Dead engine battery....quiz (2017 AI)

[WillieJ]

The same document that you can download today does not have the specific voltages found in the document I downloaded in 2013. So it is possible that they have changed something in the BIM logic, but unlikely.
= = = = = = =
Detailed Operation:
1) Relay is turned on if:
a) Ignition is on for 20 seconds &
i) 2 minutes have passed since Relay last turned off &
Coach Battery voltage low and needs charging
Chassis Battery has a charging voltage &
Chassis Battery is Less than 15.5V &
Generator is off

b) Ignition is off &
i) 10 minutes have passed since Relay last turned off &
Chassis Battery voltage low and needs charging &
Coach Battery has a charging voltage &
Coach Battery is less than 15.5V
= = = = = = =

Boxster1971,
The document on the Precision Circuits site goes on after your quote to say:

"2) Relay is turned off if:
a) Ignition goes from on to off state
b) Relay has been on for 1 hour
(prevent overcharging and allow to view separate voltages)
Note: The time the Relay will remain on is Voltage dependent and ranges from 60 minutes for high voltages to 5 seconds for low voltages.
c) Anytime Ignition and Generator are both on.
d) Anytime either Battery goes above 15.5 volts for 30 seconds."


Isn't overcharging prevention the job of the voltage regulator for the engine alternator or the charging system in the Magnum inverter/charger?

[FlyFishinRVr]

Originally Posted by VanGo

Wow. I don't know whether to feel better or worse that I'm not alone with this problem. Exact same situation. Plugged in to shore power, house power on, couple of days later, coach battery is dead.

I too have been in contact with David Perales. The most recent repy from him:

Will be very interesting to hear what they think they found because it still makes zero sense in my mind that anything could be killing the chassis battery when plugged into shore power unless there's something very wrong with either the Magnum charger and/or BIM......

[Boxster1971]

Originally Posted by WillieJ

.......
= = = = = = =
Detailed Operation:
1) Relay is turned on if:
a) Ignition is on for 20 seconds &
i) 2 minutes have passed since Relay last turned off &
Coach Battery voltage low and needs charging
Chassis Battery has a charging voltage &
Chassis Battery is Less than 15.5V &
Generator is off

b) Ignition is off &
i) 10 minutes have passed since Relay last turned off &
Chassis Battery voltage low and needs charging &
Coach Battery has a charging voltage &
Coach Battery is less than 15.5V
= = = = = = =

Boxster1971,
The document on the Precision Circuits site goes on after your quote to say:

"2) Relay is turned off if:
a) Ignition goes from on to off state
b) Relay has been on for 1 hour
(prevent overcharging and allow to view separate voltages)
Note: The time the Relay will remain on is Voltage dependent and ranges from 60 minutes for high voltages to 5 seconds for low voltages.
c) Anytime Ignition and Generator are both on.
d) Anytime either Battery goes above 15.5 volts for 30 seconds."

Isn't overcharging prevention the job of the voltage regulator for the engine alternator or the charging system in the Magnum inverter/charger?

Yes I only included the relay ON portion of the Detailed Operation.

The voltage regulator on the Sprinter holds the voltage at around 14V +/- 0.2V. After driving for many hours at that voltage it would be possibly overcharge the LifeLine AGM batteries that should be floated at 13.3 @ 77 degF. So PCI in their design added this 1 hour max to disconnect the batteries and wait 2 minutes before taking a voltage reading and then determining if the batteries should be reconnected.

[Boxster1971]

I may have to eat my words on the Battery Isolator keeping the chassis battery charged when plugged into 120VAC external power.

I've had my Interstate plugged in for past two days as we had several rainy days and there wasn't enough solar to get batteries back to 100% by end of the day. After dark I checked the voltage reading and the house battery voltage on Magnum and Tank panel meter was 12.7V. The Magnum display read Full, not Float. The chassis battery was at 12.5V. With those conditions the Magnum will not charge the chassis battery via the Battery Isolator (BIM).

