Parasitic draw of battery - how to find it?

californication · October 26

Hi,

I own a Tab 320s BD 2022 since March 2022. At the beginning of 2024 I replaced an acid battery (provided by a dealership) for a new one. 2 weeks ago I decided to upgrade to 2x 100Ah LiFePo batteries with smart monitoring.

In the past, we had about 24-36h of full charge of acid batteries, and then I had to supply a generator to keep it alive.

Sunday afternoon (6 days ago) we got back from boondocking. My LiFePo showed me approx. 63% of charge for both batteries. I parked the tab, and I checked batteries state of charge (SoC) today. It showed me 13%.

0. I didn't switch off batteries to see how long they can survive with everything disabled.

1. fridge is turned off (I switched it to zero, doors are closed to turn off the light)

2. step is in use, so the "small light" above it was always on

3. radio is turned off, so it only shows the time

4. TV is connected, so it's "waiting to be used".

5. Alde is showing the time, but the propane is off.

6. Water pump switch is off.

The Tab is not covered (solar panel is visible) and orientated north, so it gets about 30kWh of power everyday. It's not enough to even move the needle of charge.

How can I investigate what's draining the batteries? I lost approx. 100Ah in just 5 days of "doing nothing". I always thought the worst offender would be my fridge, but it seems like I might have something else going on.

Any ideas what could be happening?

pthomas745 · October 26

On your Victron app, there is a section listing "Current" on the battery part of the app. If that current is a "negative" value, that is the draw on the battery itself. A positive number is showing the battery is being charged.

When you say the time is being displayed on the Alde: is the Alde actually off? Is there a little tiny LED light showing on the power button?

What app or device are you using for these battery percentages you mention? The Victron app? What do you mean by "smart monitoring?" When you installed these new batteries, did you adjust the Victron solar controller for charging a lithium battery? If the Victron is still set for a lead acid battery, you are only charging to a lower level compared to what a lithium battery needs.

There are ways to play with the Victron devices to get a good idea of what the "parasitic drain" total is for the trailer.

californication · October 26

Hi pthomas745,

"The smart monitoring" I'm mentioning is performed by an application for LiTime batteries, called "LiTime". It shows details of state of charge, with information how many watts and amperage batteries receive.

- Alde is "on" with regard to blue light by a power button.

- I changed the profile of charge in the VictronConnect app from default one to lithium.

- When I checked the VictronConnect app it shows me "bulk" mode with power going in. I didn't notice any negative values, which would mean discharging. My Tab is parked facing north, so I'm not getting a lot of sunlight. The VictronConnect app showed me approx. 30kWh daily.

californication · October 26

The problem I'm seeing is not the issue with solar panels, but what's draining the batteries.

Based on my quick calculations, it's about 100Ah/5 days, which gives about 20Ah/day. It's about 0.8A/h which seems to be a lot for keeping just basic systems alive.

Grumpy_G · October 26

Did you accidentally pull the breakaway switch when you parked the trailer ? The magnets can easily pull 5+ amps. Does the battery monitoring show the current going in/out ?
30 kW/h sounds optimistic, unless you have 3000 W of solar panels. IIRC the boondock has a ~300W panel.

Gomers2 · October 26

You could pull all the DC fuses and then while watching the Victron current monitor put them in one at a time. Like when you put the radio TV fuse and you'll see a quarter amp draw even when those units are on standby. That way you could isolate which circuit is using the phantom energy.

Sharon_is_SAM · October 26

Turn off the inverter, too.

rfuss928 · October 27

With everything that is running described in the OP, the 0.8 amp parasitic draw seems about right. My UT is 0.35 without the step light, TV, and Alde.
In a similar method as Gomers2 describes, you can pull DC fuses one at a time and watch for the current to drop.

californication · October 27

Thank you all.

I noticed today that LiTime app shows current when it's > 1.5A so I might not even notice it through the app. The only change I see is % of State of Charge (SoC).

I'm gonna try removing fuses to see which device could be the biggest offender.

