Ecotrek batteries won't fully charge.

[RT.SS]

The AGM is indeed connected and powered via charge terminal connections. If you unplug the AGM, the inverter will not power on; however, you can try disconnecting the AGM from the Ecotrek and see if the BMS resets; it's worth a try.

900-watts will be enough; it will be pulling about 72-Amps from the AGM battery. You can just use your Multimeter to monitor the AGM battery voltage (check voltage at battery terminals) while inverting. The smaller AGM battery will not be able to handle that load for long and voltage will begin to dip and may cause the inverter to eventually shutdown from low voltage.

The AGM does not power the relays but provides a voltage reference for the BMS to open the charge relays. It needs an external > 11.5-volt for the BMS to activate the charge relay. The AGM also provides power to the BMS to wake up/reset from a complete BMS shutdown.

 

[Nic7320]

I can try that, is a 900 watt heater enough load?
...
So the inverter is always powered from the charge terminal?

900 Watts of AC load will need 1000 to 1100 Watts of DC power due to efficiency losses, so it needs 80 to 90 Amps of current. That's much more than your solar can provide but then the AGM would be providing the current.

So, then you'll be limited to about 100 Ah of charge (I'm not really sure how big the AGM battery is, so this is a ballpark number). So IF it's about 100 Ah, this test will deplete your AGM to 50% in say, half an hour, and it's time to protect your AGM from a deep discharge.

As mentioned before, your combo charger/ inverter uses one wire for both functions, so yes, it is fed by the charge terminal. Therefire, it's good the BMS uses relays since they're bidirectional.

I assume there's some sort of protocol to shut down the inverter driven by the same logic that drives the load port on your battery. If not, an unsupervised load could be a problem.

FWIW, a MOSFET based BMS would still backfeed power to the charge terminal, but it would flow through the MOSFET's body drain diode, which isn't intended for that since it has more voltage drop.

 

[RT.SS]

I agree, inverter inefficiency will add more draw from the battery. Also, when Peukert effect is taken into account, that 100Ah AGM is unlikely to last that long before the inverter shuts off. The 3-kW factory inverter has non configurable low voltage disconnect of 10-volts, inverter will start beeping at 10.5-volts. The LVD setting on most high-end inverters are user configurable.

...The Roadtrek manual specifies using them one at a time and isn't concerned with the inrush you describe. I see that KS2 now recommends using their current batteries in pairs, so something may have changed.

Due to the high idle draw of the BMS and relay (around 75-watts), it is not recommended to run your Ecotrek H-series in pairs except during high power demand. This was corrected in later Ecotrek revisions.

 

[Nic7320]

I think an AGM at 50% SOC reads about 12.0 volts. But I stopped using Lead-Acid for house batteries so long ago, I don't remember.

75 Watts is... a lot of standby power!

 

[Moto Vita]

Have you tried running the inverter with a large load without shore or engine running? You can monitor the AGM voltage while it’s inverting with large load and see if voltage dips below 12-volts. If it does, then the AGM is solely powering your inverter. If not, then the Ecotrek is somehow providing power via the charge relay, this test should confirm if the charge relay is offline. Test it with just one Ecotrek switched on, then do same test with the other Ecotrek. Using a clamp-on ammeter (if available) would be even better to monitor the current from the AGM or Ecotrek battery while inverting.

Tests completed, both batteries the same using a 600W heater, the voltage at the AGM immediately dropped to 11.7 (from 12.7) and went down slowly from there. The panel mounted volt meter registered no drop. I did try the 1500W setting on the heater (it was my old heater that had the 900W setting) that triggered the alarm on the inverter so I switched back to 600.
I did disconnect the AGM, even though I'd done so before, and left it that way for 15 minutes or so, which didn't seem to have any effect
I talked to a fellow in CO that rebuilds Ecotreks who said he could fix/update them, he would need the van for a few days and he's 8 hours away, half of that in the snow. I knew that shipping batteries would be difficult and he told me it's worse than I thought.
La Mesa RV, where I bought the van, is the only dealer around and I swore I would never let them touch my van again. They do have a new "Adventure Van" facility now, I suppose I might try talking to them sometime. It seems like somewhere in the PHX metropolis', 4.000.000+ people I should be able to find someone who can work on batteries, I'll look around.

 

[Nic7320]

Tests completed, both batteries the same using a 600W heater, the voltage at the AGM immediately dropped to 11.7 (from 12.7) and went down slowly from there. The panel mounted volt meter registered no drop.

I did disconnect the AGM, even though I'd done so before, and left it that way for 15 minutes or so, which didn't seem to have any effect...

To drop that fast, I'd say there's a bad connection hiding somewhere or you have a bad AGM battery. Its not uncommon with sulfated batteries to register a full voltage but quickly collapse even under a light load.

Sulfated batteries no longer have the same surface area on their plates so they can't deliver the same charge.

