Parasitic Battery Drain

[T_Roy]

I have been fighting a Parasitic Battery Drain on my 2015 Entegra Cornerstone. I had replaced the house batteries back in October thinking I just had bad batteries but I still was not getting the run time out of them that I should. I finally got some free time to spend on the situation this week. First with the help of member 757driver on here I discovered the setting in my chargers were jacked up and got that corrected. I then load tested the house batteries and the chassis batteries immediately following a charge cycle. The house batteries tested good and the chassis batteries tested weak. I changed the chassis batteries. The chassis batteries were then holding a good charge but the house batteries were dropping from a full charge down to 12.6 volts within 15 minutes and going back into float charging with the inverters turned off. I turned the 50 amp service off so I could watch the draw down then turned the 12 volt salesman switch off and the voltage stabilized and stopped falling. I turned the salesman switch back on and the voltage started falling quickly again. I started pulling fuses from the panel in the half bath one at a time and watching the voltage. When I pulled Fuse 4 which is for the monitor panels and water pump the voltage stabilized and stopped dropping. I watched it for one hour and did not even lose 0.1 of a volt, reminder the inverters are off at this point. While the fuse was pulled I messed with the wiring on the water pump a little bit. I did not see anything obvious but I have not opened up the looms yet. After moving the wires around I plugged the fuse back in and the voltage remained stable!! I was out of time at this point so I turned the 50 amp service back on to let the batteries charge again and cool the fridge and freezer back down. My next step will be to remove some tape and open the wire loom up to see what I can find but I may run the inverters first to see how the batteries do before fooling with the wiring again.

Sorry for this long post. Has anyone else with a classic had issues with a parasitic battery drain involving the monitor panels and water pump circuit?

[wolfgolden]

An ammeter like a victron shunt or other cheap Chinese shunt from Amazon will give you better and more accurate information than the voltmeter. The shunt will give you accurate real time information on battery drain and would likely be my first step in troubleshooting.

[Olyteddy]

A DC Amp Clamp meter is also an invaluable tool for tracing parasitic currents. Unless you need continuous monitoring or display that's what I'd use.

[voltdoc]

Prior to 2017 on a stock Entegra there is no means, like a battery cutoff switch, to completely eliminate the parasitic drain.

The biggest offenders are usually the Magnum Inverter/Charger remote panels over the entry door. Even with the Inverters "off" the panels draw about 350mA each which will flatten the house batteries in a matter of weeks. This is a very common issue for RV's and boats with inverters and no battery cutoff switch. It is similar to a TV that is "off" but still draws power so the remote control will work.

Since the Magnums (and therefore the remote panels) are directly connected to the house batteries, the only way to eliminate this drain is to physically remove the inverter cables or to install a whole coach house battery cutoff switch.

Also, the CO2 detector is powered always and will have a parasitic drain - the fuse for that is in the fender compartment in front of the driver side wheel. The Aquahot also has full time power but I don't think much of a parasitic load.

As previously mentioned, pulling fuses and observing voltage is not an effective means of determining where the drains are occurring. A DC clamp meter or ME-BMK (battery monitor kit) will show actual current drain which is much more meaningful. The ME-BMK will report the battery charge/discharge current as well as State of Charge and more accurate voltage to one of your already existing Magnum Remotes.

Keep in mind, when plugged into shore power, the Magnum charger will not constantly charge or float the chassis batteries, that is managed by the Battery Isolation Manager which will only periodically, and when needed, divert charging power to the chassis batteries by interconnecting them with the house batteries.

If your goal is to eliminate all parasitic house battery bank loads while the coach is in storage and not plugged in, addition of a battery cutoff switch is one convenient and effective option. If AC power is available, just leaving the coach plugged in will do the job.

A few Entegra owners have done this cutoff switch modification (the document title says "Aspire", but it is actually for the Anthem/Cornerstone):
https://drive.google.com/file/d/10qh...ew?usp=sharing

[K7JV]

Just a few days back, I found a table that shows fuse current as a function of fuse size and fuse voltage. It's the basic I=E/R. Rather than try to keep the table, I reduced it to just the I=E/R equation and listed the resistance for each of the standard fuse sizes. I've not played with it, but if the values are true, I really like the idea.

Two points need to be mentioned. First, the readings need to be taken with the multimeter on the lowest voltage setting available, as the voltages are going to be extremely small. (You would hope so, right? We don't want our fuse panels to be electric furnaces!). You should be looking at milli-volts.

