Battery depletion rate 3% or more per day... with EVERYTHING off?

[Snackchaser]

On 6/3/2024 at 4:32 PM, Dave and Kimberly said:

 It's not a real big deal but I can't figure out what I'm missing.  

I decided to chime in on this because I don’t think you’re missing anything, your discharge rate is perfectly correct!

All the given advice is good, but it’ can be a bit miss-leading to fully understand whats going on.  I hope to provide a better explanation, and show you a simple and very accurate way to check your “parasite” loads, which I’ll refer to as normal “stand-by” loads.

Your 390 amp hour battery with a daily discharge rate of 3% equates to a loss of 11.7 amp hours over a 24 hour period.  This further equates to a stand-by load of 0.48 amps, which is not overly excessive considering all the electronic devices in the Oliver.  Devices with memories, remotes, touch lights, rain sensors, USB ports, electronic boards, etc., can each draw milliamp currents even when turned off, and they do add up quickly.

I took some current readings from my own trailer to show you what I mean.  It’s the same year as yours and it also has a 390 amp hour battery.  Remarkably, the values add up to exactly the same current as your calculated load.  But more importantly, it shows that there is no single extraordinary load:

• Fuse 2, Various electronics = 0.117 amps
• Fuse 4, Furnace = 0.012 amps
• Fuse 5, Main lighting = .003 amps
• Fuse 6, Fans = 0.016 amps
• Fuse 7, Water heater = 0.113 amps
• Fuse 8, Radio = .204 amps
• Fuse 9, USB outlets = 0.007 amps
• Fuse 10, USB outlets = 0.009 amps
• Total = 0.481 amps

These measurements were done with a precision multimeter having a resolution of 3 decimal points.  My Victron shunt has a resolution of 2 decimal points and it showed a lessor current of 0.42 amps.  My Clamp-on Amp Meter has a resolution of 1 decimal point, and it showed a higher current of 0.5 amps.  This demonstrates how subjective and inaccurate some of these measurement methods can be when dealing with such small milliamp values.

Another potential misconception is that the Lithionics BMS App will provide the overall charge and discharge values.  It’s only true to the extent that it provides values for the battery selected, but not for each battery combined.  For example; the 390 amp hour package consists of three 130 amp hour batteries.  If the overall load is 3 amps, then the App will show each battery discharging at 1 amp.  Additionally, it’s only accurate to 0 decimal points so it won’t show anything less than 1 amp.  This is another good justification for installing a Shunt.

There are a number of ways to measure stand-by or parasite current, but the easiest and most accurate way is with an inexpensive Multimeter through the fuse box.  It will show the load of each circuit, but not each component on the circuit.  Thats okay because some of the individual component loads are too small to be accurately measured anyway.   

• Caution:  When using the ammeter function, the meter is in-line with the circuit.  This means that the current is running through the leads and meter.  So don’t use it with loads greater than it’s rated maximum current, which is typically 10 amps.

Before testing, make sure that everything is off including the inverter/charger and solar (Solar switch is in the street side overhead cabinet.)   Make sure shore power is unplugged too.  Pull each fuse one at a time and the red LED “blown fuse” indicator will light-up if there is any load.  Put your ammeter leads on each leg of the fuse socket and read the current.  Add up the values and you will have an accurate overall stand-by load.  FYI, the inverter/charger does not go through the fuse box, but it will add another 0.2 amps load if left on.

I keep my trailer undercover without shore power and the batteries also discharge rather quickly.   In fact the shunt screen shot below shows that it will discharge in 10 days.  I considered adding a battery master switch, but it wasn’t a viable option for a number of reasons which is why I believe that Oliver doesn't install them either.  I ended up getting an auxiliary solar panel, with charge controller, and I mounted it on the roof to keep the batteries at 100%.  It was better than running an extension cord and risking complete discharge mishaps.

Hope this helps

Cheers, Geoff

[Geronimo John]

On 6/9/2024 at 2:32 AM, Dave and Kimberly said:

I'm not familiar with another fuse panel in the attic?  Do you mean the rear storage space (above rear window) where the EMS, TV antennae on/off area?

I'm not familiar with the wiring on your trailer, but for many years YES, there is a fuse panel in the Attic, right side.

[Geronimo John]

20 hours ago, Snackchaser said:

I considered adding a battery master switch, but it wasn’t a viable option for a number of reasons which is why I believe that Oliver doesn't install them either

Geoff: 

What a great post.  It certainly sheds a technical light on the amp draw issue.  Knowledge is good.

Speaking of which, would you please elaborate further on not installing a high quality Battery Master Switch?  There are some owners who are on the fence in this regard, and your perspective would be beneficial.  

Thanks,

GJ  

[Snackchaser]

1 hour ago, Geronimo John said:

Geoff: 

What a great post.  It certainly sheds a technical light on the amp draw issue.  Knowledge is good.

Speaking of which, would you please elaborate further on not installing a high quality Battery Master Switch?  There are some owners who are on the fence in this regard, and your perspective would be beneficial.  

Geromino John, thanks for the kind words.  Sure I can elaborate why I haven’t installed a Master battery switch, and I’ll also provide a better solution if the objective is to switch off all the stand-by loads when the trailer is in storage.

The battery switch will add resistance to the circuit from the additional cable length needed to reach the switch, and through cable lugs and switch contact resistance.  Granted it’s not much, but anyone who has ever dabbled with cable resistance knows that it doesn’t take much to create a voltage drop, particularly in high amperage battery systems like the Oliver.   Voltage drop impacts the systems efficiency and it means your creating heat and burning watts.

