Nova 20C Li3 - Promaster with 2nd Alternator Issue

[bwatters60]

The following instances have occurred in our 2024 Nova 20C Li3 built on a 2023 Promaster 3500. It was delivered with about 1700 miles and currently has about 2700 miles.

With the lithium battery being fully charged at the onset, after being parked for about 20 minutes with the A/C running, I turned the A/C and Inverter off, started the engine and began driving on a residential street. The engine seemed to hesitate a couple times. At the end of the block I stopped
at a stop sign and then began my turn left. The van started to roll but hesitated and then didn't seem to want to move as the engine didn't seem to have any power. I was practically stalled in the middle of the intersection and had to press hard on the gas peddle before the engine finally responded and
I was able to continue.

A couple weeks later I had left the solar panel off (battery switch in Store position) for a few days with the RV parked in our driveway, which has a pretty good incline. The lithium battery had dropped from full (630A) to about 620A. I started the van and after a about a minute of idling,
I put it in Drive to move it forward a few feet while turning the wheels, and the van just started to roll backwards down the driveway. I applied brake, shifted back to Park, and then to Drive, released the brake and it started to roll backwards again. It felt like it wasn't shifting into gear. So I tried to
both Reverse and, manually shifting it into low gear but neither worked. I knew the 2nd alternator would be producing a high current to charge the lithium, so I started the Li3 Battery app. At this time the 2nd alternator was pumping about 125A into the lithium battery. I monitored the current
charge as it dropped and at various points shifted the van into Drive but it still rolled backwards. It wasn't until a minute or two later and the charge rate dropped to about 60A that the van would move forward when I shifted to Drive.

Starting out with my lithium battery full I've never had any issues with engine hesitation or shifting. So it appears that my symptoms are somehow related to the high charge rate of the 2nd alternator. But with the information I've been able to research I'm struggling to understand the correlation.

I've searched several forums and haven't found any posts with similar symptoms. Has anyone else experienced these issues?

[dmb496]

Your drive train issue is separate from the Li3 charging system. I would call a dealer and schedule it for warranty work. There will likely be stored codes that a technician can gather from the OBD II port.

[bwatters60]

I agree - they must be separate. Neither my ScanGauge or my budget scan tool extracted any codes via the ODBII port. I'd expect if there are any codes the Ram dealer will be able to read them. At this point I'm curious if this is caused by something like the ESM (Electronic Shift Module). I'll be setting up an appointment with the Ram dealer soon. Thanks again.

[booster]

I think you need to pull the fuse or disconnect on the second alternator or shut off it's charging in whatever way the Li3 lets you do it. It would pay to know for certain it isn't doing something unexpected or wired wrong.



125 amps is quite a bit for a cold 6 cylinder engine at idle if it also has to supply a large load from the stock alternator due to a very low starting battery or some big load. It "might" be possible that the voltage of the van side is getting pulled down a lot and not providing enough voltage to run the van properly. If the alternator connection is bad it could also cause that issue.


Have you watched the van voltage on the Scangauge as it happens? Also the rpm?

[bwatters60]

Booster,

There's a Wakespeed WS500 that monitors and controls the 2nd alternator, and also communicates with the BMS. Using the Wakespeed app I haven't been able to pair to the Wakespeed unit, and Wakespeed has not responded to my emails. And Coachmen provides no manual like I had with my Roadtrek (e.g., electrical diagrams, plumbing diagrams, user directions, etc.). I miss my Chevy 6.0l powertrain!

I have used the Lithionics app to monitor the status and charging of my 630A Lithium battery. It also allows me to monitor the ACR (Automatic Combiner Relay) and the charge rate of the chassis battery by the Lithium battery (as well as the voltage of both batteries). During the scenarios I didn't pay much attention to voltages and I was focused on the current draw.

In both instances of drivetrain issues, the only real drain on the electrical system was the charging of the Lithium battery as everything was powered down. My initial thoughts were the charge load was a contributing factor. But as I recall from my engineering days at MTU, 746 watts was equivalent to 1 horsepower. The second alternator, a Nations 280XP, is capable of 200A at idle. At this rate it would be pumping almost 3kW into the Lithium, which would equate to about 4 horsepower. This is less drain than an A/C compressor. Correct me if I'm wrong, but 4 horsepower shouldn't have that much effect on a 276 hp V6.

This coming week I plan to confirm that I can recreate the scenario where I was unable to shift. I will follow your suggestion and monitor the chassis voltage. If I can recreate the scenario, I'll have to figure out how to remove the 2nd alternator charging from the system and see if this resolves the shifting issue. Wakespeed stipulates in their documentation, in multiple places, that the battery "disconnect switch must always be in the ON position when the engine is running", so I'm not sure how I'm going to accomplish the isolation.