I forgot that the Mangum charger logic has a mode called “Full Charge”. Here is description from owner’s manual:

"Full Charge (Battery Saver™ mode): The fourth stage occurs
after four hours of float charging. The Full Charge stage maintains
the batteries without overcharging, preventing excessive loss of
water in flooded batteries or drying out of GEL/AGM batteries. In
this stage, the charger is turned off and begins monitoring the
battery voltage. If the battery voltage drops low (≤12.7 VDC),
the charger will automatically initiate another four hours in float
charge."

It is also possible that if the Magnum Float voltage is set low the Battery Isolator will not connect the batteries and thus cause the chassis battery to be drained over time. For example, the recommended setting of AGM1 on the Magnum charger will give a float voltage of 13.1V. It is possible that this is too low to cause the Battery Isolation relay to connect and charge the chassis battery when plugged in. Since I don’t know the actual voltage needed to connect the Battery Isolation relay this is speculation. It was 13V in 2012, but it may be higher today. If it was higher the relay might never close when plugged in once the house batteries got to Float or Full.

This is something you can check when plugged in using the “BATTERY VOLTAGE” meter on the TouchSensor tank level panel. Image of this panel attached. Check the voltages using the toggle switch to “BATT MAIN” and “BATT AUX”. If they are the same; then the batteries are connected. If they differ by several tenths of a volt the batteries are disconnected. If at a Float voltage of 13.1+ volts on the Magnum and the “BATT MAIN” voltage is lower than 12.6V the batteries are not connecting when they should be. These voltages should eb checked several times over a 5 minute period due to logic in the BIM Control module.

If you have your Interstate stored inside a building it also never gets any soalr charging and is only charger by the Magnum unit.

[amirm]

That's good analysis but whether the Magnum charges or doesn't would be secondary in my book. They must not put such heavy loads on the chassis battery to drain it in a couple of days. That load must be removed.

[InterBlog]

I don't have any specific troubleshooting advice for the OP, just this general observation:

We were having "all kindsa frigged up" for as long as our chassis and our coach remained in ANY kind of electrical communication. We have 300 watts of high-efficiency AM Solar panels on our roof and after struggling with this issue for months, I told my husband, "Just do what you have to do to isolate the coach. To hell with the connectivity, to hell with the alternator - we'll run on solar alone, and if we get bad weather, we'll cross that bridge when we come to it."

So he did, and our problems vanished immediately. My husband (LB_3) is an engineer and still has zero clues as to why this worked, but it worked.

As we now continue with our lithium upgrade, lesson having been learned, I'd like any alternator contribution to be elective, and only when needed. In other words, some kind of an isolation switch so that the chassis doesn't converse with the coach unless we absolutely need it to, and we make the conscious decision to allow it. Especially given that we still don't know what was going on in the first place, or what it might mean in the future, to me, that seems like the best K.I.S.S. approach.

[Titus]

I found this troubleshooting guide from Precision Circuits to be helpful:

Trouble Shooting of Battery Isolation Manager is complicated. It is much easier to check the proper operation.
Operational Testing:

Press Dash Switch. Relay should audibly click and Voltage from Chassis Terminal to Coach Terminal should be <0.2V. If Not, Check for 12V power from Dash Switch to Ground Terminal directly on Relay. (Do not use a Chassis Ground) If 12V present and Relay does not click or bring Chassis and Coach Battery Voltage close, replace Relay.

Release Dash Switch Start Engine & Turn on Coach LightsWait between 20 seconds and 2 minutes and Relay should click. Voltage from Dash Switch Terminal to Ground Terminal should be between 3.5Vdc to 6.0Vdc. If not check that Chassis Terminal >13.3Vdc, Coach Terminal <12.6Vdc, Ignition Terminal >12Vdc. (Check that Chassis and Coach Battery connections are not reversed)

Turn off Engine Plug in Shore Power & Turn on Battery Charger Turn on Head LightsWait up to 10 minutes and Relay should click. Voltage from Dash Switch Terminal to Ground Terminal should be between 3.5Vdc to 6.0Vdc. If not check that Coach Terminal > 13.3Vdc, Chassis Terminal <12.6Vdc, Ignition Terminal <2Vdc.

[Boxster1971]

Originally Posted by amirm

That's good analysis but whether the Magnum charges or doesn't would be secondary in my book. They must not put such heavy loads on the chassis battery to drain it in a couple of days. That load must be removed.

