Ecotrek batteries won't fully charge.

Nic7320

Solera 24S on a 2011 NCV3 chassis
13.2 Volts is high for a lead acid battery at rest and not getting any charge. I would expect 12.6 V or so. Maybe that's where your solar is connected?

Can you check your meter with a 9 Volt alkaline battery?

My starting battery typically sits at 12.7 V until the battery control center kicks on a cross connect relay to my house battery system that has solar. It's constantly getting topped off, so it should last a very long time.
 
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Moto Vita

Active member
With Ecotrek turned on and if properly working, you should get same voltage reading at the discharge and charge terminals against the battery negative post. A voltage drop at the DC house load could indicate a bad ground or poor connections.
Charge and discharge posts both read 15.1V with inverter turned off. With inverter on they measure 16.1 on the charge side and 14.9 on the discharge with no DC accessories running.
Battery ground post to chassis reads .05V - .1V. I think it was bouncing around a bit due to the quality of my connection to the chassis.
 

Moto Vita

Active member
13.2 Volts is high for a lead acid battery at rest and not getting any charge. I would expect 12.6 V or so. Maybe that's where your solar is connected?

Can you check your meter with a 9 Volt alkaline battery?

My starting battery typically sits at 12.7 V until the battery control center kicks on a cross connect relay to my house battery system that has solar. It's constantly getting topped off, so it should last a very long time.
The 13.2. is on a car with no external power, no relation to the van, just checking the meter.
A fresh Duracell measures 11.1V so perhaps my meter is a little optimistic, I will see if I can change the battery in my meter and check again.
 
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Moto Vita

Active member
13.2 Volts is high for a lead acid battery at rest and not getting any charge. I would expect 12.6 V or so. Maybe that's where your solar is connected?

Can you check your meter with a 9 Volt alkaline battery?

My starting battery typically sits at 12.7 V until the battery control center kicks on a cross connect relay to my house battery system that has solar. It's constantly getting topped off, so it should last a very long time.
With a fresh battery in the meter a 9V measures 9.55V. That never occurred to me, thanks.
 

Moto Vita

Active member
With my multimeter refreshed it now agrees with my other meters, 12.6V system voltage at the AGM and the charger terminals, with shore power on 14.3V. The meter on my solar charger is in agreement but my onboard volt meter stays at the 12.6V when the system measures 14.3V, unless I hold the reset buttons down.
I'm wondering now if I should replace my 6 year old AGM, it seems fine and I don't understand how it could cause me a problem but there is much I don't understand.
 

Nic7320

Solera 24S on a 2011 NCV3 chassis
Battery ground post to chassis reads .05V - .1V. I think it was bouncing around a bit due to the quality of my connection to the chassis.

Is that with a good load on the inverter's AC output, without shore power or UHG? We want some current flowing to really test that connection.
 

Moto Vita

Active member
Is that with a good load on the inverter's AC output, without shore power or UHG? We want some current flowing to really test that connection.
I'll have to check again with a load, I think I may have had shore power switched off at the time or it may have been when my heater died.
 

Moto Vita

Active member
I'm on the road and getting by pretty well as long as I have shore power at night. I've learned things I never knew about my system, when everything worked I was willing to just accept the magic.
One particularly puzzling feature is that my underhood AGM will power my inverter but it won't power any DC accessories. Can anyone explain that?
 

autostaretx

Erratic Member
One particularly puzzling feature is that my underhood AGM will power my inverter but it won't power any DC accessories. Can anyone explain that?
If it's MB's underhood additional battery, they only connect it to a *few* power consumers. (the radio ain't one of them)
From the Options Guide:
E21auxBatt.png

--dick
 

Moto Vita

Active member
If it's MB's underhood additional battery, they only connect it to a *few* power consumers. (the radio ain't one of them)
From the Options Guide:
View attachment 279327

--dick
Roadtrek shows the AGM in parallel with the Ecotrek batteries that of course power the inverter as well as the DC circuits in the coach. Something lets the inverter access the AGM but not the DC stuff. I don't get it. The description of the Mercedes battery matches what I have but Roadtrek may have wired it differently. I don't know if the AGM is charged by the primary alternator as you describe or by the "underhood generator" (second alternator).
 

