Ecotrek batteries won't fully charge.

Moto Vita

Active member
I recently turned on my 2 Ecotrek 200s in my 2017 CS Adventurous in anticipation of my winter migration (and cold weather). They turned on properly and the showed 13 volts, which is where I keep them while stored.
My problem is that neither Ecotrek will charge past the 13V level unless I'm holding the reset button on the control switch down. I'm getting full charging voltage from both the underhood generator and the inverter/charger but it doesn't show on the volt meter unless I'm holding the reset button down, when I release the button the voltmeter drops to the 13V that I started with.
The inverter seems to work normally. I'm currently trying to charge one bank at a time to see if I have one bad battery but it seems that both batteries are behaving the same. It seems unlikely that both batteries have failed the same way simultaneously.
I can't find an explanation of exactly what the reset buttons do, obviously they power a relay but maybe that's too simple. Can anyone explain it?
I'm planning on leaving in a few days and I don't expect I could get any professional help in that time. My current thought is to start driving and plug into shore power every night but starting a trip with an obviously malfunctioning system certainly goes against my grain.
Any advice or comments will be appreciated.
 

Nic7320

Solera 24S on a 2011 NCV3 chassis
 

Moto Vita

Active member
Thanks for the reply. I guess you didn't notice that the thread you linked me to was my thread from 2017.
 

Nic7320

Solera 24S on a 2011 NCV3 chassis
I found that reference a couple pages into the thread. And now -- a new problem exists, or do you think this is related to past failures?

If pushing a button causes an immediate rise in the voltage reading, it's not actually showing the true internal battery voltage. Due to internal resistance, the charging voltage will initially be higher than the resting voltage, but with lithium batteries, that difference is considerably less. Then as you know, it takes minutes to hours to change the battery resting voltage and only when the tail current drops to near zero, will the two voltages agree.

It sounds like your charger might be cutting off and not going through the proper multistage sequence when the button is released. Are there indicators for bulk/absorption/float (and equalization, if used) charging modes, and is it staying in bulk (constant current) mode?

If this is a string of manufacturing defects, at least register the new problem with your dealer. Your rights under the Lemon Law vary depending on your state, but AFAIK they usually don't cover RVs. Your snowbird status might help if you had service where you have greater legal rights. The Magnuson–Moss Warranty Act might also apply here.
 
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Moto Vita

Active member
I found that reference a couple pages into the thread. And now -- a new problem exists, or do you think this is related to past failures?

If pushing a button causes an immediate rise in the voltage reading, it's not actually showing the true internal battery voltage. Due to internal resistance, the charging voltage will initially be higher than the resting voltage, but with lithium batteries, that difference is considerably less. Then as you know, it takes minutes to hours to change the battery resting voltage and only when the tail current drops to near zero, will the two voltages agree.

It sounds like your charger might be cutting off and not going through the proper multistage sequence when the button is released. Are there indicators for bulk/absorption/float (and equalization, if used) charging modes, and is it staying in bulk (constant current) mode?

If this is a string of manufacturing defects, at least register the new problem with your dealer. Your rights under the Lemon Law vary depending on your state, but AFAIK they usually don't cover RVs. Your snowbird status might help if you had service where you have greater legal rights. The Magnuson–Moss Warranty Act might also apply here.
The system worked fine from 2018 until last week. I experimented today with multiple 5 minute hold downs of the reset buttons. It appears that if I held the reset buttons down long enough the batteries would charge but as soon as I release the button charging stops and the voltmeter shows the existing battery voltage. I believe that both my charging systems are working properly (underhood generator and inverter/charger) but the charging current only reaches the batteries when I hold down the reset button, or it may be more appropriate to say that the batteries will only accept the charging current when the reset buttons are depressed. When the button is depressed the charging voltage of whichever charging system is turned on shows on the voltmeter, the UHG voltage is higher than the inverter charger. I don't have a good understanding of why that would be and have searched the internet for an explanation of how the system works to no avail.
 
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Nic7320

Solera 24S on a 2011 NCV3 chassis
I can't find an explanation of exactly what the reset buttons do, obviously they power a relay but maybe that's too simple. Can anyone explain it?
In another RV (a 1997 Roadtrek class B) I have a latching relay with a switch that's there simply to disconnect the battery for storage. It's been in storage for a while, but if I recall correctly, it's a three position rocker switch with a momentary "on" and momentary "off" to toggle the relay and releasing it allows it to return to center.

With the battery removed from the circuit, the voltage on the DC distribution buss is largely uncontrolled and if the solar or AC charger get turned on, they feed whatever loads that are present but are left without a battery to stabilize and load down the charging system, so the voltage reading can be very confusing.

Without a battery connected, any "charging" current from either charging source will be limited to whatever is drawn by the loads that are present.