Thanks for your thoughts and suggestions!

[booster]

Originally Posted by bwatters60

Booster,

There's a Wakespeed WS500 that monitors and controls the 2nd alternator, and also communicates with the BMS. Using the Wakespeed app I haven't been able to pair to the Wakespeed unit, and Wakespeed has not responded to my emails. And Coachmen provides no manual like I had with my Roadtrek (e.g., electrical diagrams, plumbing diagrams, user directions, etc.). I miss my Chevy 6.0l powertrain!

I have used the Lithionics app to monitor the status and charging of my 630A Lithium battery. It also allows me to monitor the ACR (Automatic Combiner Relay) and the charge rate of the chassis battery by the Lithium battery (as well as the voltage of both batteries). During the scenarios I didn't pay much attention to voltages and I was focused on the current draw.

In both instances of drivetrain issues, the only real drain on the electrical system was the charging of the Lithium battery as everything was powered down. My initial thoughts were the charge load was a contributing factor. But as I recall from my engineering days at MTU, 746 watts was equivalent to 1 horsepower. The second alternator, a Nations 280XP, is capable of 200A at idle. At this rate it would be pumping almost 3kW into the Lithium, which would equate to about 4 horsepower. This is less drain than an A/C compressor. Correct me if I'm wrong, but 4 horsepower shouldn't have that much effect on a 276 hp V6.

This coming week I plan to confirm that I can recreate the scenario where I was unable to shift. I will follow your suggestion and monitor the chassis voltage. If I can recreate the scenario, I'll have to figure out how to remove the 2nd alternator charging from the system and see if this resolves the shifting issue. Wakespeed stipulates in their documentation, in multiple places, that the battery "disconnect switch must always be in the ON position when the engine is running", so I'm not sure how I'm going to accomplish the isolation.

Thanks for your thoughts and suggestions!

Very interesting, thanks for the update an details.


As it turns out, we have a Wakespeed running in our current lithium build in our 6.0 Chevy Roadtrek, so I am pretty familiar with them and the settings.


The Wakespeed can be paired directly to lithium batteries if the BMS is one that they are setup to communicate with. They can also connect to batteries through a Victron Cerbo. I have no idea how the Li3 is designed so can't say on how they did the linking. Taking the control away from the Wakespeed is not a bad idea, however, as we have found it has a lot of warts and weirdnesses built into it.


Of course, Coachman didn't bother to tell you that the Wakespeed itself does not have Bluetooth so you can't connect the app without opening the cover of the Wakespeed (4 captive screws, very easy) and plugging in a USB style B cable to it and connecting the cable to your phone. It might be worth doing although you may only be able to monitor as it is possible the settings are password protected. You should be able to run data logs, however.


Wakespeed has a bit of a reputation for going dark on people so don't count on much help directly from them as everything is now filtered though Battleborn (Dragonfly) who bought Wakespeed.


It is correct that you can't run the Wakespeed with the disconnect off as it will instantly fault, like many chargers that require a battery in the system. In your Li3 it almost certainly is being controlled by either the Cerbo or BMS and would be setup to stop charging when the Coachman decided to have it quit. It would be that they shut off the field to alternator from inside the Wakespeed to do the shut off. You could put a manual switch on the field of the alternator wiring but that would almost certainly void the warranty.


The Wakespeed does do one thing very well, and that is to control the charging amperage. Yours is obviously set at 120 amps for all speeds from your description. We also run 120 amps at off idle rpms, but reduce it at idle to keep the alternator and engine cooler and smooth out the engine idle. Even the 6.0 can feel 120 amps at the slow 545 rpm they run at. Your V6 will likely be running higher idle speed and they may speed it up under the heavy alternator load from the second alternator if they got access to the PCM through whatever controls the Li3 is using. So it is possible that the lithium setup is not totally standalone from the van electronics, but also not for certain it is linked into the engine controls.


