Meter reading for parasitic drain - how?

Wetstuff · 06-16-2019, 02:55 PM

From you guys and a nice mechanic on Youtube, I know I am hunting parasitic drain because the starting battery kept drawing down 'till it needed to be replaced. (my smart charger basically put: 'Don't waste my time again on this.' on the screen. I now have a new battery.

My meter is not like the one in the video, but I suspect I stumbled into the right setting? But, there appear to be two 'right' settings: 40A and 400A and they both 'read'.

....and do the leads themselves need to attach in some specific series to match the flow of current?

So, maybe you can fill me in with meter information before I go on the quest to find the source of my problem. Thanks.

Jim

https://www.youtube.com/watch?v=KF1gijj03_0

Wayne M · 06-16-2019, 04:23 PM

The amp meter needs to be in series by following the video, disconnecting the negative lead of the car battery and attaching the positive lead to the disconnected battery and the negative lead to the negative post. This completes the series connection. As stated in the video, make sure the vehicle is as you would exit and leave it. (Everything off, key removed.) Current (amps) is measured in series.

I am surprised that the meter you have registers 400A as that is one hefty meter. Are you sure it is not 400mA (Mili-Amps) 400mA is equivalent to 0.4 amps. Start out with the 40A. If your vehicle is pulling 40 Amp you have a big problem.

Jim, Winnebago typically uses the service battery to operate the steps. When I was having a problem with parasitic drainage I was leaving the step switch in the on position. Talking with Winnebago the explained that the current draw on the steps when the switch is in the "on" position creates a current drain that the trickle charge cannot keep up with. Once I left the switch in the "off" position I did not have a parasitic drain. Just some food for thought. Charge the battery to full and turn off the step switch when you leave the MH. Yes the steps will be out unless you can reach the switch through the screen door when it is closed. If the screen door activates the magnetic switch. I had a mid door entry and was able to use a short stick to push the switch to off.

BobC · 06-16-2019, 06:12 PM

I assume the photo is of your meter. I Googled the model # and see that it will read both AC and DC amps via the clamp. This greatly simplifies things since you only need to clamp it on the wire in question and there's no need to disconnect the wire. Note that one side of the clamp is labeled + and the other -. This is how it should be oriented. Were you to accidentally reverse this, I'm pretty sure it would only reverse the +/- sign of the resulting reading.

Your manual should have the instructions on how to do this. Here's a video that shows this (starting at about 1:35):

https://www.youtube.com/watch?v=KAgR_yLKp9g

Keep us posted on your progress.

By the way, the specs do say it has a 400A capacity.

Wetstuff · 06-17-2019, 06:46 AM

Thanks, guys... Ya, Wayne - it looks like I guessed right about the orientation, but another video, like Bob's video, points out: this is a 'clamp' meter for a reason ...I do not need to use the probes.

Wayne... I also suspect the automatic stairs. They have been a problem since the first month and have now completely retired. I am unable to work lying on my back (tho' I sleep that way) I lose blood pressure if I have to raise my arms to do work. So...

I have a young mechanic putting in the Trik-L-Start this week and will have him disconnect drive arm for the stairs to look for a method to make the steps manual.

Jim

BobC · 06-17-2019, 12:06 PM

If the issue is a parasitic drain from the steps, disconnecting the actuator arm isn't going to help. It's not the actual extending/retracting that's the issue, it's the current draw while on standby. It shouldn't be difficult to bypass the automatic stair switch and put in a manual one but you'll need to wire it so the existing on/off switch is out of the circuit and the step is controlled by a single actuating switch so that it's never on stand-by. I would thing the wiring diagrams would show this pretty clearly.

Wayne M · 06-17-2019, 12:23 PM

Yep, clamp amp meters work as long as they are capable of the small, or large, amperage.

I don't know the make and model of your MH, but is there a way to reach the step on/off switch when you exit? As I said, I was able to reach mine with a short 2 foot stick. I'd close the screen door and reach in through the opening and turn the switch off when it was retracted. My newer one I cannot reach the switch so I just leave it in the off position extended. I don't know if my newer coach has sufficient trickle charge with the steps on, and I'm not going to find out. :-)

Another alternative may be to just cut the power going to the step controller and splice in a toggle switch somewhere where it can be reached. This is assuming it may be the step.

p.s., the steps are controlled by the controller electronic current limiting switch. When a high state of current is reach the controller goes into high current state and stops the motor but the current remains.so the step is continuously drawing current.

At least, that is how I understand it and I'm just a layman on the subject.

Wetstuff · 06-17-2019, 01:20 PM

Roger - understand pretty much both. Using the meter as a 'clamp meter' vs. those pointy leads, I get a 6+ amps draw with nothing (I can see) going on. Step switch is in the OFF.

....I'll seek out the 'controller' also.

I plan to raise the gauge cluster cowling as that seems to be where at a lot of chassis (Workhorse P32) knife fuses are located ...over by the 110v converter, there does not seem to be anything listed that pertains.

Bob, I would rather do away with the auto open/close feature. If gravity will open it and it does not take a lineman to close it - I imagine I can rig a simple pin-lock I use on tractor implements. Thanks.

Jim

4x4van · 06-19-2019, 01:51 PM

There is no way that your steps are drawing 6 Amps in standby mode; something else is going on.

