Parasitic Draws?

Joined
Jun 26, 2022
Messages
15
Location
Surrey
I am having an issue with my batteries holding their charge while our trailer is in storage, and I am hope that someone might have an idea of what possible parasitic draws might be causing this? We have a 2022 Escape 21C with 2 lithium batteries. It is not connected to shore power, and it is being stored with the battery disconnect switch in the off position, which in our model means the propane detector is disconnected. We charged the batteries two weeks ago and now they are almost dead. The only draw on the batteries, that I know of, are the battery monitor and the two solar controllers. I know they are all still receiving power because I am able to connect to all of them by bluetooth. The solar controllers are not receiving power from the solar panels because they are covered and both controllers have the Charger Enable switch in the off position. I am assuming that these devices would have a very small draw and would not be enough to drain 2 - 100Ah batteries in less than two weeks. The battery monitor shows that only 1.4Ah have been consumed over the two week period and whenever I check the monitor to see if there is any draw, the current reads 0.00A and the power reads 0W. Does anyone have any suggestions on what the parasitic draws might be?

Where we have our trailer stored for the winter, it is a bit of a hassle to get access to shore power, so I think until I get this figured out I will just disconnect the batteries. Other than removing the negative terminals first, does anyone have any suggestions on the order I disconnect the battery terminals?
Does it matter which negative terminal I disconnect first?
Can I leave the battery shunt connected to the board and just slip the batteries out from underneath if I decide to remove the batteries from the trailer?

Thank you as always for your assistance.


IMG_3268.jpeg
 
Other than removing the negative terminals first, does anyone have any suggestions on the order I disconnect the battery terminals?
Does it matter which negative terminal I disconnect first?
If I were you, I would disconnect at the negative cables at the location shown, taking care to insulate the lug-ends, as each is removed, and be done with it. Though disconnecting the negative cables alone will do the job of completely isolating the batteries from each other and the trailer system, you can also disconnect the positive cables if that makes you feel better.
IMG_3268.jpeg

Then reverse the sequence to put the batteries back in service, placing the lugs to the fuse and shunt respectively on top of the lug to the adjacent battery.

After disconnecting I would use a VOM to measure the voltage of each battery, anticipating they should be the same, note that, and do the same before reconnecting, just to see if there's any meaningful difference in the 'self-discharge' during the out-of-service period, perhaps indicating an issue in one of the batteries,

IF there's a difference of voltage between the two batteries when it comes time to reconnect, I'd use a stand-alone charger to get them to the same voltage or use a pre-charge resistor between the batteries before making the final connection to the shunt, to avoid any in-rush / sparking when placing the negative cable between two batteries of dissimilar voltage.

Just for your consideration.
 
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While a draw of only a few milliamperes may seem trivial over time, 24 hours per day / seven days a week, this will definitely deplete your battery bank in short order. As well it’s not uncommon for a shunt / battery monitor to become less accurate under these conditions, in addition some equipment may be wired in such that the shunt does not report that current draw. I see you have the Hublion batteries, if you have discharged them below low voltage cutoff then the internal BMS will have shut them down. You can confirm this with a voltmeter or any device that will measure 12V. If you are in the disconnect condition then you will have to restart them and then bring them back up to the proper voltage very very slowly. You will need a battery charger specifically designed to do this function such as the Victron IP65

I have 4 Hublion 100 Amp hr batteries and remove them while my trailer is in winter storage. As these batteries are not heavy removing and reinstalling is not that great a task.
 
If I were you, I would disconnect at the negative cables at the location shown, taking care to insulate the lug-ends, as each is removed, and be done with it. Though disconnecting the negative cables alone will do the job of completely isolating the batteries from each other and the trailer system, you can also disconnect the positive cables if that makes you feel better.
View attachment 513432
Then reverse the sequence to put the batteries back in service, placing the lugs to the fuse and shunt respectively on top of the lug to the adjacent battery.

After disconnecting I would use a VOM to measure the voltage of each battery, anticipating they should be the same, note that, and do the same before reconnecting, just to see if there's any meaningful difference in the 'self-discharge' during the out-of-service period, perhaps indicating an issue in one of the batteries,

IF there's a difference of voltage between the two batteries when it comes time to reconnect, I'd use a stand-alone charger to get them to the same voltage or use a pre-charge resistor between the batteries before making the final connection to the shunt, to avoid any in-rush / sparking when placing the negative cable between two batteries of dissimilar voltage.