There is also a possibility of another link or two to the van electrical system in that the Wakespeed and some of the lithium electronics may be powered from the starting battery. The Wakespeed has a bit of a bad design in that even though it probably senses engine rpm from the stator output tap of the second alternator it does not use that to determine if the engine is running. They only use the "run" signal from the PCM if it is high enough voltage or the 12v from the ignition switch if the PCM voltage is under 9v like ours is. Of course, it is also possible that has been addressed in the Li3 controls and it powers from there from either the van, Wakespeed, or lithium batteries. The power for the field is wired separately from the Wakspeed start and control side of things so the field could also come either from the van battery or the lithium batteries. It gets tough to handle with lithium that might be in cold shutdown or dead so no way to power the charging even if engine is running if the field comes from the lithium. The field is going to pull about 7-8 amps at full field current, which it probably will be at or near at idle speed and 120 amp output. We are running at a bit under 60% field at idle as you can't set amps for that setting. We get between 40 and 60 amps at idle depending on conditions. Alternators are not anywhere near 100% efficient and get worse at full field so you have to figure that into a hp calculation at idle. You also have torque converter load at idle and not moving to account for. Many engine have idle speeds as low as possible but still prevent stalling with their normal loads so if they have access there probably is an idle speed up in place from the Li3.


Does any of all this have any real affect on your problem. A definite sorta/kinda maybe thing, I am afraid.


Your biggest issue may be being caught between multiple vendors in trying to get things straightened out. The van maker is going to point to the Coachmen electronics, Coachman will point at the van and the lithium system manufacturer, and the lithium manufacturer will point at everybody else in the worst case scenario.


I would go to Coachman first, in writing, first by electronic contact and if they don't respond by certified mail to get a basic history start point. You can also check with the a Ram dealer to get their opinion on it, but they probably will want you to pay for any troubleshooting they do unless they find something wrong with the van and then you would have to try to recover the cost from Coachman. Having it done first would probably gets things rolling faster but you could get stuck with the bill at the dealer.



Not the best place to be stuck, for sure, I hope you can get is all sorted out quickly so you can use the van.

[booster]

Originally Posted by bwatters60

Booster,

There's a Wakespeed WS500 that monitors and controls the 2nd alternator, and also communicates with the BMS. Using the Wakespeed app I haven't been able to pair to the Wakespeed unit, and Wakespeed has not responded to my emails. And Coachmen provides no manual like I had with my Roadtrek (e.g., electrical diagrams, plumbing diagrams, user directions, etc.). I miss my Chevy 6.0l powertrain!

I have used the Lithionics app to monitor the status and charging of my 630A Lithium battery. It also allows me to monitor the ACR (Automatic Combiner Relay) and the charge rate of the chassis battery by the Lithium battery (as well as the voltage of both batteries). During the scenarios I didn't pay much attention to voltages and I was focused on the current draw.

In both instances of drivetrain issues, the only real drain on the electrical system was the charging of the Lithium battery as everything was powered down. My initial thoughts were the charge load was a contributing factor. But as I recall from my engineering days at MTU, 746 watts was equivalent to 1 horsepower. The second alternator, a Nations 280XP, is capable of 200A at idle. At this rate it would be pumping almost 3kW into the Lithium, which would equate to about 4 horsepower. This is less drain than an A/C compressor. Correct me if I'm wrong, but 4 horsepower shouldn't have that much effect on a 276 hp V6.

This coming week I plan to confirm that I can recreate the scenario where I was unable to shift. I will follow your suggestion and monitor the chassis voltage. If I can recreate the scenario, I'll have to figure out how to remove the 2nd alternator charging from the system and see if this resolves the shifting issue. Wakespeed stipulates in their documentation, in multiple places, that the battery "disconnect switch must always be in the ON position when the engine is running", so I'm not sure how I'm going to accomplish the isolation.

Thanks for your thoughts and suggestions!

Very interesting, thanks for the update an details.


As it turns out, we have a Wakespeed running in our current lithium build in our 6.0 Chevy Roadtrek, so I am pretty familiar with them and the settings.


The Wakespeed can be paired directly to lithium batteries if the BMS is one that they are setup to communicate with. They can also connect to batteries through a Victron Cerbo. I have no idea how the Li3 is designed so can't say on how they did the linking. Taking the control away from the Wakespeed is not a bad idea, however, as we have found it has a lot of warts and weirdnesses built into it.


Of course, Coachman didn't bother to tell you that the Wakespeed itself does not have Bluetooth so you can't connect the app without opening the cover of the Wakespeed (4 captive screws, very easy) and plugging in a USB style B cable to it and connecting the cable to your phone. It might be worth doing although you may only be able to monitor as it is possible the settings are password protected. You should be able to run data logs, however.


Wakespeed has a bit of a reputation for going dark on people so don't count on much help directly from them as everything is now filtered though Battleborn (Dragonfly) who bought Wakespeed.


It is correct that you can't run the Wakespeed with the disconnect off as it will instantly fault, like many chargers that require a battery in the system. In your Li3 it almost certainly is being controlled by either the Cerbo or BMS and would be setup to stop charging when the Coachman decided to have it quit. It would be that they shut off the field to alternator from inside the Wakespeed to do the shut off. You could put a manual switch on the field of the alternator wiring but that would almost certainly void the warranty.