Second, do NOT pull the fuse. And do NOT operate devices or open doors or turn systems on or off right before doing this. There are many systems in our coaches that are time sensitive. For example in a car, the dash or interior lights may stay on for some time after the doors are closed. Or there may be systems that "arm" after a minute or two or three, like a security system.

Just go to your fuse panel and start down the line. You should hopefully see zero or near zero on every fuse except those that you know to be active with everything off, such as radio memory power, or security system power, or propane alarms.

Take the milli-amps that you calculate, multiply that by 24 to find how many amp-hours that will take from your battery in a day. At the bottom of this table is an example test result.

Fuse Resistance - Standard ATO/ATC Fuses

1 Amp Black .121 Ω
2 Amp Grey .053 Ω
3 Amp Violet .031 Ω
4 Amp Pink .023 Ω
5 Amp Tan .018 Ω
7.5 Amp Brown .0109 Ω
10 Amp Red .00769 Ω
15 Amp Blue .00480 Ω
20 Amp Yellow .00338 Ω
25 Amp Clear .00252 Ω
30 Amp Green .00197 Ω
35 Amp Blu/Grn .00161 Ω
40 Amp Orange .00144 Ω


EXAMPLE
I = E / R

15 Amp Fuse
E = 0.0023 v
R = .0048
I = 0.479 A

I x 24 = 11.5 amp-hours per day.
That equals 345 amp-hours per month.

In a month that would pretty much kill a typical 400 amp-hour house battery bank!

[T_Roy]

I guess me saying I am fighting a parasitic drain was a poor choice of words. What I am fighting is a large draw that is taking my voltage on the brand new load tested house batteries from 13 volts down to 12.1 volts, which is where the AGS is set, in about 30 minutes or so. This is with the inverters turned off and none of the 12 volt systems switched on and all lights turned off. Normal parasitic loads will still be there but some large draw is also there that should not be.

[RVFunlovers]

T Roy, I see what you are saying.
Something well beyond a small parasite draw is needed to drop your batteries that fast in under an hour. Unless your batteries are bad.

I would trust an amp meter and see what your amp draw really is.

Newer coaches can see the amp draw on vegatouch. Not that I would call that trustable but at least it is something to start with.

[voltdoc]

Originally Posted by T_Roy

I guess me saying I am fighting a parasitic drain was a poor choice of words. What I am fighting is a large draw that is taking my voltage on the brand new load tested house batteries from 13 volts down to 12.1 volts, which is where the AGS is set, in about 30 minutes or so. This is with the inverters turned off and none of the 12 volt systems switched on and all lights turned off. Normal parasitic loads will still be there but some large draw is also there that should not be.

Ok that's different, but something is way out of whack there. A load that will drain your house bank with allegedly healthy batteries from a full charge to 12.1v (around 50% discharged or 400 amp-hours) in 30 minutes is just massive. That would be an 800 amp load! Well ok probably less due to Pukerts Law, but in any case I doubt that is actually happening or you would be seeing smoke and flames. Plus, the auto reset breakers for the 4 subsystem feeds are only rated at 120 amps. The inverter class T fuses are rated for 300A and 400A.

Are you sure the house bank battery wiring was/is installed correctly?
What are you using to measure the battery voltage? Have you tried measuring with a good DVM directly at the battery?

To continue looking for a large draw, after checking the battery cabling, short of installing a shunt and BMK, suggest you invest in a clamp on DC ammeter something like this one (note the cheaper clamp on meters only measure AC), and take some actual DC current drain readings.

See the house bank wiring schematic here:
https://drive.google.com/file/d/1z0O...ew?usp=sharing

There are 3 fat 3/0 red cables coming off your house battery bank, inverter 1, inverter 2 and main house feed. The main house feed goes to a stud on the back wall of the battery bay. The schematic also shows a 2/0 cable off the upper bank that feeds the generator starter thru a 120A auto reset breaker, but I'm not sure that is correct, I don't recall ever seeing that cable connected directly to the batteries.

From the isolation stud on the back wall, you have 3 additional subsystem feeds thru 120A self resetting breakers:
- Leveling Jack Pump
- Battery Disconnect Solenoid (main house feeds controlled by the Salesman Switch)
- Battery Interconnect Solenoid (parallels Chassis and House batteries to boost engine starting).

Start with measuring amps on the inverter cables, with the inverter and charger both off, there should be only a small drain, probably under an amp. If there is something more significant then something may be going on with one of your inverters.