So for this reason, find out exactly what your relay does. It may be faulty. Also, your troubleshooting data will be more helpful if you can measure your battery current along with the voltage. Then we can really see what is going on.
 
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Moto Vita

Active member
A "latching relay" sounds like what I have that is being turned on by my reset button, but it's not staying latched. Also there would be two of them, one in each battery, that failed simultaneously, which seems unlikely.
To measure battery current I think I would need a DC ammeter with an inductive clamp, is that right? Then should I measure current in or out of the battery and what would I do with that information?
 

Nic7320

Solera 24S on a 2011 NCV3 chassis
I would hope they paralleled both batteries and ran the pair through one disconnect relay. If they used two relays, that would raise issues when the two batteries have different voltages, and that would result in a large spark from the current when they cross connect.

But this video seems to indicate two separate switching circuits, since they show two switches for each bank:

So they may have an engineering problem there. If they do have two relays, how do they keep from frying the contacts? You've mentioned a reset button and a control switch, and I'm also puzzled what function a reset button would have.

To measure current, you can use a DC clamp on meter. Alternatively, you can wire in a current shunt that goes to a device to read the current. Victron sells both a "Smart Shunt" with bluetooth for this purpose as well as a BMV712 battery monitor with a small display that includes a current shunt.

FWIW, a DC shunt circuit is quite a bit different than a simple AC inductive shunt. Both measure the primary wire current, but the DC shunt circuitry constantly nulls out the core's flux and keeps track of it to make a DC measurement. This goes into more detail if anyone is interested: https://electronics.stackexchange.com/questions/341156/how-does-a-dc-clamp-meter-measure-current
 
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Moto Vita

Active member
Update.
I called KS2 this morning and talked to a very helpful person. His suggestion is that my underhood AGM battery is bad, which makes sense since my issue is system wide rather than with a single ecotrek unit, even though it shows system voltage. I will disconnect it and he believes the voltage will drop after an hour or so once disconnected.
This all makes sense to me, the AGM is 6 years old. I will try this this morning and report back.
 

Moto Vita

Active member
More likely they paralleled both batteries and ran the pair through one disconnect relay. If they used two relays, that would raise issues when the two batteries have different voltages, and that would result in a large spark from the crossover current when they connect.

You mention a reset button and a control switch, and I'm also puzzled what function a reset button would have. Can you post a picture of the control panel, including any manufacturer's name? Or did Roadtrek make it or rebrand something?

To measure current, you can use a DC clamp on meter. Alternatively, you can wire in a current shunt that goes to a device to read the current. Victron sells both a "Smart Shunt" with bluetooth for this purpose as well as a BMV712 battery monitor that includes a current shunt.
The two batteries are switched seperately, I don't know how they deal with suddenly adding a charged battery to the system. I too wonder what the reset buttons actually do, that is what I've been searching the internet trying to find out.
The controls are labeled "Ecotrek" and unique, I believe they are supplied by KS2, who I believe is the designer and supplier of the Ecotrek system.
 

Moto Vita

Active member
Update.
I called KS2 this morning and talked to a very helpful person. His suggestion is that my underhood AGM battery is bad, which makes sense since my issue is system wide rather than with a single ecotrek unit, even though it shows system voltage. I will disconnect it and he believes the voltage will drop after an hour or so once disconnected.
This all makes sense to me, the AGM is 6 years old. I will try this this morning and report back.
The underhood AGM battery checked out good, too bad that would have been an easy fix.
The guy I talked to at KS2 told me that my symptom of batteries only charging when the reset button is held down has never happened before, but a quick internet search finds several instances of it, unfortunately without good solutions.
 

RT.SS

Active member
The Ecotrek battery module has three connection ports: charge, discharge, and ground. The charge and discharge ports are controlled by the BMS via internal relays. To protect the battery, the BMS will turn off either the charge/ discharge relay or both under certain conditions (overheat/undertemperature, overcharge, and/or excessive discharge). The reset button resets or wakes up the battery from a complete protection shutdown. During reset, the charge and discharge relays come online; if a malfunction persists, the BMS instantly shuts down. The BMS requires external 12-volt power to reset, which is one of the functions of the AGM kicker battery in addition to supply a voltage reference for the UHG. Holding the reset button forces the relays to latch, which is useful when the Ecotrek battery is severely depleted and the BMS will not turn on. Holding the reset button while the engine is running forces charging current to the Lithium cells until the voltage threshold is satisfied, causing the BMS to remain active.

Your battery symptom maybe consistent with either:
  1. Unbalanced Lithium cell (s), over voltage cell condition of >3.6-volts. Remedy, apply battery load.
  2. Supply voltage is less than 11.5-volts. Bad AGM kicker battery or charging source or connections.
  3. Freezing battery temperature. Remedy, run UHG or connect to shore to activate the internal battery heater.
  4. Faulty Ecotrek BMS.
In the above protection modes, the charge relay is open, but the discharge relay may remain closed and continues to power the coach.