The Wakespeed does do one thing very well, and that is to control the charging amperage. Yours is obviously set at 120 amps for all speeds from your description. We also run 120 amps at off idle rpms, but reduce it at idle to keep the alternator and engine cooler and smooth out the engine idle. Even the 6.0 can feel 120 amps at the slow 545 rpm they run at. Your V6 will likely be running higher idle speed and they may speed it up under the heavy alternator load from the second alternator if they got access to the PCM through whatever controls the Li3 is using. So it is possible that the lithium setup is not totally standalone from the van electronics, but also not for certain it is linked into the engine controls.


There is also a possibility of another link or two to the van electrical system in that the Wakespeed and some of the lithium electronics may be powered from the starting battery. The Wakespeed has a bit of a bad design in that even though it probably senses engine rpm from the stator output tap of the second alternator it does not use that to determine if the engine is running. They only use the "run" signal from the PCM if it is high enough voltage or the 12v from the ignition switch if the PCM voltage is under 9v like ours is. Of course, it is also possible that has been addressed in the Li3 controls and it powers from there from either the van, Wakespeed, or lithium batteries. The power for the field is wired separately from the Wakspeed start and control side of things so the field could also come either from the van battery or the lithium batteries. It gets tough to handle with lithium that might be in cold shutdown or dead so no way to power the charging even if engine is running if the field comes from the lithium. The field is going to pull about 7-8 amps at full field current, which it probably will be at or near at idle speed and 120 amp output. We are running at a bit under 60% field at idle as you can't set amps for that setting. We get between 40 and 60 amps at idle depending on conditions. Alternators are not anywhere near 100% efficient and get worse at full field so you have to figure that into a hp calculation at idle. You also have torque converter load at idle and not moving to account for. Many engine have idle speeds as low as possible but still prevent stalling with their normal loads so if they have access there probably is an idle speed up in place from the Li3.


Does any of all this have any real affect on your problem. A definite sorta/kinda maybe thing, I am afraid.


Your biggest issue may be being caught between multiple vendors in trying to get things straightened out. The van maker is going to point to the Coachmen electronics, Coachman will point at the van and the lithium system manufacturer, and the lithium manufacturer will point at everybody else in the worst case scenario.


I would go to Coachman first, in writing, first by electronic contact and if they don't respond by certified mail to get a basic history start point. You can also check with the a Ram dealer to get their opinion on it, but they probably will want you to pay for any troubleshooting they do unless they find something wrong with the van and then you would have to try to recover the cost from Coachman. Having it done first would probably gets things rolling faster but you could get stuck with the bill at the dealer.



Not the best place to be stuck, for sure, I hope you can get is all sorted out quickly so you can use the van.

[dmb496]

I installed a Nations 2nd alternator kit in our 2020 Galleria. It is the identical kit that Coachmen installs in their Galleria Li3 system. Connections are basically simple; the alternator connects with the "house" batteries, there is a 12 volt "keyed" connection to trigger the alternator, there is a "sense" wire between the regulator and the battery bank, and the alternator is connected to a dedicated regulator.

Your 2nd alternator will be identical to mine, the exception being the specific brackets to mount the alternator to the engine.

Attached is a Nations wiring diagram.

[bwatters60]

Booster,

You were a wealth of information when I had my RT 210P, and although I've only had my new rig for 3 months you've already greatly surpassed the support I've received from Coachmen! Thanks for sharing your knowledge!

I have read some of your posts on your lithium upgrade. Very interesting project! A couple years ago I considered converting my 210 to lithium but ultimately decided to forego the lithium until our next van.

I did read that one would have to remove the Wakespeed cover and insert a cable in order to communicate with it. In the Nova the Wakespeed is communicating with the Lithionics external BMS. And it is set to allow 200A charge at idle (see picture from Lithionics app - 206.3A). It's slightly greater than 200A due to the solar panel. I've thought of accessing the Wakespeed to see if I could limit the charge rate to 50 or 60A, which may solve my problem if Coachmen or Ram can't. The way we travel that rate would work for us, but before doing so I need to research if that would be detrimental to the charge requirements of the lithium battery. I did something similar with my Xantrex 3000 charger/inverter which has a default charge rate of 150A. Since I only have 15A and 20A receptacles available at home where my van is stored, to keep the breakers from tripping I set the maximum charge rate to 50A. I rarely plug in though since the sun in TX provides plenty of charge thru the solar panels to keep the lithium full.