RT.SS

Active member
Your test confirms that Inverter/Charger is connected to Ecotrek charge terminal which is a critical info. All charging sources are connected to the charge terminal (UHG, AGM battery, solar, Inverter/Charger). The “device” between the AGM and Ecotrek charge post is a fuse/ breaker.

From what you’re describing, it appears that the charge relay is offline, either on protect mode or the BMS is faulty. Holding the reset button forces the charge relay to engage thus connecting the charge and discharge terminals and voltmeter reads the higher charging voltage from the charge side.

Your AGM cannot power the house DC load if charge relay is open (see picture below), but can power the inverter as they are parallel connected. Without shore or UHG, the AGM cannot power a high load for long due to its limited capacity.

Maybe try changing the inverter battery charge profile to a different one, try AGM 1 battery type. AGM 1 profile bulk charge voltage is lower at 14.1 volts. The current battery type profile you have is charging at 14.3-volts which is close to the BMS charge protection limit of 14.4-volts (I think), it’s worth a try.
Ecotrek-Wiring_Flattened.jpg
 

Moto Vita

Active member
Your test confirms that Inverter/Charger is connected to Ecotrek charge terminal which is a critical info. All charging sources are connected to the charge terminal (UHG, AGM battery, solar, Inverter/Charger). The “device” between the AGM and Ecotrek charge post is a fuse/ breaker.

From what you’re describing, it appears that the charge relay is offline, either on protect mode or the BMS is faulty. Holding the reset button forces the charge relay to engage thus connecting the charge and discharge terminals and voltmeter reads the higher charging voltage from the charge side.

Your AGM cannot power the house DC load if charge relay is open (see picture below), but can power the inverter as they are parallel connected. Without shore or UHG, the AGM cannot power a high load for long due to its limited capacity.

Maybe try changing the inverter battery charge profile to a different one, try AGM 1 battery type. AGM 1 profile bulk charge voltage is lower at 14.1 volts. The current battery type profile you have is charging at 14.3-volts which is close to the BMS charge protection limit of 14.4-volts (I think), it’s worth a try.
View attachment 279352
Thanks very much! I'll be at my house Wed. where I have a good place to work and will try that. I have 3 Dr. appointments this week so I may not get right to it.
It struck me as odd that both BMS' failed, or perhaps did their job, at the same time which suggests to me a problem elsewhere that affects both BMS', like the inverter/charger.
 

autostaretx

Erratic Member
When you have two BMSes in parallel, they can get into a situation where they have to be separated before they're willing to return to "normal".
If you have two EcoTrek batteries, try removing the "extra" one from the circuit to see if the Main one regains sanity.
(you may have already run that test... i didn't roll back through the postings this morning)

--dick
 

Moto Vita

Active member
Your test confirms that Inverter/Charger is connected to Ecotrek charge terminal which is a critical info. All charging sources are connected to the charge terminal (UHG, AGM battery, solar, Inverter/Charger). The “device” between the AGM and Ecotrek charge post is a fuse/ breaker.

From what you’re describing, it appears that the charge relay is offline, either on protect mode or the BMS is faulty. Holding the reset button forces the charge relay to engage thus connecting the charge and discharge terminals and voltmeter reads the higher charging voltage from the charge side.

Your AGM cannot power the house DC load if charge relay is open (see picture below), but can power the inverter as they are parallel connected. Without shore or UHG, the AGM cannot power a high load for long due to its limited capacity.