Wetstuff · 06-19-2019, 02:48 PM

4X, It seems the only immediate culprit. It has been disconnected and things are reasonably stable. I bought one of those cigar-lighter gizmos that monitor the voltage and adds extra USB outlets. It's gone from 12.6v to 12.4 as you see. That's over a 24hr period. Tomorrow my mechanic is going to install the shore power charger for the chassis battery and see if we can mechanically disconnect the steps.

I put in a new aux. fan and it works a charm! $40. The OEM's drive pin finally gave up; the motor would run but the blade was stationary.

Jim

JoeC · 06-23-2019, 04:21 PM

The steps and other loads must have a fuse or breaker somewhere. Use it to isolate loads.

JoeC · 06-23-2019, 08:59 PM

Battery voltage dropping from 12.6 to 12.4 overnight means nothing. Lead-acid batteries can drop voltage at that level without any load. If you really want to know what's going on with your battery, properly install a battery monitor using a shunt, where every load's return path has to go through the negative-connected shunt. I use the Victron BMS-712 for the coach batteries, and there are other similar type devices. Each load or circuit can be monitored after all are shut off through pulling the DC fuses and then enabling one at a time.

As for your starter battery, it can also be monitored but don't forget about the ECM (engine computer) and other electronic devices that may be active even though the ignition switch is off.

Mbarton557 · 06-23-2019, 09:17 PM

Quote:

Originally Posted by Wayne M

The amp meter needs to be in series by following the video, disconnecting the negative lead of the car battery and attaching the positive lead to the disconnected battery and the negative lead to the negative post. This completes the series connection. As stated in the video, make sure the vehicle is as you would exit and leave it. (Everything off, key removed.) Current (amps) is measured in series.

I am surprised that the meter you have registers 400A as that is one hefty meter. Are you sure it is not 400mA (Mili-Amps) 400mA is equivalent to 0.4 amps. Start out with the 40A. If your vehicle is pulling 40 Amp you have a big problem.

Jim, Winnebago typically uses the service battery to operate the steps. When I was having a problem with parasitic drainage I was leaving the step switch in the on position. Talking with Winnebago the explained that the current draw on the steps when the switch is in the "on" position creates a current drain that the trickle charge cannot keep up with. Once I left the switch in the "off" position I did not have a parasitic drain. Just some food for thought. Charge the battery to full and turn off the step switch when you leave the MH. Yes the steps will be out unless you can reach the switch through the screen door when it is closed. If the screen door activates the magnetic switch. I had a mid door entry and was able to use a short stick to push the switch to off.

I keep a battery tender plugged in at all times. The memory on the radio helps drain the battery. Once I plugged in the battery tender I have had no more problems. I plugged a plug strip so the BATTERY TENDER could reach. As long as you have 110v to it u are good while driving and overnight you r ok. It is when it sets up is when it drains down

Don G · 06-24-2019, 05:40 AM

You mentioned that your steps have completely quit on you. I had a class c that the steps stopped working and the problem was the pivots on the steps had rusted to the point where the motor could not move them any more. Could this cause a high amp draw if the steps are not completely closed. Try unplugging the step motor and see if the draw goes away.

RzRzRzR · 06-24-2019, 06:31 AM

Quote:

Originally Posted by JoeC

Battery voltage dropping from 12.6 to 12.4 overnight means nothing. Lead-acid batteries can drop voltage at that level without any load. If you really want to know what's going on with your battery, properly install a battery monitor using a shunt, where every load's return path has to go through the negative-connected shunt. I use the Victron BMS-712 for the coach batteries, and there are other similar type devices. Each load or circuit can be monitored after all are shut off through pulling the DC fuses and then enabling one at a time.

As for your starter battery, it can also be monitored but don't forget about the ECM (engine computer) and other electronic devices that may be active even though the ignition switch is off.

I agree. You should look into a battery monitor with a shunt. The Victron BMS-712 is great!

skyking · 06-24-2019, 06:58 AM

Wetstuff,
It would be a shame to eliminate the automatic step feature. My last RV was a 2007 Adventurer that had parasitic drain, that would kill the battery in 2 to 4 weeks. I installed a small battery disconnect on the chassis battery (Walmart). It took about 1 minute to lift the stair and turn the knurled knob to connect or disconnect. No trouble after that.

I have corrected two entirely different, quirky problems with the steps on the Adventurer and the Journey and was very happy to have reliable steps again. That may be for another thread, but I wouldn't mind helping.
Richard

LeonardoBF · 06-24-2019, 10:27 AM

I had a similar problem and after changing the engine battery twice discovered the culprit was the engine/coach radio switch. Make sure it is on coach when not driving. p.s. I also installed the Trick-L-Start and strongly recommend it to keep the engine battery charged while on house power.

JoeC · 06-24-2019, 01:09 PM

LeonardoBF,

You are on the right track now, except for installing a Victron BMV-712, or similar shunt-style battery monitor, to monitor your coach and start batteries. Maybe some day the RV manufacturers will start putting decent electrical systems in the coaches, or at least make them an option. The Amp-L-Start (Trick-L-Start but better) however, is mandatory in my opinion.

Wetstuff · 06-24-2019, 02:55 PM

Thanks, guys. It seems a couple of problems are solved. I now have a 5 amp Trik-L-Start wired into the new starting battery and my young mechanic refused to make my steps manual without looking at them. He found my problem.

Mine are funky looking, but without the issues you had Don. I wonder if there was a lot more salt on your roads. (I made a separate posting about the steps)

Anyway, these ghosts have been chased out of this 2002 graveyard - for the moment at least.

Jim