I'm afraid you may be right - the Lithium electronics may in some way be connected to the chassis electronics, and I may end up getting a lot of finger pointing in the resolution. I like your suggestion of starting with Coachmen. I'm going start with an email to the Nova rep and cc my dealer. In the meantime I plan on doing some tests to make sure I can duplicate the problem on demand.

Thanks again for suggestions and sharing your knowledge!

[booster]

Originally Posted by dmb496

I installed a Nations 2nd alternator kit in our 2020 Galleria. It is the identical kit that Coachmen installs in their Galleria Li3 system. Connections are basically simple; the alternator connects with the "house" batteries, there is a 12 volt "keyed" connection to trigger the alternator, there is a "sense" wire between the regulator and the battery bank, and the alternator is connected to a dedicated regulator.

Your 2nd alternator will be identical to mine, the exception being the specific brackets to mount the alternator to the engine.

Attached is a Nations wiring diagram.

That wiring diagram shows a Balmar regulator that wires in and works a lot differently than the Wakespeed does. Do you have a Wakespeed in yours or Balmar? Nations sells both, I know because that is where my Wakespeed came from. The Wakespeed has a shunt for accurate control of voltage and current and the Balmar does it with an algorithm so very different.



Is the BMS connected to the alternator regulator to control it?

[booster]

Originally Posted by bwatters60

Booster,

You were a wealth of information when I had my RT 210P, and although I've only had my new rig for 3 months you've already greatly surpassed the support I've received from Coachmen! Thanks for sharing your knowledge!

I have read some of your posts on your lithium upgrade. Very interesting project! A couple years ago I considered converting my 210 to lithium but ultimately decided to forego the lithium until our next van.

I did read that one would have to remove the Wakespeed cover and insert a cable in order to communicate with it. In the Nova the Wakespeed is communicating with the Lithionics external BMS. And it is set to allow 200A charge at idle (see picture from Lithionics app - 206.3A). It's slightly greater than 200A due to the solar panel. I've thought of accessing the Wakespeed to see if I could limit the charge rate to 50 or 60A, which may solve my problem if Coachmen or Ram can't. The way we travel that rate would work for us, but before doing so I need to research if that would be detrimental to the charge requirements of the lithium battery. I did something similar with my Xantrex 3000 charger/inverter which has a default charge rate of 150A. Since I only have 15A and 20A receptacles available at home where my van is stored, to keep the breakers from tripping I set the maximum charge rate to 50A. I rarely plug in though since the sun in TX provides plenty of charge thru the solar panels to keep the lithium full.

I'm afraid you may be right - the Lithium electronics may in some way be connected to the chassis electronics, and I may end up getting a lot of finger pointing in the resolution. I like your suggestion of starting with Coachmen. I'm going start with an email to the Nova rep and cc my dealer. In the meantime I plan on doing some tests to make sure I can duplicate the problem on demand.

Thanks again for suggestions and sharing your knowledge!

More good information, thanks.


The Promaster second alternator is in a better place than our Chevy, but even on a Sprinter which mounts similarly we have data that you can't maintain 200 amps continuously even driving. At idle the alternator will get hot in a few minutes and the Wakspeed will turn down the output, assuming the temp sensor is in place and working on the alternator. The 120 you are seeing is probably at turned down point by the Wakespeed. You will be able to see the alternator temp sensor on the APP so that is a good thing. You will also be able to see field %.



As long as you can get into the settings, you will be able to set the field percent at idle in a couple of minutes, and you can change the max charge rate even quicker. The problem comes in that sometimes uploading the existing settings doesn't work right in Wakespeeds, I know ours sometimes won't do it, but it doesn't matter much to me because I made the settings file and use that to make changes and reload them. You can't just change one setting in the unit itself, you do it on a copy of the settings and reload the whole thing. I will dig out the default setting for the access code for you to try as I don't recall what it is offhand. You may not need it, though.

[dmb496]

Originally Posted by booster

That wiring diagram shows a Balmar regulator that wires in and works a lot differently than the Wakespeed does. Do you have a Wakespeed in yours or Balmar? Nations sells both, I know because that is where my Wakespeed came from. The Wakespeed has a shunt for accurate control of voltage and current and the Balmar does it with an algorithm so very different.



Is the BMS connected to the alternator regulator to control it?

I have the Balmar. The BMS isn't connected to the Balmar.

[booster]

Originally Posted by dmb496

I have the Balmar. The BMS isn't connected to the Balmar.