Grumpy_G said:

Did you accidentally pull the breakaway switch when you parked the trailer ? The magnets can easily pull 5+ amps. Does the battery monitoring show the current going in/out ?
30 kW/h sounds optimistic, unless you have 3000 W of solar panels. IIRC the boondock has a ~300W panel.

I'm confident the breakaway switch is off. I have a very tight parking spot, so I need to unhook my trailer and push it in place.

What I meant about 30kWh is my daily charge. I believe that's what VictronConnect app is telling me.
I'm gonna double check tomorrow during daylight.

Sharon_is_SAM said:

Turn off the inverter, too.

I didn't know I have inverter in the 320s. How can I do that?

Grumpy_G · October 27

californication said:

Thank you all.

What I meant about 30kWh is my daily charge. I believe that's what VictronConnect app is telling me.
I'm gonna double check tomorrow during daylight.

"Optimistic" was a clearly failed attempt at humor. There is no way you're getting 30 kWh per day, that might be the lifetime amount generated. My 2000 sqft home uses ~22 kWh per day.

However I agree something isn't right in your case. My 320 with a single 100 Ah LiFePo and a 200 Watt panel fully charges the battery when I return from a trip, and keeps it charged when sitting. I only plug in shore power to cool down the fridge before heading out.

Sharon_is_SAM · October 27

@californication - you may not have an inverter. Just throwing that out as it is frequently overlooked.

californication · October 28

For my experiments I used a solar generator I own, which gives me live values.

Lessons learned:

To charge the batteries, the main switch must be "ON". Otherwise it just delivers power to subsystems in the tab (probably it's somewhere mentioned in the manual, but I missed that).

Steps:

1. I used the solar generator and I noticed ~22W going into the tab. I became worried, because it's not enough to charge my batteries (like mentioned in the other thread: https://tab-rv.vanillacommunity.com/discussion/comment/212126#Comment_212126 )
That was the moment I learned I had to turn the switch "ON" to charge the batteries.

2. I pulled off the fuse for TV/Radio and the draw went to zero. I placed it back ~ 19-22W.

3. I unplugged the TV, no change in the draw. I plugged it back, no change in the draw. I turned on the TV -- the draw went up to ~35W. Turned it off, it went down to ~22W. Pulled out the cord from the TV, the draw stays at 22W

4. I left TV unplugged. Turned on the radio, no change in the draw. Turned off the radio, no change in the draw. Pulled out the fuse responsible for TV/Radio -- my generator showed 0W.

Conclusions:

The radio, it doesn't matter if it's on or off, it constantly pulls ~22W. When I'm approaching my tab with my phone, it tries to connect with bluetooth in the radio (even when the radio is technically "off").

Questions:

1. Is it normal that the radio is always drawing battery?

2. Is there a way to disconnect the radio without pulling the fuse?

3. Preferably, I'd like to have an option to use the radio, but without constant 20W. Did anyone else notice similar issues?

Further actions:

I pulled out the fuse for TV/Radio, my 2 batteries are showing 105Ah total at this moment. I'm gonna see what's the value in the morning.

EDIT:

The radio is advertising via bluetooth as JWM22. It seems to be a Jensen JWM22.

californication · October 28

@Sharon_is_SAM acknowledged. Yeah, I bought a brand new tab, no one told me about an inverter. I didn't install anything like that, so I'm assuming I don't have it.

@Grumpy_G you were obviously right xD I misread the VictronConnect app. It showed "30Wh", not "kWh". My total for last 30 days is about 66kWh

I have 200Ah, based on my experiments I'm losing 22W constantly. It gives me about 110h ~ 4.5 day. When I'm getting about 60Wh, it's impossible for me to top it off.

@rfuss928 you mentioned you're not running TV and Alde. For Alde it's just "power off" button. How did you turn off TV? Did you pulled the plug?