The OP, ScottP, said his Interstate sat for a week before he checked it and found a dead chassis battery. He has also reported past incidents of running his chassis battery flat. My conclusion is the battery is weakened and can't sit for a week uncharged.

Of course my conclusion is based on limited data. Without some voltage and current measurements, done regularly over time, we are all just speculating on the causes and solutions based on our experiences.


- - Mike
2013 Lounge EXT on 2012 Sprinter

[Boxster1971]

Originally Posted by InterBlog

I don't have any specific troubleshooting advice for the OP, just this general observation:



We were having "all kindsa frigged up" for as long as our chassis and our coach remained in ANY kind of electrical communication. We have 300 watts of high-efficiency AM Solar panels on our roof and after struggling with this issue for months, I told my husband, "Just do what you have to do to isolate the coach. To hell with the connectivity, to hell with the alternator - we'll run on solar alone, and if we get bad weather, we'll cross that bridge when we come to it."



So he did, and our problems vanished immediately. My husband (LB_3) is an engineer and still has zero clues as to why this worked, but it worked.



As we now continue with our lithium upgrade, lesson having been learned, I'd like any alternator contribution to be elective, and only when needed. In other words, some kind of an isolation switch so that the chassis doesn't converse with the coach unless we absolutely need it to, and we make the conscious decision to allow it. Especially given that we still don't know what was going on in the first place, or what it might mean in the future, to me, that seems like the best K.I.S.S. approach.

Right on InterBlog!! After upgrading to 400 watts of solar my battery issues also vanished. I've measured a constant load of about 0.5A on the coach batteries, mostly from the Magnum Inverter/Charger. This is why Airstream installed a relay to disconnect the Magnum unit; what was SB-164.

I modified my Battery Isolator (BIM) to give me better control and monitoring. Added a switch to disable the BIM and an indicator LED on my main control panel to easily tell when the batteries are connected. Also changed the momentary Battery Boost switch to a ON/OFF switch with indicator light to force BIM relay connection of batteries when needed.

I've observed that with Magnum charging only, as when Interstate is stored inside a building or without adequate solar, the chassis battery may not get a proper charge.


- - Mike
2013 Lounge EXT on 2012 Sprinter

[FlyFishinRVr]

I was thinking about this some more, and wonder if what's going on is a problem with people's understanding of how the new relay works (aka SB-164) vs. anything with the BIM, Magnum, or new Fusion system.

Here's what we know:

- The chassis battery draining issue is only on the newer coaches (mainly '17s, but likely also some late '16s)
- This only happens when connected to shore power
- No solar is present as these units are being stored indoors
- Users are reporting that they are leaving the Main Disconnect switch in the ON position (i.e. red LED is ON, so there is power to the lights, fridge, etc)......

In this config, according to the docs, when connected to shore power the Magnum should be charging the house batts, and when those reach 13.0v, the BIM should connect the house and chassis batts together so all 3 batts are being charged. When they reach a max voltage, the Magnum should be floating them for a period of time according to its charging algorithm.

Instead, what folks are reporting is their chassis battery is going flat (11.0v or less) in a matter of days. I'm not sure what the house batts are doing, and this is important to understanding if these systems are working properly.

If the house batts are 13.0v or higher, then the Magnum is indeed providing a charge to them. If it wasn't, the house batts would be flat in 2-3 days just due to the Magnum being on and connected to them (I think the number was something like 0.5A/hr draw). If the house batts are significantly below 13.0v, then I would start to suspect the new "SB-164" relay or people (owners or dealers) not understanding how their Main Disconnect switch should be set when connected to shore power (it should be ON, with the red LED next to this switch ON) on the new Interstates.

If the house batts are 13.0v or higher yet the chassis battery is flat, then one of two things is the likely cause: Either the BIM is faulty (highly unlikely but not unheard of), or the chassis battery is bad (most likely due to multiple deep discharges).

