House Batteries and Chassis Batteries

[DoghouseII]

Good morning-

Does anyone know ANY condition that would drain both the chassis battery AND house batteries. I did leave the Inverter on and I also was not familiar enough with AGS system, so it was set improperly. However from research, this condition should never exist, since theoretically the two (house and chassis batteries) should only meet when using the battery boost.

I have an all electric Ventana 4002 2015 DP Magnum Inverter / Conv etc..

Apologize in advance if I missed any previous posts on this issue or if this is an old issue that does not need rehashing.

Thank you all

[twinboat]

Depending on how long it sat, both battery banks could have independently discharged.

There are other conditions when the batteries are linked, but that is only when a charging source is avalable. e.g.: inverter/charger on shore or generator power OR when engine is running and alternator has recharged the chassis battery.

How long did the rig sit before you found the batteries down.

[DoghouseII]

it sat for two days.

[C.Martin]

Two days is awfully quick unless you had the fridge running. My Ventana has about -1.6 amp drain on the house side. I have never measured the chassis parasitic drains. The amp draw goes up co sideravly with the fridge running. -17.6 amps at time with compressor running. As already pointed out...there is an Intellitec BIM behind your cord reel (hidden on bulkhead behind plastic panel) It only ties a charging source...ie Alt to house when engine is running, or Magnum Charger (& solar if installed and charging) to chassis when house is being charged. Unless the boost switch is depressed. There should also be a lockout if Ignition is ON and Generator running.

If the fridge was running off the inverter while unplugged...two days is about right. Otherwise, you might have to charge and test batteries. Replace if weak or have dry/dead/shorted cell(s). After fully charging all banks...disconnect from charge source and use a dc clampmeter to measure amperage draw. If you find a cable with an unusually high load...investigate.

There are a few drains that can become nuisance when stored that may be overlooked. Lighting in basement...some have incandescent bulbs, with switches...front hood, left rear compartment, wet bay, I know there are others. I replaced them with LED's last year. The pass thru is already led with a door plunger switch. Cycling water pump.

Anyway...start there. I hope it's an easy find.

Might be time for new batteries.

When you have time...we need to check you out on the AGS and double check the LBCO on the Inverter.

[vsheetz]

Two days for house batteries to go down with no disconnects enabled and RR operating woukd be expected.

Chassis batteries down in two days, something not right.

[DoghouseII]

That's my issue. I have no issues with house batteries dying, but cannot figure out how the chassis batteries got drained.

[twinboat]

Get them all charged up then shut everything down and pull the shore power plug.

Now turn on the inverter and boil some water in the microwave, while monitoring the chassis battery voltage.

The inverter will drag the house batteries down but the chassis batteries shouldn't drop below 12.6 or .7 volts.

If they do, your isolation relay may be activated when it shouldn't be.

Disconnect the small wire on it and test again.

["007"]

I just post this in another thread should help you out read all links.
Any time you have at least 110 to plug in shore line make sure you have BCO switch on.
With the first link in that thread you have a Newmar search engine to ask questions about your AGS and inverter/ converter or just go into QT's#3 and find the section that covers them or may also find in PROBLEM SOLVERS of same link.
If you coach is not plugged in shut off inverter could be one or two switches dependent on type inverter so hpuse batteries do not discharge.

[DoghouseII]

Where do I find the isolation relay? And how do I test it?

Thank you very much.

["007"]

There are pictures in that master link in the BIRD and BIM charging systems from 97 to present and in your owners guide you got with your coach.

[twinboat]

Have someone push the boost switch on and off and listen for it clunking.

Read the volts on each big terminal to ground.
When boost switch is pushed and held, both readings should be the same.

[CoreyinWP]

BIM 2017 ventana...behind cord reel and plastic cover

[imnprsd]

The obvious is that your AC-residential refrigerator was drawing an average of 1A to 2A-AC for 10 hours/day. (Starting stopping.) That’s the equivalent of 20 AC amps/day or 200-DC amps/day. ...Now add for your inverter current loss (85% efficient); and other systems current drain... and you now know you need to recharge daily. (And you really should not drain your batteries below 40% if you want them to last. Hence the green range in the chart.)

