I don't know your circuit, so I can't get real specific here, but start tracing and disconnecting positive wires until the ammeter goes to zero. Then follow that wire until you identify where it goes. Solenoids and isolators can be trouble spots. This is a good opportunity to clean connections, too.

Good advice Bill..I don't think I own a ammeter but I will here soon.

quote:

Originally posted by hilarlee:
Good advice Bill..I don't think I own a ammeter but I will here soon.

Take a look at one Sears sells. It is a digital multimeter with clamp on reading of AC and DC current. Nifty critter.

Say Bill, when I got home I realized my Fluke 77 multimeter has ammeter functionality. I put the meter in series with 1 of 2 RED load circuit cables. I forgot you said to use the grounded side...is the POS side method ok too? I set the meter to the 300mA DC Amperage setting and got a reading of 99VDC. I started looking for fuses to check and noticed the ignition key in the "accessory" position. How long has it been like that? I'm guessing maybe for some reason I started turning the key too far to the left to shut everything off? Anyway checking the meter it now reads "0".
Next I checked the second heavy RED Load cable and I get a reading of .13VDC...Is that significant? Again this is with the meter set at 300mA. It suddenly got dark so I havn't traced where these leads go. My guess is the second cable goes to the starter and the first cable goes to the front left power dist. panel?
So waaatttaya think of that .13VDC? I'm hoping I had brain fade and the key left in the "Accessory position" was the culprit. I took some readings and will keep taking readings over the next week or so..

.13 DVC doesn't tell you much. In any event, the issue here is current, as that's what discharges batteries. But I think you're on to something with putting the key into the ACC position - that can lead to a lot of discharge issues.

Well, Larry, if you have a Fluke 77, you are getting accurate readings. I don't know how you are reading it, but I can send you the manual for the meter if you wish. That volt reading on the amps setting is confusing to me.

It really makes no difference where you measure current, positive or negative from the battery, as current is the same in a series circuit. I just said ground because it is often simpler, due to fewer wires.

At any rate, it sounds like you found the problem. I use a flashing red LED as a reminder for things I am likely to forget. Like the water pump or my electric radiator fan.

Yeah Bill, I don't know why the display indicates VDC either. I tested the circuit with the RED probe in the 50A position first....then the 300mA position. I have the meter set in the A-DC Current position too..This morning I isolated each of the two batteries so one battery is feeding one circuit and the other battery feeding the other. So I'll keep monitoring the voltage. I hope it was just brain fade and I turned the ignition key to the wrong position the last few times I parked. Either way, I learned a little bit more from you guys...

The easiest way I have found to locate a power draw...

1)Disconnect the ground cable and try to use (light) something. If nothing works for that circuit then step two...

2)Hook up your test light clip to the ground stud on one side and touch the cables with the test light pointed.

3)If you have no drain then the test light will stay off and you have bad batteries... If the test light comes on then you have a current draw condition.

4)trace out current draw by disconnecting all memory leads for anything that needs to save info... like a radio preset, clock memory, alarm system and recheck the test light. If it goes off then your done and there's no real power draw. If it stays on then start disconnecting fuses until the test light goes out. Reinstall all other fuses that will not relight the test light.

Thoses fusses that are out is the ones that are drawing power. Recheck by plugging in each fuse that's drawing power. The brighter the light the more volts it's drawing. A radio clock will give you a real dim lamp but an interior light will really light up the test light.

It works for me...

DO NOT USE AN LED TEST LIGHT FOR THIS!!! An led test light is easy to light up low voltage draw and hard to tell by looking how strong it's drawing.

I do this in the field all of the time to trace out voltage draw down conditions.

I have been snake-bit by using a test light in series with a load. A bulb does indeed work fine in a certain range of current draw, depending on the bulb. But a higher load turns the filament into a fuse, and it lights up for only a millisecond. A lighter load turns the filament into a conductor, and it doesn't light up at all.

If you unhook the battery cable and a spark jumps out the cable and your arc welding with it then you'll have a problem.

Hilarlee doesn't seem to be talking about a 1-2 hour power draw down but something that seems to take a little while.

Chances are they will find a relay sticking, light in compartment on, switch on etc...

I too have been bit by using the test light method. If a relay powers down and then disconnects thru the magnetic coil there's might not be enough to pull it back to draw down again until you hook the batteries back up.

Most test lights have enough of a filiment to allow this to pull the coil back, mine does.

Use an ammeter if you have one. Try this if you don't.

There is one thing - I caught it before I drained the batteries - I left the basement lights on once - and there's none in the battery compartment...

quote:

Originally posted by Rusty:
- I left the basement lights on once -...

One of my pipe dreams is a mercury switch on every basement door for a compartment light. Or a plunger switch like a refridgerator.

WOW, all this great troubleshooting advice! After isolating the two chassis batteries from each other but leaving each battery connected to its respective circuit, here are the readings after one week.6/27 12.74 12.72
7/5 12.43 11.90 The reading of 11.90 is from the battery wire going towards the engine compartment. I guess I'll take out the test light and start poking around the maze...I have a suspicion it has something to do with the stupid alarm system..

I disconnected the alarm system and tested the circuit for draw with my meter in series with the discharging battery positive post and the load cable. I still show a draw of 10.2 VDC. The battery voltage is 9.4VDC with no cables attached. So how can there be a 10.2VDC draw? The battery that is draining supplies the starter circuit. I confirmed this by following the positive battery lead down to the starter. I checked all the fuses on top of the dash and in the lower left front breaker compartment. No power found. The left front compartment is dead with the exception of power going to the main bus relay. So......any more suggestions where I should check? BTW, the second chassis battery has been isolated from the draining battery and continues to hold a 12.6VDC charge.