Where is the parasitic battery draw?

[koneill]

I am having trouble understanding what is drawing my batteries down.
I have a 2022 International 27 FBT with 2x100AH BB batteries. Shortly after getting the AS, I installed a Victron SmartShunt IP65. Recently I noticed that my batteries did not seem to be holding a charge. My shunt shows that I am drawing about 3 amps, even with all the DC loads shut off (including frig). Turning off the main power switch (ie, putting it in storage mode) doesn't make any difference--still drawing 3 amps. I even pulled out, one at a time, all the fuses in the power center. Still drawing 3 amps. Not a lot but if the trailer sits for a week or 2, I have dead batteries.
This is a new problem. Previously I would store the trailer for 1-2 months without even thinking about it. In the past, with everything off, I would typically draw 0.1-0.2 amps.
Any ideas where this low level but persistent current draw is going? What else can I do to isolate the source?

[kb0zke]

Even with "everything" off there are still some things that are running. The CO detector is one, the various computers that run the television, radio, refrigerator, etc. also fit into that category. When you pulled the various fuses, did all of those things go off? If so, then there is something else that is drawing current. I'd suggest you pull ALL of the fuses, then go around checking everything. You may end up following wires to find the draw.

[Daquenzer]

I recommend installing an external cut off switch to disconnect batteries completely from the camper. I did. A lot of people do. I don’t know why they just don’t do it at the factory. But I suppose it is some code they have to follow.

Also what kind of batteries do you have?

[Wazbro]

Did you make sure the inverter is off?

[PaulBristol]

I agree with Wazbro. 3 amps is about right to run an inverter that is running, but not powering anything.

A lithium battery heater may also do that.

I have a main battery disconnect in my Trade Wind. The solar and the tow vehicle charging are still connected. Presumably that allows the trailer emergency brake to still work.

Check for miscellaneous wires connected to the positive terminal of the battery.

[vanderwielen]

Battery heaters are on.

[Mollysdad]

Install a real battery disconnect at the batteries.
Then there's no current getting to the hardware.

[jeffb831]

Originally Posted by Daquenzer

I recommend installing an external cut off switch to disconnect batteries completely from the camper. I did. A lot of people do. I don’t know why they just don’t do it at the factory. But I suppose it is some code they have to follow.

Also what kind of batteries do you have?

There are safety issues with a complete disconnect switch that AS doesn't want to be part of. Consider, if someone forgets to turn on the batteries and there is an incident where the emergency brakes don't activate or there is a fire/CO/propane incident, and the alarm doesn't go off

[OrangeCrush]

Battery heaters are internal and bypass the shunt so something else is causing the 3 amp draw. Inverter makes sense and/or possibly your propane gas detector has gone bad. Also make sure your light on the jack is not on and maybe even remove jack fuse as a test.

[JeffKim]

Yes, a battery cutoff is a good idea or just disconnect them. However, 3A (36W) is a significant draw even for parasitic devices and not good even when out of storage. I'd track down where it's coming from especially since it wasn't happening before. A lot of good suggestions, here.

[vanderwielen]

Originally Posted by OrangeCrush

Battery heaters are internal and bypass the shunt so something else is causing the 3 amp draw. Inverter makes sense and/or possibly your propane gas detector has gone bad. Also make sure your light on the jack is not on and maybe even remove jack fuse as a test.

Depends. BB heaters can be directly connect to the +/- terminals or can draw from the + bus downstream from the shunt via switch. I've seen both. BB heaters draw 1.5-1.8 amps. So, when the OP said a 3 amp draw on a pair of BBs, this came to mind.

[c3man]

Router key to off position ?

[uncle_bob]

Hi

There are a lot of fuses all over your trailer. The ones in the main fuse panel are only a start. In most cases (this is "never do it the same way twice Airstream ... ) the main fuse panel is driven off the use/store switch.

Like others I'd bet on the inverter being on. There's a giant fuse in series with it. Ours is under the kitchen sink. Who knows where yours might be. The light on the power jack (if you have one) is another possible gotcha. What you may find is that a switch has gone bad (rare, but it happens). It shows as "off" but is actually on.

How to track this nonsense?

Get a DC clamp amp meter with a 40A full scale. It will show you a 3A drain. Then run around checking cables. Eventually you will find the culprit. Yes, I'd check that big fat wire to the inverter first .

Bob

[thiel]

Is inverter off?

Other parasitic draws:

-- Propane/CO detector
-- Subwoofer (crazy, right?)
-- Rain sensor on fantastic fans (look for red light.. set to 0 to kill off)

[Wazbro]

Originally Posted by jeffb831

There are safety issues with a complete disconnect switch that AS doesn't want to be part of. Consider, if someone forgets to turn on the batteries and there is an incident where the emergency brakes don't activate or there is a fire/CO/propane incident, and the alarm doesn't go off

While true, if power to the jack is also off most people would figure it out by the time they use a jack to hitch up and unbolt the electric jack to get on the road.
Those that don't figure it out are pretty much going to have problems no matter what.

[ROBERT CROSS]

Put in storage 10/26/24.
Disconnect & LP detector switch's engaged, fuse removed from jack.