I don’t think there’s an optimum place to install a switch given the stiffness and limited bending radius of the size cable that you would need.  It's best to keep the cable as short as possible and that really limits the mounting options.

I haven’t see a compelling reason to install a huge battery switch.  I’m in and out of the trailer enough where it would be an unnecessary burden to turn the battery off.  The only reason I can think of for installing a switch, is to shut off the stand-by loads while in storage.  I personally think stand by loads are not a significant concern.  There are not many scenarios where solar or shore power is unavailable and, if so, there are other solutions.  

If there is a desire to shut off the stand by loads while the trailer is in storage, then simply shut off the DC breaker that supplies the DC fuse panel. It’s located next to the inverter.  You can see from my previous post that all the primary loads are fed by the DC fuse box.  However, I’d recommend re-powering the CO2 detector so that it always stays energized.

Hope you find this useful!

Cheers, Geoff

[Wandering Sagebrush]

On 6/8/2024 at 10:29 PM, Geronimo John said:

<snip>

Meanwhile, we'll just poke along.  Anybody have some slide rule wax?  After 60 years it's getting a bit sticky.  Numbers seem to be smaller than before too!

<snip>

John, I still have my old Pickett 1010 Power Trig, that I could loan you.  I keep it behind glass with a sign that says “Break glass in case of emergency.” for those times my computer is down

[gbergh]

10 hours ago, Wandering Sagebrush said:

Anybody have some slide rule wax?

The beauty of the Sun Hemmi  257L “Chemical Rule” made of Bamboo never needed lubricants as Bamboo tends to be self lubricating. 

[FloraFauna]

My Ollie does the same.  About 3% per day with everything off including the battery heaters. I assume there is some draw occurring amongst the electronics just to keep everything in monitor mode. I have two 320 Ah Lithionics batteries.  While I would it rather not degrade this fast, I have not attempted to chase it down at this stage and am not overly inclined to do so - too many other projects.   

[Geronimo John]

On 12/23/2024 at 1:22 PM, Snackchaser said:

Geronimo John, thanks for the kind words.  Sure I can elaborate why I haven’t installed a Master battery switch,

Geoff:

 Thank you. From your perspective, use, & trailer options; I can understand and respect your justification for not seeing the need for a master battery switch for your trailer.

 Concerning your responses in the context of most of our trailers: 

Increased Resistance: Yes resistance is bad and should be minimized especially with the high amperages ... as you stated.  The suggested switch install in the battery box, as several of us have done, uses a short copper flat bar, and no additional lugs or extra wire.  The increased resistance induced is inconsequential compared to the terrible efficiency of many of our Inverters.  Especially the older ones!

 No Place to Install:  The suggested Blue Seas Series 9000 E switch has nicely been installed in the battery bays, under the dinette seats, and under the street side bed of our trailers.  Depends on your priorities.  If you wanted access inside, it can be mounted inside.  If you want it outside we have space the battery box for many Litho Battery installs.  (But not all).  Either way, locations are not an issue.

 Huge Size of Switch:  Tilt, see above.

 No Compelling Reason:  How about the Fire/Rescue having the ability to stop the flow of power to an inside fire?  This is especially the case for Lithium installations.  One of the reasons to put the switch where they will first look for it. 

 Un-necessary Burden of turning the battery off when In and Out of the Trailer:  For most of us, that is not the purpose of this switch.  Many of us only use it for storage and emergency use.  It takes me less than 15 seconds to turn on/off, and that happens on our first season’s voyage and off  3 - 4 months later in the fall when we winterize.  But some owners likely do so more often.  

 For Standby Power Losses During Storage:  Some lucky owners such as yourself have solar and/or shore power in their storage site 365 days a year.   Some owners don’t need to worry about their batteries freezing.  On the other hand, some owners do not see their trailer for months at a time over winter.  Collectively this means that many owners do need to isolate their batteries.   Additionally some battery manufactures do not recommending keeping their Litho's at full charge when not being used, especially where deep freezes occur occasionally.  

 Simply shut off the DC breaker that supplies the DC fuse panels:  The purpose of the Master Switch is to shut off ALL DC power to the trailer from their batteries.  The 60-amp DC breaker does not do this.  I believe that it does not terminate the power to the Inverter which is wired into the 300-amp fused via 4/0 wiring.  For our trailers, if we want to kill all DC current flow, without a 300 amp breaker, which I am not aware any OTT trailer has, we would have to remove the 300-Amp fuse.  But that is a PITA.  So, we do so in 15 seconds or less by turning off the Master Switch.     

To summarize, many of our OTT owners don’t have such a great storage solution as apparently you are blessed with.  Likewise, many of us have chosen the peace of mind that the DIY installation of a Master Switch provides. 

 I hope you and the family are enjoying a great Christmas!

 GJ

 

Edited 5 hours ago by Geronimo John

[Geronimo John]

On 12/22/2024 at 2:43 PM, Snackchaser said:

Remarkably, the values add up to exactly the same current as your calculated load.  But more importantly, it shows that there is no single extraordinary load:

• Fuse 2, Various electronics = 0.117 amps
• Fuse 4, Furnace = 0.012 amps
• Fuse 5, Main lighting = .003 amps
• Fuse 6, Fans = 0.016 amps
• Fuse 7, Water heater = 0.113 amps
• Fuse 8, Radio = .204 amps
• Fuse 9, USB outlets = 0.007 amps
• Fuse 10, USB outlets = 0.009 amps
• Total = 0.481 amps

Geoff:  Again great work on the parasitic losses.  I wonder what your amp meter would show if you physically disconnected the 4/0 wire to the Inverter with your 60-amp breaker off?