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weirdstuff · 03-20-2015, 11:43 AM

Four weeks ago we went on a 4 night trip and were boon-docking. During the sunny days, our 200 watts of solar panels seem to completely charge our house batteries (12.85 v reading). Within a couple hours of the sun going down, our house batteries were already dropping down to a reading of 12.45.

At night, the only thing we had on was the fridge, and a few lights for about an hour. By morning, our batteries were reading 12.25.

Since that trip, the vehicle has been stored at our indoor storage facility and has been plugged in the whole time. Today, the manager went to move our unit in order to get somebody else’s rv out, and our chassis battery seems to be dead. He said that it didn’t even turn over when he turned the key.

WTF???!!! Anyone have any ideas??

weirdstuff · 03-20-2015, 12:31 PM

Forgot to mention....the storage facility manager also said that the key fob would NOT work to unlock the doors and he had to use the manual key in the driver's door to open the rv.

Mjgman · 03-20-2015, 02:12 PM

I had a similar problem.. The coach battery and car battery were losing charge and everything was dead.

I took it in for service and they found that there was a wire that had a screw through it and that was causing a fault.. They fixed the wire and when I got it home I let the coach battery drain to make sure it was fixed..

You could also have a bad battery separator..

Protagonist · 03-20-2015, 02:34 PM

Key fob remote doesn't work if chassis battery is dead. Fob sends a signal, but lock doesn't receive.

The thing that confuses me is that the BIM should have isolated the house and chassis systems before a drain on one system dragged the other battery down with it. I'd expect house or chassis battery to be dead but not both. This leads me to one conclusion; the batteries were overcharged, and the damage was done before the voltage dropped to the point where the BIM would isolate the systems. But it doesn't hurt to check a few other things first, just to be sure it's not something simpler.

I'll eliminate old decrepit batteries as a cause, right off the bat. A 2013 Interstate isn't old enough for the batteries to be kaput due to age. But it's a safe bet they're kaput now! Plan on replacing them.

Basic rule of troubleshooting, check the easy things first. Easiest thing, just because shore power cord is plugged in doesn't mean shore power is turned on! Easy to forget to flip on a breaker. If the shore power wasn't on, the charger couldn't charge.
Second easiest thing to check, does the shore power source have correct polarity?
Third easiest, is the inverter/charger even working? Could be a blown fuse. In order for the unit to work at all, it's powered by the 12vDC (else it couldn't invert), and it's independent of the main disconnect (else it couldn't charge the batteries with the disconnect switched off). So it must have an internal fuse separate from the fuse panel.

Getting into my speculation above, it makes a difference if you have a TrippLite or a Magnum inverter/charger. And if you've added a temperature sensor on the Magnum so that temperature compensation will work.

Especially with the TrippLite, which is a less-sophisticated unit, if it was left plugged in and turned on for a whole month, it could easily have over-charged your batteries, which would damage the batteries as surely as over-depleting them will. But even a Magnum unit without temperature compensation could conceivably do the same thing; it's just not as likely.

Even when I'm camping, I won't leave my TrippLite turned on for more than a week on shore power. If I'll be camping longer, I turn on the TrippLite for the first few days, shut it off for the middle of the stay, and turn it back on a day or two before breaking camp, to make sure it doesn't cook the batteries by over-charging in between.

InterBlog · 03-20-2015, 03:02 PM

A common problem is described in this thread - cooked batteries. For anyone who is interested in more info, here's a post on the subject. Knock wood, we have had no further issues since upgrading to a converter that has an integrated temperature sensor. At first, the temp sensor thing seemed a little gimmicky to me, but FWIW, the battery appears to be performing very well five months post-replacement (knock more wood).

THE INTERSTATE BLOG: REPLACING THE ELECTRICAL CONVERTER IN AN AIRSTREAM INTERSTATE

weirdstuff · 03-20-2015, 03:21 PM

Our house batteries were replaced in June 2014 by Lew. We have two 6v golf cart batteries. And we have a Magnum inverter/charger.

I should clarify something...the coach battery seems to be dead now. BUT...we have to get out to storage to see what the house batteries are currently doing. Until then, I don't know if the house batteries are also depleted. When we experienced the house batteries not holding a charge (4 weeks ago), we did not have any issues with the chassis battery.

weirdstuff · 03-20-2015, 03:22 PM

mjgman....who did you take it to for service? Airstream or Mercedes?

weirdstuff · 03-20-2015, 03:32 PM

Re-reading Protag's post, here's some other info:

1. Yes, we DO have a temperature sensor on the inverter.
2. When we go out to the rig, I will check to see if inverter is actually inverting.

Mjgman · 03-20-2015, 03:36 PM

I took it to an Airstream dealer.

Protagonist · 03-20-2015, 03:43 PM

Quote:

Originally Posted by weirdstuff

Re-reading Protag's post, here's some other info:

1. Yes, we DO have a temperature sensor on the inverter.
2. When we go out to the rig, I will check to see if inverter is actually inverting.

If you have a Magnum with temperature sensor, the chances of your batteries getting cooked by overcharging is virtually nonexistent. So scratch that idea.

So it comes back to three possibilities, near as I can tell:
1 - shore power system not providing shore power;
2 - inverter/charger not converting shore power to 12v to charge the batteries.
3 - parasitic drain that depletes the battery faster than the inverter/charger can charge them, from something inadvertently left on.

jerhofer · 03-20-2015, 06:43 PM

Will the batteries charge if the inverter is switched on?

