Battery drain with disconnect off. Tab400 2023

Ghannan

My tab is in outdoor storage in My higan.  Battery disconnect switch set to "off", but victron shunt shows 0.14aH drain.  With switch on, of goes to 0.47aH.  I know there will be a draw when switch is on, but my battery is down to 51%SOC with disconnect switch off.  I thought the battery disconnect should isolate the battery completely.  Anyone have an explanation??

Gomers2

If the shunt itself is powered on and using Bluetooth to communicate then it's drawing something... Not sure how much. I believe the smartshunt flashes blue when it's Bluetooth is on. The additional 
.3 amps that shows up when you connect the battery could be something else in standby mode like the radio. For what it's worth I had read that 50% charge is actually sort of an ideal storage level for the winter. I believe that was on the battleborn site. I know there are some battery experts here who can weigh in as well.

Ghannan

I will check the radio in a couple days, but it is downstream of the battery shut off,bos it should not be a draw.  I will check, though ..  smartshunt Bluetooth must be on- i use the victron app to check it.  Not sure what it draws.

pthomas745

I've been looking over this in your FB thread, and I know you have answered every question possible about what is on or off, etc. 

So: with everything off, why is the Victron still showing a drain?  Some drain is "normal" after a couple of months, but to believe your Victron numbers, something is drawing about 20 amp hours per month, which seems a bit off.

I'm sure everyone spends their sleepless nights reading the Victron Shunt manuals, and I looked it over last night.  I found this troubleshooting section.  Look at section 10.3.3.  There are some things to check: the wiring to the shunt, etc.

https://www.victronenergy.com/upload/documents/BMV-712_Smart/9172-Manual_BMV_and_SmartShunt-pdf-en.pdf#UUID-ec008a3b-6c1c-f675-47d6-0605d5e18ced

In 10.3.3, it says something about "there is a current reading when no current flows". And refers the owner to the "Current Threshold" setting, Paragraph 7.2.8.

7.2.8. Current threshold

When the current measured falls below the “Current threshold” parameter it will be considered zero. The “Current threshold” is used to cancel out very small currents that can negatively affect the long-term state of charge readout in noisy environments. For example, if the actual long-term current is 0.0A and, due to injected noise or small offsets, the battery monitor measures 0.05A the battery monitor might, in the long term, incorrectly indicate that the battery is empty or will need to be recharged. When the current threshold in this example is set to 0.1A, the battery monitor calculates with 0.0A so that errors are eliminated. A value of 0.0A disables this function.

In typical Victron fashion, it mentions  "injected noise or small offsets".....and then Victron does not explain what they mean by that statement or what to look for.  And, even with that, it still doesn't explain why your controller section of the app is showing the same state of charge.

At this point, it might be time to simply pull the battery fuse at the battery (near the Gloso breaker) and see if that removes the drain on the Shunt.

Ghannan

My plan:
Confirm Battery switch to off
Remove pos battery cable
Measure battery voltage
Check shunt connections, while I'm under the bed!
Reconnect pos cable to battery
Battery switch to "on"
Check victron app current via shunt (should read 0, or close to it)
If negative, pull one fuse at a time at fuse panel and check victron shunt current
Repeat for each fuse (to see what is drawing current when everything is turned off; i.e., standby power)

Turn battery switch off and, if shunt shows a current draw from batter, pull one fuse at a time to see if it drops to zero when pulled.

I will also check the victron settings for what is set as a "noise"  current draw.

Thanks

Ghannan

First, I will check the battery switch to make sure it is actually cutting the current flow to zero.  Maybe it is leaking a little.  Tripping the breaker or pulling the fuse should determine that

Horigan

I would check for things connected to the battery before the battery switch.  Solar chargers are an example and are generally not part of the battery switch circuit.  Same goes for any added chargers.  I would check the small distribution block that the positive battery cable connects to to see if any other devices are connected there.  From that distribution block is the wire that goes to the battery switch, and then on to the power panel with fuses.

rfuss928

Many electrical issues are substantially easier to sort out with an Amp Clamp style meter.  Some include a multimeter as part of the same instrument.  There are several adequate models available in the $20 -$30 range.  Make sure it has low range selection with ~5.00 amp maximum so you can detect low parasitic currents. 
These meters can be quickly clamped around any single wire and measure magnitude and direction of current.
It is a great help during investigations like Ghannan describes.  It also provides confirming amp values for the other measuring devices in the system (like the Smart Shunt).
FWIW - I think the Victron Smart Shunt & Solar Controller are the 140mA drain described in the OP.