This latter point is my guess because I don't think dealers are yet familiar with how to maintain the chassis batteries while these new coaches are sitting on their lots and they are killing them before they reach the new owners. I think they are somewhat "stuck" in their old ways and at night they are switching the Main Disconnects OFF (i.e. red LED is OFF) and leaving for the weekend, then turning things back on when they come in on Monday morning (or not....). Prior to SB-164, this used to work just fine because the Magnum was connected to the batteries regardless of the position of the Main Disconnect switch so the charger would maintain everything. Post-SB-164, that's no longer the case. With the Main Disconnect OFF (red LED OFF), the Magnum charger is no longer connected to the batteries so it can't charge them. Since we have also heard reports of dealers complaining that the chassis batteries on the Interstates that are sitting on their lots are dying, I think this adds to the theory that they are not properly maintaining these things prior to selling them. As a result, these chassis batts may very well be ruined by the time people are taking possession of their new rigs. Note that all of this supposes dealers are keeping their stock of Interstates plugged in. My dealer keeps them inside and connected to shore power, but this may not be the case for others.

Here are a few other thoughts that support this theory: For rigs sitting outdoors, like mine, which are only being maintained by solar, everything is relatively fine. Other than an average max chassis voltage of around 12.5v (this is a problem with there not being sufficient solar on the roof, which has been discussed many times in other threads), the batteries are being maintained. Since the BIM/BS doesn't care where the charge is coming from, if there was something systemically wrong with its operation, my batteries would be suffering just like those of the folks who are plugged in, and they aren't. Note that when being stored outdoors and disconnected from shore power you should have your Main Disconnect OFF (i.e. red LED OFF). This ensures your Magnum isn't drawing your batteries down with it's 0.5A/hr parasitic, and it also completely removes things like the new Fusion Infotainment system from the equation (just as a side note, also remember to turn the propane OFF as it draws a whopping 1A/hr just by having that switch on!).

So, that's my theory. In the end, I believe this situation is being caused by the same thing that causes most auto accidents and air disasters: human error.

[FlyFishinRVr]

Originally Posted by Boxster1971

I've observed that with Magnum charging only, as when Interstate is stored inside a building or without adequate solar, the chassis battery may not get a proper charge.


- - Mike
2013 Lounge EXT on 2012 Sprinter

Mike can you elaborate on this? Why is your chassis battery not being properly charged with the rig plugged into shore power?

[Boxster1971]

Originally Posted by FlyFishinRVr

Mike can you elaborate on this? Why is your chassis battery not being properly charged with the rig plugged into shore power?

Because the Magnum is holding the batteries between Float at 13.1V and Full at 13.0-12.7V as discussed in the Magnum documents. In that range the BIM will not connect the chassis battery. I've seen this parked in my driveway and at campgrounds when plugged in without sun light to power solar. Unless I place a load on the system to draw power form the coach batteries the Magnum never switches to the higher Bulk charging voltage.

In Titus' post above with PCI's BIM troubleshooting tips it looks like the BIM needs a charging source at 13.3V to connect the batteries. To me this helps confirm the problem. Basically the Magnum is just doing such a good job keeping the coach batteries at Float or Full voltage that the BIM never connects the chassis battery.

When the sun is available and I'm not plugged into 120VAC power the batteries get a good Bulk charge voltage as soon as the sun is up because the coach batteries have been drawn down a bit overnight. This higher voltage (13.7-14+) makes the BIM connect the chassis battery and give it a nice charge.

My conclusion is Solar is the best thing to keep your batteries topped up when parked and not in use. If no adequate solar is available then a separate charger for chassis battery would be best. Another option is to disconnect the Sprinter chassis battery ground cable near the accelerator - that is quick and easy.

BTW - this problem is not limited to Interstates. I see the problem on other Sprinter/RV forums. A lot of owners solve the problem by adding a trickle charger to keep the chassis battery charged. Advanced RV delivers their B-vans with a built in trickle charger for the Sprinter chassis battery.


- - Mike
2013 Lounge EXT on 2012 Sprinter

[busb2]

Mike I used a trickle charger for the chassis battery on my 2009 AI, after it kept going dead while the AI was stored plugged in. After that, no problems. When I got my 2014 AI, I installed a charge line attached to the chassis battery, with the connection peeking up through the floor under the front of the dash. I keep a small multi stage trickle charger inside the AI and when I store the unit, I just plug it in the charge line and plug it into the power outlet on the left side behind the drivers seat. Simple solution has worked for two years now.