That is what I thought as that wiring diagram is for the standard setup that they have been selling for probably more than 10 years. The hard part with the lithium and the Balmar is getting the settings right to limit current because they don't specifically tell you how to do it, and it is not obvious either because it uses features that were intended for other purposes like belt load reduction and such. They will run full field at idle unless you limit them and at full field going down the road if the batteries will accept it and lithium normally will. Depending on bank size of the lithium and if you want to limit to the now more common .2C charge rate we see, you do need to limit current.

[booster]

I just did some reading on the Lithionics site and it appears that the Wakspeed is going to be controlled by the Lithionics BMS system via Canbus. This will mean that the settings in the Wakespeed will not be used as far as I know, and also that you won't be able to change anything.



The 200 amps max charge rate is what the battery is rated for as recommended max, but they also give an absolute max of 300 amps. The 200 amps is about .3C so in line with many of the newer specs for lithium charge rates, but not on most conservative .2C rate. The Wakspeed has got two settings for amps to the batteries. One is in the charging settings and called something like charge amps and the other is stated as max battery amps, I think. Perhaps the Li3 is set at 125 amps for normal charging which would be good on your system, IMO, and just happens to be at .2C. Using the load shaping to limit amps at idle would still be good, though, I think and perhaps Lithionics could do that for you with a BMS programming flash if you ask for it as the Wakespeed is setup for doing it.


In the original post you mentioned that the AH meter had dropped to 620AH from 630AH full, which is only 10AH if I read it correctly. You would be well within the fast tapering part of the charge profile by then so load would be dropping very quickly and not charging very quickly. If it went from 630ah SOC to 620ah state of discharge, you were very far down and would be charging at max.

[bwatters60]

Originally Posted by dmb496

I installed a Nations 2nd alternator kit in our 2020 Galleria. It is the identical kit that Coachmen installs in their Galleria Li3 system. Connections are basically simple; the alternator connects with the "house" batteries, there is a 12 volt "keyed" connection to trigger the alternator, there is a "sense" wire between the regulator and the battery bank, and the alternator is connected to a dedicated regulator.

Your 2nd alternator will be identical to mine, the exception being the specific brackets to mount the alternator to the engine.

Attached is a Nations wiring diagram.

Thanks for the info and diagram. I've used a wiring diagram from Lithionics that I would think be pretty close to how Coachmen wired my Nova. The diagrams on the Wakespeed site have also been helpful. But still, there's enough unknowns that I want to be careful and not make a move that may void a warranty. Thanks again!

[bwatters60]

Originally Posted by booster

I just did some reading on the Lithionics site and it appears that the Wakspeed is going to be controlled by the Lithionics BMS system via Canbus. This will mean that the settings in the Wakespeed will not be used as far as I know, and also that you won't be able to change anything.

I knew they were communicating via Canbus, but I always thought the Wakespeed was in control of the 2nd alternator based on inputs from the 2nd alternator as well as inputs from the BMS.

The 200 amps max charge rate is what the battery is rated for as recommended max, but they also give an absolute max of 300 amps. The 200 amps is about .3C so in line with many of the newer specs for lithium charge rates, but not on most conservative .2C rate. The Wakspeed has got two settings for amps to the batteries. One is in the charging settings and called something like charge amps and the other is stated as max battery amps, I think. Perhaps the Li3 is set at 125 amps for normal charging which would be good on your system, IMO, and just happens to be at .2C. Using the load shaping to limit amps at idle would still be good, though, I think and perhaps Lithionics could do that for you with a BMS programming flash if you ask for it as the Wakespeed is setup for doing it.


In the original post you mentioned that the AH meter had dropped to 620AH from 630AH full, which is only 10AH if I read it correctly. You would be well within the fast tapering part of the charge profile by then so load would be dropping very quickly and not charging very quickly. If it went from 630ah SOC to 620ah state of discharge, you were very far down and would be charging at max.

While trying to set up my configuration in the Wakespeed app (not knowing at the time I was going to have to cable into the Wakespeed and download the configuration), I asked Coachmen about the shunts installed. Their response was as follows. "We do not use any kind of shunt and as far as connectivity to WakeSpeed via BT, that is something we haven’t looked into because it does not provide much data that would be of benefit in the way we currently use the WakeSpeed.". This didn't make much sense to me at the time but now with what you've provided it's apparent that the BMS controls the Wakespeed.

Earlier today I ordered an On The Go cable so I can connect my Android to the Wakespeed. Now it appears now this just may enable me to download the Wakespeed configuration, if there is much of one?

Regarding the original post information, you were correct that the SOC had only dropped 10AH, from 630 to 620. In spite of this relatively small drop, the 2nd alternator appears to be running near max to quickly restore the Lithium to 630AH. And as you said, the load does drop rather quickly.