Also, if you don’t know, DC amps x 10 is the approximate equivalent to AC amps. (Ratio 120Vac/12Vdc = 10). So 1A-AC is equivalent to 10A-DC.

So… How many house batteries do you have and what are their Amp-hour ratings? Then multiply that by 60% or 70% (the useful battery range) depending on how old they are you will see you probably just drained your batteries down below 11.3V. (See picture.)

Note: 4 GC-2 Golf cart batteries (6V) are rated at 220-AH. That said, 2 batteries are in series; and 2 are in parallel... for a total of 440AH. So 70% of that is 264-308A-DC. Which means your battery bank will be exhausted if you don't recharge after this point.

The less obvious means you might have:

* A house or engine solenoid leaking current to ground. (Use a 12V DC test light to see if you have a gross failure, but this will not tell you if you have a weak or leaking solenoid.)

* Battery boost/jump switch sticking. (As suggested above. Listen for a click.)

* Ignition key switch starting to go bad. (Aka “Switched” Power problem.)

* …And my favorite: You don’t want to overlook the possibility of your engine alternator diodes (for the voltage regulator) might be going bad. These will often leak current to ground and can undetected for years! …Then one day. Poof! In the meantime, these diodes leak current to ground and then your house batteries often follow what the engine batteries do. (Not the other way around thanks to the BIRD relay diodes working like they should. Or your BIRD Relay diodes might be suspect!)

On my RV I had a Leece Naville DUVAC alternator go bad. This alternator was designed for charging the house batteries off my engine alternator, but for years (since I bought the RV) I never could track down the premature battery drain on my house batteries. (And I had new house batteries.) Then one day my alternator went out; and after I replaced the alternator... my house battery life was better.

If your alternator has this option, and I’m not saying it does, you might try disconnecting these alternator (small gauge) wires and then check to see if the current draw goes away.

Important note: Be sure you know how to test for current. This is more dangerous to you and your engine/coach, and checking for current is not the same as checking for voltage. Voltages can easily be checked with a 12V test light in parallel to ground, but current must be checked in series, and all that battery current is like an arc welder in action. So unless you want to FRY SOMETHING… you really need to make sure you have everything isolated from ground or sparks with fly!

* Alternatively, you might look at some YouTube.com videos to learn about how to find a short in your car/RV.

Good luck. Let us know what you find.

[C.Martin]

The chassis batteries...

Should get a trickle from the 10W panel on the roof.

Inside the chassis battery compartment. Look inside the fuse box to the right of the battery switch. That will give you an idea of what things are powered. The two big fuses...100A iirc, power two cables that go to the front left compartment under the drivers seat. Look at the fuse panels there as well. If the batteries aren’t just going bad from age, heat, vibration, etc...then chances are one of these circuits is drawing power when it shouldn’t be.

Plus...if you are a second owner...someone could have added aftermarket toys to the rig. TPMS repeater, 12vdc power port for chargers, add-on gps...???

Most things are very low aH...more like mAH...

A seatbelt pushing against a power seat switch? Leaving a dash radio powered. I don’t trust the quality of the ignition switch. Might turn in on/off...to make sure it’s off. Check to make sure that things power with ignition ON are really Off when you turn the coach off and remove that key. A bad ignition switch could be leaving a lot of things powered.

And of course...a stuck BIM relay. If you place a charger on your chassis...if you look at the tank monitor panel...if yours is the same vintage as mine...one page shows the house voltage and chassis voltage. If they are both the same...chances are that relay is closed...and the two are tied together. Of course, it could be a coincidence...but that’s where I look when my coach is getting charged by solar. If I see both reading 13.9v ...I know solar is charging both the house and chassis at that moment.

Heated mirror switch? I don’t know if that works ignition on or off...but something like that could pose a problem.