Expion360 (2x162ah) batteries not fully charging

[PCMcE]

Recently had my 2015 25' FC re-wired and upgraded with 2 Expion360 162ah batteries (324ah total). Also upgraded to Victron 12/3000 Charger/Inverter and had a Victron SmartShunt installed for good measure. All connected to a Victron Cerbo GX and display.

(Note: Install work was done by an Airstream dealer service department. Yes, I am chasing them almost daily for a solution but so far their "first class customer service" has been less-than-evident. I will keep after them but am posting here in hopes this is just a setting mismatch somewhere. I've spent ~10 hours digging into everything I can think of but I'm a noob with most of this stuff and so far no joy.)

The issue I'm fighting is simply that when the SmartShunt reports 100% SOC (via the VictronConnect app), the Expion360 "SmartTalk" app says the batteries are only 79% full (254/324ah). It's been plugged into shore power for many days without any change/improvement (I hoped it might converge over time.)

See pictures attached including 'Battery Settings' from the VictronConnect app. (FWIW, since taking the pictures below I have upped the 'Charged voltage' to 14.6v as per the Expion360 spec sheet. Didn't seem to change anything.)

Any ideas on what to look at next while I chase the installer would be very much appreciated. As far as I can tell, the next thing to do is to connect to the Victron Charger/Inverter via ethernet and use the VEConfigure software to make sure the charging profiles are set for lithium. I'm reluctant to do that as I don't know what I'm doing and it would require a fair bit of mucking about to be able to access the Charger/Inverter. This was all installed under the dinette bench in the front street side.

If nothing else, I'll follow up here with the eventual cause/solution in case it will help others in future.

Thanks in advance!

[PaulBristol]

From the posted status displays, this is my expert analysis. (Expert is a drip under pressure.)

Voltage:
Victron Shunt = 13.6 volts
Experion = 13.8 (both)
0.2 volts difference is more than I like to see, but it is still good. I would trust the Victron on this.

Current:
Victron Shunt = -0.65 amps (too small to be a concern)
Experion = too low to register

Current and voltage are accurate enough and the two systems agree close enough.

State of Charge is calculated. It is always an approximate number. In this case the two Experion calculations need re-calibrating. It is possible they were never calibrated properly from the start. Instructions for the batteries may tell how to reset them.

I would trust the Victron Shunt. It provides superior approximations and has a pretty good automatic re-calibration. It also agrees with the voltage reported by both systems. 13.6 static is 100% fully charged when current is negligible.

Calibrating the Experion

See the Experion app "Calibrate" and "Synchronize" for good instruction.

The following may be need:

• Let the batteries discharge down to less than 20% using the Victron readings. Maybe 10% would work better. Try not to go below 5%, other things may happen at that level.
• Fully charge using shore power with the Victron readings.
• Continue charging for at least an hour after reaching 100%.
• Let the batteries rest for a few hours.

Is the problem solved?
If not, call Experion support for better instruction.

I expect the Airstream dealer technician could determine all this himself and call Experion for resolution. It is possible his manager pushed him for time due to heavy service load.

An alternative is to ignore the Experion results. Depend on the Victron shunt. The Experion may re-calibrate itself some day.

[PCMcE]

Originally Posted by PaulBristol

From the posted status displays, this is my expert analysis. (Expert is a drip under pressure.)

Voltage:
Victron Shunt = 13.6 volts
Experion = 13.8 (both)
0.2 volts difference is more than I like to see, but it is still good. I would trust the Victron on this.

Current:
Victron Shunt = -0.65 amps (too small to be a concern)
Experion = too low to register

Current and voltage are accurate enough and the two systems agree close enough.

State of Charge is calculated. It is always an approximate number. In this case the two Experion calculations need re-calibrating. It is possible they were never calibrated properly from the start. Instructions for the batteries may tell how to reset them.

I would trust the Victron Shunt. It provides superior approximations and has a pretty good automatic re-calibration. It also agrees with the voltage reported by both systems. 13.6 static is 100% fully charged when current is negligible.

Calibrating the Experion

See the Experion app "Calibrate" and "Synchronize" for good instruction.

The following may be need:

• Let the batteries discharge down to less than 20% using the Victron readings. Maybe 10% would work better. Try not to go below 5%, other things may happen at that level.
• Fully charge using shore power with the Victron readings.
• Continue charging for at least an hour after reaching 100%.
• Let the batteries rest for a few hours.