Grumpy_G · October 28

~20W is too much for a radio in standby. Assuming you have the JWM22 the spec sheet lists 110mA in standby, which is ~ 1.3W. The radio should not try to connect to the phone when turned off, you could try to switch it to radio mode and see if the draw is still there when turned off, or try the hard reset button on the front.

californication · October 28

@Grumpy_G yes, it's Jensen JWM22.

When I press the RESET button in the middle of the console, the draw goes down to 0W. The moment I release it, it immediately goes back to ~19-20W.

When I turn the radio ON, it starts playing, the battery shows 20W. When I long press "Power On/Off" button, the radio goes silent, but the draw stays without any change, continuing 20W.

I didn't notice any difference between Radio/HDMI/BT modes.

EDIT:

When I turn the radio off, it only shows current time (by default it's 12:00 AM). When I turn it on, it shows everything else: radio frequency, BT info, whatever.

The display shows it going to "standby mode", but the draw doesn't confirm it.

rfuss928 · October 28

I sounds to me like the "radio fuse" is also powering the gas detector and USB/12v outlets. Unless those are disconnected you will see ~.2-.3 amp draw.

californication said:

@rfuss928 you mentioned you're not running TV and Alde. For Alde it's just "power off" button. How did you turn off TV? Did you pulled the plug?

I removed the televisions. No Alde in a UT.

californication · October 28

The WFCO 8735 AD has 7 separate fuses:

1. 7.5A Lights/Alde/LP Alarm

2. 15A TV/Radio

3. 15A USB Outlet

4. 20A Refrigerator
5. 15A Vent Fan/Toilet/nuCamp monitor

6. 30A Converter Power

7. 40A Reverse battery protection

I only removed Fuse2. My fridge is turned off to "zero" and doors are closed.

I'm assuming that other draw is so minuscule, that my external battery (and its monitor) is not even noticing it. If it's about 0.3A it would be about 2-3W

ColleenD2 · October 28

This is embarrassing to ask but where do I find those fuses and are they labeled? We are still struggling with camping off the grid after all these years and hope to find the solution in 2025.

californication · October 28

@ColleenD2 my fuses for Tab320s boondock are located in the WFCO 8735 AD unit. It's mounted under the bed, big black box: https://nucamprv.com/wp-content/uploads/2024/09/2025-tab320-detail-slider-01-1.jpg

When I open it, I can see all labels, like here:

Image: https://us.v-cdn.net/5021717/uploads/editor/l2/muxdjt72y4lq.jpg

californication · October 28

I contacted Jespen customer service.

They suggested to verify if dimming of the radio would change anything. After switching in options (Zone B, Dimm On/Off, Dimm 0), I didn't notice any change.

The service person suggested to send the radio for evaluation, which I requested.

Removal of the radio was easier than I thought.

The radio has a plastic frame around the front panel. It just pops out when pulled. 4 square head screws kept it in place. In the back there are 3 connections: HDMI and antenna (just pulls out) and the main connector which hosts DC and all speakers.

Interesting fact. On the inside, the radio model is described as JWM20

Gomers2 · October 28

I don't like the radio, partly because it sounds pretty crappy, partly because the glowing light is annoying even when it's off, and partly because it's always drawing power even if not much. My plan is to tap into the power line for that unit and add a switch that will physically disconnect the unit. That would be a lot easier than messing with the fuse and you won't get the annoying red fuse-missing light. I'll put some photos up once I get around to doing the modification.

californication · October 28

@Gomers2 that's another idea I was playing with.
However, before going this route, I'm gonna ask Jensen to verify if the unit isn't faulty.

Couple things I don't like about the radio:

1. Like you mentioned, it has this awful glowing light. Today I learned, you can dimm it to zero (pitch black)

2. Sometimes when playing music, it disconnects out of the blue. I noticed it happening several times in the night, when playing soothing sounds of waterfall or similar. It starts playing via bluetooth, I can fall asleep... and in the middle of the night I notice it's quiet. The radio turned off and it's not playing anymore.
3. The radio, even if it's on "standby" is advertising BT (it might be faulty behavior). Yesterday I was listening an audiobook on my headset, and when I approached my trailer, I couldn't hear anything anymore. Because the JWM22 took over my bluetooth... even in the "standby".