dsfdogs

@Ghannan I don't know all that's been discussed in the FB group, but I'll offer what I know from my own experiences.
First, I don't look at the % of battery life as it's not accurate. Rather I look at the voltage and reference this chart:

14.4V = 100%
13.6V = 100%
13.4V = 99%
13.3V = 90%
13.2V = 70%
13.1V = 40%
13.0V = 30%
12.9V = 20%
12.8V = 17%
12.5V = 14%
12.0V = 9%

Second, the solar controller is still on and draws some power with battery switch off. (Which is nice so it'll charge battery while in storage). 

Third, check the battery heater switch is off. I had an issue last year and it was off, and yet my batteries dropped real low in prolonged low temps (high teens). I have now removed the red heater cable from the battery.

I had a system switch installed so when it's off, batteries are off, solar off, etc.

Lastly, with everything off, and batteries charged to 14.x, they will slowly drop and settle around 13.32v and sit there.

Good luck with your testing,

Ghannan

I didn't know the heater could do that.  One more thing to check!

Ghannan

I just ran some tests at the battery shutoff switch to see if the switch is defective: it is not.  Switch off: shunt reads -0.12A.  Switch on, but glosso breaker tripped: shunt reads -0.12A.    Switch on, breaker on, 30A inline fuse pulled: shunt reads -0.12A.
Clearly, there is a 0.12A drain from the battery, coming from upstream of the battery switch/breaker/fuse.  That leaves only the solar controller, which only draws 10-19mA, the bmv712 shunt smart (and included Bluetooth system).  The shunt should draw < 1mA (from victron data sheet), so, how much does Bluetooth draw??  Someone posted a measurement of 300mA with backlighting of the wired display off and the shunt active (whatever that means), and much less (was it 10 or 30?)when inactive. I can't find other info about amps used, but these numbers suggest that ther might be a draw of as much as 1+19+300= about 320mA, or as little as 1+10+10=21mA.
So, I think my draw of 0.12A with battery switch off is in the range of possible phantom load.
My 100Ah lithium battery dropped from 97%SOC to about 50%SOC in 24 days.  Let's say 50 Ahrs used in 25 days, or 2Ahr per day.   0.12Ah x 24 hr/day=2.8Ah per day.  Close enough for government work.
Sorry about the techno-geekiness about this.

Maxcamp

One longterm solution is to ensure every battery terminal lead, positive and negative, is wired via an inline fuse or breaker.  Keep in mind if you do a major electrical rewire in the future.
It also facilitates checking battery health individually. 
I just flip off my pos and neg breakers between the battery terminals and my load terminal strips.  Great for maintenance activities and for storage.

Rather than yank inline 30a fuses on the solar charge controllers I wired a double pole switch on those, and on fridge line.  Kills any phantom draws.

bjn2

I have a cover on our trailer, so solar isn't a factor at the moment. Each Victron component in our system is drawing power even with the cutoff engaged (there's a SmartShunt and two solar controllers in ours). I also have a transmitter for our TPMS that's wired directly to the battery. So all those are a drain with the battery cutoff engaged.

One thing I've found is that with the trailer on shore power and the battery active, our "lithium ready" WFCO converter doesn't provide high enough voltage to prevent 12 volt system loads from drawing the battery down. 

I use a Victron charger to charge the battery. I'd like to keep the battery at 80% charge so I can quickly top off the battery should we take off for a weekend, but I can't drain it to 80% and leave it for an extended time. I'm considering adding breakers to use as switches on the solar controllers.

Ghannan

I just checked loads on various wires with a clamp ammeter.  Battery switch off, solar charging off (via app).  At solar controller: red wire into controller is 0.21A.
In from solar panel is 0.02A (cloudy, with fabric cover on).
Black main battery cable between battery and smart shunt is 0.022
Red main battery cable to distribution block is 0.008A, two thin red wires from positive battery terminal that disappear under the kitchen cabinetry read 0.012 each (are these for powering the solar controller?  If so, why are there 2 wires, not one?).  I'm pretty sure these measurements were done correctly, but they don't add up to the measured solar controller current at the solar controller box.
Inverter is off, but I measured it's red input cable at 0.009A (close enough to equal the main red battery cable going to distribution block).
Smart red battery heater wire measured 0.004 (heater is not on, so why is it not zero?).  I will try to put the on a circuit diagram