Bob
🇺🇸
27*f today

[koneill]

Thanks for everyone’s help. Here is an update on my mystery.
I have 2 Battle Born Lithium batteries, 100Ah each installed by the dealer.
When I installed the Victron IP65 shunt, I also installed a battery disconnect switch on the negative post. There is nothing connected to the negative side of the batteries, just cable to the switch, then to battery side of the shunt, then the load side of the shunt to the negative busbar with all the negative connections attached there. I have not checked for current draw with the battery switch off because I think that this cuts off power to my shunt and I lose shunt readings. I may try this later.
I don’t have a DC clamp amp meter to see if there is any current in the cable to the inverter, but I think that my inverter is off. My reasons: The indicator light is off. And when I turn the inverter on, my current drain jumps up from -2.90 to -3.50 amps. If I plug in a toaster into an inverter outlet, it reads -70 amps.
I double checked to see if my current draw decreased by turning off or unplugging or pulling fuses for everything that I could. None of these steps reduced my current draw. No drop in current with the master switch in “storage” mode.
My jack light is off. I tried but could not find any easy way to disconnect the power to the jack. One fuse on the positive side of the battery terminal I suspected, but the jack still worked when this fuse was pulled.
I checked out possibilities with propane detector, subwoofer and fantastic fans, all came up empty.

Here is my current theory and why. Is it possible that my shunt is giving false readings? Could it be reading current draw of -2.90 amps when really the current flow is zero? Has anyone heard of this happening? If the shunt is falsely thinking there is current draw, it will wrongly conclude that the battery % charge is declining. In fact the shunt says that my battery is down to 14% but I still have 13.2 volts on the shunt and on the SeaLevel meter. I can confirm that the % charge is false by running the batteries down lower and see if I still have functional voltage when the shunt says 0% battery left.
Most importantly, I disconnected the negative busbar from the load side of the shunt. Therefore, there is absolutely nothing connected to the negative terminals of the batteries. STILL showing -2.90 amps! (Also, with this disconnected, the jack did not function.) Battery heater is internal and therefore not measured by the shunt, has pointed out.

I can’t think of any other explanation than faulty readings from the shunt. Is my next step a call the tech support at Victron?

[Daquenzer]

Originally Posted by jeffb831

There are safety issues with a complete disconnect switch that AS doesn't want to be part of. Consider, if someone forgets to turn on the batteries and there is an incident where the emergency brakes don't activate or there is a fire/CO/propane incident, and the alarm doesn't go off

Yet I had my disconnect switch installed at an Airstream dealer. But you are probably somewhat correct. Airstream no doubt guided by regulators who assume people that buy Airstreams have an IQ of 50 or less.

[Daquenzer]

Originally Posted by koneill

Thanks for everyone’s help. Here is an update on my mystery.
I have 2 Battle Born Lithium batteries, 100Ah each installed by the dealer.
When I installed the Victron IP65 shunt, I also installed a battery disconnect switch on the negative post. There is nothing connected to the negative side of the batteries, just cable to the switch, then to battery side of the shunt, then the load side of the shunt to the negative busbar with all the negative connections attached there. I have not checked for current draw with the battery switch off because I think that this cuts off power to my shunt and I lose shunt readings. I may try this later.
I don’t have a DC clamp amp meter to see if there is any current in the cable to the inverter, but I think that my inverter is off. My reasons: The indicator light is off. And when I turn the inverter on, my current drain jumps up from -2.90 to -3.50 amps. If I plug in a toaster into an inverter outlet, it reads -70 amps.
I double checked to see if my current draw decreased by turning off or unplugging or pulling fuses for everything that I could. None of these steps reduced my current draw. No drop in current with the master switch in “storage” mode.
My jack light is off. I tried but could not find any easy way to disconnect the power to the jack. One fuse on the positive side of the battery terminal I suspected, but the jack still worked when this fuse was pulled.
I checked out possibilities with propane detector, subwoofer and fantastic fans, all came up empty.

Here is my current theory and why. Is it possible that my shunt is giving false readings? Could it be reading current draw of -2.90 amps when really the current flow is zero? Has anyone heard of this happening? If the shunt is falsely thinking there is current draw, it will wrongly conclude that the battery % charge is declining. In fact the shunt says that my battery is down to 14% but I still have 13.2 volts on the shunt and on the SeaLevel meter. I can confirm that the % charge is false by running the batteries down lower and see if I still have functional voltage when the shunt says 0% battery left.
Most importantly, I disconnected the negative busbar from the load side of the shunt. Therefore, there is absolutely nothing connected to the negative terminals of the batteries. STILL showing -2.90 amps! (Also, with this disconnected, the jack did not function.) Battery heater is internal and therefore not measured by the shunt, has pointed out.

I can’t think of any other explanation than faulty readings from the shunt. Is my next step a call the tech support at Victron?

Clearly you have a puzzle. I would call tech support at Victron.

By the way the jack fuse is in the line going from the battery to the Jack (at least in mine). It looks like a plastic tubing. It is a buse fuse. I know this because one time my jack didn't work and found that I had accidentally disconnected the fuse line when I was installing my Propride hitch.

But it seems if you have pulled all the fuses something may be wrong with your readings.

[JeffKim]

So, disconnecting all the loads from the shunt and it's still reading -2.9A? Hard to come up with any explanation other than a defective shunt. Did you try disconnecting its positive lead and reconnecting it (reboot)?