This weekend, if the weather cooperates, I plan to run the A/C on battery and drop the Lithium SOC down significantly more than I have to date, and then see if I can duplicate the powertrain issues. If successful I'll be emailing Coachmen (in three short months I've already lost faith in my dealer).

I appreciate your thoughts and suggestions.

[booster]

Originally Posted by bwatters60

While trying to set up my configuration in the Wakespeed app (not knowing at the time I was going to have to cable into the Wakespeed and download the configuration), I asked Coachmen about the shunts installed. Their response was as follows. "We do not use any kind of shunt and as far as connectivity to WakeSpeed via BT, that is something we haven’t looked into because it does not provide much data that would be of benefit in the way we currently use the WakeSpeed.". This didn't make much sense to me at the time but now with what you've provided it's apparent that the BMS controls the Wakespeed.

Earlier today I ordered an On The Go cable so I can connect my Android to the Wakespeed. Now it appears now this just may enable me to download the Wakespeed configuration, if there is much of one?

Regarding the original post information, you were correct that the SOC had only dropped 10AH, from 630 to 620. In spite of this relatively small drop, the 2nd alternator appears to be running near max to quickly restore the Lithium to 630AH. And as you said, the load does drop rather quickly.

This weekend, if the weather cooperates, I plan to run the A/C on battery and drop the Lithium SOC down significantly more than I have to date, and then see if I can duplicate the powertrain issues. If successful I'll be emailing Coachmen (in three short months I've already lost faith in my dealer).

I appreciate your thoughts and suggestions.

Interesting comment they made about the shunt and not having one. It is probably within the BMS itself. I think Victron does that type of thing. They need to have accurate amperage data input to control charge amperage and things like exceding max charge rate and when reducing output to keep the batteries or alternator within temp ranges. I think all the cheap BMS units even have some sort of current measuring capability, our SOK units do report amps on Bluetooth, but I know ours don't have anything resembling a full size shunt on the board. They are probably using inductive amperage sensing which is not as accurate as the ones a battery monitor uses.


Even if you can't see much for settings, being able to monitor what the temps, voltage, and amps are that the Wakespeed is seeing may be interesting. The field % could definitely give some clues to what is going on and it will be shown in the monitoring mode of the APP. A lot of the information may also be displayed on the Li3 panel, but maybe not all of it.

[bwatters60]

Originally Posted by booster

Interesting comment they made about the shunt and not having one. It is probably within the BMS itself. I think Victron does that type of thing. They need to have accurate amperage data input to control charge amperage and things like exceding max charge rate and when reducing output to keep the batteries or alternator within temp ranges. I think all the cheap BMS units even have some sort of current measuring capability, our SOK units do report amps on Bluetooth, but I know ours don't have anything resembling a full size shunt on the board. They are probably using inductive amperage sensing which is not as accurate as the ones a battery monitor uses.


Even if you can't see much for settings, being able to monitor what the temps, voltage, and amps are that the Wakespeed is seeing may be interesting. The field % could definitely give some clues to what is going on and it will be shown in the monitoring mode of the APP. A lot of the information may also be displayed on the Li3 panel, but maybe not all of it.

I completed a test today to see if I could duplicate a couple powertrain issues (i.e., upon starting the engine unable to shift into gear while 2nd alternator was charging the Lithium battery in excess of 70 amps, and hesitation while accelerating).

Coach had been parked for several days with the battery off, Ion Gage on, Solar charging on, and Lithium battery at 100% SOC or 630AH, and 13.4V. Relocated van to a flat surface along street for test.

Parked van and turned off engine, turned Battery on, Xantrex 3000 on, and Solar off. ACR was off. Outside temp was 80F. Turned on Truma Aventa 13.5K BTU A/C and set to 72F. Lithium battery was supplying about 88A.

After a one hour run in this setup, Lithium battery SOC had dropped to 539AH or 86%, and 13.0V on the Ion Gage.

Turned Truma off, Xantrex off, Battery off, and Solar off and allowed system to rest for 30 minutes. Lithium voltage rose to 13.3V. ACR was still off, Lithionics app indicated that House battery was 13.28V and Chassis battery was 12.56V.

Started engine. Scangage indicated an instantaneous chassis battery voltage drop to 10.45 but it immediately rose to 14.30V when the engine started. At idle the 2nd alternator was supplying 187.4A to the Lithium battery. Shifting into gear went smoothly and as I accelerated the charging current rose to 226+ amps. Drove around the block and upon return, at idle (680 rpm according to the Scangage) the SOC had risen to 87% and the current had dropped to 167.1A. Parked and attached shoreline to complete charging.