A voltmeter only needs a few hundred microamps or maybe a few milliamps to take a reading. But it's not a load test at all, so a when you take an unloaded voltage reading, you're implying there's enough battery behind that voltage to do something useful.

Making a voltage reading without a load is like reaching into a tall bin and pulling out one apple -- and then assuming the rest of the bin is full of apples at that same height over the length of the whole bin.

 

[RT.SS]

Tests completed, both batteries the same using a 600W heater, the voltage at the AGM immediately dropped to 11.7 (from 12.7) and went down slowly from there. The panel mounted volt meter registered no drop.

This confirms that the Ecotreks charge relays are offline, either BMS is on protect mode due to badly unbalanced cell(s) or BMS itself is faulty. Only way to find out is to open the Ecotrek batteries and test each cells and the BMS. Many RT owners have replaced their H-series BMS to commercially available ones like JK BMS and reused the Lithium cells and case.

75 Watts is... a lot of standby power!

The early Ecotrek uses solenoid type relays which consumes lots of power when energized/on. The later Ecotrek revisions are likely using latching relays.

 

[Moto Vita]

This confirms that the Ecotreks charge relays are offline, either BMS is on protect mode due to badly unbalanced cell(s) or BMS itself is faulty. Only way to find out is to open the Ecotrek batteries and test each cells and the BMS. Many RT owners have replaced their H-series BMS to commercially available ones like JK BMS and reused the Lithium cells and case.

So fitting a JK BMS would involve removing the original relays etc and then fit inside the original case and operate like the original? If so I'd be glad to find someone who could do that for me.

 

[Moto Vita]

To drop that fast, I'd say there's a bad connection hiding somewhere or you have a bad AGM battery. Its not uncommon with sulfated batteries to register a full voltage but quickly collapse even under a light load.

A voltmeter only needs a few hundred microamps or maybe a few milliamps to take a reading. But it's not a load test at all, so a when you take an unloaded voltage reading, you're implying there's enough battery behind that voltage to do something useful.

Sulfated batteries no longer have the same surface area on their plates so they can't deliver the same charge.

So making a voltage reading without a load is like reaching into a tall bin and pulling out one apple -- and then assuming the rest of the bin is full of apples at that same height over the length of the whole bin.

My AGM is original, nearly 7 years old, I certainly wouldn't be surprised if it was bad. I suppose I could drive up to the tire shop and have it load tested. A bad AGM would make me feel better because I'm having a hard time swallowing that both batteries failed at the same time without some common cause. My problem persists though even with the DC charger or the underhood generator charging the AGM.

 

[Moto Vita]

The La Mesa dealer that I thought was van exclusive isn't and they don't have a service dept. at that location. Screw em!

 

[RT.SS]

The AGM kicker battery usually last longer due to low cycling and it's always fully charged. My house AGMs are over 8-years old and still good with plenty of capacity left. The Colorado repair shop you mentioned, is that Durango RV Repair? I have heard of them and if I recall correctly, they do replace the BMS with an aftermarket one. A replacement Ecotrek battery from KS2 will cost you several thousand dollars for a single 200Ah battery, they are way overpriced. Hope your Ecotrek battery is still under warranty.

 

[Moto Vita]

The AGM kicker battery usually last longer due to low cycling and it's always fully charged. My house AGMs are over 8-years old and still good with plenty of capacity left. The Colorado repair shop you mentioned, is that Durango RV Repair? I have heard of them and if I recall correctly, they do replace the BMS with an aftermarket one. A replacement Ecotrek battery from KS2 will cost you several thousand dollars for a single 200Ah battery, they are way overpriced. Hope your Ecotrek battery is still under warranty.

Yes, Durango RV. I bought my Roadtrek back when they had a 6 year warranty, 2 years before they shut down, the new owners offer a 2 year warranty and honored it for existing owners but since the factory was shut down for 2 years it only benefitted people who bought old stock RVs while they were closed, I'm on my own.

 

[Nic7320]

If the AGM battery voltage collapses that fast, and the Ecotrek lithium packs need that as a "kicker," then it's an easy problem to fix.

It may be the problem is hiding is the transient nature of a start-up cycle. You would need specialized equipment to see what took place in the milliseconds before everything shuts down.

Here is what I think is going on: As a BMS tries to start up, the kicker battery voltage collapses and then the BMS immediately goes into protect mode. After that, when you look at it with a voltmeter, the voltage on the weak battery voltage recovers just enough to fool you into thinking it's okay.

So the common failure to both Ecotrek battery failures could very well be the kicker battery or a connection to it.

 

[Moto Vita]

If the AGM battery voltage collapses that fast, and the Ecotrek lithium packs need that as a "kicker," then it's an easy problem to fix.

It may be the problem is hiding is the transient nature of a start-up cycle. You would need specialized equipment to see what took place in the milliseconds before everything shuts down.

