1. the diagram shows the multi meter in series with the negative cable but it doesn't clearly show that the negative cable is disconnected. you mention in the text but the diagram is no clear.
2. you say you can find the parasitic load by pulling the fuses in the load center. it is quite possible tha the fuse you to the parasitic load is not in the load center. if the parasitic load is something like a co sensor or propane sensor that is 'designed' to always be on the fuse for it may be directly cable to the battery and not through the load center.
other then the above, keep it up! your articles are good!
I accidentally put in the wrong graphic, but updated it immediately after posting the article. And yes, I’ll cover all the other parasitic possibilities next week.
If the Amp meter is connected across the battery disconnect switch (and it is off) this would work fine. But the there is no label so we don’t really know if it is a disconnect switch.
Clearly that Airstream's "Battery Disconnect" switch does not actually disconnect the battery. It leaves something still connected. I am puzzled why the factory would wire it that way. I hope you will address this in your follow-up article. I added a disconnect switch to my rig that actually opens the entire connection to the negative battery post, leaving nothing connected. Another option would be to pull the negative connector from the battery post.
Thanks for these articles! Like so many other readers, I also appreciate and learn from them.
Yes, obviously the current is going somewhere! An AC/DC clamp meter is a great tool to find out just where it’s ending up. As you note, it might need a secondary negative disconnect switch added. But that will also disconnect the breakaway brake power which is why manufacturers put the disconnect on the positive battery pole. That allows the breakaway switch for the brakes to have power at all times.
That’s true, but it shouldn’t be drawing current unless the breakaway cable is pulled out and the brake switch makes contact. Then it should be drawing around 6 amperes per axle.
That is the best description of a problem that I have seen in a while. I like the troulbeshoot8ng method of using the clamp on ammeter on the negative battery post. Thank you for the troubleshooting description.
Every RV I've ever seen has loads connected to the battery that do not go through the central DC distribution/fuse panel. So if removing every fuse doesn't find the drain, all wires leaving the battery need to be checked as well.
I don’t know the battery monitoring system that is in use but I would think if it can display SoC, that it can display current drawn by the system and read it out directly.
More details on meter brands and parasitic leakage possibilities next week. Please stand by…
two comments about your reply.
1. the diagram shows the multi meter in series with the negative cable but it doesn't clearly show that the negative cable is disconnected. you mention in the text but the diagram is no clear.
2. you say you can find the parasitic load by pulling the fuses in the load center. it is quite possible tha the fuse you to the parasitic load is not in the load center. if the parasitic load is something like a co sensor or propane sensor that is 'designed' to always be on the fuse for it may be directly cable to the battery and not through the load center.
other then the above, keep it up! your articles are good!
I accidentally put in the wrong graphic, but updated it immediately after posting the article. And yes, I’ll cover all the other parasitic possibilities next week.
If the Amp meter is connected across the battery disconnect switch (and it is off) this would work fine. But the there is no label so we don’t really know if it is a disconnect switch.
The diagram shows a traditional negative disconnect switch which I’ll go into more detail about next week.
Clearly that Airstream's "Battery Disconnect" switch does not actually disconnect the battery. It leaves something still connected. I am puzzled why the factory would wire it that way. I hope you will address this in your follow-up article. I added a disconnect switch to my rig that actually opens the entire connection to the negative battery post, leaving nothing connected. Another option would be to pull the negative connector from the battery post.
Thanks for these articles! Like so many other readers, I also appreciate and learn from them.
Yes, obviously the current is going somewhere! An AC/DC clamp meter is a great tool to find out just where it’s ending up. As you note, it might need a secondary negative disconnect switch added. But that will also disconnect the breakaway brake power which is why manufacturers put the disconnect on the positive battery pole. That allows the breakaway switch for the brakes to have power at all times.
hello Mike!
what brand is your clamp meter? Can this exact test be run when there are 3 305ah lifepo4 redodo batteries?
thannks for all you do!
Dani
Things I have seen that have run down batteries accidentally:
(Many of these items my bypass the main power switch, especially if added by a current or previous owner)
Tongue jack light left on.
Breakaway switch activated.
Some lithium batteries with integrated heater left turned on while in storage.
Tank heater left on.
Some RV's the stereo can be switched between the house battery and the chassis battery.
Some RV's have a solenoid that turns the propane tank valve on and that uses power in the on position.
Leaving the inverter powered on (even with no AC loads).
Storage compartment light left on.
Some older USB outlets use some power even with nothing plugged in.
Backup camera wired to a circuit that is always powered.
Tire pressure monitor or extender that is wired to a circuit that is always powered.
Leaving a phone charger plugged in to an outlet even without the phone attached.
Leaving 7 way cable plugged into truck if truck doesn't disconnect charging line with ignition off.
If you have an inverter (not inverter/charger) that powers whole AC breaker panel, leaving both the inverter and converter on at the same time.
Cell booster, amplified antenna, or internet router left turned on.
Oh yes. And troubleshooting begins with measuring the parasitic current. An AC/DC clamp meter can be your best friend for this.
Also the trailer break away switch is wired separately and does not go through the battery disconnect switch.
That’s true, but it shouldn’t be drawing current unless the breakaway cable is pulled out and the brake switch makes contact. Then it should be drawing around 6 amperes per axle.
That is the best description of a problem that I have seen in a while. I like the troulbeshoot8ng method of using the clamp on ammeter on the negative battery post. Thank you for the troubleshooting description.
Every RV I've ever seen has loads connected to the battery that do not go through the central DC distribution/fuse panel. So if removing every fuse doesn't find the drain, all wires leaving the battery need to be checked as well.
That’s part 2 of this article which is why a DC clamp meter is so handy for troubleshooting.
Great, simple explanation! Siskel and Ebert (so how many of us get that statement??) give it 2 thumbs up! Loggenrock
I don’t know the battery monitoring system that is in use but I would think if it can display SoC, that it can display current drawn by the system and read it out directly.