[FlyFishinRVr]

Originally Posted by Boxster1971

Because the Magnum is holding the batteries between Float at 13.1V and Full at 13.0-12.7V as discussed in the Magnum documents. In that range the BIM will not connect the chassis battery. I've seen this parked in my driveway and at campgrounds when plugged in without sun light to power solar. Unless I place a load on the system to draw power form the coach batteries the Magnum never switches to the higher Bulk charging voltage.

In Titus' post above with PCI's BIM troubleshooting tips it looks like the BIM needs a charging source at 13.3V to connect the batteries. To me this helps confirm the problem. Basically the Magnum is just doing such a good job keeping the coach batteries at Float or Full voltage that the BIM never connects the chassis battery.

When the sun is available and I'm not plugged into 120VAC power the batteries get a good Bulk charge voltage as soon as the sun is up because the coach batteries have been drawn down a bit overnight. This higher voltage (13.7-14+) makes the BIM connect the chassis battery and give it a nice charge.

My conclusion is Solar is the best thing to keep your batteries topped up when parked and not in use. If no adequate solar is available then a separate charger for chassis battery would be best. Another option is to disconnect the Sprinter chassis battery ground cable near the accelerator - that is quick and easy.

BTW - this problem is not limited to Interstates. I see the problem on other Sprinter/RV forums. A lot of owners solve the problem by adding a trickle charger to keep the chassis battery charged. Advanced RV delivers their B-vans with a built in trickle charger for the Sprinter chassis battery.


- - Mike
2013 Lounge EXT on 2012 Sprinter

It's as if the entire system was designed for flooded batteries which have a 13.4v float voltage vs. AGMs that have a 13.1v float voltage, and nobody told the design team they switched to Lifeline AGMs.....

Maybe this could be avoided by changing the battery type to Flooded in the Magnum setup. According to the Magnum manual this sets the Float voltage to 13.4v, and looking at the Lifeline specs they can handle a Float voltage between 13.1v and 13.4v. This would pretty much guarantee any time the Magnum is Floating the coach batteries the BIM will be on and therefore Floating the chassis battery too.

Thoughts?

[Boxster1971]

Originally Posted by busb2

Mike I used a trickle charger for the chassis battery on my 2009 AI, after it kept going dead while the AI was stored plugged in. After that, no problems. When I got my 2014 AI, I installed a charge line attached to the chassis battery, with the connection peeking up through the floor under the front of the dash. I keep a small multi stage trickle charger inside the AI and when I store the unit, I just plug it in the charge line and plug it into the power outlet on the left side behind the drivers seat. Simple solution has worked for two years now.

Great solution! I'd recommend the same for anyone storing their Interstate inside, plugged in.


- - Mike
2013 Lounge EXT on 2012 Sprinter

[don000]

Adding a data point to the theory of FlyFishinRVr, I took delivery of my 2017 within days after it arrived from the manufacturer, and have not experienced the problem. The pale sunshine of northern New England generates little current so I've left it connected to shore power with the main disconnect "on". The Magnum shows 'float' status whenever I look at it, and the voltage of the chassis and house batteries is almost invariably the same to the hundredth of a volt in the neighborhood of 13.55, once stabilized after a drive.

I think busb2 offers an elegant work-around, but like amirm I wonder what kind of parasitic loads might drain the chassis battery. I have a variety of vehicles but none of them will drain a battery in less than two or three months. Especially with the infotainment system connected to the house, what could be draining the chassis battery ? Maybe someone more handy with a multimeter than I could answer this.

[Boxster1971]

Originally Posted by FlyFishinRVr

It's as if the entire system was designed for flooded batteries which have a 13.4v float voltage vs. AGMs that have a 13.1v float voltage, and nobody told the design team they switched to Lifeline AGMs.....

Maybe this could be avoided by changing the battery type to Flooded in the Magnum setup. According to the Magnum manual this sets the Float voltage to 13.4v, and looking at the Lifeline specs they can handle a Float voltage between 13.1v and 13.4v. This would pretty much guarantee any time the Magnum is Floating the coach batteries the BIM will be on and therefore Floating the chassis battery too.