Is the problem solved?
If not, call Experion support for better instruction.

I expect the Airstream dealer technician could determine all this himself and call Experion for resolution. It is possible his manager pushed him for time due to heavy service load.

An alternative is to ignore the Experion results. Depend on the Victron shunt. The Experion may re-calibrate itself some day.

Thank you Paul! Your observations are super helpful and make sense. I’ll chase this down. I had previously run the batteries down to about 50% and then charged back up but suspect this isn’t enough to cause the battery calibration. I do have the Expion360 app (not Experion - assuming that is just a typo) but don’t see anything in that related to calibration instructions. I’ll dig through that again, along with the manual and their website. If nothing turns up I can and will contact support directly to see what they suggest.

And, agree with your suggestion about the Airstream service department. They do seem pretty harried.

Thanks again and I will report back after working through the next steps.

UPDATE: Turns out I have/had an old version of the app. Apparently, about a day or so after I downloaded the “Expion360” app they released a new app (requiring a new user registration) called ExpionSmartTalk. I now have the new app and will see what it reports for the batteries SOC and dig around for calibration instructions. Stay tuned…

[richard5933]

The Victron shunt needs to be calibrated. Once the batteries are actually fully charged use the menu in the shunt to calibrate. This does need to be done from time to time.

[Redbarron55]

If you look at the trend page and compare the current and state of charge you will see when the batteries are fully charged as the current will drop fairly quickly when the internal BMS is satisfied for the battery(s).
At this point the voltage will often increase as well.
When this occurs you need to synchronize the 100% battery condition and then the Smart Shunt should give good readings.
Since the shunt measures the Amp hours in and out and there are some losses taken into account the actual value may be slightly off over time and may need to either have the correction factor changed or resynchronized.

[PCMcE]

Originally Posted by Redbarron55

If you look at the trend page and compare the current and state of charge you will see when the batteries are fully charged as the current will drop fairly quickly when the internal BMS is satisfied for the battery(s).
At this point the voltage will often increase as well.
When this occurs you need to synchronize the 100% battery condition and then the Smart Shunt should give good readings.
Since the shunt measures the Amp hours in and out and there are some losses taken into account the actual value may be slightly off over time and may need to either have the correction factor changed or resynchronized.

Thank you Richard and RedBarron! Suggestions make sense overall but I have the opposite problem. The SmartShunt reports 100% SOC (which aligns to the voltage curve). The issue is that the System Capacity as reported by the battery app reports they are only at 80% capacity at the same time. More specifically, the charger is in Absorbtion Mode, the system is at ~14.3v (reported by the SmartShunt and by the battery app) and the batteries (as reported through app presumably from the BMS) says the batteries are Idle and there is no voltage going into them. And, at the same time, the battery app is reporting 80% System Capacity (250/324 ah).

Other than a bad BMS (on both batteries?) I have no idea what could cause this.

[JeffKim]

Echoing @Richard. The shunt will reset to 100% based on the settings.

This synchronization, or reset to 100%, occurs when the battery voltage exceeds the "Charged Voltage" setting and the charging current drops below the "Tail Current" setting, and these conditions persist for a set "Charged Detection Time".

I kept having the shunt reset when I knew the batteries weren't fully charged. You can mess with the settings and get this right, however I gave up and manually reset it* periodically when I've had the batteries plugged in for a long while and I see they are no longer absorbing a charge (current is near zero). You shouldn't have to do this too often.

The shunt is a "bean counter" so it just measures all the current going and coming in verses your stated battery capacity. So there's no magic way it can detect what the battery's charge state is directly. Every time it resets you've lost any previous count, so it's meaningless unless it has truly reached 100%.

*I'll have to check to see how to turn off the automatic reset.

Edit: Humm... looking through my settings the "Keep SOC" should prevent it from resetting which is what you have. So I'd wait until you know the batteries are fully charged and reset it manually and see if the battery states diverge again.

[PCMcE]

Originally Posted by JeffKim

Echoing @Richard. The shunt will reset to 100% based on the settings.


I kept having the shunt reset when I knew the batteries weren't fully charged. You can mess with the settings and get this right, however I gave up and manually reset it* periodically when I've had the batteries plugged in for a long while and I see they are no longer absorbing a charge (current is near zero). You shouldn't have to do this too often.

The shunt is a "bean counter" so it just measures all the current going and coming in verses your stated battery capacity. So there's no magic way it can detect what the battery's charge state is directly. Every time it resets you've lost any previous count, so it's meaningless unless it has truly reached 100%.