If all seems normal on the inverters, clamp on to the house feed and see what you get. If there is something excessive, from there follow the wiring that disperses thru four auto reset breakers and see to which subsystem is the culprit.

[voltdoc]

Originally Posted by RVFunlovers

T Roy, I see what you are saying.
Something well beyond a small parasite draw is needed to drop your batteries that fast in under an hour. Unless your batteries are bad.

I would trust an amp meter and see what your amp draw really is.

Newer coaches can see the amp draw on vegatouch. Not that I would call that trustable but at least it is something to start with.

Actually, unless the newest coaches have added a shunt and some form of battery monitor (very doubtful), the Vegatouch doesn't know anything beyond what the original Magnum Remotes provided (typically an ME-RC50 was installed on non-Vegatouch Entegras). The amp readings in either case are amps provided via the Magnum inverter, such as to the TV's and refrigerator (when not on shore power). Or charger total output all of which isn't necessarily going to the batteries.

Ordinary 12 volt DC loads, for example the lights, water pump, etc are powered directly from the battery so the Magnum has no idea what they are doing. To measure the real power status, a shunt is required in the battery negative and an accessory like the ME-BMK (Battery Monitor Kit) or equivalent to measure actual amps in/out of the battery bank. The BMK will also track the total amps in/out over time which can more accurately approximate the actual state of charge (SOC) based on amps consumed instead of voltage.

For example, if the Magnum Remote or Vegatouch says the charger is putting out 20 amps, but you have all your lights on, and they consume 5 amps, the batteries are actually only getting a 15 amp charge. A ME-RC50 plus a BMK can tell you that, but a stock coach with only a Vegatouch or ME-RC50 and no BMK cannot.

I have also noticed the battery voltage from the BMK is much more accurate than the voltage measured by the Magnum without a BMK. I recently observed that the BMK reports a significantly different voltage vs the stock Magnum - for example, with 97% SOC under a 42A load on the inverter, the BMK reported voltage was 12.48v and the ordinary Magnum reported voltage was 12.2v That's huge if you are trying to guess state of charge by watching the voltage. I expect this is due to voltage drop across the wimpy 3/0 cables used. The magnitude of the error will increase with size of the inverter load.

[T_Roy]

Originally Posted by voltdoc

Ok that's different, but something is way out of whack there. A load that will drain your house bank with allegedly healthy batteries from a full charge to 12.1v (around 50% discharged or 400 amp-hours) in 30 minutes is just massive. That would be an 800 amp load! Well ok probably less due to Pukerts Law, but in any case I doubt that is actually happening or you would be seeing smoke and flames. Plus, the auto reset breakers for the 4 subsystem feeds are only rated at 120 amps. The inverter class T fuses are rated for 300A and 400A.

Are you sure the house bank battery wiring was/is installed correctly?
What are you using to measure the battery voltage? Have you tried measuring with a good DVM directly at the battery?

To continue looking for a large draw, after checking the battery cabling, short of installing a shunt and BMK, suggest you invest in a clamp on DC ammeter something like this one (note the cheaper clamp on meters only measure AC), and take some actual DC current drain readings.

See the house bank wiring schematic here:
https://drive.google.com/file/d/1z0O...ew?usp=sharing

There are 3 fat 3/0 red cables coming off your house battery bank, inverter 1, inverter 2 and main house feed. The main house feed goes to a stud on the back wall of the battery bay. The schematic also shows a 2/0 cable off the upper bank that feeds the generator starter thru a 120A auto reset breaker, but I'm not sure that is correct, I don't recall ever seeing that cable connected directly to the batteries.

From the isolation stud on the back wall, you have 3 additional subsystem feeds thru 120A self resetting breakers:
- Leveling Jack Pump
- Battery Disconnect Solenoid (main house feeds controlled by the Salesman Switch)
- Battery Interconnect Solenoid (parallels Chassis and House batteries to boost engine starting).

Start with measuring amps on the inverter cables, with the inverter and charger both off, there should be only a small drain, probably under an amp. If there is something more significant then something may be going on with one of your inverters.

If all seems normal on the inverters, clamp on to the house feed and see what you get. If there is something excessive, from there follow the wiring that disperses thru four auto reset breakers and see to which subsystem is the culprit.