Thoughts?

The Lifeline manual I have says Float at 13.3V +/- 0.1V, but the Absorption voltage should be 14.3V. The Magnum Absorption voltage for Flooded batteries is 14.1 rather than 14.3V. Not sure using a setting other than AGM1 for Magnum is a good idea.

But it's always made me wonder why Magnum lists AGM1 profile for Lifeline batteries and then list the Float voltage as 13.1V.

There is still the problem when Magnum lets the coach batteries drop to 12.7V. If the BIM voltage check occurs when voltage is that low it won't connect batteries. I'm not sure but the cycle for the BIM voltage check is likely every 10 minutes based on the logic I listed earlier for BIM with "Ignition" OFF.




- - Mike
2013 Lounge EXT on 2012 Sprinter

[WillieJ]

Originally Posted by Boxster1971

Great solution! I'd recommend the same for anyone storing their Interstate inside, plugged in.


- - Mike
2013 Lounge EXT on 2012 Sprinter

That would work for me too, because in winter in NW Washington state with the stock solar set up, the chances of getting enough sun to have an effect under the grey cloud deck is approaching zero.

That also calls to mind why I like the totally manual system on battery management on my boat. One 2 bank Blue Sea switch connects the battery banks with the charger/inverter, and another connects to the 12 volt system which includes the engine alternator an an external Balmar regulator. The nice part of the Balmar regulator is that it programmable for battery types among other advanced options. This is simplified on the boat by having the same deep cycle/starting battery types for both house and starting(chassis) batteries. I can make sure the batteries are connected for optimum charging whatever the circumstances.

The operating parameters for voltage in the Precision Circuits BIM seems to be hard coded and conflict in some ways with the proper settings for the Magnum Inverter/Charger for the AGM1 battery type. Some ability to program voltage thresholds in the BIM might be helpful in solving the issue pointed out by Boxter1971. Without that we will have to depend on workarounds.

[wildwilly.]

I had problems with the inverter and house batteries from day 1. On our first road trip we had a service call in Chicago and they replaced a solenoid on the inverter which allowed us to use the inverter for our trip but the house batteries were not holding a charge. When we returned we brought our one month old AI to the dealer for them to trouble shoot the battery issue. Among other issues were low brake pressure so they took the AI to a Mercedes dealer to have them investigate. After a delay caused by the AI dealer locking the keys in the AI (the Mercedes dealer couldn't open it, Yikes!!!), the Mercedes dealer found a dead chassis battery. Mercedes trouble shot the issue and determined it was due to the inverter/converter. Back at the AI dealer they replaced the inverter solenoid again as they had been advised by Airstream that the Magnum solenoids were defective and could cause the chassis battery to drain.

I do not know how the inverter solenoid could cause this situation but you might ask your dealer to investigate this potential

BTW the dealer finally replaced the house batteries as they determined that they had been either defective or dramatically deeply discharged. This must have happened before our purchase as we had problems from the start. Our dealer believes it was the faulty inverter solenoid that was causing the issue. We just returned from a 10 day trip with no battery/ inverter issues so we are hopeful this issue is solved. We had a couple other issues I will post separately to avoid bringing additional issues to this string.

Good luck!

[VanGo]

Originally Posted by FlyFishinRVr

I was thinking about this some more, and wonder if what's going on is a problem with people's understanding of how the new relay works (aka SB-164) vs. anything with the BIM, Magnum, or new Fusion system.

Here's what we know:

- The chassis battery draining issue is only on the newer coaches (mainly '17s, but likely also some late '16s)
- This only happens when connected to shore power
- No solar is present as these units are being stored indoors
- Users are reporting that they are leaving the Main Disconnect switch in the ON position (i.e. red LED is ON, so there is power to the lights, fridge, etc)......

This is not the case for me. For me:
- It only happens when connected to shore power with house power on.
- The only time I have the house power on is when I'm using the unit.
- In Storage I am outside, with house power off. After sitting for a week or 2 in storage, I check on the unit and both batteries are pretty much fully charged.
-In the cases where my coach battery is drained, I was able to start by using the boost from the house battery.

My unit was ordered and picked up within a week of delivery so I don't think it has anything to do with dealer handling.