*I'll have to check to see how to turn off the automatic reset.

Edit: Humm... looking through my settings the "Keep SOC" should prevent it from resetting which is what you have. So I'd wait until you know the batteries are fully charged and reset it manually and see if the battery states diverge again.

Thanks Jeff - but again, I actually believe the SmartShunt so resetting it manually to 100% won't help. It's already at 100% - it is the batteries themselves (via the Expion360 app) that report *not* being fully charged. I *could* manually set the SOC on the SmartShunt - there is a setting for this - but I'm assuming that it would jump back to 100% next charge cycle when the criteria that the SmartShunt is using get hit.


Doing some testing yesterday I took these pictures/screenshots. As the system is charging and as the voltage increases it transitions from Bulk Charging to Absorption Charging. During Absorption Charging the batteries (as reported by the battery app) continue to charge. The voltage increases and the current drops off until the batteries are in 'Idle' mode although the system is still in Absorption Charging. This is all what I would expect as the batteries approach being fully charged *except* that the battery app is reporting the batteries (both of them) are *not full*. In fact, they are at only 77% capacity even though the voltage is >14v. I worry that some of the battery cells in the batteries are damaged (but a cell in *both* batteries?) and that is what is causing the battery to increase the voltage before they are at their full capacity. Or the BMS/firmware is horked up. Or, I dunno, sunspots.


I've also included a picture of the battery installation in case that helps. Note: the batteries are *not* (AFAIK) in a 'master-slave' configuration.


I would be more than grateful if anyone has any suggestions for what might be causing this behavior.

[mike2025]

I have been following this thread because I am interested in Expion360 batteries, but I do not own any, so take my suggestion with that in mind.

From the Expion360 manual, the first battery turned on becomes the master and the following batteries turned on become the slaves. I do not think that matters in your case because you do not have the batteries connected together over their CAN bus. That is something you may want to do in the future since you have a Cerbo GX. It could communicate with the Expion360 BMS and optimize the charging.

Here is my suggestion - turn both batteries off, then turn on just one of the batteries and see if it will charge up to 100%. If so, then turn that battery off and turn the other battery on and let it charge up to 100%. Turn both batteries off and then turn both on. At that point they should both be charged up to 100% and the Expion360 app should show that. I have read that batteries in parallel should be charged individually the first time so that they are charged to the same amount. If their charge level is different enough, the system will have a hard time getting them both to 100%.

In order to charge either battery up to 100%, the Multiplus inverter / charger will need to be programmed to match the Expion360 suggested voltage, although it sounds like you have already changed that setting in the Multiplus.

[JeffKim]

Interesting (probably not for you). I was thinking the shunt was wrong. I see where they are not absorbing any more charge although the charging drops off quite a bit in a minute. It's reaching 14.4V so that indicates the charger is in lithium mode. I don't know anything about these batteries but I think @Mike's approach is worth a try. However, I'm skeptical that it should take gyrations like that to get both up to 100%.

As @Paul suggests I'd talk to Expion. As you gathered, either the batteries have something wrong and won't fully charge (but not if you beleive the shunt) or they are at full capacity and the app isn't resetting. They aren't cheap batteries so I'd hope they back them up with good service.

[PCMcE]

Originally Posted by JeffKim

Interesting (probably not for you). I was thinking the shunt was wrong. I see where they are not absorbing any more charge although the charging drops off quite a bit in a minute. It's reaching 14.4V so that indicates the charger is in lithium mode. I don't know anything about these batteries but I think @Mike's approach is worth a try. However, I'm skeptical that it should take gyrations like that to get both up to 100%.

As @Paul suggests I'd talk to Expion. As you gathered, either the batteries have something wrong and won't fully charge (but not if you beleive the shunt) or they are at full capacity and the app isn't resetting. They aren't cheap batteries so I'd hope they back them up with good service.

Thanks Mike and JeffKim. Appreciate the suggestions.

The batteries are installed in a "not convenient" place - under the street side bench. The bench is screwed in and tough to wrestle in/out of place. Not impossible of course but I'm reluctant to go down that path. I am a newbie in this world but I agree it just doesn't seem like the "one-at-a-time" charging approach should be needed.

Earlier today I did contact Expion technical support. So far so good - I got to a real person and described the issue. I sent him the info/screenshots and he is going to investigate. Be happy to report my overall experience here as that process plays out. Stay tuned...