Here is what I think is going on: As a BMS tries to start up, the kicker battery voltage collapses and then the BMS immediately goes into protect mode. After that, when you look at it with a voltmeter, the voltage on the weak battery voltage recovers just enough to fool you into thinking it's okay.

So the common failure to both Ecotrek battery failures could very well be the kicker battery or a connection to it.

If that scenario caused my batteries to shut down I can't tell. Trying to turn on the batteries with either the inverter/charger or underhood generator charging the AGM at 14V seems like it would take care of that problem, and it doesn't. My immediate problem is getting the batteries to connect to the system by any means necessary, then I could try to troubleshoot the system.
I've been talking to the guy at KS2 about my issues, he is very diplomatic and patient with me but much of his advice ends with "see your dealer". The message I get from him is that my "H" batteries are obsolete and no longer supported and that I need to replace them before going any farther.
I don't have a local dealer anymore, I did call one of the closest and asked for a quote on batteries, they will hopefully call me back, they did tell me that they are scheduling appointments 3 months out. I've been searching the Phoenix area for someone who might be able to rebuild/modify my batteries for me without success, I'll keep working on that.

 

[Nic7320]

Check and clean your AGM connections and/or replace it first.

 

[Moto Vita]

After several weeks and numerous unreturned calls I finally got a dealer (La Mesa RV) to quote me a price on batteries, $4600. each plus labor plus an unspecified amount for freight. The freight cost will be substantial since they will ship truck freight Hazmat. That aint happening.
Now I see why people go to such effort to be "Ecotrek Free".
Next I may see if I can find a local repair shop to do the exchange then buy the batteries and the specific tester from KS2 and have it shipped there.

 

[D&C Erv2]

Curious about your solution to your problem. I have the same Ecotrek system and found a dead battery in mine after a lot of conversation with KS2 and a lot of YouTube videos and research.

 

[Moto Vita]

Curious about your solution to your problem. I have the same Ecotrek system and found a dead battery in mine after a lot of conversation with KS2 and a lot of YouTube videos and research.

No solution yet, I have an appointment with an independent shop next month. It appears to me that there's several ways to fix the problem, my problem is finding someone to work on it for me.

 

[D&C Erv2]

I live in Iowa and have the same problem with finding anyone that could give me a quote or has the experience needed to be comfortable that they would do the job correctly. Given these setbacks I have decided to rebuild the battery myself to save money and have something that I could fix in the future. I am assuming that your system has the batteries outside under the Van the same as mine and that changing the batteries to something you could order will not work without finding a new home for them or modifying the mount. Because of this I am ordering new cells and a bms for the battery that I found to have a bad cell. I will be changing the wiring so that all charge cables to the batteries are the same length and all positive cables go to a buss bar before going to the batteries. I have watched a couple of videos that show the best way to do this and get max charge for the lithium's and protect the AGM is to install a DC-to-DC charge controller on the cable from the AGM to the battery bank. If there may be more information, I could give I would be happy to converse about what I have found. Ross Lukeman on You tube is very good for a start just to help understanding the way these systems work but I have about a dozen subscriptions now for also understanding how to build a lithium.

 

[Moto Vita]

I live in Iowa and have the same problem with finding anyone that could give me a quote or has the experience needed to be comfortable that they would do the job correctly. Given these setbacks I have decided to rebuild the battery myself to save money and have something that I could fix in the future. I am assuming that your system has the batteries outside under the Van the same as mine and that changing the batteries to something you could order will not work without finding a new home for them or modifying the mount. Because of this I am ordering new cells and a bms for the battery that I found to have a bad cell. I will be changing the wiring so that all charge cables to the batteries are the same length and all positive cables go to a buss bar before going to the batteries. I have watched a couple of videos that show the best way to do this and get max charge for the lithium's and protect the AGM is to install a DC-to-DC charge controller on the cable from the AGM to the battery bank. If there may be more information, I could give I would be happy to converse about what I have found. Ross Lukeman on You tube is very good for a start just to help understanding the way these systems work but I have about a dozen subscriptions now for also understanding how to build a lithium.

I just noticed this reply, thanks.
My van is at an out of town repair shop now, he has tested the cells and found them good and balanced. I think he'd like to replace both BMS before further troubleshooting, that makes sense to me since I'd like to eliminate the large solenoids anyway. Can you explain the DC to DC charger to me and what it would do in the system, I'm completely ignorant on the subject.
And yes my 2 ecotreks are mounted under the van in sealed steel boxes. I really wish I could have removed them myself and worked them but I have physical limitations that prevent that. I've read that there are batteries with internal BMS that will fit inside the Roadtrek boxes and wonder if that might be a simpler solution. The guy that's working on it is a former Roadtrek dealer and I think isn't real interested in researching, and tracking down, components.