Just for your consideration.
Thank you for the clarification on the correct order for disconnecting the batteries. I also appreciate the advice on checking the voltage before reinstalling. I would not have thought about the fact that an imbalance in voltage could potentially cause a spark. Thanks.
 
While a draw of only a few milliamperes may seem trivial over time, 24 hours per day / seven days a week, this will definitely deplete your battery bank in short order. As well it’s not uncommon for a shunt / battery monitor to become less accurate under these conditions, in addition some equipment may be wired in such that the shunt does not report that current draw. I see you have the Hublion batteries, if you have discharged them below low voltage cutoff then the internal BMS will have shut them down. You can confirm this with a voltmeter or any device that will measure 12V. If you are in the disconnect condition then you will have to restart them and then bring them back up to the proper voltage very very slowly. You will need a battery charger specifically designed to do this function such as the Victron IP65

I have 4 Hublion 100 Amp hr batteries and remove them while my trailer is in winter storage. As these batteries are not heavy removing and reinstalling is not that great a task.
Thanks for the thoughtful reply. I have decided removing the batteries for the winter is the best option. I had set out to remove them last year, but was a little intimidated when I saw the way that the shunt/battery monitor was wired on top of the batteries.

Thanks for the advice on how to recharge the batteries if they have reached the low voltage cutoff. Unfortunately, the batteries have reached the low voltage cutoff on a couple of occasions and I have just plugged in to shore power to recharge them. Being new to RVing and having limited electrical knowledge, I was paying closer attention to the SOC the battery monitor was providing and not the voltage. After losing power a couple of times with the SOC still reading 65%, I learned to focus more on the voltage. I have had Escape try to determine why the SOC and the voltage are not more closely related, but they have been unable to find a cause.

If the parasitic draws are consuming approximately 150Ahs in two weeks, it has given we a great appreciation of why it is difficult to maintain a charge when boon docking in the spring and fall. At that rate, about half of the batteries charge would be lost to these parasitic draws during a week of camping.

Thanks for taking the time to share your knowledge.
 
I've always removed my FLA 6V heavy batteries and winter stored them in the basement when I had one and now in an insulated garage. Every month or so I put them on a charger overnight. They're heavy but off-site outdoor storage under a trailer cover and no electricity available leads me to this procedure.

Take pictures of your wiring connections, with tape mark and a note attached to each of them label to where they should go and you'll be OK.
 
Thanks for the thoughtful reply. I have decided removing the batteries for the winter is the best option. I had set out to remove them last year, but was a little intimidated when I saw the way that the shunt/battery monitor was wired on top of the batteries.

Thanks for the advice on how to recharge the batteries if they have reached the low voltage cutoff. Unfortunately, the batteries have reached the low voltage cutoff on a couple of occasions and I have just plugged in to shore power to recharge them. Being new to RVing and having limited electrical knowledge, I was paying closer attention to the SOC the battery monitor was providing and not the voltage. After losing power a couple of times with the SOC still reading 65%, I learned to focus more on the voltage. I have had Escape try to determine why the SOC and the voltage are not more closely related, but they have been unable to find a cause.

If the parasitic draws are consuming approximately 150Ahs in two weeks, it has given we a great appreciation of why it is difficult to maintain a charge when boon docking in the spring and fall. At that rate, about half of the batteries charge would be lost to these parasitic draws during a week of camping.

Thanks for taking the time to share your knowledge.
If you have drained your batteries to the point of low voltage cutoff more than a time of two you may have diminished their capacity to something below 100 AmpHrs. Under voltage cutoff and over voltage cutoff are the two must destructive conditions for your batteries. If I can be of any further assistance you can PM me.
 
FWIW, I have two 12v lithium batteries in my trailer. I do keep the trailer plugged into shore power with the battery cut-off switch in the on position so that lights will work with the 12 vdc supplied by the converter. In order to comply with the battery manufacturer’s storage recommendations and to eliminate constant discharge and charging, I installed a battery cut-off device on the positive terminal (mounts to the terminal with a knob that turns CCW to disconnect and CW to reconnect). It has worked well for my needs and the only drain on the batteries is the normal expected voltage loss of “unused” batteries.
 
Does anyone have any suggestions on what the parasitic draws might be?
Since you are disconnecting the battery negative anyway...

Measure the exact phantom drain with a multi-meter between the (-) battery terminal and the battery cable that you just removed. Make sure everything that you expect to be turned off is in fact off. Multi-meters have internal fuses that are a pain and/or expensive. Start with the meter in the highest Amp position.
 

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