Maybe try changing the inverter battery charge profile to a different one, try AGM 1 battery type. AGM 1 profile bulk charge voltage is lower at 14.1 volts. The current battery type profile you have is charging at 14.3-volts which is close to the BMS charge protection limit of 14.4-volts (I think), it’s worth a try.
View attachment 279352
OK I'm back on it now.
When I switch the battery type selector from 2, where it was, to 1 the voltage from the inverter drops from 14.35 to 14.28. The brochure I found online lists the "fast VDC" as 14.6V for AGM2 and 14.1V for AGM1. It seems like the lower setting should work if I can get the charge relays to reset, any ideas on how I can do that? I have the charger turned off right now, I'll turn it on later and see if anything has changed.
 

Nic7320

Solera 24S on a 2011 NCV3 chassis
When you have two BMSes in parallel, they can get into a situation where they have to be separated...
If you have two EcoTrek batteries, try removing the "extra" one from the circuit to see if the Main one regains sanity.

I like this idea. Your BMS might be going into protect mode because the two batteries have a different voltage, and the surge current is too high when they cross connect.

Disconnect the lower voltage battery and run a load on the higher voltage battery until its resting voltage agrees with its counterpart.

You’ll have to occasionally turn off your load to measure the resting voltage; it will be a bit higher than when the battery is under load.
 

Moto Vita

Active member
I like this idea. Your BMS might be going into protect mode because the two batteries have a different voltage, and the surge current is too high when they cross connect.

Disconnect the lower voltage battery and run a load on the higher voltage battery until its resting voltage agrees with its counterpart.

You’ll have to occasionally turn off your load to measure the resting voltage; it will be a bit higher than when the battery is under load.
All the testing I'm doing is on a single battery, I should have mentioned that. Everything is the same with either battery, their current state of charge differs by a couple tenths of a volt. the display on the inverter shows each battery at 100% charge, I assume that's because the charge relay is open.
 

Nic7320

Solera 24S on a 2011 NCV3 chassis
Hmm. Another good theory dashed by... facts and reality.

But a couple tenths of a volt is considerable on a 12V system. That would push a big slug of current from one battery to the other when they cross connect. And it's quite curious that your battery voltages got unbalanced in the first place, but maybe that's from some of your load tests.

But are you actually disconnecting the battery cable or switching it off at the control panel? I'm not 100% convinced the control panel isolates everything. It probably still has parts of the BMS connected to the input, and maybe some filter capacitors.

Without schematics, I'm only guessing here, but there's definitely something odd going on with the battery BMS(s) communication and all the internal logic in this system is hiding in black boxes to keep its secrets hidden.

If it's easy to do, isolate one battery by disconnecting it and report back.
 

Moto Vita

Active member
Hmm. Another good theory dashed by... facts and reality.

But a couple tenths of a volt is considerable on a 12V system. That would push a big slug of current from one battery to the other when they cross connect. And it's quite curious that your battery voltages got unbalanced in the first place, but maybe that's from some of your load tests.

But are you actually disconnecting the battery cable or switching it off at the control panel? I'm not 100% convinced the control panel isolates everything. It probably still has parts of the BMS connected to the input, and maybe some filter capacitors.

Without schematics, I'm only guessing here, but there's definitely something odd going on with the battery BMS(s) communication and all the internal logic in this system is hiding in black boxes to keep its secrets hidden.

If it's easy to do, isolate one battery by disconnecting it and report back.
The batteries are free to be imbalanced as I was using them individually while traveling, saving one in case the other shut off. 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.
I have not disconnected a battery cable, it's not as easy as it sounds. Now that I have a good place to work I plan to crawl underneath (where the batteries are) and do some exploring, in between Dr. appointments.
 
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RT.SS

Active member
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.
 

Moto Vita

Active member
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.
I can try that, is a 900 watt heater enough load? So the inverter is always powered from the charge terminal? That never occured to me. And I can't simply disconnect the AGM and test the inverter because the AGM powers the relays in the BMS'? (I'm thinking out loud here)
I'll order a clamp on ammeter.
 

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