BillyBoy · 03-20-2015, 07:06 PM

For what it's worth, I had a dead battery problem with my brand new Grand Tour. Everything went dead within a week - chassis and house(2). I called the battery manufacturer directlky, and he told me it was a common problem because Airstream buys the chassis from MB and then it sits in their yard for months before they get to the RV dealer. Then the RV sits for months on the lot before being sold. Bottom line: the batteries have no life left when they finally get to a good home. In my case, the chassis battery was replaced by MB, and the house batteries by the RV dealer. Problem never came back.

lewster · 03-20-2015, 07:23 PM

Interesting situation.

Many unanswered questions.........

Is unit connected to shore power ?(Magnum inverter/charger should be charging house batteries and BIM should be monitoring the voltage of the chassis battery and connecting the 2 banks when: 1. a charging source is present and 2. the engine battery is below 80% depth of discharge.

These were NEW Lifeline AGM batteries installed at the time of the solar installation, so there is no relationship to the situation where they stay on a dealer lot for extended periods in an uncharged state and are ruined.

Magnum inverter/chargers will NOT INVERT in the presence of shore power, but WILL charge the house batteries......ASSUMING THAT THE CHARGER BUTTON HAS NOT BEED DEPRESSED AND THE CHARGER IS PLACED IN STANDBY MODE

If stored indoors with the solar unable to charge the house batteries and the battery disconnect left on with no charging source present, the parasitic loads WILL drain the batteries......both banks! The batteries are not 'cooked' as both the Magnum inverter/charger AND the Blue Sky 3000i MPPT solar controller have temperature compensation to regulate the charge voltages.

IF the inverter was left in the 'INVERT' position while not plugged in to shore power or exposed to solar, then it is entirely plausible that the house batteries are drained from the draw of the inverter.

Any time a coach or trailer is placed in storage INDOORS with no shore power or exposure to sunlight (assuming a solar charging system), then ALL battery disconnects should be OFF! It's even a good idea to be sure that the batteries are fully charged BEFORE placing the rig in storage, and even removing the negative battery cable from the engine battery. Sprinters have a ton of parasitic chassis loads.

I have a 2011......

NEED MORE DESCRIPTIVE DATA OF THE SITUATION.............

weirdstuff · 03-20-2015, 08:12 PM

1. Storage manager said he's had it plugged in, per our request. We even checked with him about a week after our last trip, just to confirm that he was leaving it plugged in. Is it possible he wasn't telling the truth? Yes, it's possible.

2. Prior to plugging it in, we could not get the inverter's charge button to turn green for "on." LEW, remember in Albuquerque, you had to reset that for us as well. We can not figure out how the heck to get it to turn green again.

3. The inverter was definitely in "off" this whole time (inverter was NOT on)

Saturday (tomorrow) afternoon, we will go out to storage and see if there's any more clues. Will see how much charge the house batteries are showing. Will report back.

lewster · 03-20-2015, 08:25 PM

Quote:

Originally Posted by weirdstuff

1. Storage manager said he's had it plugged in, per our request. We even checked with him about a week after our last trip, just to confirm that he was leaving it plugged in. Is it possible he wasn't telling the truth? Yes, it's possible.

2. Prior to plugging it in, we could not get the inverter's charge button to turn green for "on." LEW, remember in Albuquerque, you had to reset that for us as well. We can not figure out how the heck to get it to turn green again.

3. The inverter was definitely in "off" this whole time (inverter was NOT on)

Saturday (tomorrow) afternoon, we will go out to storage and see if there's any more clues. Will see how much charge the house batteries are showing. Will report back.

Remember that you have to 'wake up' the remote panel of the inverter, as it goes to sleep after about a minute. Hitting any button does this. Then hit the 'charge' button and press it firmly. The charge light should be solid green.

If this won't happen, you might need a re-set of the inverter. To do this, locate the area where the small grey button and green LED are located. Press the grey button and HOLD until the green LED flashes rapidly this might take a while). Wait 15 seconds and then release. See if you get to charge mode then with the charge LED solid.

If it IS solid, it should show what charging phase you are in and how much charge is going into the batteries.

weirdstuff · 03-20-2015, 08:41 PM

Lew, yes, I know you have to wake up the unit first. But when we hit the charge button, it would not light up green. When we go there on Saturday, I'll try again and I'll press it very firmly. If still no green, we'll reset per your instructions above.

Will report back what we discover later on Saturday afternoon.

Thanks....

weirdstuff · 03-20-2015, 08:56 PM

Question...I still don't understand....when we have rv stored, assuming it's either plugged in or is getting sun for solar panels, will the chassis battery also be getting charged? Does it matter whether or not we have activated the battery disconnect switch by the sliding door?

Boxster1971 · 03-21-2015, 08:46 AM

As Lew noted above the chassis batter should be kept charged by the BIM (Batter Isolation Manager). The battery disconnect switch does not effect BIM functions.

- - Mike
2013 Lounge EXT on 2012 Sprinter

Protagonist · 03-21-2015, 08:55 AM

Quote:

Originally Posted by Boxster1971

As Lew noted above the chassis batter should be kept charged by the BIM (Batter Isolation Manager). The battery disconnect switch does not effect BIM functions.

I believe that the BIM is also a (small) parasitic draw that can't be turned off. In order to monitor voltage on both the house side and chassis side, and connect or disconnect them as necessary without human intervention, it must draw power in order to meter the two systems, and it must have a solenoid switch that is closed when powered and open when not powered (so in the event of power loss the default is the house and chassis sides are disconnected).

I believe that the BIM draws the power to operate itself from the house batteries, not from the chassis side, but I could be wrong about that.

UKDUDE · 03-21-2015, 12:33 PM

It took me a while to find out - and a call to Magnum support - that the Magnum Remote Control needs to be in "Home" mode before the On/Off button will turn on the inverter and green light come on. And when you plug in shore power, it takes it OUT of "Home" mode! So press the Home (middle) button for 2 seconds to get it into Home mode. Then the inverter will turn on.
Try it and let me know.
Peter

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