Thanks a ton for your help. Thanks for the schematic. The schematic Entegra sent me was not the correct one. The only difference I see in the way mine is wired is the two cables going to the inverters are both coming off of the lower battery bank and the cable going to the isolation stud for the subsystems off of the upper bank. Like you said there is not a fourth positive cable for the generator start hooked directly to the batteries. Also, if I recall correctly I had more negative cables than what the schematic shows. I have 4. Two of them leave that compartment and disappear into the belly of the beast and the other two are hooked together on a stud on the back wall behind the batteries.

I am going to have to go get that amp meter from Harbor Freight. I had one here but it is broken.

The fast drain did not make any sense to me either. I just knew one or more of my house batteries was bad so I load tested them. I may have to load test them again to make sure I did not screw up and test one twice, missing one.

Like a dummy I did not think to test the voltage with my DVM directly at the batteries to make sure the reading on the 2 inverter remotes is correct. The remote on the right does give a slightly higher reading than the left one.

However, the voltage readings on the remotes sure did stop falling when I shut off the salesman switch and also again when I pulled Fuse number 4 in the half bath. Fuse 4 is for the tank level monitoring and the water pump.

Another anomaly is that according to the sticker on the back of the panel door, fuse 4 was originally a 7.5 amp fuse and it now has a 15 amp fuse. The water pump is a model 4048 which has a sticker on it that states the fuse should be 15 amps.

I am going to get that amp meter and do some more troubleshooting.

[The Driver]

Is your engine block heater plugged in? Entegras of your vintage had them wired through the inverter...so they would operate whenever they were plugged in. There was no light to indicate they were operating, so it was easy to forget to unplug them.

[K7JV]

Don't take readings from a DC clamp-on ammeter as "gospel". Those devices are subject to calibration issues (they need to be "zeroed" before every measurement you take) and to their environment. I had a friend call me once (a very technical gentleman whose career was maintaining large generators, in this case a 112 MW hydro generator) to tell me he had a problem. He said that he had just purchased a DC clamp-on ammeter. My first question to him was, "Oh no! You didn't go up and try to measure brush currents on the slip rings, did you?" After a long pause, he said, "Yeah, I did." They are a great tool, but know that they can give erroneous information.

It sounds like you've got quite the project going, but you've got some awesome input from the group, above. Hang in there and you'll nail it!

[brobox]

Having just been through the same thing with the newer L16 batteries and all of the testing, more toward the end of this post. https://www.irv2.com/forums/f278/rea...rs-590328.html

In our situation, I purchased a deep cycle battery charger to where I was getting a true deep cycle charge on the batteries and not a surface charge that the Vega Touch was putting out. I left the cable off over night and checked them with a volt meter....batteries held the charge. Connected the batteries with everything in the coach turned off...batteries held the charge. Once I turned everything on the coach on and drew the batteries down, then charged back up by the Vega Touch numbers, but they were only surface charging to 13.2 volt. They had about 4 hours of use time.

I would start with full charge on the batteries, disconnect the main cables and take a reading with a volt meter. Check the batteries in the morning to see if they held an over night charge with no draws.

[T_Roy]

First thing I need to say in this post is I was wrong about the positive cables in my post last night. I have one positive cable of the top bank that is going to one inverter fuse then 2 positive cables off of the bottom bank with one going to the other inverter fuse and one going to the 12V stud on the back wall.

Also, I believe it was a coincidence that the voltage stabilized yesterday when unplugging the F4 fuse. I believe the voltage was just stabilizing from 13 volts down to 12.6 and I happened to pull it as the batteries reached 12.6. I was thinking 12.9 was a 100% charge instead of 12.6.

I purchased a clamp meter this morning and the following are my readings with the inverters turned off and the 50 amp shore power turned of also. The salesman switch is on. It took about 40 minutes for the voltage to stabilize at 12.6 down from 13.0 when I first killed the shore power. I got 3.38 amps going to the 12 volt stud and I realized I still had fuse 4 out. I put fuse 4 back in and got a positive 3.45 amps so fuse 4 should be of no concern. I got a negative 3.04 amps on the inverter cable that is on the bottom battery bank with the 12 volt stud cable. I got a positive 3.4 amps on the top battery bank cable that goes to the second inverter cable.

So one inverter cable is reading positive 3.4 amps on the top battery bank and the other inverter cable is reading negative 3.04 amps on the bottom battery bank. Does this point to the top battery bank draining into the bottom bank due to battery issues on the bottom bank?? By the way, yes, I did have the clamp meter oriented the same direction on all readings. LOL