[JeffKim]

Originally Posted by PCMcE

Thanks Mike and JeffKim. Appreciate the suggestions.

The batteries are installed in a "not convenient" place - under the street side bench..

Just wondering, it looks like the battery cutoff switch is under there. Is it accessible without taking the cover off?

[PCMcE]

Originally Posted by JeffKim

Just wondering, it looks like the battery cutoff switch is under there. Is it accessible without taking the cover off?

Yes. Batteries are hard to access but the master cut-off switch is accessible. It is mounted in what used to be an interior storage compartment (under the dinette in my FC). It should completely disconnect the batteries from everything else to prevent any 'vampire load' from damaging the batteries over time.

[PCMcE]

Well, I have a resolution (for the most part). The 'System Capacity' of the batteries as reported by the Expion360 (and Expion SmartTalk) app was way off. See below for details.

I finally mustered the courage to do what PaulBristol originally suggested in response to my original post. With the SmartShunt showing the battery SOC at 100% I disconnected shore power and ran everything I could think of - 12v loads as well as AC loads via the 3000W inverter to drain the batteries. According to the SmartShunt I was able to pull ~321ah out of the batteries before the Victron Charger/Inverter shut itself down and threw an alarm for low battery voltage. Even at that point I still had some power left as the 12v loads (lights, fans, 12v fridge) were still drawing power. Pretty sure the battery BMS didn't kick in as that would have shut down even the 12v loads.

So, pretty much exactly what I want in overall system behavior. The SOC calculation by the SmartShunt hit 0% with some (but not a ton of) power left. And then past the 0% SOC (on the SmartShunt), the charger/inverter stopped inverting with some (but even less) power left.

I then reconnected shore power and everything started to charge back up as expected. The good news is that as soon as the batteries started to recharge, the 'System Capacity' measure as reported by the Expion360 app started to count up from zero. I didn't have time to let it fully recharge but I expect that now the 'System Capacity' as reported in the app will be much more accurate - reporting something much closer to the 324ah I have installed. (Prior to doing this 'bounce' the app was reporting only ~250ah available for what should be 324ah when the system was fully charged.)

What I'm left wondering is how/why the Expion360 app 'System Capacity' calculation (which must come from the BMS itself) could have gotten so skewed in the first place. There is no input/output from the battery that bypasses the BMS so how could it be so off? No doubt there will be some drift over time due to low voltage loads but I was 'missing' about 70ah of capacity. Next chance I get I will experiment with the master cut-off switch to see if somehow using this causes issues with the BMS capacity calculation (if that is even possible). Not a big deal now that I know how to 'reset' it if needed (or more likely simply ignore it and just rely on the SmartShunt). I guess it is also possible that maybe it was a side-effect of the installation process itself somehow.

In the end it was much ado about nothing. System seems to be working fine, batteries seem to be working fine, etc. It was just a persistently wonky (and to me, worrying) 'System Capacity' calculation as reported by the Expion BMS/apps.

Thanks again for all the ideas and suggestions!

[Wazbro]

Did you ever see the batteries report full from the time you got them?
From this thread my guess is no. If this is the case it's possible the cells in the batteries were partially charged when installed and that partial charge was never reported to the BMS. Then when the batteries were fully charged the BMS was never synced to 100%. Of course this is just a guess. Still I would rather have things reporting less so I would be less likely to run out of power.

[PaulBristol]

That is the way RV LiFePO4 battery BMS work. Lots of things can interfere with the state of charge calculation. Some are better than others. The Victron shunt can also be wrong, but is probably a lot better than most BMS calculations.

[PCMcE]

Thanks Wazbro (and PaulBristol, again!). I'm guessing you're correct. In fact, here is the 'final answer' I got from Expion Technical Support:

"The BMS battery monitor is in theory the same as an external, it still can get out of calibration and sometimes needs a full cycle to self-learn. If they are newer batteries this could just mean they were off from the factory and needed a good full cycle to get them set"

Which certainly makes sense given my experience and testing. What is disappointing is that this wasn't the 'default answer' when I first contacted Expion Technical Support (although they were earnest and helpful which I appreciate). Something like: “If they are new batteries, go through a full discharge/charge cycle (or two) see if the BMS just needs to self-calibrate” would have been very helpful and saved me a lot of worry about potentially damaged batteries.

Live and learn (and thanks again for all the help!). Hopefully this will help others having the same questions.