Note: The panel mounted voltmeter maybe inaccurate or faulty; it’s wired far away from the batteries with tiny wires, try checking the voltage at the battery posts. The lack of proper battery monitor makes it harder to diagnose issues, KS2 monitor is only compatible with their later battery revisions.
 

Moto Vita

Active member
The Ecotrek battery module has three connection ports: charge, discharge, and ground. The charge and discharge ports are controlled by the BMS via internal relays. To protect the battery, the BMS will turn off either the charge/ discharge relay or both under certain conditions (overheat/undertemperature, overcharge, and/or excessive discharge). The reset button resets or wakes up the battery from a complete protection shutdown. During reset, the charge and discharge relays come online; if a malfunction persists, the BMS instantly shuts down. The BMS requires external 12-volt power to reset, which is one of the functions of the AGM kicker battery in addition to supply a voltage reference for the UHG. Holding the reset button forces the relays to latch, which is useful when the Ecotrek battery is severely depleted and the BMS will not turn on. Holding the reset button while the engine is running forces charging current to the Lithium cells until the voltage threshold is satisfied, causing the BMS to remain active.

Your battery symptom maybe consistent with either:
  1. Unbalanced Lithium cell (s), over voltage cell condition of >3.6-volts. Remedy, apply battery load.
  2. Supply voltage is less than 11.5-volts. Bad AGM kicker battery or charging source or connections.
  3. Freezing battery temperature. Remedy, run UHG or connect to shore to activate the internal battery heater.
  4. Faulty Ecotrek BMS.
In the above protection modes, the charge relay is open, but the discharge relay may remain closed and continues to power the coach.

Note: The panel mounted voltmeter maybe inaccurate or faulty; it’s wired far away from the batteries with tiny wires, try checking the voltage at the battery posts. The lack of proper battery monitor makes it harder to diagnose issues, KS2 monitor is only compatible with their later battery revisions.
Thank you very much!
Perhaps you can clear up a couple of things for me.
I believe that each battery has it's own BMS, if that's the case I can't understand why both my batteries shut down at the same time. The batteries were not discharged, they had, and still have, 13V according to my onboard voltmeter. Freezing temperatures were not prevalent when the problem first occured, unfortunately they are now. I wish I could tell if the battery heaters are working, I have both banks turned on and the inverter switch on with shore power and the system voltage remains at 13V. Voltage at the output terminals on the inverter charger is over 14V.
Is there some common point in the system that could affect both battery banks and cause my problems? Simultaneous failure of both BMS's seems very unlikely to me.
I did try adding a load to the batteries by running the refrigerator on DC, that didn't seem to help, I think I'll try again one bank at a time.
I will crawl under the van (very difficult for me) and try to find a place to measure voltage at the batteries.
 
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RT.SS

Active member
Yes, each battery has its own BMS. If you have the older H revision Ecotreks they are known to be problematic. It was probably cold enough that both batteries triggered the under temp protection, just guessing. It will take a long time to heat up the battery cells to begin charging again.

The compressor fridge consumes little power and may take long time to discharge a battery; there should be no charging source when drawing the battery otherwise the charger will just power the load.

The 14 +volts at the inverter/charger DC terminals is the charger output, the AGM kicker battery/ solar charge controller/ UHG are all connected in parallel with Ecotrek charge side. The inverter/solar/ UHG will charge both batteries, charge current may not reach the Ecotrek battery if the charge relay is open d/t certain conditions detected by the BMS. Is your inverter/charger rewired to Ecotrek charge side? Does your inverter power a load without shore or engine running?
 

Moto Vita

Active member
Yes, each battery has its own BMS. If you have the older H revision Ecotreks they are known to be problematic. It was probably cold enough that both batteries triggered the under temp protection, just guessing. It will take a long time to heat up the battery cells to begin charging again.

The compressor fridge consumes little power and may take long time to discharge a battery; there should be no charging source when drawing the battery otherwise the charger will just power the load.

The 14 +volts at the inverter/charger DC terminals is the charger output, the AGM kicker battery/ solar charge controller/ UHG are all connected in parallel with Ecotrek charge side. The inverter/solar/ UHG will charge both batteries, charge current may not reach the Ecotrek battery if the charge relay is open d/t certain conditions detected by the BMS. Is your inverter/charger rewired to Ecotrek charge side? Does your inverter power a load without shore or engine running?
My van was rewired by Roadtrek in 2018 shortly before they folded up. I have no details but the system has worked properly until last week.
Yes my inverter will power a load without shorepower or UHG, I tested it briefly with a light load since I have limited battery power available.
If my battery heaters are working they've had several days to warm things up. Currently my afternoon temps are in the upper 40s F with hard freezing overnight.
And yes my batteries are marked H.
 