The system appears to be working well and at least this time I didn't have any issues with hesitation or shifting while the 2nd alternator was under a heavy load. So for now I'll just continue to monitor.

Booster - I would very much like to limit the 2nd alternator to about 100A or so. This would be sufficient for our way of travel and hopefully reduce the wear and tear on the pulleys and belts. To do so, once I get my OTG cable I'd plug my phone into the Wakespeed box, start the app, import the configuration currently on the box, adjust the max field drive (which one or all 3? - Normal, Alt Mode, or Half Power Mode) to the desired percentage, and then upload the new configuration to the Wakespeed box? I know this sounds simplistic - I do need to go thru the Wakespeed info online again. And I have my doubts that Coachmen would assist in my objective. Would appreciate confirmation from you that I'm on the right path. And I think you mentioned in an earlier response that a password may be required?

I've seen where you make an annual trip to da UP. That's where I'm from. I'm usually up there once or twice a year, maybe more now that the wife is retiring at the end of the month. If we cross paths I owe you one!

Thanks to all for the suggestions and guidance.

[booster]

Originally Posted by bwatters60

I completed a test today to see if I could duplicate a couple powertrain issues (i.e., upon starting the engine unable to shift into gear while 2nd alternator was charging the Lithium battery in excess of 70 amps, and hesitation while accelerating).

Coach had been parked for several days with the battery off, Ion Gage on, Solar charging on, and Lithium battery at 100% SOC or 630AH, and 13.4V. Relocated van to a flat surface along street for test.

Parked van and turned off engine, turned Battery on, Xantrex 3000 on, and Solar off. ACR was off. Outside temp was 80F. Turned on Truma Aventa 13.5K BTU A/C and set to 72F. Lithium battery was supplying about 88A.

After a one hour run in this setup, Lithium battery SOC had dropped to 539AH or 86%, and 13.0V on the Ion Gage.

Turned Truma off, Xantrex off, Battery off, and Solar off and allowed system to rest for 30 minutes. Lithium voltage rose to 13.3V. ACR was still off, Lithionics app indicated that House battery was 13.28V and Chassis battery was 12.56V.

Started engine. Scangage indicated an instantaneous chassis battery voltage drop to 10.45 but it immediately rose to 14.30V when the engine started. At idle the 2nd alternator was supplying 187.4A to the Lithium battery. Shifting into gear went smoothly and as I accelerated the charging current rose to 226+ amps. Drove around the block and upon return, at idle (680 rpm according to the Scangage) the SOC had risen to 87% and the current had dropped to 167.1A. Parked and attached shoreline to complete charging.

The system appears to be working well and at least this time I didn't have any issues with hesitation or shifting while the 2nd alternator was under a heavy load. So for now I'll just continue to monitor.

Booster - I would very much like to limit the 2nd alternator to about 100A or so. This would be sufficient for our way of travel and hopefully reduce the wear and tear on the pulleys and belts. To do so, once I get my OTG cable I'd plug my phone into the Wakespeed box, start the app, import the configuration currently on the box, adjust the max field drive (which one or all 3? - Normal, Alt Mode, or Half Power Mode) to the desired percentage, and then upload the new configuration to the Wakespeed box? I know this sounds simplistic - I do need to go thru the Wakespeed info online again. And I have my doubts that Coachmen would assist in my objective. Would appreciate confirmation from you that I'm on the right path. And I think you mentioned in an earlier response that a password may be required?

I've seen where you make an annual trip to da UP. That's where I'm from. I'm usually up there once or twice a year, maybe more now that the wife is retiring at the end of the month. If we cross paths I owe you one!

Thanks to all for the suggestions and guidance.

With knowledge now that the Wakespeed is controlling from the BMS it very well may be you won't be able to set things in the Wakespeed, and even if you can it may ignore them because of the BMS overriding the Wakespeed settings. You should know what is up better once you get in there. You could get lucky and have the some of the settings work in the Wakspeed, like the load shaping which you would use to turn down the idle field percent. Max amps and charging amps are very likley coming from the BMS, but the field % does not get controlled from the shunt in the Wakespeed normal use so it may stand alone as it only needs the stator input from the alternator to do the load shaping.


We will be in the UP right after labor day this fall. Probably one night in Gogebic State park on the way and then to Houghton so DW can load up on pasties from Roy's. She can eat them every day or even two a day sometimes she likes them so much. Then on to Fort Wilkens state park for 4-5 days of hiking and taking it easy.


Glad the testing went well for you this time, that is encouraging to be sure.