At least one thing I like about it:

1. When I need to, I can plug-in my HDMI cable straight to the radio, and I can watch movies on the TV, with decent sound from speakers.

Marceline · October 28

I can fall asleep... and in the middle of the night I notice it's quiet. The radio turned off and it's not playing anymore.

Have you checked the Sleep Timer? Page 7 https://asasupportdocs.blob.core.windows.net/docs/Owners%20Manual/Owner's%20Manual-JWM22.pdf?_ga=2.109631553.575873353.1730145417-1543382193.1730145417

There's also information about Bluetooth on page 10. You can shut off the Bluetooth if you don't want it to automatically connect to your phone.

californication · October 28

@Marceline thanks for pointing it out.

Actually it's not "timer" feature. I've never set it up. Sometimes it's just the radio stays on all night. Other times, it dies sometime during the night. I'm not sure if it's a surge in energy or anything. I haven't pin-pointed it. After several failed attempts, I just stopped using this.

I like the BT, I just don't like it actively trying to connect to my phone, even when it should be in "standby" mode.

I'm waiting on Jensen Support to see if I can send my unit for evaluation. It might be, that the BT issue is not really an issue, but "feature" of my radio of being "constant ON".

Marceline · October 29

californication said:

I like the BT, I just don't like it actively trying to connect to my phone, even when it should be in "standby" mode.

I'm waiting on Jensen Support to see if I can send my unit for evaluation. It might be, that the BT issue is not really an issue, but "feature" of my radio of being "constant ON".

Sorry if I wasn't more clear, per the manual (p10), you can turn off the BT on the stereo. This will prevent it from automatically connecting with paired devices. You would then simply turn the BT back on when you want it to connect to your device. Your other option would be turn off the BT on your phone so it doesn't automatically connect with the Jensen. But of course that would prevent your phone from connecting to other things, like any Victron devices.

Press and hold the ZONE B button (9) to enter system setting adjustment. Repeatedly press again the ZONE B Button (9) to access the “BLUETOOTH ON/OFF” menu function. Press or buttons (12, 11) to turn Bluetooth function On or Off.

SLJ · October 29

The T@B speakers are the crappy sound part. I added a Bluetooth transmitter to my '21 and the Bose speaker has good audio quality through the Jensen. Since it's out just add a power switch next to it. I put in a switch panel to cut power to everything that was on all the time, Jensen Stereo, TV, USB Ports, overhead lights, etc.

Image: https://us.v-cdn.net/5021717/uploads/editor/ib/je7g06jrrt5w.jpg

californication · October 29

@Marceline oh, I didn't know you can have your cake and eat it. I cannot test it now, I already sent the radio to Jensen to see if they can confirm it being "always ON". I should know more next week.

@SLJ I'm slowly playing with an idea to add hard switches to disable unused devices. I'm just wondering why nuCamp didn't design it this way out of the box.

Marceline · October 30

californication said:

@Marceline oh, I didn't know you can have your cake and eat it. I cannot test it now, I already sent the radio to Jensen to see if they can confirm it being "always ON". I should know more next week.

@SLJ I'm slowly playing with an idea to add hard switches to disable unused devices. I'm just wondering why nuCamp didn't design it this way out of the box.

I put one of these on the 12v line going into the TV to shut off all power.

Horigan · October 31

I did a similar thing with a power switch next to the Jensen.

Image: https://www.wiringdepot.com/resize/Shared/images/Product/JT-T-2701-2J-16-AMP-12-Volt-Illuminated-On-Off-Round-Rocker-Switch-Red-LED-1-Pc/2701-2J.jpg?bw=1000&w=1000&bh=1000&h=1000

AnOldUR · October 31

Horigan said:

I did a similar thing with a power switch next to the Jensen.

Used the same type of switch, but mounted it down by the WFCO. Spliced it into the wire that feeds everything on the circuit that the Jensen is on.

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Parasitic draw of battery - how to find it?

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