Moto Vita

Active member
The Ecotrek battery module has three connection ports: charge, discharge, and ground. The charge and discharge ports are controlled by the BMS via internal relays. To protect the battery, the BMS will turn off either the charge/ discharge relay or both under certain conditions (overheat/undertemperature, overcharge, and/or excessive discharge). The reset button resets or wakes up the battery from a complete protection shutdown. During reset, the charge and discharge relays come online; if a malfunction persists, the BMS instantly shuts down. The BMS requires external 12-volt power to reset, which is one of the functions of the AGM kicker battery in addition to supply a voltage reference for the UHG. Holding the reset button forces the relays to latch, which is useful when the Ecotrek battery is severely depleted and the BMS will not turn on. Holding the reset button while the engine is running forces charging current to the Lithium cells until the voltage threshold is satisfied, causing the BMS to remain active.

Your battery symptom maybe consistent with either:
  1. Unbalanced Lithium cell (s), over voltage cell condition of >3.6-volts. Remedy, apply battery load.
  2. Supply voltage is less than 11.5-volts. Bad AGM kicker battery or charging source or connections.
  3. Freezing battery temperature. Remedy, run UHG or connect to shore to activate the internal battery heater.
  4. Faulty Ecotrek BMS.
In the above protection modes, the charge relay is open, but the discharge relay may remain closed and continues to power the coach.

Note: The panel mounted voltmeter maybe inaccurate or faulty; it’s wired far away from the batteries with tiny wires, try checking the voltage at the battery posts. The lack of proper battery monitor makes it harder to diagnose issues, KS2 monitor is only compatible with their later battery revisions.
Voltage at the Ecotrek terminals measures over 16V with or without the inverter turned on, that surprised me. I duplicated my test with the UHG instead of the inverter and got a similar result. I loaded the system down by running a portable heater through the inverter with shore power disconnected and voltage dropped to 14.5V. I don't know what to make of that, I suppose my batteries may be fully charged and my onboard voltmeter is wrong. I'd hate to run my batteries down and find out otherwise.
I need to get to PHX for a Dr appointment so I'm thinking that I can drive to RV parks every night where I can plug in and run shore power through my inverter and use portable heat and flashlights. The water system is winterized so I wasn't going to have indoor plumbing until I get to warmer weather anyway.
Still looking for advice.
 

Nic7320

Solera 24S on a 2011 NCV3 chassis
When you say "Voltage at the Ecotrek terminals measures over 16V with or without the inverter turned on," is that while charging from shore power? I take it you're turning on an inverter-charger combo?

A higher than normal terminal voltage while charging can indicate the BMS has gone into disconnect mode. If you disconnect a battery wire and the charging source remains at the same voltage, that would confirm your 16V is only reading the unloaded open-circuit voltage from your inverter/charger output or UHG.

Similarly, the large 1.5 volt sag when you added a load to your inverter AC output also points at a battery disconnect. 1.5V is way too much voltage drop for a lithium battery during a short term test, but understandable if the battery is disconnected. It's the charger struggling to maintain the voltage the inverter needs.

Basically, the batteries are behaving like they aren't there. The mystery is why both banks went into protect mode.
 
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Moto Vita

Active member
When you say "Voltage at the Ecotrek terminals measures over 16V with or without the inverter turned on," is that while charging from shore power? I take it you're turning on an inverter-charger combo?

A higher than normal terminal voltage while charging can indicate the BMS has gone into disconnect mode. If you disconnect a battery wire and the charging source remains at the same voltage, that would confirm your 16V is only reading the unloaded open-circuit voltage from your inverter/charger output or UHG.

Similarly, the large 1.5 volt sag when you added a load to your inverter AC output also points at a battery disconnect. 1.5V is way too much voltage drop for lithium during a short term test, but understandable if the battery is disconnected. It's the charger struggling to maintain the voltage the inverter needs.

Basically, the batteries are behaving like they aren't there. The mystery is why both banks went into protect mode.
Yes I believe that is the mystery.
I'm baffled by the fact that 16+ volts remains at the battery terminals with no input from either charging source (shore power disconnected). I don't understand what is storing that voltage, it seems like the Ecotrek batteries have 2 components each with a different voltage?
Yes my inverter/charger is a single unit.
 
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Cheyenne

UK 2004 T1N 313CDi
Does the van have any solar charging? If the battery is open circuit then you would be measuring the output of the solar regulator.
 

Moto Vita

Active member
Does the van have any solar charging? If the battery is open circuit then you would be measuring the output of the solar regulator.
Good point.
Yes 470 watt I believe. As far as I can tell there is no way to turn it off other than disconnecting the lead at the solar controller. I wonder if the solar charger could be causing a high voltage shut down of the batteries??? When the problem first surfaced the van was in a shed with no direct sunlight to the solar panels.
 
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